I realise that this blog is the one that links from my web site. My other blog with more information on the WSPR Organ can be linked to from here.

On Sunday 25th of October I had an idea for generation of WSPR signals in a very simple KISS method using 2 Crystals and an XOR 74HC86 Mixer. By Sunday evening it was built.

It works really well, by the use of two identical Crystals and subtractive mixing any drift in those Crystals is cancelled resulting in an extremely stable Audio data stream.

A vast range of Crystal frequencies could be chosen I am using 10.0005MHz at this time, I wondered if this may be a problem for 10MHz reception but the frequency is far enough away from the Amateur allocation to cause no trouble. I have also used 8.192MHz.

The circuit shown is liable to be modified I didn't bother with an LPF after the mixer, the capacitor values were sufficient but I may try an RC LPF in there or after the Buffer. As the circuit stands the output is a very clean Sine Wave.

Notes:-

I have added an RC Audio LPF at the output during test, it cleans the sine wave of any miss shaping nicely.

The LED shown used as a Varicap is sketched upside down for me, I always use them reverse biassed, some use them forward biassed, in this way positive or negative keying can be utilised.

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Recently IZ0GNY contacted me re the Bathtub Key.

Right Click on pictures and select View Image for full size.

This key was used aboard the Lancaster Bomber and had a degree of sealing against the ingress of water. My friend and fellow Ham G3JJW knows of a good reason for this, he was a Rear Gunner on a Lancaster that ditched into the North Sea. The technique for ditching and being able to escape the Aircraft which was now in danger of becoming a Submarine was for the Pilot to hit the sea hard with the rear end, thus snapping the tail end off. His ditching went to plan and he was out of Lancaster and into a Dinghy with the rest of the crew. Orange dye was used to stain the search area for rescue crews, John G3JJW thereby joined the Goldfish Club, the exclusive group of Airmen pulled from the sea looking like a Goldfish.
Whether the waterproofing of the Bathtub Key allowed any last minute position information to be sent on this occasion I don't know.

I purchased my Bathtub Key when I was 16 Years old from a store which sold 'Army Surplus' it was new in a cardboard box and wrapped in many layers of waxed paper, straight from the Quartermasters stores. I still recall the smell as the wrapping was removed, wax and Bakelite. A rubber diaphragm between the Key Knob shaft and the Body soon perished and crumbled I completely removed this and the ring that secured it.

The top section hinges open after unclipping the Phosphor Bronze catch.

In contrast to the Bathtub Key is my Home Built Squeeze Key.

I sourced most of the material for this key which is based on a design in the American 73 magazine many years ago. The details were provided for it to be build of Perspex (Plexiglass). By this time my son was perhaps a little more than 16 years old and an apprentice Pattern Maker. I persuaded him and he persuaded his employer that this engineering task with so many varied disciplines was an ideal project for spare moments at work.
It took him some time but the results are superb. The rectangular Steel base does not rust due to an etching technique used. The Phosphor Bronze parts I purchased as scrap are similarly treated.

In the above picture I see I have knocked the left hand segment out of its pivots whilst moving it for the photograph. Those movable segments pivot on small Ball Bearings which are force fitted into holes in the Phosphor Bronze these locate into cups in the end of short Steel Pillars, four in all, the left and right top pair can be seen in the picture.

The fixed contact adjustable supports stand on a rod of Ebony timber. The contacts are Copper treated as the other metal parts I have never had to clean them.

The Paddles are solid Rosewood. To show his art (if you ever turn the key over) my son produced the base plate cover of Quartered solid Rosewood. The key is a piece of workmanship of which he should be proud.

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K1JT's WSPR Weak Signal Propagation Reporter software has enthused many operators both old and new. Several times I have noted that there is misunderstanding from many stations about the software and power level setting. More than once the statement has been made that WSPR is so clever in that you can click a box on the GUI and so set your power output down to mWatts.
Let us get that straight you can't.

This spurs me on to write a post in simple language for beginners, at least then I know it is available somewhere on the web.

Given the question 'How does the WSPR software reduce the power of my rig'.

Well it is like advertising if you can't work out how it does it, most likely it doesn't.
How could a computer program alter your radio output unless you have a full CAT control system? Those boxes on the program are Data Input boxes where you tell WSPR what information to send, like you callsign locator and power.

So let us take a look at the output of your FT-450 etc. on USB 'cranked down to 5 Watts'.

Have you noticed that with the Microphone plugged in if you say nothing into the microphone there is no output, if talk quietly the output is low, if you shout it is 5 Watts. Now there is a clue for adjusting the power output. This is due to the audio producing a variable amplitude (yes AM) drive level which on SSB results in more power out given more audio input

When you run WSPR you are putting 4 audio tones one at a time into you FT-450 etc. from the computer, the audio amplitude level of these tones will control the RF output level of your radio. Just like shouting into the Microphone will over drive and distort your signal, the computer output level can and most likely WILL overdrive the rig.

Note. Windows will change these levels when you run other programs, when you return to WSPR or other Digi Modes you need to set up the correct levels again.

Just like not speaking into the Microphone, turning the computer audio levels to zero will produce NO output from the TX. The correct levels will undoubtedly be very low, both WAVE and OUTPUT/SPEAKER level.

Each time you run WSPR or any Digi Mode set the Windows Audio Volume Controls WAVE and OUTPUT to zero and set up the drive correctly or at least check that they are right.
For Whisper level settings set WSPR to TX, measure the output power of the rig at the antenna socket into a 50 Ohm Load. Advance the Windows Audio WAVE control by one division only, then advance OUTPUT by the smallest amount possible, you should see a measurable amount of RF power out. Set your required level by increasing both WAVE and OUTPUT a little at a time to say, 40mW.
So often I have reported over driving to be told 'well I have the Windows Audio controls set about half way'. No actual adjustment. It is so frustrating to hear an ex CB guru instructing a newbie 'just set the controls about half way'.

Never increase the drive level to produce ALC action.If you are setting for a higher power level the correct method is, adjust for ALC indication then back off well below the point where ALC action starts. ALC is distortion like it or not.

Now you can enter your power level value into the WSPR Set Up drop down box and the Data you send will be valid.
I have no doubts that the majority of Hams on WSPR do not measure their output accurately consequently all Data on WSPR.net is invalid in my view.

Personally I have no trouble setting 10mW levels on any of my HF 100 Watt rigs although it does need careful setting.

Finally note that 'cranking down' (or up) the indicated front panel power level on the rig does not change the power you have set by the previous careful adjustment. Go on try it.

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When Bill of Soldersmoke fame built his MEPT the only RX he had was a very inaccurate solid state rig that drifted. These are some sugestions I made to help him find his TX frequency. The number of new stations coming onto QRSS and the same problem being encoutered prompts me to write this. In addition my memory does not get better, I use my blogs to record things so that if I go away for a few months and forget something I have a reference.

Like most things a good understanding of the Receive side is essential before venturing a signal onto the air. If you can receive other MEPT's and know their frequencies then you are 99% there.

First the RX needs to be warmed up for quite some time to make sure it has settled.

Here is my Kenwood TS870, a Transceiver I consider to be very accurate and very stable after 5 minutes from switch on the display should read above 070, it will never quite get there it is a few Hertz low but it can be seen to be heading up that way.

Here is my 'G' MEPT signal at this time received by the Italy I2NDT Grabber I have just adjusted my TX frequency to 10.140073MHz plus or minus a bit.

So how do we get Spectran or Argo and our RX to display MEPT's.
First we need to get the received signals in the audio passband of the RX, for convenience 1KHz is a good frequency to choose, it is near the middle of the passband and a round number. No matter what band we are receiving on always use USB (Upper Side Band) and the standard 2.4KHz bandwidth. To produce a 1Khz audible beat note of a particular radio frequency we need to tune 1KHz below its frequency. Hence to receive 10.14000 MHz we need to set our RX dial to 10.13900 MHz.

Next we need to set up Spectran to match.
From the Menu select Mode - Preset QRSS3. The display will now scroll Horizontally.
At the bottom select Show Controls - in the Freq Offset box enter -1000 (minus 1000) as shown.

Now point your mouse to the grey bar between the top and bottom spectrun displays. In the top display is a vertical red line it is reading -150 or more at the red line, Left click the mouse and drag the scale to the left through Zero to place 100(+100) at the red line.
The Right hand vertical grey scale now reads 10 - 20 - 30 up to 100 if it was not hiding at the top. This scale now shows the 100Hz of the 10.140000 to 10.140100 QRSS Band.

When you close Spectran these settings will be saved so you only need to set up once.

If you are new to Spectran do some thinking and tune to the frequency you need to to display WWV on what ever frequency you can hear it on, check the accuracy of your RX dial.

If you are seeing MEPT's you can put your newly built TX into a Dummy Load and adjust its trimmer to sit your signal where you want in the QRSS band
But beware there will be more than one of you, even with a few mWatts into a screened dummy load you will find it hard to get rid of your signal.

Here I have re-tuned my RX 70Hz higher than 10.13900MHz the signal is some 30dB down but strong, comparison with the Left Hand side of the trace makes it obvious which is the fundamental.

This is where the Feather comment comes in, a tiny adjustment of the trimmer can shift your signal way out of the 100Hz window, you are using a Dummy Load so tweek and twiddle to get used to it, like all things after a time minute adjustments become easy.

When you are fully confident in your skills, settings and accuracy you can put your MEPT on the air. If you are lucky like me, (I2NDT Grabber is almost a certainty during daylight hours) your signal will pop up right on your determined frequency on a Grabber. Alterantively you can get a friend to listen / look for you but beware many Hams do not know within 200 to 300 Hz where they are on the band despite what their dial reads.

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http://www.sammynetbook.com/news.php has a lot of members all of them just luuuve their Sammy and there is a lot of expertise on hand.

A user on Sammynetbook.com mentioned that his wife got shocks from her Sammy, a case of His and Hers Sammy's in that household, lucky people. He got no such thrills from either His or Hers.

I am still waiting with interest on some tests suggested, swapping Power Bricks etc. However I think that there is nothing to worry about, Induced Voltages are a fact of life. Other users have confirmed slight tickles from their Sammy too.

I measured the DC Output of my Sammy Power Brick with a DVM - 19.1 Volts. Then I looked at the AC Voltage from the Negative - Sleeve of the Power Brick to Earth (real Earth) - 69.2 Volts RMS.
I was not surprised by this figure all sorts of mains powered devices can give you a tickle to Earth due to Induced Potentials.

In order to confirm that there was nothing unusual in the Sammy results I checked the Wall Wart Charger for my Sat Nav. - 69 Volts AC from Sleeve - Negative to Earth.

I wondered what the AC waveform looked like so I hooked up the old Telequipment D54 scope and took a look.

First the ripple with the PSU plugged in but switched off as the reference.

Next I looked at a Wall Wart which uses conventional PSU techniques (transformer). There was around 20 Volts Peak to Peak of 50Hz ripple to Earth.

Next the Sat Nav Switched Mode Wall Wart. A rather spiky chopped waveform but surprisingly 50Hz, I expected to see more of the evidence of the switching frequency. The Amplitude is around 130 Volts Peak to Peak.

Finally the Sammy Power Brick an almost identical waveform and Amplitude.

Being an Induced Potential it is not going to be of any danger to users. I looked at the current capability to Earth, DVM 20mA AC range, as expected a flick of digit upon connection sometimes but no measurable Current at all, I assume a low impedance load will pull the voltage to zero.

Such Potentials could damage sensitive electronics so there is as always a lot to be said for proper bonding and / or isolation of all interconnected equipment.

One thing is certain the DC from the Sammy Power Brick is clean of noise, I understand that some Laptop Supplies kick out so much interference that they can wipe out broadband.
Also I have it on good authority one of the Asus EeePC supplies created so much noise that it spoiled communications applications.
A further great advantage of the Sammy is that considerable periods of operation can be had from the battery supply thus eliminating any chance of mains borne noise.

Incidentally I notice that back in December 2008 there were Amateurs who were Sammy lovers, users on the Ham Radio Deluxe site, well I had fun pioneering all alone. Why do we find out these things too late despite a thorough research on the web.

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The 12 Volts is stored in two 85 Amp Hour Leisure Batteries. The Solar Panel is a 50 Watt unit. Be careful when thinking in terms of rated Wattage and expected Current with Solar Panels. Current is found by dividing the Wattage by the Voltage, do not make the mistake of thinking this will be 50/12 = 4.166 Amps. Manufacturers rate the panel at its maximum Voltage which is maybe 18 Volts, therefore 50/18 = 2.77 Amps is more of a realistic figure. What is more this is the maximum output in full sun, in the winter 0.4 Amps is often encountered at mid day.

My wind power is derived from an Aerogen 4. Again giving direct figures for current output is not straight forward as the output is dependent on wind speed. Suffice to say it can produce 4 Amps in a stiff breeze and 19 Amps continuously in a good 60 knot blow.

The 12 Volts nominal Voltage from the storage batteries is no good for feeding the Sammy direct. I chose the Nikkai A33HU Car Laptop Power Unit (Maplin) to provide the 19 Volts at 2.1 Amps Max. needed. This unit rated at 150 Watts does not even get warm when providing such meagre needs.

One of the most important things a computer has to do for me is to enable connection to a Radio Transceiver and run Radio Communication software. Any computer not capable of this to me is a dead parrot. Yes they can connect to the internet and do all sorts of lovely things but that is via wires and telephone exchanges etc and at a fee.
Connected to a Transceiver it comes to life and whether I am typing on the keyboard or sending coded data or Still TV Pictures the world is at my fingertips.

We can send our position from GPS continually whilst driving (APRS) allowing other users to track us via radio. Using the right software we can send (rather high power) signals to be bounced off the moon around the world. Personally I prefer very low power (QRP) operation. At very reasonable power levels (15 Watts) I like to use the 50 MHz VHF Band (around the frequency of the old Band 1, BBC1 TV) and reflect signals from Meteors.
Some Meteor showers are large, come at pre defined times and are named, these produce the 'falling stars' often seen on dark Autumn nights. What is less known is that there are Meteors hitting the Earth's atmosphere all the time. Some are no more than the size of grains of sand or dust, when they burn up in the atmosphere they produce an ionized trail which is capable of reflecting radio signals.
Having said that I put the Sammy on whilst writing this blog and was getting a little worried that I had had no results. Early afternoon is not a good time and the predictions for meteors are low, however I was not disappointed.

At 14.53 GMT there were several reflections, one burst of signal can be seen in the capture from the Sammy desktop above and a perfect de-code of the signal data. The other station is in the UK out of direct communication range on VHF for me. The same Meteor could have reflected signals from Scandinavia, Eastern Europe, Italy, Spain or Africa.
In the software used there is quite a bit of processing going on, Fast Fourier Transforms and Fortran routines, the sound 'card' In and Out needs to be of pretty good linearity and low noise for this sort of work too.
Can the Sammy do it? yes it can.

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This blog is posted using Fedora 10 the capture is of the Sammy desktop. Good another step completed, we are ready for super safe browsing on open networks.

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Measuring current when the connection is a Cigar Lighter Socket is not easy so I am using my DC PSU meter as the not highly accurate instrument. When charging the Netbook Battery the current is slightly less than 2 Amps by the look of it and just over 1 amp once the cells are charged.
I have not gone for critical power saving settings, back lighting is at mains power level, performance full, USB GPS powered on, Wireless Internet on and connected and Bluetooth on too.

This gives me a portable radio set up using the FT-897 with a total current consumption of around 5 Amps on TX. Mind you on WSPR for an output of 1 Watt, 69 Watts consumption is still pretty disgusting.

Incidentally internal Battery powered I viewed a few videos on Youtube, tried out the GPS on a stroll up the road, slung the Sammy on chair still switched on while I ate lunch picked it up an hour later and the battery indicator said 6 1/2 hours use left. One day I will have time to run it flat.

Personally it gets my back up when people avidly support junk just because they made the mistake of purchasing it, for instance the Icom IC706.
So do not take my word for it take a look at the views of 799 other purchasers here PURCHASER REVIEWS.

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Of course being a Netbook what it does not have is an Optical Drive, there just isn't room, the thing is only twice the area of a CD anyway. This means any disk bound software has to be installed from a USB CD Drive or in my case from a Networked Drive.

Installing MS Autoroute from a Networked Drive is not straightforward, it comes up with a message immediately telling you that it can be done but not the way you are trying it. The way that is outlined didn't work for me. Solution is to put the contents of both CD's into one shared folder on the Master Machine and map that folder as a drive on the Slave (Samsung).

I have come across a couple of small problems. My Bluetooth GPS plays up, it has never been easy to pair and is old and slow so a USB GPS Module will be the best solution there. The Samsung Screen Saver and the Samsung Software Updater do not allow for a non administrative account user. Log in using a restricted user account and a. the Updater complains and b. the Screen Saver crashes. In time they will no doubt both have to go, word has it that the Software Updater is not that clever anyway.

For assured safety I am using my fully isolated home brew interface between Netbook and Radios. A poor quality photo, sorry, it has Opto Isolated USB Rig Control and Line Isolation Ttransformers for Audio In and Out.

The Ham Radio Aplications I have tried out up to now are are covered in this video. The 'Sammy' is a Netbook that thinks its a Notebook and does what a Laptop can do.

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The battery is wrecked which was a problem for Portable operation untill
I tried one last trick, I chopped the power lead fitted a couple of 4mm plugs and connected it directly to 12 Volts. It works a treat, now there is no question of battery life, well not really I have 160AH of battery storage when the sun is not shining or the wind blowing, if the Green charging is taking place its a win win situation.

What that old girl won't do is Wireless Internet and Mapping and Navigation and some of the more demanding Radio Communications tasks. Come on now you tight old git, its time you got the Plastic out ready for the next /P season.

As I have said previously, being mean I want the replacement to do shack jobs as well as /P and Internet Cafe, that is why I have researched for several months. Finally the right machine and some Sale discount have come together.

I had just a little aprehension re the loading and running of Ham Software and Linux so I have done the first checks, I have run Ubuntu 8.10 and Fldigi booted from USB Stick. Also WSPR 1.1 on Windows. No time yet to connect a rig and my Home Brew Opto Isolated USB interface but I have no concerns about it working, it was tried and tested on my Zoostorm Laptop and the software runs and Ouptuts audio fine.

When surveying the available Netbooks it is easy to get quite addicted to YouTube Unboxing Videos judging by the hits they get they do provide a valuable service. It takes a little self control to share the parcel opening process. Here is my Blue Version of the Unboxing Video. Ha! pun intended.

Blog written and posted on Samsung NC10. The keyboard is comfortably large for phat phingers, battery life 7.5 Hours, coo I haven't tested that out yet.

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A whole generation will know 'because they had one' that Linux is OK for Browsing, E-mail and a few Games but that's it.

Since the first Asus Netbooks there have been many more makes and models of Netbook, some have 120GB Hard drives instead of the SSD Cards which have a finite life of read/write cycles, this cannot be good for 24/7 use such as WSPR. I have considered purchasing one for Ham Radio use. The Linux versions installed still do not come up to scratch, a pity because the machines are capable of running a full distro.

Today I downloaded and installed Linpus Linux as used on the Acer Netbook range. Whilst it is fine for plain ordinary Netbook use it is far short of a Linux distro suitable for Ham Radio.

This leaves two options, buy the cheaper Linux version with a real Hard Drive and instantly replace the O/S, not something I would really want to do.

Alternatively purchase the Windows version and run a USB booted Linux on that. Problem is the cost is coming close to that of a real laptop with a CD/DVD drive and all the advantages that come with a higher specification machine. Shame, I would like to play with one but I still can't talk myself into it. What will the recession do to prices I wonder. I have noticed that the only price reductions in the so called 'Sales' are the reduced VAT. Otherwise the January sale price is the same as last summer. I wonder do we need to buy soon before they become unaffordable?

That is ignoring the PC World advertised prices, yes they have none for online purchase, none at any store for collection. Just like the advertised £2.49 1GB Memory Stick and the £6.95 80GB Hard Drive they don't have any. Who do they think they are kidding.

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"But hang on there I see that T1WIT is getting Spots from America I had better turn up the Power until I do" is the logic often used. No propagation to W1LOUD using 100mW means that conditions are not favourable at that time, a valid piece of Data for Propagation Study. Turning up the Power until you get results invalidates all Data, as does not knowing what your Output Power really is.

Personally I can set a stable measured 10mW Output from my 100W Commercial rigs if I need to. I would much rather build a QRP Radio that consumes a few Milliamps for a few Milliwatts Out.
Ignoring the Computer consumption, on WSPR we have many stations with an HF rig consuming 60 to 100 Watts to produce 100mW of RF. What makes me smile is the fact that a Commercial Step Attenuator is then added to the set up to dissipate the power just generated.

The Elecraft AT1 or some other commercial Attenuator is listed in the equipment used as a modern 'badge of honour'.

Well at least the AT1 is available as a kit so you can have had a hand in this Modern Farce.

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I searched through my Crystals, all I could find was a 5th overtone one which on its Fundamental was out of the top end of the band. With just 3 days to go there was no time to order an Xtal so I replied to Peter DL6NL "thanks for the invitation to the Party but I have nothing to wear."

Going back to my 40m construction I wondered if I could select the Second harmonic from a Class C stage and get 14 MHz that way. I succeeded in getting a low level signal which was rather scruffy looking on the scope. I considered a Diode Ring Doubler circuit, fine if I was after a low level signal to amplify using several stages, not really simple MEPT stuff.

I moved to a digital Oscillator. Dividing digital signals is easy, doubling is not normally done, there is little information available on any techniques. If we were to put the 7.00MHz signal through enough digital gates we would get a delay of the signal. Apply the delayed signal and direct signal to a pair of XOR Gates and if the delay is correct we will get 2 pulses in one time period.
Alternatively a phase delay can be achieved with an R/C network both methods worked and on the day of the 'Ball' I was able to announce that 'Cinderella has sewn a new Gown and would be coming to the Party'.

I used the Gate Delay method in a bread board 'lash up' with a 2n222 Driver and BFY50 PA.

The 50mW TX fared well, conditions were not good but we were all copied (Cinderella and the Two Ugly Sisters) in Nova Scotia and Northern Utah.

I am below G6AVK and DL6NL in this capture into Utah a very thin signal barely visible but I was running 3dB less ERP and of course the antennas and paths are different.

Peter DL6NL announced the switch off time for his activity Noon on Tuesday. At the stroke of Noon my Cinderella TX disintegrated into a pile of components and a single Crystal (slipper).

I embarked on the permanent version, characteristics were different without the long leads I found a combination of Capacitive Phase shift and Gate delay with critical adjustment of the Capacitor gave precise linear results.

I used to despise Veroboard. Costly,Warping Paxolin and lots of stray capacitance between the rows, however it is quick and easy for IC projects and used wisely the capacitance can effects can be minimised.

The signal generation uses two 74HC86 IC's Selection of 7.00MHz or 14.00MHz is by the positioning of a single link.

Ideally suited as a PA is the 74LS240, having 2 separately enabled banks of Inverters. Band Selection is by a movable link for Enable and another for the Drive to either section. this means the BPF for each band can be permanently connected to its PA.

Separate plug in Band pass filters are used, this including a socket for the crystal means the MEPT is in fact universal and Multi Band.

Link swapping is no problem as the whole MEPT needs re setting when band changing, the FSK shift is doubled when the signal is doubled.

The MEPT is on its test run now using my spare PIC Keyer piggy backed on.

During the tests I tried a new method of Identification conceived to try and overcome the problem of missed identification due to missing parts of Morse Code symbols.

I now call this 5/5 It is 5WPM FSK Morse with a 5Hz shift. If I send my Call Twice and the two letters of my Major Locator Square this forms a Morse Code G in QRSS5 with a filled waveform.

Here it is into Nova Scotia, doing a fine job.

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A new MEPT band, for me 160 meters. I could build the same tried and tested design for all bands but the fun is in the experimenting. This Transmitter uses only 2 Transistors. NPN Crystal Oscillator DC coupled to a PNP Output Amplifier an ideal use for the old BFX29 transistors in the junk box.

Based on an old design from G3MY called the Pippin it is capable of more power than needed for a QRP Propagation Beacon. I used a DIP Switch to select collector load resistors. power levels from 5mW to 400mW are possible. The Crystal available needed pulling low, determined to use the bits from an Energy Saving Lamp I wound the inductor on the toroid former which saw previous life as the Lighting Pulse Transformer. The output capacitor and some decoupling came from the same source.

The other variation that can be made is in the construction method, I have used the Pad on Earth Plane method for VHF PA construction, it lends itself well to this project at the other end of the frequency range. I piggy backed my old test PIC Keyer to FSK via a Black LED once again used as a Varicap Diode.

Once complete I put it on test running 100mW to my 40m 1/2 wave Doublet, my e-mail being down I could not ask for reports, it would need to be spotted by a keen Top Band monitoring station, this was a week day and the week ends are more popular for 160m experiments.

When I managed to get some incoming e-mail a couple of days later I was pleased to see.

[Knightsqrss] who is on 160m? G6AVK

Later he searched the Captures for the most readable segment and deduced the call and QRA Locator. Well done and thanks Colin.

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Thanks to Peter G8EUX I now have an insight.

The 5 Ohm resistors and the 5nH choke which also has a resistance of around 5 Ohms are all inside the chip.

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Right Click and select View Image for full view.

Due to the need for critical frequency matching I decided that the best approach was identical circuits on a PCB.

Right Click and select View Image for full view.

Sorry for the error. Pin1 goes to zero volts not +V

Run on 5 Volts and using just one gate in each bank of four on the chip and an output of 35mW the 74HC240's are not stressed.

When experimenting with oscillators using these chips I have noted that anything you do on any gate is reflected on all others, (via the power supply architecture on the chip I believe).
With the 74HC240 even enabling unused gates produces a positive move of the output frequency of a Crystal Oscillator which is using the other group of gates. I tried to use this effect to produce FSK of an Oscillator without the use of a Varicap Diode. It works, the snag being the shift is greater than we need for QRSS and the switching spike is huge.
Published designs using the 74HC240 for a single chip CW transmitter which keys the 'Enable' complain of incurable chirp, Hmm.

With the 74HC86 it is an opposite effect. FSK'ing of the Crystal Oscillator produces a mirror of the shift on the other gates.
I asked myself can we make use of this?
Yes, build 2 Crystal Oscillators on the same chip adjust the frequencies so they are close and they pull each other, get them very close and they lock.

Now FSK each oscillator 180 degrees out of phase, the positive shift of the high frequency one reinforces the negative shift of the other. This occurs when they are in a near fully locked state. Adjustment is tricky but once set up they seem to stay. The high oscillator with the positive shift becomes the master, if the frequencies are identical they fully lock, the Master will swamp the Slave, controlling its frequency to the extent of cancelling its shift.

Has this effect been noted before I wonder or is this the 'G3ZJO Lock'

The Oscillators are in fact adjusted to be 10Hz apart in frequency. The Master is set to say, 10.100000Mhz, the FSK shifts it to 10.100005Mhz.
The Slave is set to aprox 10.0999990Mhz the FSK shift is adjusted to be aprox 2.5Hz. When pulling takes place this shift is reinforced to 5Hz, i.e. to 10.100000Mhz.

The Locking and shift reinforcement can be seen in action in the following picture. The two oscillators started in lock, the PCB component side was sprayed with freezer concentrated on the Master Oscillator. The Master (top trace) is seen gradually approaching the Slave as the temperature recovers. At 130 seconds from the left hand side of the display the two carriers are seen beating together, after the next shift they lock, shaky for 45 seconds, then solid.
Note how the FSK Slave shift increases when in this state.

Right Click and select View Image for full view.

Very cold starts can be a problem if the Slave starts a little too high it is swamped requiring a finger to be poked in to pull it low. (A re-set button could be provided.)
It is still early days but at normal ambient temperatures start ups are perfect and 16 Hour periods of lock have been maintained using both breadboarded and the final PCB version.
In striving for minimum bandwidth (10Hz shift) I may be running the system too tight, tests are continuing with both oscillators set for about 5Hz shift prior to locking them. This results in a final shift of around 12.5Hz, it may avoid swamping as the FSK will force them further apart.
08.03.2008. Further I have found another lock, tighter than both previously described, when in this state the negative shift can be turned to zero level. Tests will continue to establish the long term stability of this. Maybe we are getting only the mirror of the positive shift.

When testing on the breadboard I switched off my bench light and the lock went haywire, this lead my the use of Black, Infra Red LED's (ex TV remote controls) in place of the Visible Red LED's normally used as varicaps.

The use of two 74HC240 for the PA may be an overkill, I didn't try using two halves of the same chip as I was aware of the undesirable effect mentioned above. They cost less than .5Euro each after all.

Another extravagance is the use of a LM7805 Regulator on each unit, again at 1.5Euro for a bag of 15 we get super regulation and isolation.

PA PCB Print View.

Osc. PCB Print View.

Finally the PIC Keyer, everyone has their own favourite method of generating FSK we just need two 180deg. outputs.

PIC PCB Component View.

PIC PCB Print View.

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JAB that is where, I have been using Peter lately for my component orders. Speedy and efficient with a personal touch thrown in. A Radio Ham at the other end is a great asset you know.

I have known of JAB for some time, I should have used them sooner.

Look them up on the web.

JAB Electronic Components for Radio Hams & Hobbyists
Welcome to the home page of. JAB Electronic Components. ... JAB Electronic Components PO Box 5774, Birmingham B44 8PJ UK Tel 0121~682~7045(Answer Service at ...
www.jabdog.com/

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Back in the 1970's in our little village in Northamptonshire things were quite different from today. A-10 Tank Buster Planes would appear over the houses at 7.00AM and mount an attack on the Local Railway Station. 'Oh no they do not', said the Commander of the nearby RAF/USAF Air Base.
One morning one of those planes turned back after the mock attack and did a Victory Roll just above he houses at the end of the road. 'Never' said the Commander 'any pilot that did that would be instantly dismissed from the Services'.

Daily at a regular time in the morning a Low Flying Twin Propeller Plane with a large pod added under the nose would fly low, East West. In the afternoon back she would come. Its path took it over my Allotment Garden Plot. One day it appeared flying so low that I looked up as I dug the ground with my Fork, I followed its path above my heard and lost balance. Knocked off my Fork by a low flying aircraft.

Clearly we were a strategic area for some reason and surveillance was being carried out.

My QTH was between the path taken by the Survey Plane and that of the Tank Busters. I mention this to add another dimension to an Aliens story.

There is a Magic Length for a Top Band 160m Antenna, 150 Feet, end fed. This can be tuned with a 1000pF variable capacitor. I devised a method of attaching the centre of an inverted V arrangement of such a wire to the top a mast at the apex of the house. This doubled back to the house at either end and was anchored to a post at the rear and a tree at the front of my garden.

I popped it up on my Saturday off. It tuned beautifully and worked really well. I went to bed happy with my new antenna that night.

At 5.00AM we were awoken by a high pitched noise, bleary eyed I stumbled to the shack thinking I had left a radio on, as I approached the shack I could tell it was not from there, it was very directional and there were peaks and troughs as I moved around.
My next thought was to check the TV, the Off Air test tone was much lower in frequency than this one but I had to check. As I descended the stairs the noise vanished returning as I ascended. Outside, I thought. I flung open the window which faced the front garden, as I did my neighbour opened his too.
"What are you doing", he said.

"I was going to ask you the same thing", I said.

It was very misty my new wire antenna was dripping with condensation.

"It's that aerial of yours", said the guy next door.

"No way", I replied.

"Well then", he said, "I looked out of the back it is that Power Company Transformer, I am going back to bed". He was a Geography Teacher not into anything at all technical.

"No I don't think so, but I can't explain it" I said.

I went back to bed too the noise carried on for some time then went away. We discussed it in the morning, I asked people who lived opposite, they heard nothing. We never heard that noise again.

I might have completely forgotten that episode had I not met a neighbour from a house at the rear. We met in town, typical, you do not see people who live quite near, This guy worked shifts and through the week ends.
"Hey", he said did you hear anything last Saturday early in the morning, I was on an early shift, I left my house and there was a high pitched noise above your house, do you know, it worried me, I didn't like it, I went back in the house and did not leave until it stopped, I was late for work".

"So it was nothing to do with the Supply Transformer, that is on your property."

"No definitely above you house, there was a heavy dense fog so I could see nothing".

Still this story may never have got told, had I not met another neighbour from some 150 Yards up the road, again in town and about 10 days after the event.
"I have been wanting to talk to you", he said. "On the Sunday morning before last I was going out early, poaching actually with my shotgun. I loaded the car and looked down over your house, there was a brilliant light, huge it was, I must admit I was scared, I thought it was Aliens, I got in my car and drove off in the opposite direction."

"Any noise", I asked.

"No silent and very misty", he said.

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I decided from the outset that I would use a PIC microprocessor to generate my call sign for identification purposes. Thus positive identification should be guaranteed.

My first MEPT used QRSS3, three seconds per dot Morse code. Soon it was recommended by stations in Australia to use QRSS10 for greater readability with lower signal strengths.
I thus used QRSS10 for a long period.

When looking for my own signal on the WWW network of Grabbers I sometimes had much difficulty with positive identification. I have even looked at a Morse ident and managed to fit my call letters to it only to realise after a time that it was a Capture from 40 meters and my signal is on 30 meters.

This can arise due to fading which causes parts of the Morse code to be lost. All stations running QRSS10 will be producing dots spaces and dashes of uniform length, many combinations of received elements can fit an expected pattern if some parts are lost.

Compare this with the simple Ramp, Sawtooth or Squiggle used by some stations. Providing the characteristics of the Squiggle are unique the signal can be identified with much less information.
"It is the correct Frequency there is a Squiggle therefore it must be 'X'."

Squiggles are used because they are a simple KISS approach to identification. I was thinking about building a new even lower power MEPT and considering KISS identification. Could I generate square waves with a 3 to 1 Mark Space Ratio and gate just 2.333 of them out as a 'G' in Morse.
After some experimentation I settled on an LM555 oscillator with a 27 second cycle and equal Mark Space Ratio for character timing. This signal Triggers and Gates another LM555 which generates a 3 Second Mark 1 Second Space square wave train. The use of Mylar timing capacitors ensures stable timing which has not wandered during long 24/7 test periods.

I added a long rise and fall time to the FSK modulation to give unique shape to the waveform. Another identification feature arose due to the first 'Mark' after 'Trigger' being slightly longer than the next, a feature I eagerly retained.

'G' MEPT uses two chips 74HC240 and LM556 to produce 25mW of Morse identified Beacon

OK there are 3 chips, I had no LM556's in the Junk Box.

I have again used the concept of the 'Crystal Cool Box' as opposed to a Crystal Oven. An oven could be consuming more power than the complete transmitter. The Crystal is hermetically sealed in a Polyurethane Foam Cube.

Long term temperature stability is very good using this method. The 'Cool Box' has come of age in this light weight version, the Cube being lined with adhesive Aluminium Foil. The outer box in previous versions was made from copper clad PCB.

The initial on air test produced a report from Belgium.

Quickly followed by New Zealand.

Italy

Nova Scotia

Netherlands

France

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There are some hideous Humps displayed by some users. Using the Delta 44 Sound Card provided the construction of the RX avoids loops, it is possible to obtain a 'Hole in the Middle'.

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I still run Packet Radio despite the fact that it has almost become the domain for a few cranks only. I returned from France this summer to find the regulars in an out and out character assassination of one person.

I was amazed at some of those involved, they instantly went down in my estimation, so far removed were they from the Gentlemen of Radio that I used to know. I don't know how it all started but to me it resembled Jade Goody in the Celebrity Big Brother Pig Sty, I just had to post a message on the Bulletin Board to that effect.

I was a late comer to Packet. One thing that put me off was that awful thing the TNC. Once there was the possibility of a Software TNC I joined the throng. Why is the TNC awful? Well it is like the Soundblaster Interface totally unnecessary. I did let one into my shack once it generated so much noise in the 2m Band it rendered it unusable for
low signal work. It is mode specific to the extent that many Packet folk tie up a Radio and a Computer just for Packet. Many TNC's are so old that the parameters have drifted and they cause many a frustrated operator.

When our local packet BBS went off air I set up a BBS and Node here with 2 TNC's ready for installation elsewhere. All I can say is, it was interesting but I was really glad to see the back of it.

Me, with my Software TNC, well I can be doing 6m Meteor Scatter one minute on the same Computer and Radio, then Packet the next minute all on the same famous THREE BITS OF WIRE.
Hence I sit and scratch my head in wonder what this unit is for.

Right Click and select View Image for full size.

Is that not an FT817, it has Data socket, why do you have to unplug the Microphone?

It does not isolate the Computer Audio Input whereas the Computer Output is isolated by a 600 Ohm Transformer and the PTT line by an Optocoupler.
I was prompted to look at this unit when a Ham reported blowing both his Transceiver and Computer Sound Card when connecting one up. Intrigued I looked at the circuit diagram and the danger is obvious. If there is a PD on the Rig Ground and you touch the computer Input or Output jack centre pin to it whilst plugging it in you apply the nasty PD to the computer.
Fifty Quid well spent I would say, not.

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The Spectrum display is imprecise.

Here I hunt down a CW signal and try to follow the Morse using Spectrum Display 'real time' and with Averaging.

Using other software it is possible to read Morse Code directly from the pulsing of the incoming signal, and so you should. I find the lack of real time display unnerving.

Here I hunt down an SSB signal zapping down the band with the Mouse like I do on Rocky software.

I have seen another You Tube video of Flex Radio and it did the same as I find, tune rapidly and the display collapses, the very signal you are heading for has gone, you go past, stop and whoa it appears behind you.

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Recently I ended up on some pages on the web dedicated to an interface design, I think there may even have been a Yahoo group. Was there really a Lecture Circuit too at one time? I began to wonder just how many Billions of words have been written on the subject, how many thousands of videos, how many Millions of pounds profit made by companies. Yet I cannot remember one mention of Safety.

We and our neighbours go out and purchase a Hi Fi Amplifier a Recording Device, Computer and a Radio Tuner and think nothing of connecting them together Output to Input etc. Why? well they are designed to be interconnected. Well so are our Radio Transceivers, particularly the modern ones which have a data socket.

Why do Radio Amateurs panic when they want to connect their rig to a computer. Well you can 'Blow up the Sound Card and the Radio' yes that is true but that is due to lack of Good Practice. That lack could kill the Amateur.

Also you could get RF Feedback into the computer Audio, yes true, but will 600 Ohm transformers prevent it, not necessarily, whereas a common mode choke, (winding the screened lead on a Ferrite Core) probably will.

What the transformers will do is drastically limit the Audio Response, may be a cause of some problems in the past, certainly a disaster in modern radio SDR systems.

Anyone familiar with the Icom IC706 (the rig that receives on the frequency on the dial and many others at the same time and sucks more current on RX than 3 other radios put together; but that is another story), will be familiar with what I call the Shaving Brush. A Din Plug for the Data Socket, supplied ready wired with a couple of inches of multi core screened cable, outer cover removed for an inch or so which looks just like a brush with multi colour bristles.
Some years ago there were many IC706's locally, owned by new Licensees. I was asked to provide details of utilising this for Digi Modes.

I photographed everything provided drawings, parts list and write up. I handed the draft to one keen user who was technically knowledgeable. One criticism, came the verdict, you spend more time, a whole A4 page, writing about Safety before you get down to the Interface, we wanted you to write about Interfacing.

There is my point.
Good Practice will prevent nasty voltages which will destroy the Computer Sound Card or Radio, as a small bonus it may save the Operators Life.
Good Practice will eliminate Ground loops and the need for Transformers.
Good Practice will prevent RF feedback into the audio circuit.

The big difference between the Domestic set up mentioned above and the Computer in the Radio Amateurs Shack is the fact that the Amateur is most likely going to be bringing Real Earth into the Shack and the Radio. He then is going to connect this Earth to a Computer which in the UK is most likely to have its 'Earth' connected to the Neutral of the Mains AC Supply. This Neutral is the centre point of a 415 Volt 3 Phase Supply. Under fault conditions, which I have experienced at this QTH when the underground cable Neutral failed, this can be lethal.

For Safety do not have both Mains 'Earth' and True Earth anywhere in the Shack, I leave you to implement this, or get in a professional to help. I want neither wrecked Equipment or dead Hams on my hands.

Pay 100, 200, 300 Pounds for your commercial interface and it may or may not protect your Sound Card and Radio. It will not protect your or others lives. You still have a potentially Lethal Shack.

For this reason I have not and will not mention Interfacing without dire warnings.

OK I simplify just a little with my 3 bits of wire statement, only the other day someone thought for a minute and said, not 3 bits of wire you mean 4. No I don't, the wires are screened lead. Think about it though, you do not want to produce earth loops.
Also there is a need to level change the Computer Serial port for the Rig PTT so we must add a Transistor 2 Diodes and 2 Resistors. This circuit is already published in dozens of places on the web. I just build it into the 9 pin Serial Port plug and forget it. For portable use with my Lap Top computer I required a low profile arrangement. I therefore potted the circuitry onto a skeleton plug. The top of the Transistor can just be seen through the potting.

Off you go then down to the Ham store, pay half the price of your Transceiver for a commercial interface, most modern Hams do.
Whilst you are out be sure to get some good Rubber Gloves and thick Rubber Sole Shoes, always wear them in the shack, have extra pairs ready for any visitors and invest in a good Fire Extinguisher.

Yes some of my postings are meant to promote thought and discussion.

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Living within 1.5Km of a Local Medium Wave Broadcast mast I have become used to the odd AM clatter on Top Band and higher.

This particular 'Moronic Music' was getting just a bit too strong and persistent and attracted my attention particularly on the SDR receiver.

Shortly after making the recording above I decided that perhaps I should endure the constant 'Moronic Music' to await a station ident. I wanted to find if it was a) A harmonic from the local mast. b) A pirate. c) A local receiver radiating. d) Something in my station.
One morning the Moronic Music changed to Virgin Radio and shortly after to Northant's Gold. Northants Gold comes from the local mast and is on 1.557MHz.

There was no way I could make the maths fit for a harmonic to show on 7.02670 MHz nor would any LO radiation from a receiver fit mathematically.

One thing at my station that has been in operation again for maybe the same period as the Intruder is my QRSS MEPT Beacon on 10.14070. I listened on 7.02670, flipped the switch and off went the intruder.
Now the maths fit 2 X 1.557 = 3.11400MHz. 10.14070 - 3.11400 = 7.02670MHz and yes there is a signal also at 13.25470MHz

The PA in the Beacon TX is Digital. Was a mixing taking place here? I changed to my Analogue TX, no change.

When I installed a 40m Hairspray Antenna in the Loft Space along side the 10 MHz Beacon Antenna I expected the intruder to be very strong. Wrong, it was non existent. This proves that it is not the Beacon TX or it's antenna involved in the mixing.

I therefore suspected my 40m Doublet Antenna to be the one that was doing the reception of the 1.557Mhz signal, to mix it would need a non linear device. It goes to my MFJ Antenna Tuner which of course has Diodes in its Power/SWR meter circuitry. I have never come across this problem but it was a possibility. I also have an MFJ Portable tuner, I swapped the antenna over, no Intruder.
Checking the circuits of the two MFJ's they are virtually Identical, did we have a fault in the first tuner?
There is not much external to check but before I disconnected the Ground leads I removed the link which connects one of the Balanced input Terminals to the Unbalanced Input Terminal and replaced it with a short length of silver plated wire. Intruder GONE.

We have heard of the Rusty Bolt Effect the Corroded Razor Blade, I give you the Still Shiny under the terminals Copper PCB Detector.

Previously when I had to remove the link to use different antennas it was much easier to handle than a wire link. Since purchasing the MFJ Portable Tuner, (just over 1 year), it has not been disturbed.
The tuner with the link is in daily use, I have not noticed anything detrimental on RX or TX due to the problem the link had developed.

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Soon the time for my PSK31 sked came up, swapping to the Hairspray the RX signal was solid. The set up on the Hairspray was completely separate and the TX power at least 10dB down. Would I be heard over 700Km away on a 400mm antenna? Yep about 15 to 20dB down but solid copy when the QSB didn't cause problems.

Why produce antennas that are usable only on one band, asked F6GUU.

Well these two antennas are for single frequency use. Here they can be set for resonance where they will be at maximum efficiency. One for my 10MHz QRSS MEPT beacon, the other on 7.036 MHz for Data use, so releasing my other more frequency flexible antennas for other uses at the same time.

Here is my Choke Balun I made for use on the 10 MHz Version.

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Amazing, my 80mW 10MHz signal was the only one in the world that I saw getting into Italy and that was so for most of the day. It also crossed the borders down into Cornwall on and off today.

This screen grab is from yesterday when I had a companion.

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The whip at the top is shown fully extended it is for exact trimming only. I have constructed the antenna so that it needs about 50mm of whip for resonance, thereby ensuring that whip current does not play a part in the operation.

So I cut the feeder fitted a PL259 plug connected the Choke Balun and feeder to my QRP QRSS Beacon Transmitter. For initial test I popped the antenna on the dressing table in the bedroom with the feeder along the landing to the shack. Yes the XYL was out.

A pretty in-efficient antenna installation. So yes I was pleased to see my 80mW TX getting into Italy on the Italian Grabber. Next step an outside perch after waterproofing and corrosion protection then testing of the 7MHz Alberto VO5 antenna.

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The Laptop which I delivered two years ago to France refuses to decode any JT2 signals. Today the Tower Computer was pressed into duty and reports were exchanged. F6GUU carried out local tests from one machine to the other last night, always a good idea with a new mode I feel. He proved the Laptop system works one way but not the other.

If you try new modes with a local station you need someone with trusted equipment and reliable knowledge base of techniques. Too many times I have been told that my signal is no good and cannot be decoded by someone who has not set up his own station properly.

One only has to view the 'slant merchants' on SSTV. Transmitting slanted signals and telling incoming stations that they have slant.

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Winrad versions are built to expire and be replaced. If you try to run a version after the sell by date you click on START and it dies. I installed a new version and what did it do, just as described. Now if your computer date was wrong when you started the program you would get this, my date was correct.
I have run previous versions and it is a superb piece of software so I was a little peeved.
I run software on XP under two accounts one with full privileges one without, it would not run on either. I may have done my first run without admin privileges, did this cause the problem, maybe. The cure for running with the wrong date is to download and re install the latest version as a last resort, I tried it, it worked.

It is a pity the definition of the software defined radio video is not a bit better once it has been YouTubed. The display of several different Data Modes in the bottom window is superb. Here we also look at SSB too.

Sorry it is short I have to keep the file size down.

Next Morse code, I change the LSB filter to CW and re position the filter curve on the signal.

Again short but I hope sweet.

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