It's been ages.....

Work, work and more work. That's all there is to it at the moment; finaly, however, I now have some time to:

1. Catch up with my Blog;
2. Play some Radio!

The WSPR and QRSS beacon I was begining to develop here:

http://g0mgx.blogspot.co.uk/2012/05/back-to-real-homebrewing.html

is finaly complete!

The output amplifier that I was fiddling with ended up as an Analogue Devices AD8008, which I ended up mounting on a kind of break out board that I had:

You can see how this helps with the "ugly" construction and the use of SMD devices. I can't remember where I got this break out type board from, but it certainly came in useful here!

Many, many moons ago I built myself an QRP ATU, and now I have it permanently hooked up between this beacon and a cheap vertical HF antenna I have slung up against the side of the house. So the setup looks like this:

The WSPR and QRSS beacon is written in C for Arduino:

www.arduino.cc

and I've made quite a few changes to the source code which can be found here in anyone is interested:

http://www.qsl.net/g0mgx/files/Mega_DDS_60_v2_1_G0MGX_eeprom.ino

I've got this hooked up to a GPS module which is sitting in the window of the shack, this is providing the timing data to the WSPR and QRSS beacon. Currently I've got it running on 30M and will be doing some checks for reports in the near future. It's utputting a stagering 20mW!!!!

I've also started (well nearly finided) re-writting the code for my recent DDS project in Arduino; I was never quite happy with the way that ended up, so using my new found C skills I have written (from scratch) the DDS control software.

The original project is here:

http://g0mgx.blogspot.co.uk/2012/02/dds-running-well.html

The functionality is the same as before, it's just that it works better and I have a much better understanding of how it works.

The source code for this is here:

http://www.qsl.net/g0mgx/files/G0MGX_DDS_FINAL.ino

I can claim some originality in this one!

Here's the inside of the replacement DDS, you can see that it's now Arduino based:

Please excuse the clothes pegs; they are just holding bits in place whilst the glue dries. I'll post again about this piece of work once completed. It's kind of soak testing right now as there is a calibration routine included to adjust the DDS for any misalignment in the frequency output due to clock inaccuracies.

All good though, egh?

Can we handle the power?

Well,

The ATU that I am making for Vince has finally neared completed. My mate Paul completed the drilling of the metalwork for me; after my recent experience with drill bits I decided to let someone who knows what they are doing have a go!

So here are some pics of the nearly finished article:

The quality front panel labels are courtesy of my recent e-Bay purchase of a Brother label printer:

The problem we have now is that the turns counter we bought has a metal front panel piece. This (which I thought was plastic) is connected directly to the metal shaft which in turn is coupled to the metal parts of the roller coaster and is therefore at full RF potential. This is dodgy because we don't want that potential near the user and also because the front panel itself is at ground; the screws holding the turns counter to the front panel are actually causing a short circuit.

An initial attempt at getting past this problem by using some isolating washers (the kind of thing you would use to isolate a TO3 transistor from a heatsync) between the screws and the two other metal bits has resulted in a rather spectacular light show at about 40-50 watts. Clearly no good, and even if it worked electricaly, the metal part of the turns counter would still be at full RF potential, dead ATU  users makes for little or no repeat business, so this is no use whatsoever!

I'm going to get my aforementioned chum Paul to try and make be a plastic shaft coupler... we will have to see how that works out.

You can see the offending article at the very top centre of this picture, it's all at full RF potential:

To finish, here's a recent picture of the Geddy cat:

Al good fun though, egh?

How did that happen then?

Well,

I've been trying to make an ATU for my mate Vince, G0ORC. We have been toying with the idea for some time, but have finally decided to cannibalise an old CAP Co Tuner that had a very broken turns counter. The parts have ended up inside a rack mount box and I have been slowly building these bits into a high power tuner. There are two chunky variable capacitors and a really well made roller coaster inductor:

Now, today I have been making a bracket to mount a wafer switch on, this is to be used to switch the ATU between the rig or a dummy load. Nothing complex going on here you wouldn't think.

I used a recently purchased set of drills, the result was rather astonishing:

This was a bargain set of drills from Maplin, fantastic!

I think the ATU is going to work out OK though, once I've drilled the holes I need, what do you recon?

Tuning - with less noise!

Well,

For some time I have been using an LDG Electronics AutoTuner here in the shack. It's been an OK experience and the ability to change bands and then have the tuner sense the RF frequency and auto adjust itself back to the previously stored settings for antenna and band appealed greatly. Set it up once and never touch it again - perfect!

The theory was fine, but it didn't quite work in practise. The device never quite matched the antennas correctly - I always found it necessary to tweak the automatically chosen settings and then store them manually plus on most bands I couldn't quite get a 1:1 match. My biggest concern with the unit was that the SWR reading on the tuner itself didn't ever match the readings at the radio or with the separate meter I have here. The net result was that I was tuning for the best match read by the radio, which was normally quite a miss-match according to the tuner.

Anyhow, to cut a long story short, I have purchased a MFJ roller coaster based tuner:

Looking at this picture worried me a little. There very much looks like there is a dent in the top of the unit! However it's completely invisible unless taken by a camera with a flash but I should probably consider reporting this back to the supplier.

Anyhow, using the device as a tuner seems extremely easy. MFJ tend to have a bad reputation and are often called "Mighty Fine Junk"; however, my experience is all good. This tuner does exactly what is says on the tin. I've completed some tuning charts which I will try and print out and place somewhere near the unit itself in the shack.

The cat has taken on a whole new degree of madness; he has now taken to sleeping in the cover of my 'scope on a high up shelf in the shack:

I'll keep you posted on the tuner, looks OK though, egh?

WSPR & The ATU Syndrome

Well, been back with the ATU today, and after some discussion have come away 20 quid worse off and with a Mostly Fine Junk (NFJ) 949E. This includes cross needle metering and an internal dummy load.

I've tried the tuner and unlike the previous one from Comet, it will actually tune my antenna on all expected bands, so I conclude that the other one was highly suspect.

More playing with the FT-950 today, and more menu items 54 & 55. I now have these set so that the radio is in PKT-USB and both 54 & 55 are set to 1000Hz, this seems to be working as expected and is accurately displaying the TX + audio offset on the radio. WSPR is now working find business and will be chuntering away to itself whenever I'm not using the radios inside the shack.

Trying to get to grips with Logger32 on digital modes now, so have printed some parts of the help file out and promptly ran out of ink in the printer. Guess I'll need to go get some tomorrow.

Starter Post

Well, as a licensed Ham for some years, I recently decided to get active again and thought my musings may be of interest to others.

Most recently I've got myself an FT-950 which I plan to use primarily for data modes.

Today I have been musing over the data mode on the FT-950 and most specifically menu items 54 & 55. It seems for the default settings of these menu items to work, you need the radio in PKT-USB mode; by default the data mode was in PKT-LSB. I was failing to decode signals I could hear in standard USB mode with that setting.

Seems that the radio will work well in the dedicated data mode, just some understanding of the carrier offsets involved are needed to figure out which mode the radio actually needs to be in.

I left the radio running WSPR for a few hours today, my signals (only 10W out) were heard far and wide including Japan, and I was receiving from all over as well.

I came home with a Comet CAT-300 ATU today, but it seems to be the most useless ATU I've ever come across. It wont tune anything and actually provides a higher best SWR when in-line than without the tuner at all. I conclude that it's faulty and will be taking it back tomorrow.

I'm going to take a picture or two of the shack and post them now.

Mark. G0MGX