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Wednesday, 17 February 2016

23cm from a HillTop - Most definately!


Following my recent musings about the construction of a portable 23cm station here:

Myself and Vince, G0ORC put it on the air last night in the UKAC contest, here's the result:

Not bad for a first effort, egh?

Local conditions.

Sunday, 14 February 2016



Very, very little time spent, but some excellent propagation about, including great openings on 10M. Just shows you what stable solar conditions can support on the high HF bands.

Local conditions.

Saturday, 13 February 2016

23cm - From a Hilltop - Oh Yes!


You may remember last time I was rambling on about my portable 23cm project; well I had come a little unstuck with what looked like thermal runaway in the PA block.

I managed to acquire a suitable heatsync for the PA and then had another bash at setting the idle current at the 350mA recommended by the PA designer. Eventually, after much trial and error I got the idle current set and there was no hint of the runaway I was seeing before.

So, I took a deep breath and hoked it all up ready for the TX test. The setup was the same as I described last time except I added a power meter at the output of the PA:

I've lashed everything down inside the case in my usual "bodge it and scarper" method and the birds nest now looks like this:

And the whole thing now looks like this:

I'm measuring about 50W output on the power meter, so that'll do nicely.

We've got this Wimo antenna ready for the hilltop which is currently strapped to my Wifes line post:

The return loss of the antenna looks just fine:

By my calculations, if we have 50W out of the linear, that's about 17dBW, the antenna claims 16.something dB gain, even if we call the antenna gain 13dB that makes the ERP about 1KW!

We need to make sure we don't cook too many passing pigeons with this baby.

Local conditions.

Monday, 8 February 2016

23cm - From a hilltop?


I mentioned a while ago that myself and Vince, G0ORC were planning to have a bash in the UKAC contests. We have a capability for 6M, 2M and 70cm but nothing portable yet for 23cm. So hence the project....

I bought one of these transverters:

and to go with it a PA kit from G4BAO:

Here's what I've made so far:

I used a toroidal transformer I had to create the PSU, the requirements are 28V for the PA and 12V for the transverter.

The transverter module itself looks like this:

and the PA, once constructed, looks like this:

Now, the first conundrum was how to test the RX path of the transverter given that my signal generator only goes as high as 1GHz.

What I realised was that my Spectrum Analyser can be set into zero span mode and that makes the tracking generator a fixed frequency. So I set the Spec An to 1296.5 MHz and hooked it up like this:

With the F-817 set to 144.5 MHz I have a strong carrier - so I conclude that the RX chain is working.

Now to test the TX chain - more tricky!

First of all I realised that I can tune the input and output of the PA using the Return Loss Bridge combined with the Spectrum Analyser. Here's the finished result on the input side (after some trimming in accordance with the assembly instructions):

And here is the output side of the PA:

So now to devise a way to test the whole TX chain, this is what I came up with:

Which kind of looks like this:

So we have the RF from the PA into the big block which is a Directional Coupler, the -30dB forward port is feeding the Spectrum Analyser via another 25dB attenuator, then on the antenna side we have 2 x 30dB attenuators to a 50 ohm load. The return loss of this lot is actually quite good and looks like this:

Now, I have tested the transverter without the PA and can see an output at the expected frequency:

There's much less attenuation in the chain for the test above, but when I try and set the idle current on the PA it kind of runs away. By that I mean that as the device heats up so the current drawn increases and just keeps increasing. I think this is because I don't yet have any suitable heatsyncing in place so have ordered something which I will have to wait for before I can continue.

So far, so good though, egh?

Here's our latest addition currled up with her Dad:

Local conditions.

Wednesday, 3 February 2016

UKAC - Up there, Really?


We had our second bash at entering a UKAC contest last night. Myself and my chum Vince, G0ORC headed to the top of Alport Heights in Derbyshire with a generator, some poles an antenna, a radio and other bits and bobs.

Station seemed to work well and we headed home after 100 contacts due to the cold, damp and generally miserable conditions. The site is over 1000ft ASL and it was snowing up there last night!
Here's a map of our log:

Which isn't as good as what we achieved on 70cm a few weeks ago:

Now, the results are out for the 70cm test from January here: Results and it's clear we made quite a few errors in our operating and also logging. We are currently keeping a paper log and then transcribing it to electronic after the contest - there were some mistakes in the transcription too!

This is the result of the log analysis:

So all in all we have a 3/10 must do better!

Local conditions.

Tuesday, 2 February 2016

Well, Well, Well, what's news?

It's been quite a while since I updated my blog, and there's been quite a bit going on in my life. Primarilly I have been travelling to the Far East and back working for a living.

We've also had a new addition to the family, this is Bonnie Dog, she is the daughter of our Elmo and is a Sprocker Spaniel:

She is 12 weeks old today and quite a bit bigger now than the photo above, here she is with her Dad:

The shack is more than complete and already a total mess nearly all the time:

Myself and my chum Vince, G0OIRC have started dabbling in the Tuesday evening UKAC contests.

We bought ourselves a generator:

Plus a selection of antennas to cover 6M, 4M, 2M and 70cm:

We have been operating from Alport Top in Derbyshire IO93FB:

So far, due to my travelling, we have only done one 70cm test, but the results were very impressive. We are ready for tonights 2M test, so we will see what happens:

We are also planning to get a 23cm capability for portable operation, my current plan is to combine one of these transverters:

with one of the PAs from here:

Fun egh?

Local conditions.