Saturday 31 October 2015

Receiving distant beacon OH2VHF by meteor scatter

Left the radio running last night and into the morning just to see if I could copy a signal from the distant Finnish beacon OH2VHF on 144.443 MHz. Much to my surprise I had success and received this short burst. Although not a complete callsign the letters OH2V are pretty clear. I'll try again tonight and maybe I'll receive the complete call. 


The letters OH2V can been seen

 The dash in the V is broken but "di di di dah" can be heard clearly.


Distance between IO81WM & KP20BB is 1877.73 km





Saturday 17 October 2015

About My Scrapbook

About My Srappbook

Here are some notes about the homebrewed equipment that I have made and used over the years. It has all been constructed using the well known KISS approach, Keep It Simple and Stupid. No bells and whistles here, essential features only. I make no great claims for any of it, (some pictures click to enlarge, if you do you will see why I make no claims) other than to say that building it and using it on the air has given me the opportunity to occasionally work some DX, and no small degree of amazement that it has worked at all!radio I hope that in a small way, this website might encourage more home construction, something that can only be good for the hobby of Amateur Radio. After all, if I can do it, so can you, and very likely with better results!

Sunday 19 July 2015

144MHz E's DX

Seemed to me that the E's season this year got off to a pretty slow start but fortunately improved from mid June.  Plenty of contacts on six and four and I was particularly pleased with this two metre one ;-

Distance between IO81WM & IM63NX is 1987.75 km (1235.189 miles)


At the time there was little local activity and after the contact CN8LI went back to calling CQ.

My equipment; homebrew amplifier 200Watts, homebrew hybrid SDR, 9ele Tonna.

Wednesday 15 July 2015

Two Metre Interference

Two Metre Interference: has anyone been experiencing QRM on two during the day recently. This horrible hash has been appearing on the band here. At first I thought it must be local to me but then I notced aircraft flutter indicating its was coming from someway off. So turned on rig in the van and could hear in all the way to Chippenham. Anyone else hear it?



"Large spike on right is packet, left spike is GB3VHF"


Thursday 5 February 2015

144MHz 300 Watt amplifier

Been busy making this amplifier recently.
Amp kit from the Dutch RF shop and uses the Freescale MRFE6VP6300 mosfet.
Low pass filter from Homebrew RadCom.
Relay sequencing.
VSWR protection.








Monday 1 December 2014

SIX Metre amplifier

I've built a couple of amplifiers recently. This one is for Six Metres, I just followed a design from OZ1PIF's website. It uses eight IRF510 MOSFETs. Output should be up to 250 Watts but I've not driven it hard enough to obtain that amount of power but 10 in produces 150 out so I'm happy with that. Seems to tie in nicely with the figures on OZ1PIF'S site. It's QRP to some but I've rarely run more than 20 Watts on Six from anything home-brewed here and I once worked VK with that.



Inside eight IRF510's, RX pre-amp and low pass filter















No front panel meter, no high swr protection, no cooling fan but the MOSFETs are very cheap!



Front panel. The case is from a faulty SMPS.






A card for the amp!








Thursday 18 September 2014

Listening for VC1T, was there any chance of hearing them?

How I listened for VC1T the recent Two Metre Trans-Atlantic attempt which took place 4-11 July 2014.

I have a very modest station but could I ever hear a transatlantic signal? Well maybe, after all I've heard tropospheric signals from the Azores, Madeira and the Canaries on 144MHz and UA3 via sporadic E. Distances in the order of 2500km. The distance between me and VC1T was 3600km. Yes, eleven hundred kilometres more but nevertheless I thought I should at least try and their signal could arrive via the ionosphere! So here's what I did.

To make the best of the opportunity I realised that I needed to monitor continuously and not just when in the shack. VC1T were going to be using WSJT9 modes FSK441 and JT65B.

My setup, no large antenna here


Beside the radio, the computer is a vital part of attempts like these. On mine it would be necessary to run three programs WSJT9, Radio-sky Pipe and PowerSDR-IQ. So a day or so before VC1T went on air I started up the three programs to see if there were any conflicts. None, all worked first time, WSJT and Radio-sky Pipe sharing Virtual Audio Cable. WSJT was set to record any decodes and Radio-sky Pipe set to record any signal just above the noise. PowerSDR-IQ set to 144.155MHz.

Test JT65B using GB3NGI


        I have used Radio-sky Pipe, in the past, to monitor beacons and calling frequencies when not in the shack. It can be set to record audio files to a signal level trigger point. It also draws a strip chart that helps to identify short lived signals.

So, from the first day of transmission from VC1T I was ready to monitor. FSK441 was the first mode in their schedule so WSJT9 was set to that mode, monitor only, save any decodes and the station left running.


Monitoring FSK441 for any MS from VC1T
Nothing of any interest was received on the first day, the 4th July, just one or two EU stations on tropospheric and some backscatter MS. The next day the mode would change to JT65B but that was at 0100z, so I changed mode as late as  possible but before VC1T. WSJT would not be able to decode but Radio-sky Pipe would still record any signals.

On Saturday the 5th July there seemed to be many more EU station around but nothing from VC1T.

Part call sign decode but in the wrong period so not VC1T

Sunday the 6th back to FSK441. I was in the shack all morning, lots of EU stations calling, and some very nice backscatter pings. I don't know about anyone else but that morning I had a feeling that something was different propagation wise compared to the previous two days. There was a contest in EU and I heard many pings from contest stations  on VC1T's frequency, CW and phone. Then came the exciting news. And exciting it was. And congratulations to them but I was not surprised that VC1T's signals had been decoded. It just seemed as if things were going to happen. But I heard nothing from outside EU.


A Meteor scatter ping as recorded using RadioSky Pipe but was it VC1T

The news of the decode was very encouraging and so my equipment was left running, recording away. I saved all the audio files from WSJT and Radio-sky Pipe to a memory stick and transferred them daily to another computer searching them for anything interesting. It was possible to run them all through WSJT and look for decodes.  I spend a lot of time searching the Radio-sky Pipe recordings using a spectrogram.

In the end I found just one file that I think I can say, maybe, just maybe, could have come from VC1T.  Timing seems crucial here.  The ping came just inside VC1T's transmit period but perhaps my timing was out or an EI station's timing was out or both. You can see it was recorded Sunday 6th July at 1021 and 30seconds, 0.7 of a second into VC1T's transmit period.

Could this be VC1T?


Whether I heard any thing of VC1T or not I had a great time trying. I only hope there's another attempt soon, I would certainly monitor again, you just never know your luck.

UPDATE:

A year after I made this post the saved files of the 6th July 1021:30sec  ping were sent to JT himself for analysis.  I was happy with the message back,  "it could have been VC1T but there's no way to prove it".  Better I think "than it couldn't have been because ......".