Tuesday, 15 April 2014

Sunday, 13 April 2014

Extended 2m band

With the news about possibly extending the 2m band up to 147MHz I had an idea about wide split repeaters with the output on a frequency outside the amateur band.
Wide split 2m repeaters would be a good thing, even if the output frequency was outside the amateur band (needs to be cleared anyway). There must be some space on 140, 143, 149 or 152 MHz now to allow a >4MHz split. Could also be done on 4m with 80-81.5 MHz old fire frequencies.

Monday, 7 April 2014

GB3GD

Very bad signal from GB3GD - the 70cm repeater also on Snaefell is full scale and there is nothing in the way.

The 145.625 signal is about the same as I get GB3MP on 145.750, but I'm in a bad location for MP, with a hill in the way. 

Friday, 4 April 2014

WSPR on Mac

Running the Mac version of WSPR on a Mac Mini with OSX 10.6.8 Snow Leopard. Couldn't get the serial port working so had to use VOX on the FT-817. WSPR had a list of serial ports to use but none were the port name of my USB-serial adaptor.
The display looks a bit strange as it's 1024*768 on a widescreen monitor, I used the VGA input to the monitor and the Mac wouldn't do any widescreen resolutions. 

Monday, 27 January 2014

Blogs

Here are a couple of amateur radio blogs from around here.
Norman 2E0FAS
Lawrie M3UHQ
Dave 2D0YLX

Sunday, 26 January 2014

Fire Up 99

The Fire Up 99 is a replacement top section for the Antron 99 CB antenna. I was using one on mine. The normal top section is a straight length of wire inside fibreglass but the Fire Up has a coil at the top, to lengthen the wire whilst keeping the resonant frequency at 27MHz.
The A99 is a half wave normally, so to work with the existing matching circuit, the length would have to be extended to around a full wavelength. Whether it makes any difference to 27MHz performance is debatable, I've not seen a decent review of one where anybody has measured a difference before and after adding it. When I put mine up, I was replacing a broken A99 and had no known signals to compare it with.
The A99 is just a half wavelength wire inside a tube, and without adding to the length, can't see there being a way of improving it on 27MHz without doing something like changing the matching circuit (there are losses in there, which would have an even bigger effect at lower frequencies - see this article).
At lower frequencies the top loading might help reduce these losses, so it could be an improvement for those wanting to use it on other bands like 14 and 18MHz.

I tried the Fire Up 99 on the car using a magmount which is far to small to drive anywhere with it. Not that it would be any use as an antenna on its own, as you can see from the SWR plots.
It seems to be a 3/4 wavelength at 34MHz and a 5/4 wavelength at 55MHz. Compared to a mobile CB antenna received signals are much worse at 28MHz.



Saturday, 25 January 2014

GB5LBC

Today I made my first HF voice contact for over a year (and the first voice QSO of 2014). 99% of the time the HF radio gets used to transmit and receive WSPR, with a little bit of other data modes. For that, the 5 watts from my Flex1500 is good enough (hardly anybody uses over 5 watts on WSPR), on SSB it's not that good compared to the usual 100 watts most people run.
But I had my microphone plugged in for a change (it's the one off my FT-817, the wiring is the same) and called GB5LBC (Roa Island lifeboat station) on 7.180 MHz, who was only 7.3Km away from me. That worked OK and it was the furthest this Flex1500 has ever got on SSB since I bought it.