Over the summer I managed to ‘do’ 2 out of the 5 available 2m Backpacker contests. These to me are a great opportunity for me to get out on the fells and enjoy a longer spell on a summit with a nice qrp rig and some simple gear. The trouble with contesting is that inevitably you want to do better. So what’s the likely areas for improvement. Well there’s the rig, coax and antenna.
The rig is an ft817 and its not going anywhere fast. I sold once once then instantly regretted it. So it’s not going to be changed in a hurry. Yes it has its problems but frankly it just works and is relatively light so its a keeper.
Coax…Hmm work in progress. RG213 is too heavy, Ecoflex just isn’t flexy enough for summit packing. I’m yet to find the ‘perfect coax’. I’m leaning towards a trial with some Messi & Paoloni Ultraflex 7 as I like Mini 8 as a size but am looking for perfection here kids. This just means a reduction in losses to something as low as reasonably practicable as the saying goes
Antenna. Well I do like my now obsolete Sotabeams SB270 ( A 3 element yagi that lives inside its own plastic boom). Its light and doesn’t get thrown about too much in the wind and has lasted years. Trouble is it’s looking a bit knackered now and 3 elements is a bit short. I bought a 5 element LFA off innovantennas years ago and was really disappointed with the build quality. The elements just weren’t secure enough and it was way too heavy. Too heavy for a UKAC /p so no good for a summit. But it is well designed and the elements are quite light.
So the plan is to change the coax. I’ll do that over the winter. In the mean time I’ve taken a few grams off the yagi.
The boom was very substantial 32mm2 2mm thick Aluminium (note spelling you stupid browser ;-)). The boom weighs in at 1150g as is.Swapping this for 20mm2 1mm thick boom I’m down to 560g. Roughly half the weight. Element clamps have been swapped for the G1YBB method of IML mouldings plates and cheapo pipe clamps
You can see the immediate difference in size. The original beam is clearly made for sticking up at home then forgetting about it, ignoring the defects with this particular one.
Now with the elements added. They simply snap in to the pipe clamps and are held in place without any bother.
We’ll see how easy it is to carry up the Old Man of Coniston next year but at 1240g it is nearly 500g lighter than the original with the same RF performance.
I bought 2 pieces of aluminium and have a larger 2m and 70cm DK7ZB yagi that needs the same treatment (I went the other way this time, it was too light and flimsy) that I’ll give a run out during the Christmas Cumulative content
I have put a good regenerative radio receiver design on the net:
I like the write up Alex, think I might get one to build. Still making more Cobwebbs here, phew its hot LOL. 73s from Cape Town