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On randomness and antenna length, I generally try to ensure with loops that they are at least a full wavelength long on the lowest operating frequency. If that is achieved you can tune them on that

Must have been a few oddities in previous tests with the U2 on 28Mhz. Now that I've moved mine up into the attic, and walked a mile away to do some listening tests using the FT817 the signal is as

Try it and see how it works Tony. As if often seen, random bits of wire work better on some bands rather than other, depending upon the distances in the doglegs etc etc. Sometimes results are

On the matter off loops, I am thinking of running wspr on two frequencies simultaneously and am planning to make an invisible horizontal loop of fine wire using the mountings for my plastic gutters to

Thanks, Andy, At present, I have a wire loop that goes all round the loft, following the pitches of the rafters. I'm always looking for ways to improve things, and you have given me a few

Hi David, It's nothing special at all - honest. It's a pure 8ft square loop which is fed at the bottom centre via a suitable matching unit in order to transfer as much power into it as possible

Hi Andy, Can you share a bit more info about your loop and its tuning? Especially for the lower bands. Best Wishes David G8XBZ -----Bits of Original Message----- From: QRPLabs@...

Hi Hans, Joking aside, I must admit to being drawn to your website some time ago as I was looking at stuff for various interests of mine. The valve tx being one, but it was more the NBTV stuff that

Kits for them next week then ? ;-)

Hi Andy Glad it's working so well! For those who are interested: the 1-valve TX is here: http://www.hanssummers.com/cwtx.html The receiver and ATU were also homebrew

Just for info,I've had the U2 and the UP501 module on ever since I got the beta chip in and never switched it off in the last few weeks. It's never skipped a beat! Today was the first time I'd

Do you mean that it starts high and then a few seconds later it drops ? Or do you mean that the higher the frequency = lower output ? With 3x BS170 @ 9v you will typically see:- 1.1w to 24Mhz 650mw

Indeed, very nice. cheers, Graham ve3gtc

Hi Francesco I noted a drop in power after 10MHz in my tests but didn't worry about it, not 50% at 14MHz but a full drop 50% at 18MHz which the rises to give more power on 28MHz. It is a simple

Nice and neat, and compact. Thanks for sharing. 73 de Andy

OK Slave Driver The quickest way was a Web Cam video which does give an accurate impression of size. Thoughts were:- Small size, light weight for portable use, ergonomic 2 thumbs operation of the

To forum, help me please. Have a question. I notice that on 20m the power output drops dramatically (~50%). Necessary fine-tune the LP filter? Or are other problems: eg. DDS-VFO? TKS Francesco,

Yes and with the U2 being capable of knowing where it is (although I might be unsure) and inserting the QRA Loc. automatically. I am looking forward to the Trimble GPS compatibility being

I think that's the key to it all. Throw up a wire in the nearest coconut tree, leave a U2 running and come back later after the beer has run out to check the results. Said in jest but

LOL! Maybe this one would be suitable for Eddie's hot 6m PA ..? http://tinyurl.com/ovx4bqw ;-)