"Ashlock,William" wrote:
Mal,
I experimented with multiturn 50'x50' vertical TX loops on 185k a couple of
years ago and remember the net gain in the far field signal was much less
than anticipated. Turned out that the additional wires were better-off
connected in parallel. I think the reason is that the soil loss begins to
dominate when turns are added to a loop this size. I'll get out my notes on
these experiments, tonight, and get back to you.
Thanks Bill for your loop details and any further information would be useful,
there is no good me reinventing the wheel hi. My plan was to put enough turns
on the loop to resonate it on 136 khz, parallel turns would not do this, but
would probably broaden the bandwidth, again this is not my goal. I am looking
for something that would perform as well as my 120 ft vertical on TX. I do not
have an RX problem, and my vertical performs well also on receive at this QTH.
It seems from previous articles about loops that on RX a small loop and preamp
works well and there would be only a marginal advantage with a large loop. As
far as I am aware the only amateurs using loops are just experimenting for fun,
have no room for bigger arrays or live in a noisy environment and use a loop to
null out noise.
I do not want to go to all the trouble of putting up a loop only to find it
peforms poorly and of course it would be directional.
I fall into the category of a loop for fun. There must be other loop users out
there with a lot of information good and bad.
73 de Mal/G3KEV
Regards,
Bill Ashlock
>Has anyone ever tried a large multi turn loop that resonates directly on
>a LF of interest. Most amateurs cannot get a full size one wavelength
>loop installed for 160 metres but a 40 metre loop is manageable, so
>instead of a 1 turn loop on this freq make it 4 turns plus or minus to
>get it to resonate on 160 metres. ie just a large diameter resonant 160m
>coil used as an antenna. This principle could be used on 136 khz for
>instance, the same 40 m dimensions but with as many turns as nessary to
>resonate it on the lower freq of interest.
>There will be practical differences and it will probably not work out at
>x N turns because of capacitance etc, but the approach to achieve
>resonance is the criteria on the lower freqs.
>When I say large loop I mean some thing like 40 m and nothing too large,
>but sufficient size to have a chance of working and keep the Q
>reasonable. The loop would be hanging vertically and the bottom wire at
>least 6 feet(2m) off the ground.
>73 de Mal/G3KEV
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