[Lowfer] A Different Loop Question

[Chuck Hays]

First, though, a comment on the LOG antenna. I have one, approximately 200
feet circumference. I love the thing, but there are some factors to account for.

It's a pretty "dead" antenna compared to an aerial. That's actually a good thing.
What it's most dead to is noise, so although the signal is lower strength the
noise is MUCH lower strength. I find that a preamp helps pull the signal back up
while still not amplifying the noise much. Sometimes, however I need to switch
to my transmitting vertical to dig out a weaker signal in poor conditions. In
that case, just live with the extra noise. It's good for NDBs and AM dxing.

I've been thinking about a loop for 630m. Most of the loop information I find
online is for "small," "magnetic," or other kinds of loops besides what I want
to know about. I was thinking of a full-wave transmitting loop.

To be clear, I do have enough acreage to have a single-turn 630m loop!
That would be one big loop, though and would necessitate careful layout to
avoid crossing parts of the property that I use for other things. I then
considered making a multi-turn loop, basically a large-diameter coil.

A full wave piece of wire for 630m is over 2000 feet. In my mental model
I'm thinking of four turns on a frame of approximately 500 feet circumference.
That would be a relatively manageable square 125 feet on a side. Big,
but smaller than a square 500 feet on a side for a one-turn loop.

The thing that stumps me most is the capacitor that would be needed.
I read that some small loops can have as little as 5 kHz bandwidth before
some retuning of the capacitor is needed. I don't know what this loop
would look like, but I had the second thought that since 630m is a pretty
narrow band to begin with, I might be able to simply put an appropriate
fixed cap in the antenna and it would not need retuning.

At the moment this is a "thought piece." I'm not sure I have the energy
or resources to put that up. I'd still like to know whether it'd work, and
whether I have, with the best of intentions, led myself down the garden
path.

Cheers,

Chuck VE7PJR/WB7PJR
CO90ux