Re: Multi turn Mag. loop
For a _tuned_ loop increasing the number of turns moves the tuning
range lower in frequency. For any given frequency, the single-turn
tuned loop will have a larger diameter (and thus greater capture
area) than a multi-turn tuned loop. This translates to greater
sensitivity with a single-turn tuned loop. The sensitivity of the
loop is directly related to its "Q" or effective bandwidth. The
higher the Q, the narrower the bandwidth, the greater the sensitivity
and the lower the noise.
Thumb's Rule states that for best Q the multi-turn loop should have
its turns spaced at least 1 conductor diameter.
Depth of nulls will be affected by proximity to other objects in the
near field of the loop on the horizontal plane. As the angle of
signal arrival increases above the horizontal plane the depth of null
will decrease. For signal arrival angles above 30 degrees the loop is
The 1.0" hardline should make a very good loop. The only problem with
it may be in the connections to the tuning capacitor. You will need
to make them as mechanically and electrically sound as possible...
and thoroughly weatherproofed to retard oxidation at the joints.
--- In firstname.lastname@example.org, "Garth M.Conover" <ewrtsa@m...>
> I am looking for info as to a 3 or 5 turm Magnetic loop.(using 1.0"Will
> hardline for outdoor stabilty) along with the usual tuning cap.
> it produce any better results when campared to the same diametermag
> loop but just 1 turn. Will I get deeper nulls/improved directivity?It
> This is meant to be a rcv. loop only. I want to use large dia.
> hardline due to its built in solid outer metal conductor. I figure
> will be easier to stabilize the turns. Which brings me to anotherbe
> question. I realize turn counts Vs spacing is a consideration with
> wire loops. But what are the implications with a multi turn coax
> loop. Should the hardline turns be basiclly intimate with the black
> plastic outer conductor touching or should the turns be seperated
> by "X" I would think that there should be some sort of spacing. Any
> guidance for those who have this info or links to find same would
> greatly appreciated.