Hi Jim,
I know my following info does not directly answer your question, but I do
think it's important regarding feedline isolation.
I suggest you take a look at the recommendations of N6RK regarding the use
of a matching transformer to feed tuned shielded loops as it isolates the
feedline from the antenna (shield of coax not tied directly to the loop).
I use the N6RK matching transformer method on my loops of similar design
and think it makes the most sense regarding feedline isolation, and
maintaining proper balance of the antenna.
Here is a link to his paper, and his matching transformer is shown on page
30 and 33 of his paper.
http://www.n6rk.com/loopantennas/pacificon.pdf
73,
Don (wd8dsb)
73,
Don (wd8dsb)
On Fri, Apr 1, 2016 at 3:04 PM, James Rodenkirch <Rodenkirch_LLC@msn.com>
wrote:
> I have installed a receive loop ( http://www.qsl.net/kc2tx/ ) and
> finished measuring and observing...
>
>
> Measurements:
>
>
> VSWR --- 1.7 @ 1.830
>
> ZO ----- 77 at 1.830
>
>
> Observation:
>
>
> Following ON4UN's comments regarding needing a preamp or not, measured S1
> to 2 noise level with antenna connected during mid-day, S0 with dummy load
> connected.
>
>
> During evening hours, notice some improvement - S2 drop in noise level
> when switching from xmt antenna (inverted U) to the loop - but not hearing
> much in the way of receive signals (e.g., hear a fairly strong signal from
> the west coast on the xmt antenna, nothing on the loop and I have it
> oriented east/west).
>
>
> I'm uncertain if a low noise amp will help my cause (thoughts??)
>
>
> I do not have a common mode choke installed, yet...will one make that much
> difference?
>
>
> The loop is located about 60' away from the Inverted U and radials.
>
>
> Comments/suggestions appreciated.
>
>
>
> Thank you, in advance, for constructive, relative to what I have now,
> replies....non-"constructive" means I can't erect a BOG, Beveridge or
> Waller Flag so don't ask why I didn't go that route.
>
>
> 71.5/72 de Jim Rodenkirch K9JWV
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