[Lf] Different types of antennae]

[Andre' Kesteloot]

Cantrell Bill-QA0057 wrote:

> Tim,
> On a mobile BPSK reception experiment through Arkansas, I noticed that very
> tall trees along the median of the Interstate Hiway would attenuate
> weak-signal LF reception, even though the trees were ~40 to 50 feet away
> from the roadway, but they were also ~50 to 80 feet tall]  This made the
> difference between E-field probe reception (using BPSK GRAB) and no signal.
> That is, I could receive the signal only if there were none of these trees
> in the median.  So if you can get MORE THAN 100 feet away from trees that
> are 100 feet tall, then that may be good enough.  (I am assuming that the
> effect of trees on reception would be reciprocal to transmission.)
>
> Regards,
> Bill
> "TEXAS" & WD5CVG
>
> -----Original Message-----
> From: Tim Pauly [mailto:tpauly at twcny.rr.com]
> Sent: Saturday, May 20, 2000 2:27 PM
> To: lowfer at qth.net
> Subject: Re: [Lowfer] Different types of antennae
>
> On Sat, 20 May 2000 14:10:24 -0500, Lyle Koehler wrote:
>
> >hat on your 40-foot tower and feed it the way Bruce, W0BK does for his
> >BK beacon. In the winter the trees freeze and become fairly good
> >insulators. More details on my web page at
> >http://www.computerpro.com/~lyle under "Listening for LowFERs, Part 2"
> >and the description of the BEAMHAT.ANT models under "Computer Modeling
>
> How 'close' to trees is too close? I could put a ground mounted vertical in
> the front of the house which would be open
> from trees for at least 80-100 feet in 3 directions. But it is also at the
> base of the hill, and the top of the antenna would be
> at house level (about 15 feet from the house). You'd have to see the way
> this crazy place is laid out to know what I
> mean. Our house is literally situated on the side of a very steep valley.
> The house itself is about 40 feet above street
> level (lots of steps to carry groceries up!). My tower is about 50-60 feet
> behind the house, but the base of it is above the
> second floor level (like I said, we're on the side of a very steep valley!)
> Also, my tower is grounded and mounted with
> threaded rod set in concrete. Unless I made a "folded unipole" out of it ;-)
> I don't think it would work well. There is also
> VHF transmit antenna already mounted on it, and a UHF relay antenna will be
> going on it soon...
>
>  Tim
>
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Subject: RE: [Lowfer] Different types of antennae
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