[R-390] SWL antenna

[kurt]

Dan
I lived many years in suburban Phoenix and used a wire antenna 50 to 100 
feet long depending on where it was in the yard. My experience is the 
further from the house, everybody's house the better and  use a matching 
network between the coax and the antenna. The best matching network for me 
is the I.C.E. unit. This will allow you to change the impedance for the best 
match by changing taps on the transformer. I eventually modified the unit to 
isolate the antenna ground from the shield of the coax for better noise 
reduction. I found the height above ground had little affect on the signal 
strength. Over time I was able to vary the height from 6 feet to about 25 
feet, I had to hide the antenna in the trees, which in my case would be 
about where you are talking about putting your antenna. I spent most of my 
"antenna time" minimizing noise from the neighborhood as I tried real hard 
to keep my own household noise to a minimum. As a reference most of my 
listening was utility signals not the big swl broadcasters. There were very 
few signals that I could not hear that my ham friends with serious antennas 
could hear.
The secret is noise reduction.
Regards,
Kurt Holbrook
----- Original Message ----- 
From: "Dan Merz" <mdmerz at verizon.net>
To: <r-390 at mailman.qth.net>
Sent: Monday, November 06, 2006 5:37 PM
Subject: [R-390] SWL antenna


> Hi,  I'm moving in about 6 mo to new house being built and am considering
> how to install a simple antenna for am broadcast band and HF receiving (no
> transmitting).  Currently I've got a 50 ft longwire outside at about 20 ft
> height  with some Radio Shack twin lead,  the cheap stuff,  coming down to 
> a
> hole in the basment wall.  It's been good enough.  In the new house I'm
> thinking of a couple of options,  about a 40 to 50 feet of wire about 3 or 
> 4
> feet off the roof using a couple of pvc pipes for support and serving as 
> the
> insulators with the transmission line connected on one end.  I may be able
> to put it higher but that depends on how strictly one of the covenants is
> enforced.  I've gotten the ok for what I'm describing.  But I've been
> wondering about the transmission line across and inside the attic house
> about 40 feet across and down about 16 feet into the basement.  My first
> idea was to use one of the better .240 diam coax types either 50 or 75 
> ohms
> but then I starting reading about losses when mismatch exists and thought
> maybe RG8 might be worthwhile.  Or will I be just as well off using the
> cheap 300 ohm foam twin lead that I now use.  I don't expect much noise 
> from
> things in the house but do know the current washer is a problem when it's 
> on
> - probably has more electronic controls than the older one that I had for
> years with mechanical switching.  My current system picks that up because
> the lead-in wire drapes over toward the laundry room.  But I can hear it 
> on
> a portable am radio operating on its internal antenna as well.  I usually
> lose interest in listening when the washing machine is running.
>
> The new house will have some foil-covered sheathing on the roof to lessen
> attic heating.  Does anyone have experience with this stuff with respect 
> to
> antennas nearby.  I don't think the metal volume is actually very great? 
> I
> was also considering putting the antenna below the roof in the attic since
> there's a long span over the garage and part of the house but wonder if 
> this
> sheathing might be a killer.  If there was a reliable way to connect to 
> it,
> perhaps it would make a good antenna itself.  That's about as big a can of
> worms as I can open,  thanks for any ideas.  Maybe I should just lay a 
> long
> wire on the ground !!  Dan.
>
>
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