It looks like everyone on this thread has top posted so I will just so
it continues to make sense. I did fix some of the broken formatting.

There is no problem laying the wire on the roof as long as it not near
any significantly long conductors. The impedance of the wire will be a
little lower than if it was hanging in mid air. The impedance of the
wire will drop much lower if it and the roof are wet, which will not
present a problem for receiving.

I would not use this as a transmitting antenna. It is a worse situation
when the roof is wet but even dry you are heating your roof with the RF
energy and this could start a fire if enough power is used.

In article ,
"CW" wrote:

You are quite right to question this. I have an antenna wire laying
directly on my roof. It's been there for over ten years and works as
well as the one I have in the back yard that's totally suspended. The
one on the roof is bare wire. I have used it for transmitting where
it also works fine, as long as it's not raining. In wet whether, the
SWR goes nuts but this would not be of any concern for receiving. You
are right about the house electrical wire. Thousands of ham antennas
have been made from it.

"H Davis" wrote in message
...
First, my thanks to Laura for asking a question that guys probably
wouldn't ask anymore than we would ask directions if lost. In both
cases we seem to be satisfied with wandering around.

Also, once again thanks to Joe for a somewhat complete answer to
Laura's question. (I'd love to get Joe over here for a long
conversation and just pick his brain for a few hours.) But I would
like an even more complete answer. Joe and others seem to feel that
you can't just lay a wire on your roof and hold it down somehow and
still get better reception that you get with the whip indoors. I'm
thinking you aren't satisfied with that answer. If you are, I
apologize. I'm not satisfied.

I've heard all kinds of people suggest that you can tack a wire to
the fence in your backyard and run a wire to your radio and get
decent reception or maybe just better reception. "Better reception
than what?", you ask? Good point. I guess I don't recall what the
alternative was for sure, but I think it was one of us neophytes
trying to get away from the whip again. And I haven't heard it just
once; I've heard it many times. Did they not actually mean tack it
to the fence? Did they really mean use stand-offs and attach it to
the fence. I don't think so, because most asking the question were
trying to find a way to hide the antenna from the neighbors or the
homeowners association.

I've heard others say they live out in the boonies and have laid
1000 feet of long wire on the ground and obtained terrific
reception. (I suppose a thousand feet of any kind of wire is bound
to receive something!) This seems very much like laying a wire on
the roof of one's house with one major difference: out there in the
boonies you would have less interference from the junk most of us
have in our homes and those next door to us.

Finally, I assume Laura was talking about laying insulated wire on
her roof to improve reception. I'm not sure that bare wire would be
a no-no (heck, I'm new to this stuff, too), but I've heard the type
of wire doesn't really make that much difference (within reason). I
suspect this large roll of #14 solid, insulated wire used to wire
homes will work just as well as most and better than some.

Then we have that connection thing. The guys who have been into
this hobby for a while assume we all know how and where to connect
the downlead to the main antenna wire. My head spins with all of
the detail, but its kind of fun searching for answers ....
especially when you have a bunch of people who you can drag them
out of.

All I'm sure of is that the Wellbrook is in my future.

Harlan

"Joe Analssandrini" wrote in message
oups.com...
Hello Laura,

The idea of walking around your area (and the roof) with your
radio in hand to see if interference is greater or lesser at
various locations is sound. See if you can find a place which is
relatively noise-free. I'm afraid a length of wire just lain on
the roof will probably be unsatisfactory; it should be raised
much higher and must not touch anything. It should be attached to
ceramic (or similar) insulators and those insulators affixed to
supports, with suitable strain-relief. You can use coaxial cable
(RG-6 or RG-8) as a lead-in, or you can even try a twin-lead (300
Ohm) wire and terminate that in a 3.5 mm plug. If you do use
coax, I have found that Radio Shack does indeed sell adapters for
attaching it to your radio. I have used a BNC connector at the
end of coax, then a BNC to RCA adapter, and finally an RCA to 3.5
mm plug adapter to connect an outdoor antenna to a portable radio
(I did this years ago when I was able to have an outdoor antenna;
it worked just fine.) I have done something similar to allow my
Wellbrook antenna to be used with my Sony ICF-SW7600GR.

If, however, you find that in your location there is nowhere
without electrical noise, you've got problems.

Are those restaurant ventilators ever turned off, perhaps in the
middle of the night? If you try your radio then and find no
interference, you've found its source.

If those machines are indeed the cause of your interference, the
only type of antenna which can overcome that (to a greater or
lesser extent) is a balanced loop design, such as the Wellbrook,
and, as you know, they are expensive (but well-worth the money if
you can afford them). What you'll spend or do depends just how
serious you are about short wave listening.

If you find that placing your radio (using its whip) near a
window on the side of your house farthest away from the
ventilators results in lower noise levels, you might try an AOR
WL500 Window Loop Antenna which can be mounted in that window. It
is a loop of unbalanced design, according to PASSPORT, but may
help reduce some local electrical noise. In my case, I tried it
before I bought the Wellbrook ALA 330S and found it to be a great
help in my location, better than any other antenna I had
previously tried (I still use it with my Satellit 800), and it is
a great match for a portable radio (the Sony AN-LP1 is also a
good antenna for portables, but, in my experience, does not
reduce local electrical noise at all). It terminates in a BNC so
the Radio Shack adapters I mentioned above will easily adapt that
antenna to your radio. It may be worth a try though it, too, is
expensive and, frankly, is no match for the Wellbrook. If the
WL500 works fairly well, then the Wellbrook will work very well.

I hope that is of some help to you. Some of the other posts here
also have good ideas. Antennas are "scientifically" designed. But
"science" is no good at all when it comes to determining what
will work at a specific location. Only trial and error will tell
you that.

All the best,

Joe

laura fairhead wrote:
Hi,

Can Joe or anyone else explain to me a few things; I am trying
to set up a antenna on the roof as reception is really bad using
the indoor whip (lots of interference I live next door to a
restaurant ventilator farm and I think that may be a problem).
Anyway I am thinking of getting a length of wire and just laying
it on top of the roof under a couple of bricks to stop it
getting blown around. The thing I don't get is the connection
down the side of the house - I need to use a different cable
yes?

I have heard people specify a length of "radio coax" is suitable
but I do not understand how this could be any use without the
shielding being grounded - could someone explain?

My roberts R861 has a minijack anntena input - which has 2
connections on the plug - are they both used or is only one? If
I use a thick cable to run into the house would I need any
special attention to connect that to the minijack?

What sort of length wire should I use on the roof, is it just a
case of the longer the better?

Thanks in advance for any advice

bestwishes laura


I have never owned a Sangean ATS 909 nor do I know anyone who
does. According to PASSPORT TO WORLD BAND RADIO, the
Sangean/Roberts works BEST off its AC adapter as it "eats"
batteries. An external antenna is necessary also, as it lacks
sensitivity with its whip (according to them).

A long wire, or loop antenna, mounted on your roof would be
ideal. Try buying a length of insulated wire, two ceramic or
equivalent stand-off insulators (to isolate the antenna from
whatever support you use) and some lead-in wire; attach the
appropriate plug to the lead-in to attach to the radio and
you're in business. No separate ground is necessary, but make
sure you DISCONNECT the antenna whenever the radio is not in
use and, especially, during local thunderstorms. (NEVER use
ANY electronic appliance during a thunderstorm; storms only
last a half-hour or so.)

Do NOT let your antenna proper or the lead-in touch anything
metallic; that will degrade the signal.

--
echo |sed 's/\(.\)\(.\)/\2\1/g'


--
Telamon
Ventura, California