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.
--
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