Subject: Re: Another (FM) antenna question
X-Newsreader: Forte Agent 1.92/32.572
Date: Sun, 17 Nov 2002 14:10:54 -0500
NNTP-Posting-Date: Sun, 17 Nov 2002 14:10:58 EST
Organization: Bell Sympatico
I have red all the six suggestions to fix your problem.
All of them have merit and I am familiar with all .
You don't mention the relative position to you , of the antennae of
the 92.5 CFRQ ( Mont Royal) and 93.3 ( ? ) .The only one I can locate
in Quebec is in Quebec City (CJMF).
If they are in line with your location, forget the directional
Just tell us your's and the location of the two other stations before
we go on and on .
Also. Do you have a clear path to the transmitting antenna of the 93.3
station ? Also to Mont Royal ?
A good tuner connected to a fixed 5 elements antenna pointed to
Burlington from Pointe-Claire doesn-te receive 93.3. No surprise
since your location is probably very different.
On Sun, 17 Nov 2002 14:17:22 +0000 (UTC), Martin Griffith
>On Sun, 17 Nov 2002 07:11:02 GMT, "theother_bob"
>>I have recently aquired an old (I'm guessing late 50's or early 60's)
>>Packard Bell stereophonic console, model# RPC-17, Tuner 7TU-4. It's an old
>>tube job, and we've been enjoying it, but it won't pick up our favorite
>>station (93.3 MHz) because it's drowned out by the nearby 92.5MHz broadcast.
>>Is it possible to either boost the desired frequency or filter out the
>>undesirable? (without damaging the tuner)
>>theother_bob at yahoo...
>>P.S. How can I figure out when it was made?
>Coaxial Stub Filters
>A simple piece of coaxial cable cut to a quarter-wavelength can be
>used as a filter.
>You simply install a "tee" connector in your feedline, with the radio
>connected to one port,
>your antenna connected to the second port, and the coaxial cable
>"filter" (or "stub") connected
> to the third port. The trick is to cut the "stub" to exactly the
>right length. What
>you want to do is tune it to "short out" a specific frequency, such as
>that of an offending pager.
>I tuned one using an ICOM R7000 receiver, which has an excellent
>S-meter. First, I cut the
>intended filter somewhat longer than necessary. When calculating how
>piece to start with, simply divide the frequency (in Mhz) you want to
>"kill" into 2952.72,
> then multiply by the velocity factor of the coaxial cable you are
>using. (Most coax
>will be in the range of, say, 0.66 to 0.75). Then ADD a few inches, to
>be safe. For example,
> if I want to "kill" a pager which operates at 152.2 Mhz, I divide
>152.2 to get 19.4 inches. I multiply this by the velocity factor of
>0.66 to get 12.8 inches.
> The final filter will probably end up near this length once it has
>been correctly cut to
>size. Then, I ADD about two inches for safe measure.
>Next, I tune the R7000 to 152.2 Mhz, where a pager is putting out a
>30db over S9 signal.
>I place a "tee" connector in the antenna line at the back of the
>receiver, and attach
>the stub coax to one port. Then, watching the S-meter, I begin to cut
>the coax stub down.
>As the stub gets shorter, the S-meter will begin to drop, showing that
>indeed notching out the pager frequency. As you get nearer the exact
>frequency you will
> find that even a 1/16th of an inch will make a difference in signal
>strength, so be
>very careful and work slowly. If the S-meter starts going back up, you
>went too far.
> (OK, I did trim too much the first time I tried this, but the second
>one I cut was better).
>The final length came out to be 12.5 inches.
>What you will end up with is a filter that will knock about 35 db off
>that pager signal.
>Back in the 2-meter ham band, you will also see some attenuation,
>perhaps as much as
>20 db, depending on the quality of the coax you use, but you will also
>have cut down the
> intermod from the pagers significantly.
>Besides, it doesn't cost much, and it's a start at eliminating pager
>intermod. You can
> also use this type of filter to cut down other problem stations, such
>as major FM
>Help Fight Continental Drift!