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Re: FT736r recieve gain variations?



Al, If you are using a bandpass filter on your transmit side, be sure you
don't have a notch appearing at this point.  Some of these filters look
tuned properly, but can exhibit some passband notches.  Check it again
after removing the filter from the feedline.

al lawler wrote:
> 
>   I've noticed that the recieve gain on my ft73r appears
> to take a severe nose-dive between 145 and 146 mhz
> (with the lowest reading right around 145.350 in the
> range of the ao-40 beacon... :^(
> 
>   I had originally noticed this effect with my drake
> converter, which was 250khz off in frequency, and
> attributed it to the drake,   but now my newly modified
> trans-system (which is on frequency) does a similar
> thing.  The "dead spot" occurs at the same 2 meter
> frequency, which would seem to rule out the converter,
> or a null in the antenna gain etc.
> 
> 
> 
>   With the antenna pointed at the daytime sky with
> the transystem in line (and a 24dbi bbq dish),  here
> are the no-signal white-noise s-meter readings I see
> as I  tune across the band on the ft736r.
> 
>   144 mhz -- S9
>   144.5   -- s9
>   145     -- s6.5
>   145.350 -- s0  (the noise gets louder at 145.400 mhz.)
>   145.5   -- s2
>   146     -- s6.5
>   145.6   -- s7
>   147.0   -- s7.5
>   147.5   -- s8
>   147.999 -- s8
> 
>   Can somebody with an FT736r do a similar experiment and
> let me know if they see the same type of 'dead spot'?
> (Prior to today, I've never tried to listen in that particular
> part of the band, so I don't know if this is normal for
> the rig or not...)
> 
>   THanks,
> 
>   -al
>   WB1BQE
> 
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-- 
73, Roy

Internet: w0sl@amsat.org
Home Page: http://home.swbell.net/rdwelch
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