[TenTec] INRAD 1st IF Filters

[Kenneth Stringham]

Dave,

The filter that you want to modify to improve you
audio reports is the filter immediately after the
balanced modulator. This is where the audio passband
is primarily set.

Concerning weak signal improvement, 300Hz decrease or
increase in bandwidth will make no discernable
difference. You would have to have a good set of test
equipment to notice the difference.

The additional filters in the system that reduce the
bandwidth are always in place for receive bandwidth
improvement not narrow the transmitter bandwidth. This
includes the situation where one installs a narrow SSB
filter such as the 1.8KHz filter in many radioes. The
transmitter passband will still be that of the first
filter in the train.

Ken



--- David Drake <drake at fullnet.com> wrote:

> John,
> Interesting.  I did play with the PBT control and
> don't remember seeing 
> any increase in the S meter.  I"ll look in my V
> manual again but don't 
> remember seeing any reference to the use of the
> narrow filter.   Guess I 
> could call TT.  I'm not sure this 2.8 is doing much
> for me.  Audio 
> reports don't seem to generate any Wow's, just
> "sounds the same OM, but 
> it may be band conditions".  What they are really
> saying is "Sounds the 
> same but I don't want to hurt your feelings".  I may
> send it back for a 
> 2.1 to put in the narrow and put the stock TT  2.4
> back in its original 
> position.
> I cannot tell any weak signal improvement or receive
> audio improvement 
> with this 2.8 Inrad.  Also, its doesn't seem that
> the carrier balance 
> needs adjusting, at least by my ear.
> Thanks, David Drake, Wd9cmd
> 
> ----- Original Message ----- 
> From: "John Rippey" <w3uls at 3n.net>
> To: <tentec at mailman.qth.net>
> Sent: Wednesday, September 29, 2004 3:05 PM
> Subject: [TenTec] INRAD 1st IF Filters
> 
> 
> > Dave,
> >
> > In my experience with OMNI VI, it is necessary to
> tweak the PBT knob 
> > quite carefully in order to avoid that 2 dB drop
> you are seeing with 
> > narrow filters. This is mentioned in the OMNI VI
> manual.
> >
> > Don't know if the same applies to a V.
> >
> > 73,
> > John, W3ULS
> >
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> > 
> 
> 
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