[TenTec] proper caps for Omni V?--> Sanyo Oscon

[Joe Roberts]

I wrote
>>
>> Replacing the stock 1st IF sideband filter with the 2.7 INRAD is also a 
>> fabulous improvement which goes beyond mere bandwidth considerations. I 
>> have never seem this adequately explained, but the ears don't lie (and 
>> even if they do, how can you tell?). Others have commented on this 
>> effect, so it is not just me.

to which Jerry responded...

> You may like that added bandwidth out to 3 KHz audio but I prefer to
> roll it off at about 2100 Hz with the DSP in my receiver. I find it copy
> of voice signals is more comfortable with the narrower bandwidth.
> Perhaps that comes from years of using a Collins with a 2.1 KHz filter
> bandwidth.

Jerry:

I believe there is more than bandwidth going on here, given that I also 
tried the 2.1 INRAD 1st IF filter and that was "cleaner" sounding than 
the stock TT 2.4. Better definition and clarity with either INRAD over 
the TT stock job.

What I think I was hearing with the stock filter(no measurements to 
confirm) is an anomaly of some nature WITHIN the passband. As I put it 
above, it was a combination of "edgy" and "muffled". Whether phase 
anomaly, ringing, or amplitude variation, I can't say.

Since most SSB signals are less than 2.7 kc wide, one would assume that 
passband differences between 2.4 and 2.7 filter on an in-the-clear 
signal would be moot, no?

Also, 300hz wider really isn't *that* big of a difference. I think I 
have a grip on what that magnitude of change in selectivity should 
yield. There seems to be something else afoot here.


The strange thing is that the same specimen of TT 2.4 filter sounds "OK" 
in other radios. I have never figured this out.

Maybe I'm hallucinating but if so I have switched back and forth between 
the 2.4 and 2.7 in the Omni, weeks apart, and hallucinated in a similar 
manner every time!

I have read similar comments from other Omni V users on this list over 
the years, so maybe this is a mass hallucination!! ;o)

In any case, I am a fan of the wide INRAD filter. The 2.1 is real good too.

I eventually put the 2.1 INRAD in my Paragon II NAR position, which 
indeed sounds remarkably like a Collins with that filter installed. I 
used 75A4 and S-Line gear for many years. The way that sigs jump out 
with a good 2.1 filter when tuning around is a blast from the past.

73 Joe N5KAT