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Re: [TenTec] Help selecting Paragon Inrad filters

To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Subject: Re: [TenTec] Help selecting Paragon Inrad filters
From: Ken Brown <ken.d.brown@hawaiiantel.net>
Reply-to: ken.d.brown@hawaiiantel.net, Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Sat, 19 Jul 2008 09:29:41 -1000
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>

> When I operate CW I usually run with a lower sidetone freq, say
> 500hz. When I operate SSB I would like to see a choice between
> 1.8khz and somewhere near 3.0khz. On CW, the 400 & 250 hz
> filters would be fine but which center freq do I choose?
Hi Ken,

The Paragon receives CW in USB, unlike the Omni VI which receives LSB 
CW. It appears to me that the BFO frequency used for USB and CW receive 
is 9.000 MHz. If I'm right about that, then you would want a 9.0005 MHz 
center frequency filter to get 500 Hz audio tone. I don't think you'll 
want to put a 400 Hz or 250 Hz BW filter in the 9 MHz IF, unless you 
want to make it a CW only radio.

I don't think you are going to be able to have it the way you  want, 
using 9 MHz IF filters, without some significant modification of the 
radio. You could have both of your SSB choices by replacing Y2 and Y3 , 
on the second mixer board, with 3.0 and 1.8 kHz filters,  but then you 
would lose the 6.0 kHz bandwidth capability (stock Y2 filter) for 
listening to AM. You could replace Y3 (stock 2.4 kHz) with a 3.0 kHz BW 
filter, and and put a 3.0 kHz BW filter in the 2.4 kHz slot in the 6.3 
MHz IF, then use the other 6.3 MHz filter selections for your narrower 
bandwidth listening.

It doesn't matter what the center frequency of the 6.3 MHz filters are 
(within reason) because you can shift the frequency with the PBT 
control. You could replace the 500 Hz and 250 Hz BW 6.3 MHz IF filters 
with 400 Hz and 250 Hz Inrad filters, and adjust PBT for whatever audio 
note you like.


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