Hi Alex,
Your 35.304 MHz crystal sounds just right to me. It will probably oscillate at around 35.4 MHz in the SoftRock40 oscillator circuit. This would divide down to 8.85 MHz and the SoftRock would then cover from 8.826 to 8.874 MHz. This would give you IF passband tuning at your IF frequency -4 kHz to +44 kHz, more than required I would think.
The 35.208 MHz crystal would be a little low in frequency for this application.
One ham has reported great results using the SoftRock40 with his vintage Colins RX with a 455 kHz IF. Please let us all know how it works for you.
73,
Tony KB9YIG
toggle quoted message
Show quoted text
----- Original Message -----
From: "Alex, VE3NEA" <alshovk@...>
To: <softrock40@...>
Sent: Wednesday, September 28, 2005 2:16 PM
Subject: Re: [softrock40]
I ordered two crystals, 35.208 and 35.304 KHz, from Surplus Sales of
Nebraska () about a month ago, they are saying
the crystals will arrive in a few days. The idea is to make one of those
oscillate at 8817*4 KHz and to put SR40 inside my TS-570. The 8830 KHz IF
signal will be pulled from the socket for the extra filter, and SR40 will
replace the IF/AF part of the transceiver.
What is the best way of pulling the LO frequency 36 KHz down or 60 KHz up?
Is this possible at all? If not, I will have to switch to the 96 KHz
sampling rate and use the 35.208 KHz crystal at its nominal frequency. Of
course, 96 KHz is an overkill since the bandwidth of the roofing filter in
TS-570 is 14 KHz, according to the Service Manual.
73 Alex VE3NEA
Yahoo! Groups Links
