>I'm on an email-only account and cannot read this NG so *please*
>eamil me any comments you might have regarding the following:
>Hi Folks. I've converted a RS TRC-415 cb to 10m (changed the 10.240 MHz
>xtal to a 10.635 so that now ch1 = 28.01 MHz, ch2 = 28.02, ...).
>My intention was to use this for CW, and I found a spot to splice
>the key into (between the xtal oscillator and the driver stages)
>that gives pretty clean keying.
>Now, how to add a BFO? If its rcvr had the traditional 455 kc IF,
>a BFO would be easy to install. But without a schematic I have
>no idea what this sythesized rig uses for an IF. Any ideas?
To check the IF of the equipment you need an RF signal generator capable
of coverage of from below 400 KHz to 30 MHz or so. Connect a piece of
wire to the output of the signal generator. With the CB receiver on (say
channel 20, preferably with covers off), sweep the generator over its
frequency range. If you hear a carrier try switching the channel change
knob to see if it disappears. If it does, keep tuning the generator. If
the carrier can be heard on all channels, you've found the IF (or a
subharmonic of it) with your signal generator. To check this, it's
probably a good idea to start with the sig gen on its highest frequency
and tune down - then you will pick up the first (high) IF first and the
second (low) IF next. Common IF freqs for CBs are 10.7, 7.8 & 455 kHz.
If you find that the carrier can be heard across two channels at settings
of the signal generator that are not harmonically related, your radio
probably has two or more IF. And, you can use the sig gen as a temporary
BFO until you finish building the permanent unit.
Phone: (06) 285 1004 (ah)
Amateur Radio: VK1PK
Home Page: http://www.pcug.org.au/~parkerp/
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