Yes there is a difference. The 'common' lead is the correct one. The other one will 'work', but
you have to use a specific crystal switch position, with the other just any 'open' position works.
The 'other' lead bypasses the amplifier and connects the FS-4 RF to the feedback link of the
amplifier transformer. The key with either position is that the shield of the FS-4 cable must go to
the chassis, NOT the 'other' crystal pin.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>
[email protected] wrote:
I am curious too - if I am interfacing an FS-4 to an R4B (or even a C or an SPR-4) which pin on
the crystal socket do I plug into? The manual does indicate there is a difference between either
pin on the crystal socket - just plug it in and ground the outer shield.
Thanks
Steve KD2ED
In a message dated 10/6/2011 2:34:24 P.M. Eastern Daylight Time,
[email protected] writes:
Bob -
Not particularly difficult. You need about 2-3 V p-p from it, maybe less,
which means you may
need
a transistor, or possibly an MMIC. I'm not familiar with the IQPro, but
for this duty you'll
need
to cover from about 11.6 to 40.6 MHz in 500 khz steps. It would be more
convenient if you could
program the 500 kHz steps, but not necessary. If you plan to use it for
transmitting you'd
probably
need a low pass filter on the output, depending upon how clean your DDS is.
The FS-4 output is about 300 ohms, so your 50 ohm output should drive it
ok. The BAND oscillator
stage is configured as a common Base (grounded grid!) amplifier when you
select an 'empty'
crystal
socket and feed your RF to the 'common' lead that connect all of the
crystal sockets
together. The
shield of the RF cable goes to the chassis, NOT the 'other' crystal socket
pin.
Let us know what you come up with!
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>
Robert Fish wrote:
> Hi Guys,
>
> I have an IQPro VFO that I built for a Direct conversion receiver I am
building. It is a 9854
> based DDS VFO designed by Craig AA0ZZ. I have decided to go a different
route with the DC
receiver
> LO.
> That leaves me with a perfectly good VFO to find a use for. I thought
that maybe it would
work as
> a crystal eliminator to give me general coverage for my R-4C (and R-4B).
>
> What do you guys think, will this work? What levels and impedance do
those receivers look
for at
> the accessory crystal sockets? I don't mind a few birdies as long as I
know where they are and
> there aren't thousands of them.
>
> My first thought was; This is probably more difficult than it seems or I
would have heard about
> more people doing it.
>
> Thanks as always,
>
> Bob K6GGO
>
> _______________________________________________
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> [email protected]
> http://mailman.zerobeat.net/mailman/listinfo/drakelist
>
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