Re: Bitx-40 DDS VFO


Hi Fernando
Thank you for your email
We have used the 8.192Mhz xtal in the IF filter with the same values you
can find in the original diagram.
This kind of xtal in my case are to close one of the other and the filter
are narrow enough to show a very good performance.
The VFO is working in a very low frequency, because we are substracting
IF-VFO to get the frequency work.
Now I added a new DDS using VFO-IF and work very good too in 40m.
In the final stage to have more RF power we are using the W6JL MOSFET
lineal amplifier with 6 toroid from the light saver bulb burned with only
Have a good day

2012/11/7 Fernando Krouwel <flky661@...>


Hi Juan Carlos, good morning:

I have some 8.192MHz xtals here, which I would like to use in a BITX
xtal filter.

Please, which capacitor values (input, mid and output) did you use in
the xtal filter for this new IF frequency?

73' s
Fernando - PY2FZU

On 11/05/2012 10:23 PM, Juan Carlos wrote:

Hi Fellows
We have completed a lot a Bitx-40 in Cuba using its own VFO in 40m
with the 8.192Mhz IF frequency using IF-VFO and we take off L5 because
is not neccessary to get the right tuning.
Now I am trying to add a DDS but working VFO-IF and with the same
configuration in the oscilator I can not find the right point and I
think now with the DDS I am in the USB.
Please some one can clarify me this problem And how to solve?
Thank you in advance
Jc WJ6C ex/CO6BG

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