Bandpass Filter PCB
Low Pass Filter PCB And LSB /USB PCB
Our Australian friend Om Ross Bell VK3BEL is doing wonders with Bitx Version 3.
Ross likes keeping his Bitx simple and as original design, that is without a digital readout.
Ross has successfully made the Bitx for 3 Bands presently that are 20 and 40 and 80 Mt Bands, with modules provided by us for LSB/USB Change, which is a small pcb mounted above the Bitx Main Pcb BFO.
The second PCB is the Bandpass Filter, that is made for 2 Bands and additional PCB can be added for extra bands.
The third PCB is for the LPF also for 2 Bands.
We also have a PCB for using in Crystal Filter that can be used for Changing Filter For suitable use, ie CW.
We are publishing pictures and statement on Bitx Version 3 for 3 Bands use as per Ross Bell.
Suggestions And Comments as per OM Ross Bell VK3BEL
The bandpass coils were all wound with #39 wire on the same as the
20mtr coils supplied, a fiddly job.
for 40 mtrs 18 turns / 3 turns with the capacitance values being 82p
in parallel and 8.2p in series with the coils.
for 80 mtrs 21 turns / 4 turns with the capacitance values being 270p
in parallel and 22p in series with the coils.
For the VFO ,I multi tapped the tuning inductor for the required
2.7-3mhz ,4-4.5mhz and 6.2-6.5mhz, 75, 51 and about 28 turns for all
the bands.
To set up the bandpass filters, i connected them with coax to a
receiver and tuned the coils for maximum signal on the required bands,
only a small adjustment was needed after installing in the bitx.
It is great to have 3 bands, always a signal.....
great fun...
Thank you...
Hi,
I replaced all vfo caps with npo's , waxed the coils to the pcb and
also found the replacement of the zener with a 3 terminal regulator to
be much better frequency stability.I also placed a copper shield
around the vfo and the stability is good. I use the set all the time
and plan to go portable soon. all three bands are working well.
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Well we thank Ross Bell for his Bitx Version 3 operating on three bands and wish Ross all the best for his Bitx version 3 for other bands too. :) Cheers!
ALL DUE CREDIT TO OM TONY FROM UK FOR PROVIDING DESIGN FOR BITX ADD ON MODULES
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