The best way I've found to frequency calibrate my ubitx V3 is to use WSPR.? Based on all the reports you get, you can generally tune to within 10 HZ or so.?
On Tue, Mar 12, 2024 at 6:10?AM Evan Hand <
elhandjr@...> wrote:
Hi Ashok Das VU3KFK,
Here is a link to a tool to calculate RF filters.??
The one to choose depends on the desired outcome.? For your case of eliminating odd harmonics, any of the filters should work well.? I suggest a 5-pole Chebychev LPF should be more than enough.? You could get away with a 3-pole.
The uBitx uses a 9 pole 30 MHz filter in the line to and from the first mixer for both receive and transmit filtering.
As I stated in the prior post, you do not need a filter to use an OCXO at 10 MHz.? However, you do need attenuation, as the direct output would overwhelm and possibly destroy the input to the uBitx.
I hope this is clear.
73
Evan
AC9TU
