So I have done some more experimenting and have managed to get the BITX40v3 I modified for 80 M to also work on 160 m .
It requires a total of 1100 pf additional cap across each of : c2 ,c4 and c6 in the BPF . It is not exactly a perfect bandpass match , but it works.
The TX LPF again did not need any modifications to get approx 6 wts into a 160 m dipole with a tuner . I am hoping some one has some ideas on an easy way to roll off the LPF ?just past 2 Mhz .
For 80 or 160 M conversion , you have to replace L4 in the VFO to a 3 - 7 uh adjustable coil and remove c94 if it is installed.
If you can reprogram the raduino to the proper VFO freq range required , that will work also .
As I have an early version that I have been experimenting with for 80 M , I just changed out the L4 coil for the moment
?My plan is to build a dual band unit for 80 and 160 once the 2 Raduino's I ordered show up .?
I have posted some videos on Facebook BITX40v3 site?
73s from Buzz
