Joe wrote:
The distortion is acceptable at 2.5Khz deviation, but not at 3Khz. I have had the 144Mhz and 220Mhz versions of this board and never had this problem.
As you said earlier Joe, it's the multiplication factor that is killing you, with this type of phase modulator.
I have never tried my FM modification on a 6M TA-51. I do however use it on UHF where the FM modulator replaces the phase modulator totally. I know I advertise that my FM mod is only for PL generation , but if driven from a good clipper/filter, like the AP-50, you can use it on the entire voice/pl range.
It may be difficult to FM a crystal far enough to get 5K of totally undistorted audio from a Hamtronics 6M TA-51, but I'd try it..... Use a good varactor.
http://www.repeater-builder.com/hamtronics/ta-51pl_mod.html http://www.repeater-builder.com/products/ap-50.html Kevin
