Central Testing on 3935Khz

ukdxer · Post by **ukdxer** » Tue Sep 29, 2009 19:42 pm

Is Central Radio testing tonight (Tues) on 3930?

If so, audio is not better - in fact sounds worse than on Sunday.

Just noise....

Joe K · Post by **Joe K** » Tue Sep 29, 2009 21:41 pm

Hello ukdxer,

Yes it was Central testing, I was just trying to sus out what was going wrong with the transmitter. I have found the cause of the noise and distortion, its a problem with the PLL. Its the same design that I have used for our mw transmitter and that works fine. The only difference is the frequency is higher and I think I am pushing the frequency limits of the phase lock loop chip! I supose you dont have these problems when you use a crystal or VFO. I will order a PLL chip that works up to 25mhz and I think that will cure the problem (fingers crossed)

Thanks

Joe

RadioRamona · Post by **RadioRamona** » Thu Oct 01, 2009 22:03 pm

I can hear you now in the fades at this moment and strong at the uk remote receiver.

i suspect you use a VFO now?, because i noticed a litlle drifting.

Joe K · Post by **Joe K** » Thu Oct 01, 2009 22:37 pm

RadioRamona

Yes testing using a quickly constructed vfo to just to test the Transmitter PA stage. Hopefully besides the usual vfo drifting no strange noises mixed with carrier (or bad distortion)

Joe