[TenTec] TenTec OMNI V FM'ing any ideas?

[MW0CDO]

Hi readers.

I have just written TT regarding my Omni V which is FM'ing, and received =
the following reply:

Q:
"I have also found that the radio is FM'ing on TX, the problem being =
worse on the lower bands 160/80m where it FM's approx 500Hz between min =
and max RF out. I don't have a TEN-TEC PSU, but the unit in use is =
substantial and can supply 25A continuously and is RF hardened..other =
radios work fine with it.=20
The PSU exhibits approx 60mV change in output voltage when in tune mode =
and varying the RF out from min to max into a dummy load or real =
antenna.
Any pointers on the problem?"

A:

The FM is probably caused by the high ripple (60 mv) from the power =
supply. The supply should have less than 10 mv of ripple.



I have not responded to TT regarding this, thought I'd ask here first.

Has anyone else experienced the same problem?

As stated above, the PSU output voltage does droop by 50-60mV when the =
radio is in tune mode and the RF output is wound right up. There is very =
little hum/noise/ripple on the PSU output..in the order of 15mV P-P of =
junk is observable on the 'scope.

Surely the radio shouldn't be this sensitive to small voltage drops etc? =
What about those that use it mobile powered from the car electrical =
system, not usually the quietest or most stable supply?

All input appreciated!

And yes, I am going to try a car battery in place of the PSU.

I haven't measured the voltage drop down the TT supplied power cable, =
but I'd bet it's more than 10mV at 18+ amps at full power!

73 all.. Paul MW0CDO



--- StripMime Report -- processed MIME parts ---
multipart/alternative
  text/plain (text body -- kept)
  text/html
---