Ham Radio Power Supply

[tepres]

I'm asking this on behalf of a friend:
Why would there be a ceramic capacitor across the primary side of a transformer for a Ham Radio power supply? Would there be any harm in removing it?

Also, he is trying to increase the plate voltage on tubes after the rectifier. The power supply has a multi-tap primary. However, when he changes the primaty tap from 240V to 230V the rectifier output does not reflect a linear result. The output is much higher than expected. Perhaps the diodes are operating outside their linear region? Any theories?
Thanks.

 

[steve66]

Re: Ham Radio Power Supply

Why would there be a ceramic capacitor across the primary side of a transformer for a Ham Radio power supply?

I assume you mean on the primary side of a power supply transformer. My guess is that it is there to short out any high frequency noise that makes its way back into the power supply. It would keep that noise from getting into the 120V house wiring.

Would there be any harm in removing it?

Even if I'm wrong, it lives there for some reason.

Steve

 

[jimwalker]

Re: Ham Radio Power Supply

Do not remove it.It is indeed helping him to be a good neighbor.As to raising voltage that is up to him.Side affectects i am sure he knows about.Most try to get the extra millage from the antenna but perhaps he is maxed out.Wish him luck as i once was involved in lets just say the gap beteen 10 meter and 11 meter band at 500 watts.Was fun and worked many CQ and never busted.

 

[gudguyham]

Re: Ham Radio Power Supply

Hi, the cap is there for a reason, most likely to keep RF out of the AC line. It wont affect what he is trying to do (increase power) so LEAVE it there. AS far as the tap on the primary transformer. If he feeds 240 in on a 230 tap, he should see a bit more HV on the plate. However the difference would be slight however MORE. In the long range scheme of things, you WON'T notice any difference in signal strength on the other end. You have to DOUBLE your power output to get a 3db gain in signal strength. The few extra volts he will get will not be noticeable, but the transformer will run hotter. all and all its no big deal. If he wants to increase power go with a bigger tube and more drive. REMEMBER: The FCC limits power output to 1500 watts PEP. Any more is a violation of the rules. 73 W1QJ

 

[electricman2]

Re: Ham Radio Power Supply

Originally posted by jimwalker:
I once was involved in lets just say the gap beteen 10 meter and 11 meter band at 500 watts.Was fun and worked many CQ and never busted.

Me too. We worked from 27.370 to 27.400 untill they went to 40 channels. Operated SSB with Drake twins sometimes with a Heathkit 2KW.

 

[steve66]

Re: Ham Radio Power Supply

Heathkit

Too bad I was too young to have any money when they were around!!

Steve