>
>
>: From: Richard <2@mail.vcnet.com>
>: Ä If the SB-220 is powered from a stiff 240V source, it's
>: hard on the contacts -- but not as hard as if a TL-922 is
>: powered from a stiff source.
>-
>why would it be harder on the switch contacts..?
? The 922 HV transformer has lower R, so there is more inrush I.
>-
>>I'm using a modified version of your basic design. Never
>>had an amplifier "go poof" with your or my suppressors
>>on board.
>-
>: Ä I have. Not enough L-supp will do it. Glitch protection
>: is not a bad idea. In hard cases, an exorcism may be
>: unavoidable.
>-
>What is an exorcism when applied to an SB-220?
? This gets pretty complex, however, briefly, you obtain a prayercloth
with the callsign of the station embroidered in >3" characters. The
thread used in the embroidry must be black - no sustitutions. And I
don't know why. Be absolutely sure that the
FCC license has not expired or is about to expire. Make a generous
contribution to a well-known TV and/or radio evangelist such as Jimmy
Swaggert, Pat Robertson, Oral Roberts, Ernest Angely, on and on, When
your cancelled cheque is in hand, glue it in the upper left hand corner
of the prayercloth with high-temp (red) silicone rubber. The rest of
what's needed can pretty much be seen in the movie *The Exorcist*.
Having a copy on hand in the shack is not a bad idea, especially if your
amp has ever had a bandswitch that was hellishly burned up by some
mysterious force of electronic evil. The rest of the stuff gets pretty
weird so we'd better get into that on e.mail, or the telephone.
>-
>>3. the high speed switching mod... [snip]
>-
>: Ä The original relay is too noisy for me. How do
>: you keep it from hot switching with a FT-1000D?
>-
>I remove and replace the FT-1000D with the radio I
>prefer to operate. I don't have a Yaesu HF radio.
>-
? So you use a slower T-R / R-T radio? How many mS?
>Radios that put out large unwanted RF pulses at
>the start of each transmission should be fixed.
? This problem is not due to ALC overshoot. It is R-T transition time.
Pushing the PTT button on a newer design radio can result in only a 5mS
delay before RF starts showing up at the amp input. If the amp's relays
are slower, they will hotswitch the RF.
>If the mfgr places their head in the sand, time to
>go with someone else.
>-
? The problem is the amplifier relays' lack of switching speed.
Faulting the radio is unjust. The fault lies with the 30+ year old
design of the amp.
Cheers, Skipp
- R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
www.vcnet.com/measures.
end
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