[AMPS] Re: full break in

[km1h@juno.com]

On Sun, 18 Apr 1999 11:41:22 -0700 "Radiodan W7RF" <RFpower@radiodan.com>
writes:
>
> Roy   K6XK said
>>  PS... I performed some rough estimates this morning on the life
>> expectancy
>> of a vacuum relay. If we operate 500 words per day, CW, I calculate 
>the
>> 2-million relay operations rating would be consumed in about one 
>year.
>> Ouch.
>
>PIN diodes don't like SWR and are severely derated with any value 
>above 1:1.
>They fail often in demanding service of high power and high SWR. Most 
>of us
>have some antenna on some band(s) that doesn't exhibit 1.5:1 or less 
>SWR.
>Either use a tuner to protect those delicate PIN diodes or risk an 
>early
>failure.
>Calculating exactly when PIN diodes fail has always been "just when 
>you
>needed them most", contesting, DXing for that rare one, etc.
>Vacuum relays on the other hand, can handle some really crummy loads 
>and
>keep on coming back for more. I use a HENRY 3K Premier and have 
>operated it
>into my 40M yagi which is tuned for CW. On phone the SWR can get up to 
>5:1
>at the top of the band. 3.5:1 on 12M & 17M as well (Force 12 C4XL).
>NO problem loading or high power QSK WITHOUT a tuner! No "timing" 
>problems
>or worries about the AGC of a radio allowing too much power on a first 
>spike
>either.
>Just tune and GO!
>
>I would suggest that "actual" incidence of vacuum relay replacement 
>from
>wearing out is much lower. We simply don't hear of them being replaced 
>very
>often.
>
>73, Dan Magro W7RF,


This might shock a few but I agree 100% Dan ! Been there done that.
During the DX Contest  big ice storm here a few years back the yagis
VSWR's were out of sight but as long as RF could be forced up the line
QSO's were made. Not once did the RJ1A even give a hint of discomfort.

It wasnt until 10AM the next morning that the ice started falling off.

BTW, Bob, KQ2M, who was the op won that DX contest. The PIN QSK ops shut
down and even with piss poor propagation he won.

73  Carl  KM1H



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