[Moon] All I want for Christmas...

[w2drz]

Hi,

Just recalled when I lost a DOWKEY "402" years ago
 (was $350.00 or so cost then),

We were going to run with RW1AW ??? think the was the station ?? off the
moon, many years ago,
well it was decided by the op that he wanted to use his rig as the
driver,

That is fine,
 well I used HV supply on and off to the 8877 sequenced as I have shown,

The driver was a bit hot on drive to the 8877,
 after the smoke cleared
 and we checked stuff it allowed the 8877 to output 3 KW to the coax,
?? not sure how much as it banged a 2.5 kw hard against the peg.

Ahhh, 4.5KV PA VOLTS @ over a amp of PA current as I recall the supply
then used!!!!!!

But as I had not used cathode bias cutoff, was wired with a jumper
disable for that and never wire to the sequencer, I depended on the
power supply to be off/on when switched by the PA sequencer turn on.

There was a bunch of ON/OFF chattering do to a wiring screw up with the
new rig, and flames came out of the relay, point was the PA was allowed
to output power as the supply was still up on voltage when the ON/OFF
sequencing occurred while the chattering went on......

I would hope you are not depending on the HV supply ON/OFF
 (as I just described)
 to keep the PA to be slow on power up,
 but using a cathode bias cutoff system so it must be switch on by the
sequencer and then make power normally...

By the way did work him off the moon as had a identical relay on my 432
PA and robbed that relay after all the smoke cleared out and fixed
things..


tom




Hugh VA3TO wrote:
> 
> Yes Tom, I have a VE2ZAZ programmable sequencer
> (http://ve2zaz.net/TR_Seq/Downloads/QST_032007_Sequencer_VE2ZAZ.pdf) in
> service to:
> 
> 1. switchover the relay
> 2. switch on the amp
> 3. key the radio
> 
> I forget how much delay I programmed in off the top of my head.
> 
> 73 de Hugh VA3TO
> 
> w2drz wrote:
> > Hugh,
> >
> > Big thing I see in your note is a BIG RF spike on TX??????
> >
> > Is the amp turn on in a sequence manner??
> > a 4 stage is to be 3rd stage of amp on then the driver system is number
> > 4 turn on, at that power would suggest a slow sequence, about 100 mill a
> > second between 4 stages.......
> >
> > If NOT you will need a bunch of new relays????????????
> >
> > tom
> >
> >
> >
> > Hugh VA3TO wrote:
> >
> >> ...is a new RF relay.
> >>
> >> On Friday evening I rushed home from work to participate in the DUBUS 2m
> >> CW event with hopes of working some new initials using my recently
> >> christened h/b 8877 amplifier.
> >> Something didn't seem right with the amp tuning and I quickly discovered
> >> that the SWR was terrible. A continuity check on the TX feedline in the
> >> shack showed a dead short. Today I climbed up the tower with my
> >> multimeter and quickly discovered that the relay was the culprit. Some
> >> slightly blurred photos below (too many Molsons' last night hihi !).
> >>
> >> http://home.cogeco.ca/~va3to/Relay/Relay1.jpg
> >> http://home.cogeco.ca/~va3to/Relay/Relay2.jpg
> >>
> >> I thought the Dow Key transfer relay was good for 1700W at 144MHz
> >> according to the datasheet but evidently not.
> >>
> >> So I'm looking for a replacement...doesn't have to be a transfer type.
> >> A SPDT would suffice but it must be capable of handing at least 1500W
> >> with a 12V or 28V coil.
> >> I can pay using Paypal. Anyone ?
> >>
> >> Merry Christmas & Happy New Year to all !
> >> Hugh VA3TO
> >>
> >> _______________________________________________
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> >> Moon at moonbounce.info
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> >>
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> >>
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> >>
> >
> >

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