[Moon] All I want for Christmas...

[Hugh VA3TO]

Cathode bias cutoff for my amp is being controlled by a G3SEK Triode 
board which in turn is being keyed by the sequencer.
BTW, the sequencer timing is set for 100mS between each step.

73 de Hugh VA3TO


w2drz wrote:
> 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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>>>>
>>>>         
>>>       
>
>