[Amps] Best source for Gigavac GH-1 ?

[Jim W7RY]

Larry's site has a small sample of transceiver measurements that show 
the amplifier relay close to RF flow start:

http://www.w0qe.com/amplifier_timing.html

A great resource when you want to think about QSK
73
Jim W7RY


On 11/10/2013 7:39 AM, Larry Benko wrote:
> Jim,
>
> Relay contacts stick only if hot switching is involved in some way. 
> There is no mechanism for them to stick (unless the internal contact 
> pivot wears down to nothing or the spring fails) that does not involve 
> current.  All relays are designed to be hot switched at some current 
> level (extremely low for many reed relays) and it is the job of the 
> relay manufacturer and product designed to get acceptable life out of 
> the chosen part.  Yada, yada, yada.......
>
> Now back to your issue.  I have looked at several transceivers with a 
> logic analyzer trying to determine the RF sequencing vs the key line 
> to the amp.  This value usually is controlled but I have seen on 
> several occasions where the microprocessor in the transceiver must be 
> busy or something where the timing is quite different.  This type of 
> stuff is hard to find and can be the cause of apparently random 
> failures.  Of course there are ways for an amp to guarantee no hot 
> switching but most do not spend the effort to do so.  Will probably 
> never know what caused your failures.  I do have an old Jennings RF1D 
> that I put 20 million cycles on it (via a tester) after I removed it 
> from a piece of equipment.  The operate and release times were 
> virtually the same before and after my tests. The tester hot switched 
> the contacts at level less than 1mA.
>
> 73,
> Larry, W0QE
>
>
> On 11/9/2013 11:59 PM, Jim Brown wrote:
>> On 11/9/2013 10:38 PM, Larry Benko wrote:
>>>
>>> What is failing on the relays?  Is it the coil opening up, the 
>>> contacts sticking, the receive side contact appearing open, or the 
>>> pivot getting sloppy and the contacts bouncing too much? 
>>
>> My symptoms have been sticky contacts, mostly RX, but also TX. Since 
>> I stopped doing QSK with my Titans (about 2007) I've yet to replace a 
>> relay.
>>
>> As to operations -- an active, aggressive contester will either CQ 
>> constantly and hopefully send an exchange every 20-40 seconds, or 
>> will search and pounce and do the same. I typically operate 24 hours 
>> for Sweepstakes, 24-30 hours for DX contests, 14-16 hours in RAC, 
>> IOTA, and WRTC contests and I work at least 12 such contests in a 
>> year. As Bill has shown, that's a LOT of relay operations if you're 
>> full QSK.
>>
>> As a competitive contester, it's not the cost of the relay or even 
>> the time to replace it, but simply that I don't want to have to lose 
>> 90-120 minutes of contest operating time while I do it. Being 
>> analytical about it, the relays I've replaced have mostly been those 
>> that came with the three 20-30 year old Titan 425s I bought used, so 
>> perhaps it's only my contesting that pushed them over the edge. :)
>>
>> 73, Jim K9YC
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