[Amps] Best source for Gigavac GH-1 ?

Larry Benko xxw0qe at comcast.net
Sun Nov 10 10:39:52 EST 2013


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.

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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