Continuing from N4ZR’s relay thread and Rob’s observation:
For low impedance (50 ohm ballpark) side switching, I went to Struthers Dunn
(now P&B) DPDT T92 relays with paralleled 30A contacts. I got a big boy
legal-limit amp and have been COMPLETELY happy with these at legal limit.
Several hundred thousand QSO's through these relays without a problem. These
are the "low impedance" side of my tuner switching.
Many vendors use PCB relays at legal limit “, and I’ve tried these, but I have
found these to never survive legal limit RTTY contesting. They may be OK at CW
or SSB duty cycles.
What I ended up using was much beefier relays. I went to Struthers Dunn (now
P&B) DPDT T92 relays with paralleled 30A contacts. I got a bigger legal-limit
amp and have been COMPLETEY happy with these at legal limit. Over a hundred
thousand QSO's through these new relays without a problem. These are the "low
impedance" side of my tuner switching.
Not relevant to my topband setup, but For the high-impedance (ladder line) side
of my switching, I use open-frame relays with the contacts pried a little
further apart than stock. Example part is the McMaster Carr 7384K14. N6RK
outlines the process of widening the contacts in the May 2009 QST Hints and
Kinks.
Tim N3QE
> On Dec 11, 2019, at 7:38 AM, Rob Atkinson <ranchorobbo@gmail.com> wrote:
>
> Actually, if you have a quarter wave driven element and you are
> disconnecting it at the feedpoint, your relay concern shouldn't be
> voltage so much as current. Fast switching and large contact surface
> is more important than voltage handling.
>
> 73
> Rob
> K5UJ
> _________________
> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
_________________
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
|