[TowerTalk] relays for remote ladder line switch

n0tt1 at juno.com n0tt1 at juno.com
Tue Sep 15 19:00:47 EDT 2015


Rik,

I have a pair of "surplus" open frame type of relays, the type that
was/is available on the surplus market and hamfests...has ceramic base,
DPDT contacts with wide conductors spaced ~3" apart....117AC coil that I
operate with ~70 VDC.  It is used to switch a Rhombic and 160m vertical
inside a box on a pole in the field.  I use 5W to 1500W of power.

One thing I learned about the relays is to protect the coils from
lightning surges.  I put a 1n4007 diode across the coil of each
relay, then feed the DC power via some small coils ~3/16" diam and
about 3/4" long wound on soda straws.  At the input (control side) of 
those coils, I place a NE-2 lamp to ground.   The coils give the 
NE-2's time to operate.  They turn black on the inside but 
they still seem to work just fine, but I replace those as needed (not
very often).

That setup has been trouble free for many years.  Yes, you can
use other types of protectors, but this has worked for me and the
cost was next to nothing.

I don't need static drain though resistors...my OW feedlines
are at DC ground via Baluns/Bal-Bals.

Hope that helps!

73,
Charlie, N0TT


On Mon, 14 Sep 2015 21:51:27 -0400 Rik van Riel <riel at surriel.com>
writes:
> Hello,
> 
> I am considering building a remote ladder line switch using 
> W199X-12
> relays, which are open frame DPDT with 1600V breakdown voltage 
> between
> open contacts, 2200V between poles and coil/contact.
> 
> I run with 100W power.
> 
> Does anybody have opinions on relays like those, experience with 
> them,
> or good experiences with other relays that you think I should
> consider instead?
> 
> I am looking at switching between two lazy H antennas (one 
> east/west,
> the other north/south) and maybe some doublets for lower bands.
> 
> The plan is to have each antenna switched either to a 4:1 balun, or
> to ground. Would it make more sense to leave the unused antennas
> ungrounded, or discharge static through 1M resistors?
> 
> thank you,
> 
> Rik AB1KW
> -- 
> All rights reversed.
> _______________________________________________
> 
> 
> 
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