Some time ago I posted a problem I had with the RSC12 8 position Antenna
switch controller sending out phantom voltages to the switch causing the
extra relays to close by accident. Measuring voltages at none switched
ports using the 8X1 configuration demonstrated that their existed enough
voltage on unused ports to close extra relays inside the switch box at
the tower accidentally. Of course this cause all sorts of problems with
the amp protection circuit shuting down my Alpha 87A due to high VSWR.
This problem was consistent with three Ameritron switch boxes I
purchase. With the help of Joe, W4TV the problem seems to stem from
insufficient pass transistors cut off in the RSC12 controller. I sent
one of the units back to Starkville for evaluation and repair about four
months ago but so far no reply on how they intend to fix the problem
which Joe feels might be repaired by simply changing the values of the
voltage divider on the input of each pass transistor for a more dynamic
cut off.
Out of frustration I purchased a DX-Engineering 5KW remote antenna
switch model DXE-RR8B-HP which considerably was more rugged than the
Ameritron 2KW unit. Unfortunately the problem with the phantom voltages
was still taking place using the Ameritron RCS12C controller. Then I
though about using the RS-232 on this controller output to key some 5VDC
relays that in turn would sent out 13VDC to the correct ports on the
DX-Eng box. Unfortunately the RS-232 output is just a voltage high and
not enough current to close any miniature relay. Then it dawned on me
that what I needed was a simple "electronic relay brick" that is a
common item for remote control for many Arduino applications allowing
the control of high power devices with total isolation from the
switching sours. I went to eBay and quickly bought an 8X1 "brick" for
under $20. Installation is simple and the unit even has status lights
showing which relay is sending out the antenna switching voltage. In
fact such a device may be perfect for direct interface on contest
programs like N1MM. My antennas are automatically tied to my Icom which
drives the Ameritron RSC-12C controller. This allows me the flexibility
of an override to any band like 40 and 80 where I have both vertical and
horizontal antennas. This system also allows for far away remote
operation for NP2P by simply bringing up my Icom RS-BA1 on any computer
screen via Ultra-VNC and Yuri just points and click at the needed band
while operating the station via Remote Rig and a TS-2000 from an
apartment in Brooklyn.
I highly recomend the Arduino electronic relay brick interface which
lends itself perfectly to the 8X1 outputs available with the RCS-12
contoller along with the DX-Engineering 5KW antenna box at the tower.
Maybe DX-Eng will someday offer the Arduino power switching 8X1 unit in
their catalog as a perfect add on to their remote antenna switches so
they can bbe controlled by almost any radio without serious modifications.
Herb Schoenbohm, KV4FZ
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