Re: [TowerTalk] ? AMERITRON REMOTE COAX SWITCH

[Pete Smith <n4zr@contesting.com>]

At 12:22 AM 4/30/04, Bill VanAlstyne wrote:

> I own this switch -- the model equipped with UHF connectors. It is also
> available with N-type connectors. I've found that the switch remains 
> relatively
> "flat" well up past 50 MHz -- I feed my 6M yagi through one -- but somewhere
> above that, it starts to introduce a measurable but modest amount of line
> mismatch, loss, and increased SWR. This degradation just starts to be 
> noticeable
> at 144 MHz on my setup. I don't have 220 MHz capability, but at 440 MHz the
> switch is really unusable. Of course they don't claim it will operate at 
> 70 cm,
> but since the degradation is noticeable at 2M, I would have to be skeptical of
> Ameritron's claim of usability up to 250 MHz until I actually tried it 
> there and
> measured the degradation. Of course how much loss and SWR increase is 
> tolerable
> to someone is a subjective matter.
>
> As regards contact cleaning, the guy who probably designed this box is on this
> reflector, so he can chime in and address that question if he wants to. Relay
> contacts, however, if they are designed and aligned properly, are self-wiping.
> You shouldn't need to worry about cleaning them. (With any luck, we'll 
> find out
> if I'm right about that.)

The current MFJ catalog's write-up on the RCS-8V is a little 
confusing.  The first paragraph says you can control it with standard 
telephone wire, which is 4-conductor, while later on in the ad it says that 
it needs a 6-conductor cable.  This matters because I remember W8JI writing 
about a design change to using BCD control, to reduce the number of wires 
involved.  If this has been done on the RCS-8V, and if it uses simple relay 
decoding of the BCD signal, then the internal signal path must be quite 
different than in earlier models.  From the description, the RCS-10, which 
uses a 3 or 4 conductor control line to select one of 8 antennas, must use 
BCD control, but I don't know whether they use an IC to decode the signals 
or use the relays.  If Tom's reading this, perhaps he can clarify.

73, Pete N4ZR
The World HF Contest Station Database
was updated on April 26, 2004
2706 contest stations at
www.pvrc.org/WCSD/WCSDsearch.htm  

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