Jim Brown wrote:
> On Sun, 10 May 2009 20:18:48 -0400, john@kk9a.com wrote:
>
>> I would be more concerned about whether the SteppIR will work properly
>> with that long of a run.
>
> Hi John,
>
> Thanks. I'm concerned too. FWIW, I am disgusted with the mfrs of all of these
> products, including SteppIR, for not publishing specifications for what is
> essentially a simple Ohm's law problem that all of their customers need to
> solve when doing due diligence. It is a very simple matter to specify the
> currents involved, the output of the controller, any adjustment that is built
> into the controller, and the IR drop that can be tolerated. Starting current?
>
> Fine. Specify it.
>
> I'm told that SteppIR cable is paired, but there's no indication of which
> conductors are pairs. In fact, if I wanted to order my own #18 rather than
> use
> their #22, I wouldn't know that from reading their documentation. BTW -- if
> their cable is a foil shield with drain wire, that drain wire can couple RF
> shield current onto the signal pair by a mechanism called Shield-Current-
> Induced Noise.
>
> Ohms Law still works. Give us the data on the product so we can use it!
>
that's the difference between amateur radio (essentially consumer) gear
and professional. Amateur gear makes the assumption that you're going
to plug and play, and not do any engineering.
Complicated by the plethora of products in the amateur market that are
essentially commercialized versions of something someone built from
parts they had laying around or were able to find cheap at a hamfest or
surplus. Again, not much engineering or analysis went into it, more of
a "try it and see if it works,ok, ship it"
Interesting indicator: very few things sold into the ham market have UL
listing.
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