Topband: Two wire beverage question

[ZR]

While I would never buy anything from DXE that I can do a whole lot cheaper 
Ive been running voltage down runs of CATV hardline up to 750' for Beverage 
switching for up to 22 years with no such problems.

Send those useless DXE boxes to me, I'll even pay postage..

Carl
KM1H


----- Original Message ----- 
From: "Herb Schoenbohm" <herbs at vitelcom.net>
To: <topband at contesting.com>
Sent: Friday, March 23, 2012 12:40 PM
Subject: Re: Topband: Two wire beverage question


> Ken,
>
> I would avoid any attempts to do relay switching by supplying voltage
> down a coax cable but rather use two coax runs.  The relay, blocking
> cap, diode and associated circuit in my case with two DXE boxes have
> deteriorate within less than a year to be useless, mostly due to
> electrolysis and zillions of ants attracted apparantly by the voltage or
> relay coil vibration when pulled in. (Yes I covered all the edges with
> silicon sealant)   DXE refuses to send me a print to repair the board
> for what reason I don't know, thus  making repair very difficult.   They
> worked well when I got them but are useless today.    Another
> disadvantage of having a blocking cap in the signal line is that you can
> not determine the coax run continuity through the windings of toroid
> back to the shack with a common VOM. This is an easy troubleshooting
> tool that is not possible via the DXE system.
>
> Herb, KV4FZ
>
>
>
>
>
> On 3/23/2012 11:10 AM, Kenneth Grimm wrote:
>> I'm in the process of building a new two wire beverage control box to
>> replace the one that Thor destroyed the other day.  Fortunately the coax
>> lead in was disconnected at the time!  The top of the box has not been
>> recovered and much of the contents vaporized.  The inside of the box has
>> lots of scorch marks...and not much else.  The reflection transformer, 
>> some
>> 580 feet away, appears to be unaffected as does the 450 ohm twin lead.
>>
>> I plan to do a PC board for the new control box and so I had a look at 
>> how
>> the DX Engineering box was laid out.  I also had a look at the board made
>> by RA6LBS.  Both of these boards appear to have an electrolytic capacitor
>> installed.  On both boards the electrolytic appears to be associated with
>> the direction switching relay.  None of the two wire beverage diagrams 
>> that
>> I have seen have such a cap and I wonder what its function is and how it 
>> is
>> connected in the circuit.  I am told that the value is 100 mfd @ 50 
>> volts.
>>
>> Apparently the cap isn't necessary, but since I have a few in my junk 
>> box,
>> this might be an opportunity to put one of them to use!
>>
>> 73,
>>
>
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
>
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