[TowerTalk] Dow Key Series 71/72 -ID

Tue Dec 30 13:14:35 EST 2014

I have the 1970 spec sheet from Dow Key on this series. There are nine 
different coil voltages and the schematic is included in the data sheet 
that spells out the pin out on the control connector.
I can scan the data sheet and e_mail you a copy if you give me your 
e_mail address.
It's a great switch I have both the 71 and 72 in use since 1966.

Frank W9JCC
e_mail W9JCC at wi.rr.com

On 12/30/2014 11:00 AM, towertalk-request at contesting.com wrote:
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> Today's Topics:
>
>     1. Re: Arrestor placement (Gary Schafer)
>     2. Identity of DowKey relay (John King via TowerTalk)
>     3. 40/80 stub (Tom Osborne)
>     4. Re: 40/80 stub (Dave Hachadorian)
>     5. Re: Identity of DowKey relay (Jim Brown)
>     6. Re: Identity of DowKey relay (Jim Lux)
>     7. 275W EFJ Matchbox for sale (k7mks at comcast.net)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 29 Dec 2014 11:33:52 -0600
> From: "Gary Schafer" <garyschafer at largeriver.net>
> To: <towertalk at contesting.com>
> Subject: Re: [TowerTalk] Arrestor placement
> Message-ID: <5F5939907F3649F589CABEE9138D94CE at garyPC>
> Content-Type: text/plain;	charset="us-ascii"
>
> Part of the reason for the arrestor on the coax line is because the center
> conductor is going to have a voltage different from the shield.
>
> The tower and all of the lines coming down the tower share any strike
> current. Even if the center conductor is bonded to the shield at the top of
> the tower you will still end up with energy on the center conductor.
>
> Because of the high current on the shield during a strike,  the resistance
> of the shield allows voltage drop over the distance of the cable. Energy is
> induced onto the center conductor.
> Because the propagation time on the inside of the cable is slower than on
> the outside you end up with a voltage difference at the end of the cable
> between center and shield. For more information on this look up "transfer
> impedance".
>
> This center conductor voltage can be induced on the cable even if the cable
> is on the ground. Anywhere there is current on the shield some of the energy
> ends up on the center conductor.
> This is why you want the protector close to the shack. The length between
> the tower and the shack can allow the energy to be induced onto the center
> conductor.
> This current can come from the tower strike or ground currents from another
> direction.
>
> One other important thing that no one has mentioned, although most here
> know, is that your AC power must also be protected and bonded to your
> entrance panel where the coax suppressors are installed.
> You do not want any difference in potential between the AC power and your
> coax lines. The easiest way to accomplish this if your power panel is not
> close to your coax suppressor panel is to run an AC line (large extension
> cord is fine) over to the coax entrance panel. Install AC protectors on that
> line with them bonded to the coax panel.
> Feed all of your power and antennas from only that panel. This will insure
> that everything stays at the same potential. Of course include any phone
> lines, rotor cables etc the same way.
>
> 73
> Gary  K4FMX
>
>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Mon, 29 Dec 2014 11:46:53 -0800
> From: John King via TowerTalk <towertalk at contesting.com>
> To: towertalk at contesting.com
> Subject: [TowerTalk] Identity of DowKey relay
> Message-ID:
> 	<1419882413.37167.YahooMailBasic at web160301.mail.bf1.yahoo.com>
> Content-Type: text/plain; charset=us-ascii
>
> I have a REMOTE DoiwKey relay with the nomenclature P/N 71 on it. It has seven female connectors on it.  There are 6 connectors in a circle and 1 in the center which indicates to me that the feed line  connects via a PL-259 to the center connector and the relay switches through the 6 in the circle to select the desired output feed line.
>
> It has a round female multi pin  control receptical where the control attaches. I do not have the control or selector box so I have no idea as to voltage to operate. It appears to be a SUPER multi-coax selector switch.
>
> Is anyone familiar with this remote antenna selector switch? I need data regarding voltage required and a diagram   if I can get one.Your help will be greatly appreciated. 74, John, K5PGW
>
>
> ------------------------------
>
> Message: 3
> Date: Mon, 29 Dec 2014 13:23:44 -0800
> From: Tom Osborne <w7why at frontier.com>
> To: towertalk at contesting.com
> Subject: [TowerTalk] 40/80 stub
> Message-ID: <54A1C660.1020906 at frontier.com>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> Hi All
>
> It is possible to make a ~23' stub with a switch in the end to open and
> short for 20/40.  Can you do this with 40/80 by making an 80 meter stub
> and put a switch on the end like the 20/40? I've never seen this done.
>
> I have a 40/80 elevated vertical I'd like to put a stub on.  Thanks and 73
> Tom W7WHY
>
>
> ------------------------------
>
> Message: 4
> Date: Mon, 29 Dec 2014 14:41:39 -0700
> From: "Dave Hachadorian" <k6ll.dave at gmail.com>
> To: "reflector Towertalk" <towertalk at contesting.com>
> Subject: Re: [TowerTalk] 40/80 stub
> Message-ID: <8C79B933354A407BBF5C26898CCCE772 at Toshiba>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> 	reply-type=response
>
> I have done this at 100 watts, with a dinky little panel-mounted
> toggle switch.  You could probably use a wall switch or a relay
> at high power.  I have used a 3-way wall switch to make a
> 2-position antenna switch for high power.
>
> Dave Hachadorian, K6LL
> Yuma, AZ
>
>
> -----Original Message-----
> From: Tom Osborne
> Sent: Monday, December 29, 2014 2:23 PM
> To: towertalk at contesting.com
> Subject: [TowerTalk] 40/80 stub
>
> Hi All
>
> It is possible to make a ~23' stub with a switch in the end to
> open and
> short for 20/40.  Can you do this with 40/80 by making an 80
> meter stub
> and put a switch on the end like the 20/40? I've never seen this
> done.
>
> I have a 40/80 elevated vertical I'd like to put a stub on.
> Thanks and 73
> Tom W7WHY
> _______________________________________________
>
>
>
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>
> ------------------------------
>
> Message: 5
> Date: Mon, 29 Dec 2014 20:28:16 -0800
> From: Jim Brown <jim at audiosystemsgroup.com>
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] Identity of DowKey relay
> Message-ID: <54A229E0.6050904 at audiosystemsgroup.com>
> Content-Type: text/plain; charset=windows-1252; format=flowed
>
> I have one that comes close to that description that came from the junk
> box an SK. It's 120VAC.
>
> 73, Jim K9YC
>
> On Mon,12/29/2014 11:46 AM, John King via TowerTalk wrote:
>> I have a REMOTE DoiwKey relay with the nomenclature P/N 71 on it. It has seven female connectors on it.  There are 6 connectors in a circle and 1 in the center which indicates to me that the feed line  connects via a PL-259 to the center connector and the relay switches through the 6 in the circle to select the desired output feed line.
>>
>> It has a round female multi pin  control receptical where the control attaches. I do not have the control or selector box so I have no idea as to voltage to operate. It appears to be a SUPER multi-coax selector switch.
>>
>> Is anyone familiar with this remote antenna selector switch? I need data regarding voltage required and a diagram   if I can get one.Your help will be greatly appreciated. 74, John, K5PGW
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>
>
> ------------------------------
>
> Message: 6
> Date: Mon, 29 Dec 2014 20:43:02 -0800
> From: Jim Lux <jimlux at earthlink.net>
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] Identity of DowKey relay
> Message-ID: <54A22D56.2060906 at earthlink.net>
> Content-Type: text/plain; charset=windows-1252; format=flowed
>
> On 12/29/14 8:28 PM, Jim Brown wrote:
>> I have one that comes close to that description that came from the junk
>> box an SK. It's 120VAC.
>>
> I'd get a variac and slowly ramp the voltage up and see where it pulls in.
>
> The coils could be 12V, 24V, or 120V
>
>
>
>
>
> ------------------------------
>
> Message: 7
> Date: Tue, 30 Dec 2014 05:02:30 +0000 (UTC)
> From: k7mks at comcast.net
> To: towertalk <towertalk at contesting.com>
> Subject: [TowerTalk] 275W EFJ Matchbox for sale
> Message-ID:
> 	<1637810143.11473798.1419915750843.JavaMail.zimbra at comcast.net>
> Content-Type: text/plain; charset=utf-8
>
> Excess to my needs. 275W Johnson Match box w/o SWR meter/coupler. Cosmetically excellent. Decal on back of tuner is unblemished. Can provide photos. $85 + shpg from W WA. joe k7mks
>
>
> ------------------------------
>
> Subject: Digest Footer
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> ------------------------------
>
> End of TowerTalk Digest, Vol 144, Issue 66
> ******************************************
>