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RE: Re: AM antenna switch for 5kW ?
To: "'CRTech'" <crtech@crtech.org>
Subject: RE: Re: AM antenna switch for 5kW ?
From: "Bill Hurne" <billhurne@pilgrimradio.com>
Date: Mon, 14 May 2018 10:53:25 -0700
Content-language: en-us
In-reply-to: <alpine.WNT.2.10.1805121115410.3300@Lyle-Dell-D630>
References: <alpine.WNT.2.10.1805111649050.3300@Lyle-Dell-D630> <259A7239-C5DF-44A0-8432-9AA6580D3D10@bu.edu> <alpine.WNT.2.10.1805121115410.3300@Lyle-Dell-D630>
Thread-index: AQKP1CNg2gVxxVD9liI01aPPaosIUAKWH3WrAayec9eilZXpUA==
With the tower only a couple hundred feet away it would be a very
significant source of RFI unless the shipping container if very well
shielded.   I would expect more RF from the tower than from a hole in the
transmitter.   At only 200 feet and 5KW the field strength off the tower is
probably several volts per meter.   Learned this when I maintained a studio
in a converted metal mobile home only 200 feet from the 5KW AM tower.  RFI
was very significant.


-----Original Message-----
From: lylehenry@fastmail.fm@mail.messagingengine.com
[mailto:lylehenry@fastmail.fm@mail.messagingengine.com] On Behalf Of RADIO
Sent: Saturday, May 12, 2018 9:36 PM
To: Pubtech
Cc: CRTech
Subject: [CRTech] Re: [Pubtech] AM antenna switch for 5kW ?

Thank you Michael, Jim, Kevin, and Ira for your comments today.

As hinted in my request below, I'm inclined toward coax with 7/16" DIN 
connectors and being RF tight in the transmitter shack (an insulated 
shipping container).  Reason being there will be a computer or two in 
there along with other potentially sensitive equipment.  There's already 
too much RF floating around from the old MW-5 transmitter where the coax 
runs through a hole in the cabinet to terminals inside the rig.  The 
tower is a couple hundred feet away with the ATU next to it.  Though the 
MW-5 has been a workhorse, it is available for parts.

> On May 11, 2018, at 8:21 PM, RADIO DOCTOR <lylehenry@fastmail.fm> wrote:
>> What remote control switches are being used for AM nowadays? 
>> Shielded for coax or open relay(s) on a panel/board?  Controllers? 
>> Automatic?
>> 4 Port would be nice so dummy load would be connected to the
>>   transmitter that's not on the air.
>> The transmission line is a 1/2" late 1980's version of the current 
>> 1/2" CableWave (RFS) LCF12-50J.
>> What's best for jumpers?  Should I bother with connectors or just 
>> wire it up?  Transmitter will probably be 7/8" EIA output, but DIN 
>> connectors might be nice for hooking everything together.  Is there a 
>> 7/8" EIA to appropriate size DIN adapter.  I've never used DIN 
>> connectors anywhere.
>> Being an FM Guy, I've rarely dealt with real AM.  Always tried to 
>> keep AM at least 50 dB down :)
>> Thanks mucho for your comments and suggestions.  ...Lyle

FMeXtra digital SCA systems - encoders and receivers
SCA/FM/FMeXtra radios: fixed & tunable-wood cases-nice sound
Sidekick SCA generators - 67/92kHz-checked and calibrated
   Lyle Henry, CPBE  THE RADIO DOCTOR  K9DKW  Los Angeles, CA
SCA Consultant:  Brazil, China, India, Mexico, Taiwan, SE Asia
        323-660-4690 Home/Office     213-880-4690 Mobile

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Follow-Ups: Re: Re: AM antenna switch for 5kW ?
(Lamar Owen <lowen@pari.edu>, 15 May 2018 05:21:54 -0000)
References: AM antenna switch for 5kW ?
(RADIO DOCTOR <lylehenry@fastmail.fm>, 12 May 2018 00:20:15 -0000)
Re: AM antenna switch for 5kW ?
(RADIO DOCTOR <lylehenry@fastmail.fm>, 13 May 2018 04:35:57 -0000)
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