To: | towertalk@contesting.com |
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Subject: | Re: [TowerTalk] Siamese type Coaxial Cable with /4 wire needed. |
From: | "Joe Subich, W4TV" <lists@subich.com> |
Date: | Thu, 7 Jan 2016 10:15:13 -0500 |
List-post: | <towertalk@contesting.com">mailto:towertalk@contesting.com> |
Don, On 1/7/2016 9:53 AM, n8de@thepoint.net wrote: > Why the 4-wire control cable? The question specifically stated the need to control an Icom AH-4 tuner. The Icom tuners require +13.8V and ground (which can be supplied via a bias T) but they also require control lines "start" and "key" which can not be multiplexed onto the coaxial cable. One could possible use "siamese" coax plus single pair with a bias-T but the Icom tuners still require some individual control lines. *Unfortunately*, most siamese cable is 75 Ohm, not 50 Ohm. 73, ... Joe, W4TV On 1/7/2016 9:53 AM, n8de@thepoint.net wrote: Why the 4-wire control cable? You can use the coax for switching ... I invented the idea in the 70's... it's very much like what is in the ARRL Antenna Handbook (and the ARRL Handbook) ... similar switching is available from MFJ/Ameritron .. and was used by Drake and Heathkit years ago. Just need to build a small blocking circuit at each end of the coax. 73 Don N8DE Quoting jimlux <jimlux@earthlink.net>:On 1/7/16 4:23 AM, John K0CQW wrote:Looking for 8X type coax with 20 ga / 4 wire control Siamese together. approximately 50 feet.(OR variations)You might find some 75 ohm coax with wires as used in security/video/ ENG systems. Belden 9265 is RG59 + a shielded twisted pair. 9165 has 3 pairs. http://www.belden.com/techdatas/english/9265.pdf 1dB/100ft loss at 10 MHz There's also Belden CCTV cable RG6 + 18/2 For only 50 ft, I'd get some black heat shrink and use it to bundle your coax and control cable. something like a half inch of heat shrink every foot. Or, depending on the environment, just spiral black tape the length of it.Any sources ? Looking to get a OM on the the air in a assisted living. Working with a Icom AH-4.Are you fixed on the AH4? There are other remote tuners that can be powered/controlled via the coax.HAVE to make this a "CLEAN" installation. Specifically looking for the coax and control wire together. Thanks de John KØCQW _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk_______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk_______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk |
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