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Re: [Amps] Experience with Heart Pacemakers?

Subject: Re: [Amps] Experience with Heart Pacemakers?
From: Jim Brown <>
Date: Sat, 02 Aug 2014 10:49:17 -0700
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On 8/2/2014 10:28 AM, George wrote:
What Pacemakers do best with most amps?

I know nothing about Pacemakers or their RF susceptibility, but I do know a bit about RFI. As far as I know, there are two issues. One is the leakage magnetic flux from the power transformer. The other is radiated RF. Unless the amp is a poorly shielded POS, all the RF gets radiated by your antennas, with some possible leakage from el-cheapo coax and connectors, and connectors poorly installed.

So the key issues are:

1) locate the power supply as far from where you will operate as possible. This may mean using a different power amp.

2) eliminate the use of any antennas that put a lot of RF in your shack. This generally means use only well-behaved beams and dipoles fed with coax, again as far from the shack as practical.

3) go through EVERYTHING in the RF path between your power amp and your antennas and make sure that it is well shielded, all the coax has a beefy copper braid shield, that all connectors are first quality Amphenols, all are properly installed, and there are no el-cheapo junk connectors, barrels, adapters, etc. in line.

4) study the construction of your power amp to verify that it is, indeed, well shielded. Are all cables either shielded or properly bypassed? Do shields go directly to the chassis where they enter the amp? (They must for shielding to work).

5) Find out from the manufacturer of the pacemaker the specific range of frequencies to which it has sensitivity.

73, Jim K9YC
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