[TowerTalk] Remote switch

Martin Sole hs0zed at gmail.com
Fri Oct 25 13:03:11 EDT 2019


Adding a bit here, there are some simple ways to make a good switch 
using relays. Use two relays so the contacts are in series. Arrange the 
layout for good physical separation, a central common point with the 
ports arranged in a circle works good, especially with 2 relays. Okay at 
HF maybe less so at 50MHz and up. Even double pole relays with the 
contacts arranged in a double series arrangement can work okay. Open the 
relay, cut the wires and solder a bridge directly between the two 
contact pairs.

There are some relays that will give a much higher isolation than the 
typical average. These are super secret relays that nobody wants to 
share the part numbers for  ;)

Martin, HS0ZED




On 25/10/2019 23:56, Martin Sole wrote:
> That sounds like the difference between a mechanical switch and a 
> basic relay.
>
> Martin, HS0ZED
>
>
>
> On 25/10/2019 23:26, Steve London wrote:
>> Thanks for the tips on measuring isolation, Wes.
>>
>> Measured a few switches I had laying around. Old B&W round switch. 70 
>> dB @ 3.5 MHz, 60 db at 28 MHz. Not bad, considering. Array Solutions 
>> 2 antenna Stackmatch. 45 dB @ 14 MHz. Hmmm.
>>
>> 73,
>> Steve, N2IC
>> _______________________________________________
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>>
>>
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