[TowerTalk] 6m QRO 2 Position Manual Antenna/Coax Switch

[John Simmons]

The spec on switches few look at is- isolation. This isn't terribly 
important if you are switching antennas for a transceiver. It IS 
terribly important if you are switching radios between an antenna- or 
even more so if you are using an amp! Two relays in series will give you 
up to 80 dB.

If you are using an amp and switching to different antennas.... if the 
antennas are on the same band that you are operating on, what is the 
effect? If the switch has poor isolation then some of your transmitting 
power will be radiated on the unselected antenna(s). Interesting thought.

-de John NI0K

Jim Brown wrote on 7/22/2020 6:50 PM:
> On 7/22/2020 10:03 AM, Wes wrote:
>> I have not looked inside one of their switches, but based on 
>> examination of some of their surge protectors, I would not recommend 
>> Alpha Delta.
>
> I've used Alpha Delta switches for years,all 1x4s, mostly before 
> replacing them with good coax relays and relay-switched boxes, but 
> also on portable setups like FD and CQP. I HAVE looked inside, since I 
> had one that was bad. It wasn't broken, it was MADE that way, with a 
> part missing so that there was no way that position #4 was going to 
> work. So much for final test. Electrically they're fine. The 1x2's are 
> made the same way.
>
> I also have a few 1x2 Daiwa switches that seem pretty good. I haven't 
> measured any of them, but their mechanical construction of all of 
> these switches suggests that crosstalk/leakage should be very good.
>
> The only other Alpha Delta product I've seen was their dipole 
> insulator, which includes a GDT. When it fries (shorted) on a 
> lightning discharge or too much TX power, the antenna must be lowered 
> to correct the problem. That can be a real PITA, depending on how the 
> dipole is rigged. And, IMO, it's the wrong place for a GDT to protect 
> the radio. This was one of a half-dozen dipole insulators I bought to 
> figure out which were suitable for my needs.
>
> 73, Jim K9YC
>
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