[Amps] keying issue resolved

[Jim Garland]

Yes, an optically coupled MOSFET relay will work fine, and is what I use 
in my StationPro keying circuit. Two other considerations are the 
on-state resistance and the switching time. The PLA140 relay which I use 
has a maximum on-state resistance of 8 ohms. Relay data sheets always 
include this info.
73,
Jim W8ZR

On 12/28/2016 8:04 AM, ka9egw at ka9egw.com wrote:
>
> You make a good point…but I was thinking a MOSFET-output AC/DC SSR…
>
> *From:*Jim Garland [mailto:4cx250b at miamioh.edu]
> *Sent:* Wednesday, December 28, 2016 8:37 AM
> *To:* ka9egw at ka9egw.com; amps at contesting.com
> *Subject:* Re: [Amps] keying issue resolved
>
> Better be careful, Brian! Most AC solid state relays use thyristors 
> for switching and depend on the zero crossing of the AC load to switch 
> off. In other words, if you try to use one of those relays to key a DC 
> voltage, such as in the 30L1, it will key up the amplifier but won't 
> turn it off when the control voltage is removed. Also, if I recall 
> correctly, some solid state relays have minimum load requirements, 
> which you might not reach with a big 30A power relay. Personally, I 
> think you need a better solution than what you're intending.
> 73,
>
> Jim W8ZR
>
>
> On 12/28/2016 7:17 AM, ka9egw at ka9egw.com <mailto:ka9egw at ka9egw.com> wrote:
>
>     My sincere thanks to all who responded.  After serious consideration I got
>
>     inspired to keep it simple-a 240VAC 30A solid state relay with the low side
>
>     of the 3-32VDC input pulled to ground by any of several radios will
>
>     facilitate keying the +160VDC-keyed-line 30L-1, and also the
>
>     6.3VAC-keyed-line Hunter 2000C [which some say is the amp the 30L-1 could
>
>     have and should have been], and also the Dow-Key relays on the Heath
>
>     Warrior.
>
>       
>
>     Thanks to all who responded!
>
>       
>
>     73, Brian KA9EGW
>
>       
>
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