There is no reason to speed up a vacuum relay. 1.8 mS is more than enough
time. Please see:
http://home.earthlink.net/~wd7s/updates.htm
73
Jim W7RY
On Sun, Feb 21, 2010 at 7:31 PM, Jim Thomson <Jim.thom@telus.net> wrote:
> Date: Sun, 21 Feb 2010 08:16:28 -0800
> From: "Mike" <noddy1211@sbcglobal.net>
> Subject: Re: [Amps] Hotswitching issues 30s-1
>
>
>
> Key the amplifier and send the PTT signal from it to the transceiver!!!
> Alex 4Z5KS
>
> ## IF you key the amps relays 1st....THEN send a signal back to the xcvr's
> PTT input, what happens is you have now truncated the 1st 2-18 msecs,
> or what ever the amps T/R relay's operate time is.
>
>
>
>
>
>
> How about using one of the simple Heil Foot switches, it has two switches
> and keys the Amp slightly before rig.
>
> This would be the simplest way to address your problem.
>
> ### great, but now you are stuck on PTT/footswitch mode. The simple
> opto isolator method will eliminate the 15 msec mech spst relay in the
> MK-V. As other's have noted,on CW mode only, the yaesu has the adjustable
> 0-30 msec digital delay [buffer] and no dits and dah's get truncated.
> [Gives
> the T/R relay in the amp a 0-30 msec head start].
>
> ## the heil footswitch is an excellent footswitch though. With a
> conventional
> footswitch /ptt... IF u start talking b4 u hit the footswitch, you will
> have RF
> coming out of the xcvr, b4 relay's in the amp operate.
>
> ## to get around that problem on the yaesu's.. on ssb mode, we used an
> external
> 9-12 msec delay circuit, that inhibits the yaesu's built in TX inhibit
> lead. With that setup,
> you trip the vox, the opto keys the amp, then after the 9-12 msec outboard
> delay, the
> yaesu TX inhibit lead is switched, and RF now flows from the xcvr. Problem
> solved.
>
> ## This external 9-15 msec delay is not required, IF the T/R relay's in
> the amp are
> fast.. like sped up vac relays. [1.8 msec] In our case, we were using
> slow vac relays
> [RJ2-B] which have a 18 msec op time. Even when we tried to speed the
> RJ2-B up, it's
> still only 9 msec operate time.
>
> ## The TX ibhibit lead function on the 1000-D and MK-V are slick, but
> both operate
> differently. The 1000/D requires a simple grnd to ENABLE the TX inhibit
> lead. [ grnd
> on TX]. The MK-V requires +12 vdc to enable it's tx inhibit lead.
>
> ## in the case of the 1000/D.... the opto keys the amp, and the spst mech
> yaesu relay
> [after 15 msecs] applies a solid grnd to the TX inhibit lead, THEN RF
> flows from the xcvr!
> This works good on SSB, BUT will truncate the 1st 15 msec's on CW.
>
> later... Jim VE7RF
>
>
> Mike, K6BR
>
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