[Elecraft] K3 TX DELAY

[Vic Rosenthal]

Agreed. With a K3 you don't need any special sequencing -- just replace the relay with a reed relay for input and a vacuum relay for output (or two vacuum relays). It is much more pleasant even if you don't use QSK or VOX.

Vic 4X6GP/K2VCO 

> On May 31, 2015, at 7:21 AM, Guy Olinger K2AV <k2av.guy at gmail.com> wrote:
> 
> Expecting a transceiver to somehow neutralize all amp obsolescence is
> putting the burden where it doesn't belong. And it really can't come
> close to doing the entire job.
> 
> Existing mod kits from Harbach, W7RY, etc, can convert many older amps
> internally (all the way back to SB200 SB220) to *excellent* modern
> status, QSK, modern interface voltages and behavior, good for years of
> slick operating to come. Array Solutions has an excellent external QSK
> device, for those who don't want to tackle an internal mod.
> 
> You didn't say which specific amp with slow frame relays. Many (most?)
> of these were designed back when the expectation was something like a
> footswitch or a toggle switch would be used to place the shack in
> transmit mode.
> 
> I own an FT1000MP.  On CW (only) it has a first in first out bucket
> brigade delay (menu 7-4 keyer break-in time) which allows it to apply
> T/R assert to the amp and allow continuously delayed CW up to 30 ms to
> be transmitted from the MP. With the clunkier amps actually needing
> the max 30 ms delay like my older AL1200, you had to listen to the
> input monitor on the MP if you were sending with a key. Listening to
> the actually sent signal would is so divergent from physical input at
> 30 ms that many simply can not send CW with it.
> 
> But it doesn't fix the parallel problem on SSB.
> 
> Even if the MP's delay was working OK for CW, there is no delay for
> SSB. This would require a continuous bucket brigade voice delay with
> sufficient fidelity. That isn't impossible, but a lot more expensive
> and complex than a faster relay. And it STILL does NOT fix all the
> issues of clunk involved. This includes the recovery time from T back
> to R so slow that in contests often the first baud or two of a reply
> would be lost while the relay is waiting for the contacts to restore
> the RX path through the amp, which now only has the spring to propel
> points to normally closed state.
> 
> IMHO to put it bluntly, any amp relay with T/R duties that won't close
> in 8 ms is obsolete and needs to be replaced by something modern.
> 
> The aftermarket mod boards will modify old tube amps for QSK, low
> voltage low current T/R keying (soft key), step start power-on etc.
> Amps modified with current QSK circuitry will switch quickly enough to
> support VOX on SSB. All the Ameritron amps have superior aftermarket
> QSK mods available, in addition to the manufacturer's own QSK option.
> 
> W2CS helped me QSK my AL1200 with the same circuit he used to upgrade
> his SB220. This was before the current crop of excellent mods were
> available. No excuses.
> 
> 73, Guy K2AV
> 
>> On Saturday, May 30, 2015, David Raymond <daraymond at iowatelecom.net> wrote:
>> 
>> I'm running an older borrowed K3 to get various I/O issues worked out while awaiting arrival of my K3S.  I am interfacing the K3 into an older tube amp with large open frame relays for antenna IN and OUT.  The maximum TX DELAY limit of 20 ms on the borrowed K3 is not enough to avoid hot switching the amp output relay contacts. I had the delay in my old FT1000MP set for 30 ms which was adequate with some margin (it had a max delay of 40 ms I believe).  Are there any options in newer K3's for more than 20 ms of TX DELAY?  Hopefully the K3S will have more than 20 ms or my options for QRO are QRT. . hi.          73. . . Dave, W0FLS
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>> 
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to k2av.guy at gmail.com
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to k2vco.vic at gmail.com