[Elecraft] Fix the old amplifier......leave the K3 alone!

[Brian Alsop]

If I recall correctly earlier K3's failed the "AMTOR" -like mode turn 
around time from rx to tx and back.
I believe that is about 15 ms.   This was apparently fixed.   The 10ms 
delay between PTT and RF helps it meet this.

So if it is too slow, some group complains.  If it is too fast others 
complain.   The need is apparently more than user dependent.  It can be 
mode dependent.
 
There is an xmit inhibit pin (aux i/o 7)  that (at least in the 
transverter mode) can inhibit RF until it is set high.   Those of you 
into serious VHF/UHF/Microwaves probably already have some kind of 
sequencer.  Using this pin with your sequencer can solve the "slow 
waveguide" relay problem.  See Page 19 of manual.

Has anybody tried to use this pin yet?  Maybe it can also be used for HF 
applications with some menu setting.

On the FT-1000MP many HF'ers used it's inhibit pin to avoid hot 
switching of their amps.  Same idea here.

73 de Brian/K3KO

AD6XY - Mike wrote:

>This is a mots worrying post. I think it demonstrates considerable ignorance
>of the many and varied applications of the K3. There is so much more to life
>than HF.
>
>How do you suggest we speed up a waveguide relay to 10mS?
>
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>Fern Rivard wrote:
>  
>
>>Hi Ian and the group:
>>
>>    I would suggest that you fix/modernize your old amplier and leave the
>>K3 as is!  The problem is NOT with the K3 but rather your amplifier.
>>Upgrade the darn linear with more modern faster switching relays and
>>vacuum relays are not that expensive if you shop around for some good used
>>ones.
>>
>>    73 from Fern VE7GZ with a fine K3 transceiver
>>
>>
>>
>>
>>
>>
>>----- Original Message ----- 
>>From: "Ian White GM3SEK" <gm3sek at ifwtech.co.uk>
>>To: <elecraft at mailman.qth.net>
>>Sent: Thursday, March 20, 2008 11:31 AM
>>Subject: Re: [Elecraft] K3 and linear amp
>>
>>
>>Roger Marrotte wrote:
>>    
>>
>>>I guess as of now I'm out of luck if I want to use my amp with a K3.  I 
>>>just checked the manual for my AL-811H and "The open frame relay in the 
>>>AL-811H takes approximately 15ms to switch states".  My K3 is on order. 
>>>I hope there's a K3 firmware change made before I get my K3, that will 
>>>allow me to adjust the change over timing.  I'm far from an expert with 
>>>amps.  I have no idea what an average switch over time is for amps in 
>>>general.  Ameritron sells a high speed switching option, the QSK-5, 
>>>that reduces the switching time to 1ms.  It costs around $300.00.  A K3 
>>>firmware change would sure be less expensive.
>>>
>>>      
>>>
>>That firmware change is surely needed, but there is another inexpensive 
>>way which often works - speed up that open-frame relay.
>>
>>The circuit shown in the link below uses the existing relay supply rail, 
>>and it will shorten the switching time of most relays by about one-half. 
>>The same circuit will also convert many older amplifiers to a modern 
>>standards +12V, low-current switch interface.
>>
>>http://www.ifwtech.co.uk/g3sek/in-prac/best-of.htm#speedup
>>
>>
>>-- 
>>
>>73 from Ian GM3SEK         'In Practice' columnist for RadCom (RSGB)
>>http://www.ifwtech.co.uk/g3sek
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