[Elecraft] PR-6 issue when QRO

[Joe Subich, W4TV]

Greg,

Is that SB-200 a "modified for 6 meters only" amplifier, one that has
six meters added to the HF bands or is the problem happening when
operating on HF bands?

Is the K3/PR6 configured to bypass and turn the PR6 off when operating
on HF?

73,

    ... Joe, W4TV


On 4/29/2012 11:10 AM, Gregg Marco W6IZT wrote:
> Don:
>
> I have replaced the open frame relay with Schrack relays
>
> 73
> Gregg
>
> -----Original Message-----
> From: Don Wilhelm [mailto:w3fpr at embarqmail.com]
> Sent: Sunday, April 29, 2012 10:12 AM
> To: Gregg Marco W6IZT
> Cc: 'elecraft'
> Subject: Re: [Elecraft] PR-6 issue when QRO
>
> Gregg,
>
> Unless you have changed the open frame relay in the SB-220, it will take at
> least 15 ms to switch and be clear of the contact bounce.  I would suggest
> you change the stock relay for something faster.
>
> 73,
> Don W3FPR
>
> On 4/29/2012 8:55 AM, Gregg Marco W6IZT wrote:
>> I use my K3 on 6 meters with a concerted SB-220. When using the PR6
>> connected to the KXV3 as intended and using the amp, the GaAs FET is
>> destroyed immediately. My work around was to employ an external TR
>> relay on the K3 to switch TX RX, connecting the PR6 to the RX side of
>> the relay and to the RX input of the KXV3.Using this arrangement has
>> worked fine for the past few years.
>>
>> With E skip season approaching I thought that I would try to resolve
>> this problem and get rid of the extra RF plumbing.
>>
>> My initial thought was the TR relay in the amp might be too slow and
>> RF was being reflected back into the K3 during the transition from TX
>> to RX. After looking at the K3 block diagram I doubt that this is the
>> case as the PR-6 should be switched out of the circuit well before any
>> RF is present at the output.
>>
>> For reference the TR relays in the amp are spec'ed at 8 msec to switch
>> and the K3 is set at 8 msec TX delay, which I believe is the default.
>>
>
> ______________________________________________________________
> 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
>