[Elecraft] [K3] Detuning antenna per band and QSK

[Wes (N7WS)]

I have no idea how you are feeding the inverted-L but I suspect some kind of 
series feed.  Nevertheless this seems like a job for some PIN diodes.  Depending 
of the situation, switching in something that would shift resonant frequency or 
otherwise disturb the matching would do it  (nearly instantly).

(OT but I once saw a presentation by a Navy reservist who did a summer tour at 
NAA.  One thing he mentioned (confirmed here: 
http://www.navy-radio.com/commsta/cutler.htm) was the fact the antenna was tuned 
differently between mark and space of the MSK modulation)

Wes  N7WS


On 12/20/2014 1:45 PM, Jim Miller wrote:
> I use and like QSK on my K3 but I'm now looking at detuning my 160 inverted
> L to avoid reradiation into my beverages when in receiving.
>
> I'm looking at what it will take to do that and it appears that if the 160
> inv-L is just deselected by the remote DXE relay box it will just be an
> ungrounded 1/4 wave which shouldn't present problems on 160.
>
> I could implement a sequencer in the shack to do this by interrupting the
> relay select line that controls the 160 antenna on a per band basis but
> that leaves the question of what to do about QSK since the relay is
> specified to operate no sooner that 15mS. That will likely impact the clean
> CW and be undesireable.
>
> I can decode the band info and get the info about whether it is in TX or RX
> mode and probably inhibit the K3 until the delay has expired.
>
> But I'd need to kill QSK on 160 alone to do this.
>
> Is there a way to do QSK on a per band basis?
>
> 73
>
> jim ab3cv
> ______________________________________________________________
>