[K3] - Retrofitting synthesizer board stiffeners

[GW0ETF]

After upgrading my Softrock based panadapter to the more sensitive Lp-Pan some time ago I was seeing microphonic sidebands on cw signals when using the internal speaker with my early (#145) K3. These increased as AF volume was turned up and the spacing of the +/- pair corresponded to the selected tone frequency when looked at carefully. These presumably would have been transmitted too but wasn't a major problem as I normally use headphones, though not always.

So I took the opportunity of a recent visit to New York to buy a pair of stiffeners (and avoid the horrible shipping costs to the UK) and there is now no sign of the sidebands even at full speaker volume. I fitted to both synthesizer boards (have the 2nd receiver) so I can swap them if needed in the future; some have reported they improve the birdie situation but haven't come to any conclusions on that yet. Elecraft were very helpful and delayed shipping so they arrived at my hotel 2 days after I checked in, just like they promised. 

Some earlier postings questioned the necessity of the stiffener plates in earlier K3s; for me I now feel it's a cleaner radio with them in.

73,
Stewart Rolfe, GW0ETF
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[Wes (N7WS)]

No question about it, they're necessary.  I discovered these spurs five years
ago.  (My how time flies...seems like only yesterday)

Wes  N7WS


On 3/1/2014 5:35 AM, Stewart Rolfe wrote:

> After upgrading my Softrock based panadapter to the more sensitive Lp-Pan some time ago I was seeing microphonic sidebands on cw signals when using the internal speaker with my early (#145) K3. These increased as AF volume was turned up and the spacing of the +/- pair corresponded to the selected tone frequency when looked at carefully. These presumably would have been transmitted too but wasn't a major problem as I normally use headphones, though not always.
>
> So I took the opportunity of a recent visit to New York to buy a pair of stiffeners (and avoid the horrible shipping costs to the UK) and there is now no sign of the sidebands even at full speaker volume. I fitted to both synthesizer boards (have the 2nd receiver) so I can swap them if needed in the future; some have reported they improve the birdie situation but haven't come to any conclusions on that yet. Elecraft were very helpful and delayed shipping so they arrived at my hotel 2 days after I checked in, just like they promised.
>
> Some earlier postings questioned the necessity of the stiffener plates in earlier K3s; for me I now feel it's a cleaner radio with them in.
>
> 73,
> Stewart Rolfe, GW0ETF
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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