[Elecraft] 4mhz and C22 bandspread.

Thu Sep 4 22:53:04 2003

Ron;
I would guess that for some reason your 4 MHz oscillator is wandering off
frequency under some conditions such as transmit.  If this oscillator gets
too far off frequency, it could cause problems with AuxBus communications
within the K2, and this could lead to all sorts of unexpected behaivor.
This is a good illustration of why you do need to be careful about mods (and
know how to remove them) unless they have been thoroughly checked out by
Elecraft with a formal field test.  Parts variations can cause some
unexpected side effects.
-John
 KI6WX

----- Original Message ----- 
From: "Ron ZL1TW" <[email protected]>

>
> Today was a typical wet Spring day here and with nothing better to do, I
> decided to have a go at the bandspreading mod
> as outlined  by John KI6WX (ie the replacement of C21 with a 10pf N750 ,
and
> another 10pf N750 across X2)
> The mod went Ok and I was certainly able to align C22 better , but didn't
> quite have the range I needed, so  changed the 10pf across  X2 with a
6.8pf.
> This time I had sufficient range and the alignment  and Cal PLL went
> well.....or so it seemed.
> However.....this evening I fired the rig up to work a sked, and the ATU
> seemed strangely reluctant to obtain a match.
> When I transmitted CW , the telephone out in the Lounge started ringing in
> unison with each dit and dah, and the computer screen here went nuts and
> pulled down all sorts of windows!! needless to say I didn't transmit long.
> I checked the general installation and it seemed OK. I tried another
> transmitter on the antenna and the SWR was fine, so I pulled the Control
> board out again and replaced the original C21 and removed the cap across
X2.
> After realignment and Cal PLL, , the rig worked fine again.
> Obviously the mod didn't work for me ....appeared fine on receive.....but
> something wasn't right on transmit.
> The mod obviously works OK for John, but my rig didn't like it, so C21
will
> be staying "stock" from now on.
> I post this message  FYI and not a critism of  the mod. YMMV.
>
> 73......Ron ZL1TW
>
>
>
>
> _______________________________________________
> Elecraft mailing list: [email protected]
> You must be subscribed to post to the list.
> To subscribe or unsubscribe see:
http://mailman.qth.net/mailman/listinfo/elecraft
> Elecraft Web Page: http://www.elecraft.com
> Also see: http://www.elecraft.com/elecraft_list_guidelines.htm
>