Posted by
Vic K2VCO on
Oct 13, 2004; 3:08am
URL: http://elecraft.85.s1.nabble.com/Question-about-K2-s-T7-windings-tp370877p370881.html
Tom Mc wrote:
> I have built K2 s/n 1103 and used manual version B. My manual (ver. B)
> states that the winding ratio should be 11:3. Don states that newer manuals
> are stating that T7 should be 20:5.
>
> Don's post also states that an additional 3 dB of gain should be
> accomplished by this change.
>
> Does 3dB of additional gain on the audio mean the same as 3dB on an
> antenna system? Like double the output? That would seem to be pretty
> significant.
Actually, 3 db of audio gain is not signigicant in the same way that a 3 db
increase of antenna gain is. In the case of the antenna, the gain improves the
overall signal/noise ratio, since the internal receiver noise remains the same.
If the antenna gain comes from directivity (it can also come from increasing
efficiency), the result is even more significant, because desired signals are
stronger while undesired signals and noise from other directions are weaker.
Obviously, increasing audio gain increases internal and external noise as much
as signal.
> Can anyone let me know if they have made this change and if they have
> experienced the same results which Don says (Don also mentioned that he
> hasn't had the chance to make this change in his Field Test K2).
I made this change to my K2 #709. While I didn't notice an increase in overall
gain, it did decrease the additional loss I had when the crystal filter was set
to 200 Hz by a couple of DB.
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco_______________________________________________
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