Posted by
G3VVT on
Jan 16, 2005; 11:56pm
URL: http://elecraft.85.s1.nabble.com/Birdie-at10m-a-choice-between-a-turkey-and-an-ostrich-tp373605p373606.html
In a message dated 15/01/05 23:36:15 GMT Standard Time,
[hidden email]
writes:
I know there was a recent discussion in the forum about this birdie singing
at the low end of the 10m band, but did not recall seeing any definitive way
to kill it.
In my case, I want to think of the birdie living in my K2/100 as a
substantially bigger one, a turkey (with the K2100 enabled -power >11w) at
28.266 (USB), Signal strength S2 with the preamp enabled changes to .... an
Ostrich (think logarithmically) of a solid S5 !!! at 28.264 when disabling
the 100W option.
------------------------------------------------------------------------------
-----------------------------------------
As a benchmark with the antenna socket terminated, i.e. no external antenna
connected, the only birdie of any real significance with my QRP K2 #4168 is
at exactly on 28.000MHz.
This is exactly where it should be as the 7th harmonic of a correctly
adjusted MCU 4.000MHz clock for U6 on the K2 Control board. There are other birdies
between 28.000 to 29.000MHz, but are so feeble that they fall into
insignificance and none of them move the S meter at all even with the preamp on. This
is with a receiver that gives S9 on 28.200MHz at 50uV PD with the preamp
*off* and meets the MDS spec for the K2. I am aware of the birdie at 28.000MHz as
that clashes with a band edge beacon I receive via an external VHF
transverter. Even with this present it is possible to copy the beacon down to an
extremely low level with the K2 preamp on.
The reported birdie at 28.276MHz is there, but extremely faint at about
28.275.6MHz on USB and shifts up to about 28.277.7MHz on LSB. I would think it
fair to comment that most ham receivers have birdies somewhere if you want to
try hard enough finding them.
With what I have found on my particular QRP K2 it may be a good idea to
remove all the various options added to the offending K2's and go back to basics
to see what the effect is then. Once that test is sorted out the gradual
addition of the various option boards should find the offending one(s) to enable
a solution to be sought.
There or no turkeys or ostriches in my K2!
Bob, G3VVT
K2 #4168
_______________________________________________
Elecraft mailing list
Post to:
[hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help:
http://mailman.qth.net/subscribers.htmElecraft web page:
http://www.elecraft.com