[Elecraft] Elecraft technology >> K2+

[George, W5YR]

Vic, connect a 22 pF cap to the Noise Blanker input and bring out the other
lead with RG-174 to one of the Xverter hole into which you have installed a
BNC connector. Run a shielded cable from that BNC to your 850 antenna
connector. Set the 850 to around 4915 kHz and tune around until you pick up
the K2 signal. Get it tuned properly and you will have all the features of
the 850 to use with the K2 front end. With my Icom PRO2, I get a Spectrum
Scope display of the K2 signal.

A better tap for downconverting to an external receiver is the output of the
AGC amp through a 0.005 uF cap in series with a 47K resistor to RG-174 to a
BNC installed in the other Xverter hole. The output here is around 154 kHz.

With either tap, tune the external receiver until it produces the same sound
as the K2; i.e., CW tones are the same, SSB voice sounds the same, etc.

Depending upon the band and mode, the external receiver may be tuned to the
same mode as the K2 and it may also have to be tuned to the "other" mode,
depending upon your external receiver. For example, on some bands and modes,
CW on the K2 is CW-R on the other radio. Or USB on the K2 may be received as
LSB on the other radio.

I find that this is an excellent addition to the K2 for in-house operation.
I have all the DSP IF tools of the PRO2 available, including excellent notch
filters and 50 Hz IF filters if needed.

These taps have no measurable effect on the K2 operation and performance as
far as I can determine. The 47K resistor in the AGC tap point was chosen to
make the PRO2 S-meter show about the same reading as the K2 meter.

If you try any of this, I would interested in hearing the results. O guess
we can call this the "K2+" . . .

73, George W5YR
w5yr@att.net


----- Original Message ----- 
From: "Vic Rosenthal" <vic@rakefet.com>
To: "Elecraft" <elecraft@mailman.qth.net>
Sent: Monday, December 29, 2003 10:47 AM
Subject: Re: [Elecraft] Elecraft technology >> K2+


> Mike McCoy wrote:
>
> > I'm not a big fan of 'toggling' thru filters ala AFIL/XFIL ('oops,
> > that last selection was the best choice'). I guess I prefer the 599ZX
> > being external and adjusting the 599ZX's 'infinite' variability using
> > front panel knobs/switches and having the settings displayed on the
> > Timewaves LCD and/or LED's.
>
> A couple of reasons why I prefer the Elecraft DSP to my Timewave 59+
> (not as fancy as the 599ZX):
>
> 1) Sidetone is is injected in the K2 after the DSP, so there's no
> trouble with delay or with the sidetone being attenuated by the DSP
> filter.  I know the Timewave units can be switched out on transmit, but
> it isn't practical with high-speed QSK.
>
> 2) The denoiser in the Elecraft DSP works better than the one in my 59+.
>
> Having said that, I agree with Mike's comments.  Perhaps the K2+ or K3
> needs a bigger panel and some old fashioned switches instead of buttons.
>   I also agree with the previous poster's comments about the need for a
> better IF filter.  I have a TS850s with a pair of 400 Hz INRAD filters
> and I miss the IF filter performance in the K2 (although I prefer the K2
> overall and the 850 is now my standby rig).
>
> -- 
> 73,
> Vic, K2VCO
> Fresno CA
> http://www.qsl.net/k2vco