[Elecraft] L34 on K2 tuning question?

[David Woolley (E.L)]

Geoffrey Mackenzie-Kennedy wrote:
> 
> To avoid any misunderstanding about my use of the term 'strong', the 
> level of the internal spurious signal at 7 MHz in my K2's receiver was 
> approximately 10db above the noise floor at the output of the product 
> detector when viewed with a suitable spectrum analyzer, with the 

What's the analyzer bandwidth (resolution)?

> receiver connected to a 40m reference dipole at 70ft. The background 
> noise here on 40m is usually 'below S1' with either dipole or beam, 
> storm noise excepted. Receiver IF bandwidth was set to 400 Hz ,which is 
> not, of course, the receiver's noise bandwidth because of the actual 
> response of the K2's IF filter.

I get -21dB with an analyzer bin width of 10.8Hz, using spectrogram and 
an indoor doublet, consisting of about 20m of wire, but with only about 
10m horizontal.  Note that is 21 dB below the noise in 10.8 Hz, or about 
  37dB below the noise in 400Hz, and I cannot hear it.  I did turn the 
AGC off.

Using a 50 ohm dummy load at about 21 degrees C, I get about +28dB in 
the same bandwidth.  Looking at last month's RadCom article on noise, it 
looks like a quiet 7MHz should generate about 35dB over a 25 degree 
resistor, which would give -7dB in 10.8Hz even in ideal conditions. My
antenna noise, at 49dB over the resistor, is roughly in the middle of 
the range suggested in that article.

Either you are misinterpreting the effective noise bandwidth of the 
analyzer, or you have a faulty K2. The birdy, itself, will have very 
little bandwidth.

-- 
David Woolley
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