Re: Bitx40 75KHz Spurious, How to solve it. #bitx40

Tim Gorman
 

Raj,

What then are the exact beginning and ending of the scan?

If the center frequency is 7.029Mhz then a 500khz scan would run from
6.779Mhz to 7.279Mhz.

I can come up with no spurious products that would result in an
harmonic progression increasing in amplitude as you move away from the
carrier frequency, especially as close in as 75khz.

The bitx40 uses a 12Mhz oscillator and a 5Mhz oscillator. I can't think
of a combination of these two frequencies that will give you a signal
at 7.104Mhz or 6.954Mhz as well as the carrier of 7.029Mhz.

I am still suspicious that something else is going on here besides
spurious products from the bitx40 itself.

tim ab0wr

On Tue, 26 Jun 2018 16:37:08 +0530
"Raj vu2zap" <@Raj> wrote:

Tim.

That is the marker M 7.049 , its very low in level and not seen.

Raj

At 26-06-18, you wrote:
It shows scanning from 7.029Mhz to 7.049Mhz. That's only a 20khz
scan, not 50khz. And certainly not 50khz per division on the screen.

The funny thing is that those unknowns are *increasing* in amplitude
as you move away from the carrier instead of decreasing. I'm not
sure what would generate this.

Could these be products from overdriving the spectrum analyzer?

tim ab0wr


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