[hpsdr] hardware question ( Mercury HPSDR)

[Gediminas Kasparaitis]

Hi,

so many people responded, thank you my friends. Pdf  is so nice.

No, I do not have RF source with known level, but I got good advice from 
where to get one
not too big , not too expensive ( Elecraft).

Today I did some aditional testing, now I have no doubt,  my board has that 
instability,
sometimes everything is OK, sometimes a bit bigger noise
( very hard to understand if it is bigger than it should be)
, sometimes terrible noise increase.

When it works good, sensitivity is close to that of my radio, when it has
problems, then  base line just goes up  ( 10-30 db) and weakest signals 
dissapear,
strongest became weak... It takes time to duplicate this.

The idea to put heatsing on top of the chip ( on my board at least) turned 
to be totally wrong.
On the opposite side it doesn't hurt at least and helps somewhat with 
cooling.
It seems to me, that  the best thing is keep everything away from that A/D, 
then it ( or front end ) is the most stable.
Strange, but it becomes apparent only after few hours of warm up......

In CW skimmer  problem is  very visual..., but I misplaced somewhere cable 
from camera, so can't share
screen shots.

For a while I will play with extra fan, mightbe I still can get it more 
reliable ....If that won't help,
I don't know...will try to look for the best A/D  ( -40 - 85 C) and try to 
replace with it.....

73, Gedas, nx2px


----- Original Message ----- 

Subject: Re: [hpsdr] hardware question ( Mercury HPSDR)


> Hi,
>
> The basic shape of the noise looks OK but the base line is high - have you 
> calibrated PowerSDR against a known signal level?
>
> 73's Phil...VK6APH
>


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