[hpsdr] Transmit issue

f6bki at orange.fr f6bki at orange.fr
Wed Dec 12 07:10:57 PST 2012


Hello all , new on the transmit part of HPSDR .
Using Atlas ,Metis,  Mercury, Penylane , Alex.
Just started testing Penny with a spectrum analyser and a 50 ohms load , not
going through any filters.
Just red the pennylane manual not seen much , is there more to read
somewhere on the transmit part?

Using the internal signal generator I create an outup power , with the drive
button I can modify the output level , I see on 6M a carrier, spurious
about -50 dBc ( -20 dBc at low output ) at 49.2 MHz , is it normal ?

If I put Alex filter in serie between Penny and the 50 Ohms load I see 
spurious , (almost noise) about -50 dB below the carrier that was not 
present without Alex? looks like Pennylane board does not like to see low 
pass filters in serie with the load ! Checked the filters and they are OK .
When I put my fingers on the output side , close to the 50 Ohms output 
connector , between T1 and the first output IC the noise disapear !!!
With the fingers on the signal(carrier) to noise ratio is about 70 dB , 
without it is about 50 dB. It is the same ( bad)on all bands except 20 m !!

Can somebody comment and help?

Thank you
73
Jacques F6BKI 


 1355325057.0


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