[hpsdr] Transmit issue

[Kjell Karlsen]

Hi Jacques.

Are you using one of the latest versions of PowerSDR? And selected  
PennyLane, not Penelope?

Have you set the Gain By Band found in the PA settings? The maximum output  
is when set to 38.8 dB. If set to 38.8, there may be some spurs  
transmitted.

Use the Two Tone Test to generate the output and look for IM3 products  
with the Spectrum Analyser.

73, Kjell





På Wed, 12 Dec 2012 16:10:57 +0100, skrev <f6bki at orange.fr>:

> ***** High Performance Software Defined Radio Discussion List *****
>
> 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 _______________________________________________
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