Alberto, thank you. Changing the input levels does make a difference and I am now going in the right direction My background is Pro Audio so I was a little concerned at the lack of audio headroom. It is possible to vary the input to the Delta 44 so I'll play with that as well. When I mentioned the attenuator I was refering to audio not RF
Could you answer one question please. In Winrad where does the S meter normally idle when there is no audio input to the Delta 44? I shall at some time probably over the Christmas holiday put the Delta 44 in another machine and see if there is any difference. Thank you very much for your help Clive G8POC ----- Original Message ----- From: Alberto I2PHD To: [email protected] Sent: Saturday, November 29, 2008 1:41 PM Subject: Re: [soft_radio] Looking for trouble? Clive Lorton wrote: Alberto and Alan thank you for responding Alberto the baseline is slightly better than -115db 96 kHz Clive, that seems to be about 10 dB worse than what it should be. This is a capture I have just made Done with the Delta 44, with no input. In any case, consider that Winrad has to deal with many possible different input : from the sound card, from the USB port (SDR-IQ, Perseus, etc.) so it is not possible to have a correct S-meter reading without any previous calibration. In its present form, I have calibrated the S-meter reading of Winrad to have it indicating S9 when the input is coming from a Perseus receiver, with a -73 dBm generator connected to its input. This calibration is also almost good for the SDR-IQ Rx. Maybe you are pumping too much audio into the Delta 44. First of all set the Delta Control Panel in this way : This will ensure that you are not driving too hard the sound card. If still the level seems to be too high, put an atteniator NOT in the antenna RF path (which would degrade the noise figure of the receiver) but between the Softrock output and the Delta 44 input. Experiment with the attenuation factor to find the optimum value. 73 Alberto I2PHD ------------------------------------------------------------------------------ No virus found in this incoming message. Checked by AVG - http://www.avg.com Version: 8.0.176 / Virus Database: 270.9.11/1818 - Release Date: 28/11/2008 19:31
