QtRadio - Operation
Contents
Connecting to a server
Tuning the radio
Fixed frequency radio
For crystal locked radios such as the softrock lite II or YU1LM sdr's It is necessary to use subRx. The procedure is to set vfoA to your centre frequency, usually the crystal frequency / 4 and leave it alone as changing it will affect your centre frequency. Using the button on the vfo panel or the 'Receiver' Menu / subRx choice switch on the subRx. You can now tune within the limits of the sample rate of your sound card (48, 96 or 192 KHz) with your centre frequency offset from centre by 9 KHz.
Note there is still a bug in the display where the lower 9 KHz wraps to the upper 9 KHz but the audio doesn't track the spectrum so you lose 9 KHz of possible bandwidth.
si570 tunable radio
Setting the noise floor
The height of the spectrum from the baseline is adjusted by rolling the mouse wheel with the pointer over the level calibration markings on the extreme left hand side of the spectrum window. This will at the same time change the base colour of the waterfall.
The procedure is: After setting the sound-card gain you should remove the antenna and roll the mouse-wheel to give a spectrum display line just above the bottom of the window. When you apply the antenna the spectrum will rise in the window and the waterfall base colour should be dark blue unless the band is particularly noisy.
Calibrating the S meter
To calibrate the S Meter, a signal equal to S9 (-73 dBm) is injected into the sdr and the soundcard gain is adjusted until the S meter reads S9. It will then probably be necessary to adjust the spectrum noise floor level.
A subjective calibration may be performed by tuning into a signal considered S9 and performing the above procedure.
VFO and Split selection
Using RIT
Changing bands
Using Quick Memories
Using subRx
To be constructed
The Menu choices
Receiver
Connect/Disconnect
You can connect to a server either by selecting the server in the Configure > Server list and then click Connect, or by selecting the server in the Quick Server List and click connect.
After you Disconnect from a server, you must wait at least 10 seconds for the disconnection to take full effect before connecting to another server. This is to allow the internet connection to really disconnect (remember there is network latency and the server will continue to send data till its buffers are emptied). Failure to do so will often result in error in QtRadio and may even hang QtRadio.
Quick Server List
If you see that a public server's status is "Busy", please do not connect to it. Doing so will disrupt the user already connected. If you see a server's status is "Idle" or "0 client(s)", you can connect to it. If you see "1 client(s)" or "2 client(s)" etc., you are sharing a connection to the same server. The first client is the master who has control over the vfo and Tx etc., and you will be connecting as a slave. You will only be able to listen to the audio and see the spectrum passively as an observer. When the clients before you disconnect, you will automatically become the master. This is a queuing mechanism.
Configure > Audio
If you are connecting to a public server on the Internet (ie not your own server on your LAN), please set Audio to 8000, aLaw, and 1 channel. If you use other settings, your QtRadio and/or the dspserver/server will hang.
