HamRadio Deluxe and elimination of the Doppler effect

Satellite operation is difficult to control. Anyone who wants to fully utilize the potential of a satellite transponder and have an excellent signal on both the uplink and downlink needs to pursue:

• rotate antennas in azimuth
• rotate antennas in elevation
• debug RX (TX) on the downlink
• debug TX (RX) on the uplink
• make a connection
• write down the connection

Doppler effect

With LEO FM satellites such as SO-50 and AO-51, the uplink is in the 2m band and the Doppler effect is smaller than at 70cm, so it is usually enough to set the transmitter to the uplink frequency. However, the Doppler on the downlink in the 70cm band is three times as large as in the 2m band and even though the FM modulation is understandable even with minor detuning, tuning to 70cm cannot be avoided. However, if we do not have the device connected to the computer with the HamRadio Deluxe program.

Calculating the Doppler effect in HamRadio Deluxe

The Doppler effect is calculable, which is used by HamRadio Deluxe in the Satellite Tracking function. So how to use this function?

• We will insert the current Keplerian data into the "amateur.txt" file in the Satellites subdirectory
• We will connect the device to the computer with a CAT cable
• After starting HamRadio Deluxe, we select the manufacturer, radio, COM port and transmission speed. If we have a CAT powered from a COM port, we also select the output, from which the supply voltage is taken (DTR or RTS). Of course, the device must be switched on and CAT configured
• The correct connection is indicated by loading the control screen, where the frequency lights up. If it failed, check the settings, or CAT cable
• Now tap on the Satellites icon in the top menu, which will open a window
• We select those from the list of satellites, which we are interested in
• We tap on the Observer folder and enter our position, confirm Add
• We tap on the Ground Control folder. We select satellite and mode. VFO check RX and write the downlink frequency in the Satellite field. To the right, under the name of the device, we see the frequency recalculated by the Doppler frequency shift. Of course, it changes with the movement of the satellite

This is what the abbreviated tuning plan looks like during the AO-51 flyby:

 AO-51 TX: ____.___.___ RX: _435.300.000  Date / time               Azim   Elev  Receive       Transmit --------------------------------------------------------------- Sat 02-Dec-2006 16:56:00  76.6   -1.1  435.305.386   0            Sat 02-Dec-2006 16:56:30  73.1   -0.2  435.304.883   0            Sat 02-Dec-2006 16:57:00  69.3    0.7  435.304.323   0            Sat 02-Dec-2006 16:57:30  65.2    1.5  435.303.704   0            Sat 02-Dec-2006 16:58:00  61.0    2.1  435.303.031   0            Sat 02-Dec-2006 16:58:30  56.5    2.7  435.302.308   0            Sat 02-Dec-2006 16:59:00  51.9    3.1  435.301.545   0            Sat 02-Dec-2006 16:59:30  47.1    3.3  435.300.752   0            Sat 02-Dec-2006 17:00:00  42.3    3.4  435.299.945   0            Sat 02-Dec-2006 17:00:30  37.5    3.3  435.299.138   0            Sat 02-Dec-2006 17:01:00  32.8    3.1  435.298.348   0            Sat 02-Dec-2006 17:01:30  28.2    2.7  435.297.587   0            Sat 02-Dec-2006 17:02:00  23.7    2.1  435.296.868   0            Sat 02-Dec-2006 17:02:30  19.5    1.5  435.296.199   0            Sat 02-Dec-2006 17:03:00  15.5    0.7  435.295.585   0            Sat 02-Dec-2006 17:03:30  11.7   -0.2  435.295.028   0            Sat 02-Dec-2006 17:04:00  8.2    -1.1  435.294.529   0

 

The described method reduces the number of "necessary hands" again - satellite operators know what it's all about, HI. The description itself, what Ham Radio Deluxe offers would suffice for several articles. But what will I write, try it for yourself. You can find the HamRadio Deluxe program on the site .: YOUR .: