HORIZON TEMPERATURE PLOTS
For 23, 13, 9 and 3cm from the QTH of G4DDK


10GHz horizon temperature plot

10g horizon
This plot was obtained using Spectravue on the SDR-IQ receiver, using the Continuum plot function.
My 10GHz system uses a 60cm Andrew Corp dish, DEMI 1dB preamp and DB6NT transverter (system nf about 2dB).
The mast is in the down position so that the dish is looking below the roof line.
Spectravue is set up with 0.5dB/Division and an FFT of 2


3.4GHz horizon temperature plot
9cmhorizon

                  Note that the 9cm plot is at 0.2dB/div due to the much higher noise temperature of this system.
                    This plot was taken using a 112 element quad loop yagi and nearly 6cm feeder loss into the 1dB nf transverter.
                    The same features can be recognised as in the other band plots.
2.3GHz horizon temperature plot
13cmhorizon



1.3GHz horizon temperature plot

23cm Horizon

The vertical scale depends on receiver system gain and is slightly different on each band. 23cm has slightly higher gain than 13 and 3cm.

The  13cm system uses a 84 element G3JVL quad loop antenna, whilst the 23cm system uses 2 x 44 element yagis (Wimo).
The receiver system noise figure is about 2dB in each case.
Antenna gain on 23 and 13cm is roughly the same. The plots seem to indicate that the 13cm antenna is not working as well as the 23cm one as the variation in peak to trough is slightly less. However, performance is probably perfectly acceptable for 13cm terrestrial use.



Updated 17/11/10

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