UK TV RIP!

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I have obtained a TV which I could read at some distance in bright sunlight. It was propped up in the shade of my car boot with the Fortec Star Passion HD receiver alongside. After initial tests with a twin coax video/sound cable I swapped to a short HDMI betwen the two. The picture was easily bright and sharp enough to read from the dish at some distance. I set the receiver menu to Signal Strength and Quality display. While the readings might not be scientifically accurate they are easily repeatable within the same system. No more is required for testing purposes.

First I confirmed that the Kathrein 2.2m dish was indeed aligned perfectly on 28E UKSB as tightly as possible. No movement of the dish (in any direction) increased the Signal or Quality. In fact the readings fell. So there was no more to be had here. The wind was light enough to be having no effect.

I could then move on to maximising LNB focus and skew. The brass feedhorn was already set at the calculated focal distance of 75cm. I peered through the small hole in the middle of the dish to ensure the feedhorn was centred and pointing straight at the centre of the dish. No change in Strength or Quality was noted with increased accuracy of alignment.

Quality dropped with all changes in feedhorn focusing so I left that alone too. Skew was fairly insensitive but I found the mid point of the angular limits and tightened the LNB clamping screws. 

I then noted the signal Strength and Quality readings on the screen and removed the home-made brass feedhorn to fit the cast alloy IRTE. Quality immediately increased by 2%. So the IRTE (despite a slight theoretical F/D mismatch) was obviously the better choice. I tried changing the focus and skew with the IRTE but they remained best at the same, brass feedhorn settings.

The HD100 cable had softened slightly in the unusual 76F heat and bright sunshine. So I stretched it out as straight as possible. Though this had no visible effect on the signal readings there is a theoretical chance of signal being lost with too many tight turns at such high frequencies. No point in leaving anything to doubt.

The Inverto Black Pro C120 LNB is highly thought of on the satellite forums. Unless I have been unlucky and received a poor example there is not likely to be any serious improvement by fitting any other LNB.

The IRTE feedhorn could be swapped for an Invacom Universal. Whether this would be worth the extra expense is difficult to say. The gain is likely to be only very marginal. 

The Fortec Star Passion HD receiver fails to lock below about 53% signal Quality. I have tried a borrowed Kathrein receiver and found it almost the same for sensitivity and ability to lock onto weak signals. There may be slight gains to be had from a change of receiver but I doubt it would be worth the expense of actually importing one.

Which only leaves the Kathrein 2.2m dish. Though old, it is a professional quality, spun aluminium dish in undamaged condition. Unlike some plastic dishes with embedded, open mesh reflectors the solid aluminium dish cannot lose signal by changing between C and Ku band. Thanks to its rear, skeleton reinforcing frame the Kathrein is unlikely to lose its shape. So it should have retained the surface accuracy with which it was originally made.

I recorded my maximum signal levels across the range of UK TV channels and transponders between 13.00 and 13.15pm. By 14.00 signal quality had already dropped by around 5% in many cases. While signal Strength had strangely increased by 2-3%. No changes were made to the system when 14.15pm marked the local death of most of the BBC channels. With many of the ITV channels falling out at 14.30pm. Only a few stragglers remained with solid reception until I finally lost patience with hiccuping sound and lack of pictures at 14.45pm.

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