Right then Llew, this is what we have so far. Just using simple display readouts from TM 5402 M3. (sorry G).
Last nights readings with slight cloud cover sampled at around 7.30pm:
16East--21577H.
1.2 Gibby ------------- Promax 9.3dB. TM5402 10.5dB absolute max.
1.8 CM -------------- Promax 10.4dB. TM5402 12.2 dB absolute max.
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This mornings readings, slight cloud cover as well, sampled at around 11.05 am.
1.2 Gibby ------------- Promax 8.6dB. TM5402 9.5dB max.
1.8 CM ---------------- Promax 10.4dB. TM5402 11.5dB max.
1.2 Precision --------- Promax 9.1dB. TM5402 9.6 db max.
** Not a bad performance for a lashed up Precision, might be improved apon with slight lengthening or shortening of 1/2" Ka inner tube. More testing on that one.
View attachment 98139 View attachment 98140
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Will do all three readings again around 7.30pm[/
Right then,
All three dishes measured again at around 7.30pm.
1.2 Gibby ----------- Promax 9.1dB max. TM5402 9.9dB max.
1.8 CM ------------- Promax 11dB max. TM5402 12.4dB max.
1.2 Precision ------ Promax 9.4dB max. TM5402 10.1dB max.
Conclusion: The Precision 1.2 has the slight advantage over the 1.2 Gibby. Using the Ka adapter tube of 12.5mm I/D tube down the middle of the Inverto and potruding 3mm out of the original Precision feed certainly works. Tried lengthening & shortening the centre tube by 3mm and did not offer any better results.
Removing the Ka centre tube drops the Ka performance down quite a lot, around 3dB.
So: Not really worth butchering a new Inverto Ka/Ku lnbf just to give good results on Ka only, but enjoyed doing the research.