70W C-Band

[Captain Jack]

View attachment 151296

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[John]

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EnoSat is showing, highlighted in red text on his graphic, the different graphic representation of rx signal footprint as apposed to where the visable Horizon boundary is of the 70°W satellite when looking from the satellite position.
To be honest , iv'e never seen the term 'Draw Footprint' used anywhere else , so have to say that iv'e been educated.
Back on topic - I did a bit of tweeking of focal point of the 2.2 PF, moved the feed block back just over 2mm and managed to gain a drop more performance, noticable on this mornings look at 70°West analog signals which looks better than iv'e seen them before.
Comparison readings of before and after focal point adjustments are noted on the Analyser grabs, every extra drop helps .... 55.5°W used .
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[Captain Jack]

Thanks John for the explanation. A host of single-line posts (or no words at all) is very confusing.

That's a nice grab - is that still with the full blown LTE still in action?

 

[John]

Thanks John for the explanation. A host of single-line posts (or no words at all) is very confusing.

That's a nice grab - is that still with the full blown LTE still in action?

Yes, LTE at max, although dropping the setting down a notch or two does not show too much difference. Also same with the deviation setting - it's a bit of a juggling act between the two settings to acheive the best result, another advantage for me is to do the viewing early morning before the lnb gets warmed up in the sun etc. Usually for me , late Autumn onwards when the outside temparatures drop and the big Oak tree about 150 mtrs away in line of sight looses most of its leaves gives me the best results.

 

[Andreasgrdx]

These are charts of satellite channels about StarOne D2 (70.0° West) [C-band , KU-band] .

StarOne D2 (70.0° West)

Lyngsat
230810
Star One D2 at 70.0°W - LyngSat

Portalbsd
11/08/2023
PORTAL BSD

Lineup
02/08/2023 C
10/08/2023 KU

Line-UP StarOne D2 - Banda C

www.lineup.tv.br

Line-UP StarOne D2 - Analógico

www.lineup.tv.br

Line-UP StarOne D2 - Banda Ku

www.lineup.tv.br

Line-UP StarOne D2 - Sat HD Regional

www.lineup.tv.br

 

[John]

Ok, starting off then - three grabs, Original 60mm I/D feed throat / 41mm I/D throat sleeve / 56.3mm I/D throat sleeve, sleeve's made from available scrap box metals. The experiment with 41mm I/D sleeve works but in the wrong frequency range. Anything below 4.5Ghz is dramaticaly reduced to the point of signal loss from 3.6 to 4.5GHz - signal very slightly degraded from 4.5 to 4.8GHz but getting through.
I'm pretty sure that the 56.3mm I/D sleeve marginally reduced the 5G signals without noticeably degrading 3.6 to 4.8GHz signal levels.
It would be interesting to try a 55mm I/D sleeve at some point but would have to buy in the material.
Looking at the feed entry pic, it shows how the sleeve will slide in and butt up to the Circular poloriser front input face - the Norsat 8000RI 3.6 to 4.8GHz is at RHC reception.
It passed away a few interesting hours to satisfy the curiousity i suppose but 5G interference, depending how close to the source you are is always going to be a tough one to eliminate successfully , if at all.
It might be interesting for people using an lnbf to experiment with inserting various sleeve pieces - you never know.
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View attachment 151239View attachment 151240

Brief OT thread update for experimental enthusiasts - - -
On my system , based on my 5G cell tower interference distance from me , this simple inner sleeve reduction exercise to find the best rx compromise for some low band 5G interference reduction without reducing performance from 3.7GHz or so upwards is actually baring fruit. I'm no RF engineer but alongside using my excellent Promax HD Ranger+ to record progress , i have made an improvement to my fringe low level signal receptions on more than one band. I have also been using a on line Circular wave guide cut-off calculator to get me in the ball park. Currently at 50mm I/D of the feed sleeve with good results , a section of 47.5mm I/D is next to try which if i take the calculator result as somewhat near to being reasonably accurate , also remember-i'm not a professional RF engineer, just a simple experimenter , this will possibly give me a rx range from ~ 3.7GHz upwards & giving some resistance to the interfering 5G signals lower down the band ?.
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[Satfaca]

This brings me back memories on Chaparral's "Golden ring" solution in the 80s/90s, a ring was used in Polarotor/Corotor for deep dishes (f/D < .32) in order to reduce terrestrial interference (radar mostly at that time).

 

[duck77]

My signal today.

 

[John]

My early morning scan, 2.2 PF, 17K North of Nottingham UK
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[John]

My early morning scan, 2.2 PF, 17K North of Nottingham UK
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View attachment 151448View attachment 151449

Latest 5G interference C-band frequency reception damage at my QTH, 17k North of Nottingham UK.
Reception now limited to 3.8 to 4.2 GHz normal, 4.5 to 4.8GHz Extended.

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