Ka B/C overlap (Hughes) Thread

Vipersan · Jul 29, 2014

Llew said:
Do rou reckon the ferrites are making a difference? I've a mind to try them myself .

In a word Llew..
Yes ..
I can't measure the effect ,,but I can show you a scan using the SL3 earlier today ..with the switch indoors ...
remember the 'crushed' signal at 42 E ?
..well crushed no more ..and very close to what I'd normally expect ..

Remember I am not using inductive coupling yet ..
Still to be experimented with ..
Simply the beads slid onto the breakout wires ..to act as chokes ..

rgds
VS

Llew · Jul 29, 2014

A difference indeed. I'm happy enough with mine as it is, but may try your breakout method to lose the extra cable coming out of the box.

Plenty of scope to try/test different methods with the switch, early days yet.

Vipersan · Jul 29, 2014

Llew said:
A difference indeed. I'm happy enough with mine as it is, but may try your breakout method to lose the extra cable coming out of the box.

Plenty of scope to try/test different methods with the switch, early days yet.

Agreed buddy ..
Something about Neccessity and Mothers I think..
lol

Vipersan · Jul 29, 2014

Totally as an aside Llew ..
I'm thinking the polariser tube on the Hughes might benefit from an extra Notch position being cut ..
You know that it can be rotated through 90 degrees left 45 or right 45 in order that it can be set for RHCP or LHCP ..
Well what about cutting another nothch so it can be set 45 / 0 / 45
I would expect this would allow almost linear passage of signals ..
Not that there are any in band C that I'm currently aware of ...but that doesn't mean there are non ..
It would allow another string to the Hughes bow..
what do you think ?
Now we have a working switch ....might as well 'eh..
rgds
VS

Llew · Jul 29, 2014

Certainly worth a try, it won't compromise the polariser's existing two settings.
As you say, a scan of the arc could possibly find something else.
Would that be just one notch?

Vipersan · Jul 29, 2014

Started with just one ..
Might include another at 90 degrees to it ..
But certainly appears to be working ..
The mixed overlap signal at 20185 ...RHCP ..now dropped from 10.3 db to 6.6db ..using the switch and both H and V ports of the Hughes.
Suggesting I'm now 'seeing' it through Linear 'eyes'..
a roughly 3 db loss ..as expected.
rgds
VS

Llew · Jul 29, 2014

Ah, I see now - photos help. Time for my dinner, might just be able to try that before sunset.

Vipersan · Jul 29, 2014

To prove a point ..just moved carl over to 12 W ..and rescanned ..
The signal 20730 which I previously got around 11.2 db is now lower at about 8.4 db ..
again not unexpected...as it appears in both H and V linear scans ....thus we conclude it is definately Circular..
rgds
VS

hvdh · Jul 29, 2014

Possible 20.2...21.2 GHz (band C) candidates:

Non-inclined:
52.6°W: WGS 5
12.0°W: WGS 3
5.2°W: Syracuse 3B
4.0°W: Amos-3
12.0°E: Sicral 1B
37.8°E: Athena-Fidus
47.0°E: Syracuse 3A
47.5°E: P360/PAN
47.6°E: Yahsat 1B
52.5°E: Yahsat 1A

Inclined, with Clarke belt passes for 30 July:
38.9°W: Milstar 1, incl. 10°, 00:31/12:28 BST
15.3°W: FltSatCom 8, incl. 12°, 07:17/19:15 BST
19.2°E: SBIRS-Geo 2, incl. 5.1°, 00:34/12:32 BST
21.8°E: Sicral 1A, incl. 5.5°, 06:56/18:53 BST
30.0°E: Milstar 5, incl. 6.2°, 05:20/17:18 BST

Vipersan · Jul 29, 2014

Thanks for the List Hans ..
Nothing new found at this point ...and certainly nothing linear ..
But only checked the non inclined birds I can see at this point ..
My summer limit being 45 East..
I shall check the inclined birds as and when they they pass through the belt.
cheers buddy
VS

Llew · Jul 29, 2014

Vipersan said:
Started with just one ..
Might include another at 90 degrees to it ..
But certainly appears to be working ..
The mixed overlap signal at 20185 ...RHCP ..now dropped from 10.3 db to 6.6db ..using the switch and both H and V ports of the Hughes.
Suggesting I'm now 'seeing' it through Linear 'eyes'..
a roughly 3 db loss ..as expected.
rgds
VS

About the same here, down by 3 to 4dB. 12W to try. Eastern arc restricted for the Triaxes, so a lot of Hans's possibles I can't check.

Vipersan · Jul 30, 2014

The peaks from 19.2°E: SBIRS-Geo 2 also appear in both H and V scans ..
So looks like this too is circular

Vipersan · Jul 30, 2014

So ..there IS a linear transponder in Ka band C
It's location Sicral 1B @ 12° East ..
According to Flysat this transponder is Vertical at 20534 ..
So I placed Carl at what I believe to be 12 East ..but can only aproximate this position by pulse counting either East from 10E or West from 13 E by pulse counting on the Gbox ..
I then scanned using the Hughes set in linear mode ...but the footprint does really extend to cover the UK ..so wasn't expecting anything ...but I got a tiny peak at exactly 20534 ?
Problem ..it only appeared on what I believed was the Horizontal scan ..
Are we sure with the OMT placed vertically on the Hughes the Top port is Horizontal ...Llew ??
Perhaps we are wrong to assume this and the open port which doesn't need switching isn't actually the V port ?
Sadly we have nothing else to reference so cannot confirm for sure we have it right ..
..and to be sure it comes from the arc ..I moved Carl 10 clicks either side and the tiny peak vanishes.

I will definately have to file a second slot in the Hughes polariser now ...just to see if perhaps this makes a difference ..
Another possibility is the de-polariser used in linear mode ..
Could the de-polariser possibly rotate the signal through 90 degrees ..??
Experiment will tell ...
here is the scan :-
rgds
VS

Llew · Jul 31, 2014

Horizontal is the top port, I remember from the last time I looked.
In that case, my potential divider circuit going into the comparator +/- might be reversed - I took a guess at which inputs switched H and V - an evens chance that it was correct, but I didn't know which ports the Hughes receiver switched to. We may need to reverse the resistor configuration.

Vipersan · Jul 31, 2014

Not a problem Llew ..
Just wish we had concrete evidence what I am looking at ..
but sadly I can't see another linear transponder in Ka B or C..
So frustrating..to be this much in the dark..
rgds
VS

Would just swapping the 7k5 for the 1k5 and vice versa do the job ?..or is it neccessary to swap both potential dividers to pins 2 and 3 ..
ie the 10k/10k divider and 1k5/7k5 on pins 3 and 2 moved ..

Trying to have as little impact on the verro as possible ..so as not to damage it..
Very much a tight squeeze on there now.

Vipersan · Jul 31, 2014

Thinking about it this morning Llew ..

The Bottom Port on the Hughes is the one opened by switching on the 27mhz osc ..which in turn is activated during the Vertical scan ...13v
Proven using the port coverup method ..
This being the case ...it leaves a few unanswered questions and/or possibilities.
That the small peak I am seeing is not the carrier from Sicral 1B
That it is incorrectly labelled polarity wise at Flysat and 20534 is actual Horizontal not Vertical..
That the polariser which I assumed when positioned between the 2 preset notches isn't allowing the signal straight through ..but rotating it through 90 degrees..?

Personally I think we have the 2 Hughes ports incorrectly labelled..
ie UNswitched is Vertical ..not Horizontal
???

Llew · Jul 31, 2014

Vipersan said:
Would just swapping the 7k5 for the 1k5 and vice versa do the job ?..

No VS, way too high voltage into the comparator to compare with the reference 10K/10K 2.5V.
V at 7.5K/1.5K as it is now is 2.2V with 13V applied, and 3.2V with 19V. So switch operates when voltage > the 2.5V reference.

(V=R1/R1+R2)

Llew · Jul 31, 2014

Vipersan said:
Thinking about it this morning Llew ..

The Bottom Port on the Hughes is the one opened by switching on the 27mhz osc ..which in turn is activated during the Vertical scan ...13v
Proven using the port coverup method ..
This being the case ...it leaves a few unanswered questions and/or possibilities.
That the small peak I am seeing is not the carrier from Sicral 1B
That it is incorrectly labelled polarity wise at Flysat and 20534 is actual Horizontal not Vertical..
That the polariser which I assumed when positioned between the 2 preset notches isn't allowing the signal straight through ..but rotating it through 90 degrees..?

Personally I think we have the 2 Hughes ports incorrectly labelled..
ie UNswitched is Vertical ..not Horizontal
???

...yes, I reckon we need to swop comparator inputs. as I said, knowing my luck I had to choose the wrong inputs out of the two choices.

Vipersan · Jul 31, 2014

Llew said:
No VS, way too high voltage into the comparator to compare with the reference 10K/10K 2.5V.
V at 7.5K/1.5K as it is now is 2.2V with 13V applied, and 3.2V with 19V. So switch operates when voltage > the 2.5V reference.
(V=R1/R1+R2)

yep ...realised this shortly after I posted it ..
Silly me ..not thinking straight ..but it was late ..
my excuse and I'm sticking to it ..
lol

Vipersan · Jul 31, 2014

Llew said:
...yes, I reckon we need to swop comparator inputs. as I said, knowing my luck I had to choose the wrong inputs out of the two choices.

I suffer a lot from 'Sods' or indeed Murphys Law myself Llew ..
perhaps you should leave the Nags alone this week ..
;)

Ka B/C overlap (Hughes) Thread

Emmett Browns Ghost

Attachments

cerca trova...

Emmett Browns Ghost

Emmett Browns Ghost

cerca trova...

Emmett Browns Ghost

Attachments

cerca trova...

Emmett Browns Ghost

Specialist Contributor

Emmett Browns Ghost

cerca trova...

Emmett Browns Ghost

Emmett Browns Ghost

Attachments

cerca trova...

Emmett Browns Ghost

Emmett Browns Ghost

Attachments

cerca trova...

cerca trova...

Emmett Browns Ghost

Emmett Browns Ghost