Upper band Ka reception

[Vipersan]

Ltm on 16 E appears to have gone and replaced by LCF ?
same settings but had to rescan so different PIDs ..
here is the proof..
Highly unstable lock here even at +8db
rgds
VS

Well I guess it aint new ..
Flysat has it down as La Chaîne du Futur
but it didn't stay long here ..
gone now..
This ka stuff is real frustrating
;)

 

[Llew]

Yes, LCF comes and goes regularly. Last time I had it was back in post #230, Thread 12.

Only get Vision 4, Golfe and Impact this morn.

 

[Vipersan]

Yes, LCF comes and goes regularly. Last time I had it was back in post #230, Thread 12.

Only get Vision 4, Golfe and Impact this morn.

Same here Llew ..
That's Ka for ya ..
'unpredictable'

 

[Llew]

7E Feed 'Africa Live' 21603H. I think this uplinked from Somalia, having seen the feed earlier with a Mogadishu logo.

 

[Vipersan]

Nice catch Llew ..
A bit late for me to try and catch the feed ..but I do have a question..
Muvi mux is barely lockable today at 5.3db (usually solid locked at about 8db)...but Azam mux for me has vanished ??
usually 10db plus ..
Do you still get this ok ?
TPA still locks as does 2STV ..which has been solid here for over a week..
rgds
VS

 

[Llew]

Just doing a scan...

 

[Llew]

At present, I get Azam at 9.9dB, but no Muvi! Make what of that what you will, VS

 

[Vipersan]

Odd stuff this Ka ain't it ...
I guess fringe reception will always behave oddly at these frequencies...but it does make me wonder if these transponders are steerable ...

..and your scan shows no sign of 2STV either ?? (7.3db here)

 

[Vipersan]

Looks like Azam was a temporary outage ..
back now at 12.2 db ..
..and Muvi mux now up at 9.2db
talk about weird..
lol

 

[Llew]

Yes, odd but keeps us on our toes.

As an aside, I couldn't resist getting hold of a Triax Ka LNB for some experimenting. I'm doing some tests on the DRO to try shifting the frequency with a mod on the adjusting screw - I've managed to bring the LO up to around 22.4GHz from 21.2. Which maybe would allow reception of upper band frequencies on the LNB (assuming the bandpass filter allows them through...)

Or I'm chasing the impossible...

 

[Llew]

Looks like Azam was a temporary outage ..
back now at 12.2 db ..
..and Muvi mux now up at 9.2db
talk about weird..
lol

Yup, both up now here.

 

[Vipersan]

Looking forward to seeing your results on the modded triax Llew..
gotta go for now ..
Python movie on tv ..and I love my Python..
So time to stop this as it's all getting very silly....
lol

 

[Vipersan]

Just locked CCTV Africa sat HD - using the same specs as yesterday posted by Llew..
8.5db here..(F15)

Now at 9.8db...

reporter Wang dong reporting on the France Nigeria game ..
Is his name a double double entendre I wonder ;)
rgds
VS

 

[Llew]

Just locked CCTV Africa sat HD - using the same specs as yesterday posted by Llew..
8.5db here..(F15)

Now at 9.8db...

reporter Wang dong reporting on the France Nigeria game ..
Is his name a double double entendre I wonder ;)
rgds
VS

I think they're one and the same VS. Africa Live appears a couple of times a day on that network according to the CCTV Africa website -

http://cctv.cntv.cn/lm/africalive/01/index.shtml

 

[Vipersan]

Yes, odd but keeps us on our toes.

As an aside, I couldn't resist getting hold of a Triax Ka LNB for some experimenting. I'm doing some tests on the DRO to try shifting the frequency with a mod on the adjusting screw - I've managed to bring the LO up to around 22.4GHz from 21.2. Which maybe would allow reception of upper band frequencies on the LNB (assuming the bandpass filter allows them through...)

Or I'm chasing the impossible...

Any progress with this experiment Llew ?
I ask because I'm reassembling my cut up inverto dual for experimental duties..
lol
As you know I'd cut a chunk out of the casing which included the feed and a right angled section..
So I'm replacing this section and the feed with a simple 12mm OD section of copper pipe and copper plate..
Can't see any reason for it not to work..but of course there is no longer a concentric ring feed on the end of the waveguide..
This is open to experiment ..but not thinking that far ahead as yet..
Just getting it going again will be enough for now.
rgds
VS

 

[Vipersan]

Oh well ..
Still can't get Saorsat ..but no surprise there ...and the lnb is basically pseudo linear now anyway..
Still ..
Good to know it still functions with the Hughes feed rough cobbled onto the 12mm waveguide..
rgds
VS

 

[Llew]

That's a pretty good stab at matching the LNB to a feed VS. Maybe the inner diameter of the pipe is a little too wide for a good match?
Maybe a closer size tube would improve things, something like the brass tubing KS137 or 138 from here -

http://www.alwayshobbies.com/materials/metal/section/k$4s-brass-tube

I did think of doing something similar with my Triax LNB, as with the 'experiment' I tried, I couldn't get the LO to be stable enough at the frequency required for upper band working, also I think it had dropped off too far for the mixer diodes. So I've detached the feedhorn from the body, and I'm now using it for the XMW LNB.

Interestingly, by happenstance two of the holes for screwing the inner cover of the Triax LNB through the circuit board to the LNB body exactly match the WR42 screw holes, so it was just a question of drilling them out for the screws that hold the feed to the XMW, and making two more holes.

I notice the Triax feed has fewer concentric rings than the Inverto's, but on initial checking of various transponders, there appears to be little difference in performance compared to the Inverto feed.

 

[Vipersan]

Fairly close match the internal Diameter of the copper pipe ..
approx. 10mm ..
Just the outer that's actually 12mm ..
1mm wall thickness.
Interesting design differences with the Triax and the Inverto..
Perhaps home brew feeds are more viable with less rings.
As you recall the all copper feed was modelled on the inverto and I swore I'd not make another cos of the difficulty
But less copper rings is certainly a more doable proposition..
Have you got any callipers Llew ?
If so some measurements would be VERY useful..
although possibly time consuming.
rgds
VS

 

[Llew]

Yes, I have digital calipers VS. Good idea. I'll attempt to measure up and compare, although my eyesight's not so good these days. But I'll do my best.

 

[Llew]

Some measurements of the feed rings Of the Triax feedhorn VS.

Ring 'A' 35mm O/D
Ring 'B' 28mm O/D
Ring 'C' 20mm O/D

All rings 2mm thick.

Diameter of hole 'D' 10.83mm.

Distance between ring 'A' to 'B' and 'B' to 'C' (inside wall distances) 4mm.

Distance between ring 'C' and hole 'D' (inside wall distance) 10mm.

Those are as near as dammit that I could manage VS, good luck if you're up to doing something with them.