..and so it begins ..

[Vipersan]

Going to have to leave this a day or so to fully cure such that I can drill or tap it..
but here is what I was hoping for ...and might well back fill the gap previously occupied by plasticine at a later date..
rgds

 

[Lazarus]

Suddenly, with mention of Plasticine, I'm all ears

 

[Vipersan]

Suddenly, with mention of Plasticine, I'm all ears

Everyone lurvs plasticine G ..
Brings out the big kid in everyone ..lol

 

[Vipersan]

Hmm ..the liquid plastic cured much quicker than usual ..
but then it's quite warm atm..
So drilled 3 holes and mounted the XMW feed with 3 tappers..
Obviously can't mount a 4th..
Still it seems strong enough..
Reassembled the lnb guts..but only connected one output..
Tomorrow the back plate goes on ..and I get to see if it still functions..
lol

Wish me luck..
;)
Done for tonight ..
The 'Prof' (Cox) is on soon...

 

[Vipersan]

So ..I got impatient ..
No surprise there..
Went out and fitted the modded SL3 on Neil...
No Idea what I'm looking at fequency wise ..all I can tell you is that it's Ka low band and pointing at Astra 19.2 East.
Here are 2 scans first in H and then in V..
Only one of the probes is effectively in use due to the slot positioning of the XMW feed ..and the disn of the SL3..
ie only one of its probes actually in the bottom of the waveguide..the other is offset outside the waveguide ..and signals are funneled sideways to it.
Making it neccessary to manually rotate the assembly to receive the opposite polarity..
But I DO believe this is now accepting linear feeds to that one central probe..
There is a massive peak resolveable in H ..and I'm also attatching the constellation 32psk..

I believe this is appearing in what is considered to be 'the military use part of the Ka spectrum'.
There is a second smaller peak ..but I can't lock this atm..
maybe circular ..maybe just not strong enough..
I certainly think this is at least a partial success..
rgds
VS

 

[Vipersan]

Did a check on Flysat ..and according to the SR 5200 ...the peak is actually Vertical not Horizontal ..and frequency wise 18509 ..
So tomorrow I'll manually rotate the lnb ..and try for Ocko ...
A longshot but you never know ..
lol

 

[Vipersan]

Assuming I am correct about the massive peak ..then I can get it to use a range in crazyscan ..indicating roughly the correct frequency by setting the LO to 16570 ..and adjusting the range start and end limits accordingly..
This 'fudge' is neccessary firstly cos I am not absolutely sure of the LO inside the SL3 ..
Not sure how much _out_ the modded SL3 is now I have been inside its guts ..
and the real fly in the ointment ..the SUP2400 upconvertor has to be in line as well.
But ..now I have a known reference signal ..I can at least use the SL3 correctly to some degree.
Nice

 

[Vipersan]

Last pix for tonight ..
The Modded SL3 on Neil ..
at the focus and weight supported by the XMW feed..

 

[Analoguesat]

Superb mods VS

 

[hairybadger]

Tidier than my bog-standard installs......

 

[Vipersan]

Ok ..Ocko was a longshot ..with this modified setup ..and such a low signal ..
But attached is a composite double scan .
In both instances ..both H and V were scanned ..
The difference between the two images..
the SL3 was rotated through 90 degrees at the dish ..The top scan favours Horizontal in this position .
The bottom scan biased in favour of Vertical signals..
Proving that signals do indeed get to both probes including the offset funneled one...as well as the one in direct line of fire.
Hence the bias on rotation of the SL3.

Images of the scans are aligned such that the massive peak at roughly 18509 ...present in both images ..but only large enough to be locked and produce a 32psk constellation when the SL3 is rotated for vertical bias..
I think this proves conclusively that the modded SL3 is functioning -more or less- in Linear mode ..where once it was Circular..
I'd call the experiment a success ...
..but am frustrated that the SL3s pcb layout makes it impossible to bet 2 probes at 90 degrees to each other ..directly in the signal flow within the main waveguide.
rgds
VS

 

[pride21]

well done VS i have been watching this to see how you have been moding this,very interesting.

 

[Vipersan]

got to go open the shop now ..but interestingly ..this peak has appeared in the last 20 minutes ...
Possibly Ocko ...
It's certainly in the right region of my hastily cobbled and guesstimated scale..
later
VS

 

[Llew]

Mightily impressed with your mods with that LNB combo so far VS. Did you find the exact LO of the SL3 eventually?

 

[Vipersan]

Mightily impressed with your mods with that LNB combo so far VS. Did you find the exact LO of the SL3 eventually?

Sadly not Llew..though I suspect it is 18050 approx..
it gets a bit more complex of course when up converted through the SUP ...as another oscillator becomes involved before the signal finally arrives at the TBS card.
This of course assumes I haven't affected the osc too much by disassembly..
Reference transponders always help in this regard.

I'm concentrating on a fully circular waveguide feed next..to see if this is compatible with the altered SL3..
I have a choice to try and make one ..eeek.
Or get my hands on a duff inverto Saorsat lnb to butcher for its feed..
If anyone has one they don't want ..I'd gladly buy it for a reasonable sum..
Dont want to butcher a worker ..and 30 quid plus is too expensive for a new one just to cut up.
rgds
VS

 

[Vipersan]

Today I seperated one of the Ka feeds from the lump removed from the SL3 ..with a view to making it attachable to any of my Ka lnbs with a flange fitting..
No doubt I'll employ my old friend ..liquid plastic to make the flange..
..and of course it will require a collar to make it round and thus fit a standard offset dish bracket..
Something to play with I guess..and I take pleasure in re-purposing rather than binning the offcuts..
The septum was removed as well from the waveguide part of the horn.
rgds
VS

 

[Vipersan]

Some key slots filed into the bottom of the oval feed ..approx 1/4 & 1/2 inch up from the bottom..

Found a pill tub about the right diameter ..
trimmed for depth..
this type of pill tub has a centre pip extrusion inside ..so makes for esier cetntering of the feed horn..
a quick squirt of carpet tack on the bottom edge of the feed where it connects to the lnb..and quickly pushed into place inside the pill tub..
one centred and attched ..a small mix of liquid plastic and poured into the surround ..
the carpet tack prevents it flowing into the feed center ..and welling inside.
..and now for the wait ..
Should be about 30 minutes before I can peel off the pill tub.
I'll add a photo once removed..
rgds
VS

 

[Vipersan]

The Pill tub was mightly reluctant to let go ..
Luckilly it was brittle plastic so easily broken away in chunks ..
Result attached.
rgds
VS

 

[Lazarus]

My dear Edison Evan, I am in awe!

 

[Vipersan]

My dear Edison Evan, I am in awe!

..Wouldn't go _that_ far G ..but for as long as I can remember I have been able to look at a thing and see roughly how it works ..and if I needed something ..and it wasn't available..
More often than not I can make it ..or make something else do the job..
If I have a gift ..that's it..
Edison..crossed out or otherwise ..I ain't.
lol
kind comments nonetheless..
VS