Another Logistics nightmare solved :- Hughes KA lnb

[Vipersan]

I am not sure if this is any use VS, but its all I can find.
http://www.uhf-satcom.com/kaband/

Yep thats one of the relevant pages Martin.
Also ..this PDF link attached is carrying relevant data regarding the SL3 and upconvertor ..
http://www.tele-audiovision.com/TELE-audiovision-1305/eng/vitorsworkshop.pdf
Finally a link showing the relevant component parts of the Hughes beastie.
http://www.techtir.ie/taxonomy/term/1000371
rgds
VS

 

[JOHN896]

I bought one of those Hughes lnbs back in 2011 from the usa,for the early days of 9 east Saorsat i had too take it apart from the feedhorn.Still have the feedhorn and lnb.

 

[Vipersan]

I bought one of those Hughes lnbs back in 2011 from the usa,for the early days of 9 east Saorsat i had too take it apart from the feedhorn.Still have the feedhorn and lnb.

Looking forward to getting mine to take apart John..but may be a while yet ..
It's currently on holiday in Jamaica.
How do you rate the lnb sensitivity compared to a dedicated Saorsat Inverto ?

 

[JOHN896]

The last time i used the Hughes lnb was back in 2011,i find it easier just to use the Inverto lnb.

 

[Vipersan]

..Bet you'd forgotten about this ...
I hadn't ..but it still came as a surprise when I answered the door this morning and my neighbour presented it to me.
A well travelled Hughes indeed ..having been sent overland from middle america ...to Seattle ...then taken by my neighbour when he went from his brothers home to visit parents in Jamaica ..
Finally returning home to the UK this week ..he brought it with him.
Here are a few photos..
I particularly like the 7 concentric ring ..conical oval feed ..
If nothing else ever gets used ..this bit certainly will..
lol
something to play with over the winter months I think.
rgds
VS

 

[Lazarus]

Yep, a concentric ring is always good value for a spot of tinkering during those otherwise unfulfilling Winter months.

 

[Vipersan]

Not had much time to experiment yet ..but took apart the various components of the Hughes..
The OMT looks interesting..btw
Lashed the eliptical feed directly to one port of the lnb ..
Horizontal I think..
Substituted for the band D Ka lnb on the gibby ..and pointed at Hylas (34W)
Here are the photos ...including a quick blind scan of Hylas.
Just to establish functionality.
rgds
VS

 

[Llew]

Looks like you have an interesting setup with the added Hughes LNB VS. Scope for plenty of experimentation there.
I must get the Gibby LNB bar and holders myself, to save having to swop out Ka and Ku LNB's. Where did you get yours VS?

 

[Vipersan]

Looks like you have an interesting setup with the added Hughes LNB VS. Scope for plenty of experimentation there.
I must get the Gibby LNB bar and holders myself, to save having to swop out Ka and Ku LNB's. Where did you get yours VS?

This is the one I bought Llew ..
Came from Germany.
151139319252
perhaps not the best one ..but the price was right.
rgds
VS

 

[Llew]

Ho hum. Just ordered one from a UK supplier costing half as much again. Might not be a Gibby original, but should be OK.

Thanks anyway.

 

[Vipersan]

I reassemled the Hughes to include the OMT/filter and depolariser.
More to see how it works and how effective it was..
The lnb expects linear inputs for H and V..
Since I dont know how to switch between the 2 input ports of the LNB ..I have to let the OMT split this and I assume only one of the ports is active.
The depolariser is a nice bit of precision engineering..
The Oval feed takes circular signals from 9 East ..and the depolariser then converts these RHCP or LHCP signals to V or H..to be then split and sent via the OMT/Filter to the correct orifice on the LNB.

What's Nice about the depolariser conduit is that it can be rotated through 90 degrees ..

Thus one can depolarise either RHCP or LHCP to the one active port on the Hughes LNB..
So even though I can't select which port I use ..I can resolve either L or R ..mechanically.
In short it works..
Here is a snapshot of the Vertical Carrier (I call it the Jamming carrier) at 20185 ghz
IE the Saorsat freqency..
very much TOD but on a par signal level wise with the Inverto Dual lnb.
rgds
VS

 

[Vipersan]

Oh ..and I since found out that the way to switch the Hughes between H and V _apparently_ is by injection of a 28MHZ signal into the IF line ..in much the same way as a 22khz band switch..
Not tried this as I haven't the necessary gear ..but maybe one day..
;)

 

[Lazarus]

No old CB Radio gear lying around that you could tweak a little?

 

[lovelyperson]

...... ..but thats what being a curious DXer is all about .........

and we would not want to change a thing!

Whatever, every day in this hobby is different, its great and peeps like you and folk here keep the interest there for us all.

 

[Llew]

Oh ..and I since found out that the way to switch the Hughes between H and V _apparently_ is by injection of a 28MHZ signal into the IF line ..in much the same way as a 22khz band switch..
Not tried this as I haven't the necessary gear ..but maybe one day..
;)

VS, you could try something like this that I constructed while pending (aborted) arrival of the Hughes upper band LNB assembly.

Choosing receiver Vertical polarisation gives high output from the comparator LM393, which enables the Xtal oscillator to output 27MHz.

Choosing Horizontal polarisation, comparator goes low and switches off the 27MHz.

If the LNB needs Horizontal to output 27MHz, just reverse the - and + inputs to the comparator.

No doubt the 27 MHz injection to the LNB will need a capacitor for isolation between the circuit and LNB input.

Xtal oscillator is available at Farnell http://uk.farnell.com/epson/hg-2150ca-27-00mhz-svh/osc-high-stability-27-00mhz-5v/dp/1907492

Voltage comparator can be any similar chip you have to hand I suppose. The comparator output pull-up resistor I used (8.2K) can be 10K, I had run out of them at the time.

R3 two 15K's in parallel if you don't have a 7.5K.

 

[Vipersan]

VS, you could try something like this that I constructed while pending (aborted) arrival of the Hughes upper band LNB assembly.

Choosing receiver Vertical polarisation gives high output from the comparator LM393, which enables the Xtal oscillator to output 27MHz.

Choosing Horizontal polarisation, comparator goes low and switches off the 27MHz.

If the LNB needs Horizontal to output 27MHz, just reverse the - and + inputs to the comparator.

No doubt the 27 MHz injection to the LNB will need a capacitor for isolation between the circuit and LNB input.

Xtal oscillator is available at Farnell http://uk.farnell.com/epson/hg-2150ca-27-00mhz-svh/osc-high-stability-27-00mhz-5v/dp/1907492

Voltage comparator can be any similar chip you have to hand I suppose. The comparator output pull-up resistor I used (8.2K) can be 10K, I had run out of them at the time.

R3 two 15K's in parallel if you don't have a 7.5K.

Interesting Llew ..
I will certainly give it a try If or When my other Hughes ODU ever gets here ..
The OMT and feed have as you know already been assigned ..and the feed modified and fitted on the Ka Hi band lnb ..so would have difficulty trying the lnb atm.
It requires the OMT to interface with both H and V ports ..them being separate on the hughes lnb.
cheers
VS

 

[Llew]

OK, fair enough. Just an idea. Will need some further elaboration, e.g a low-pass filter at the input similar to the microstrip filter used in LNB inputs; maybe a low microHenry choke would suffice.

BTW, you mention a 28MHz signal, but the only reference I can find for the signal is 27MHz at UHF-Satcom.com. Perhaps you have another source?

 

[Vipersan]

OK, fair enough. Just an idea. Will need some further elaboration, e.g a low-pass filter at the input similar to the microstrip filter used in LNB inputs; maybe a low microHenry choke would suffice.

BTW, you mention a 28MHz signal, but the only reference I can find for the signal is 27MHz at UHF-Satcom.com. Perhaps you have another source?

Probably the same reference I read Llew ...and I just remembered incorrectly..
If it says 27mghz then that will be correct.
I read so many bits of info cruising t'internet and forget more than read..
old age y'know..
lol

 

[Llew]

Not sure what to make of this VS. I switched the H and V ports of my Hughes LNB using a 27MHz injection, and compared the resulting scans.

Without the switch, I get the usual 20185H/L locked. With the switch on, the scan at 20185 (V/R) is presumably a different carrier on 9E. Nothing locks on that.

I can't find any info on what's transmitted on these V/R TP's, if that's what I'm receiving. Or am I deluding myself with this switching?

 

[Llew]

These scans might be a little clearer.
Definitely two separate carriers around the Saorsat frequency.