Can I use Octagon dual ports for NB and WB transponder

Latest News and Discussion about the use of the DATV transponder on Es'hail-2
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g4bbh
Posts: 71
Joined: Thu Mar 13, 2008 7:19 pm

Can I use Octagon dual ports for NB and WB transponder

Post by g4bbh » Sun Apr 14, 2019 9:17 pm

I have used the Octagon LNB for one job at a time but would like to have one port for horizontal polarisation and the other port for vertical polarisation simultaneously. Sot of multitasking QO-100. Is it enough to feed 13V to one port and 18V to the other simultaneously?
By the way I have wrapped some foam insulaion around the LNB body and the drift is much slower so easier to follow any SSB drift.
Dick G4BBH

G1BVI
Posts: 145
Joined: Wed Aug 02, 2017 7:32 am

Re: Can I use Octagon dual ports for NB and WB transponder

Post by G1BVI » Sun Apr 14, 2019 9:31 pm

That is exactly what I do.
Mine is actually Horizontal so Mini Tiouner feeds port 1 in my case on LNB with 12v.
I have an ebay DC -DC up converter to feed a bias T.
The output of this is actually switched so I can have 12V or 18V out.
Normally 18V is output and this feeds a SDR for trveiving SSB.
Its quite stable but does drift over time.
I think your idea of an insulating wrap is a good one and is what I will do next week.
Drift is however very slow and easily rectified with a few mouse clicks.
73

Nick

g4bbh
Posts: 71
Joined: Thu Mar 13, 2008 7:19 pm

Re: Can I use Octagon dual ports for NB and WB transponder

Post by g4bbh » Sun Apr 14, 2019 10:58 pm

I now have some of the ebay bias tees but am still using a home-made one. I also use a Chinese step up DC converter with a switch for 13/18V switching. Now I have built he Minitiouner V2 (it worked first go!) I want one port on the LNB to moitor the video whilst I use the other port with a Funcube Pro+ to receive SSB/CW at the same time. I just wasn't sure if you could feed two different voltages to the two LNB ports at the same time. I would hate writing off the Octagon now that they are rather rare.
Meanwhile I am also working on the transmit side but that will take a while.
Dick G4BBH

G1BVI
Posts: 145
Joined: Wed Aug 02, 2017 7:32 am

Re: Can I use Octagon dual ports for NB and WB transponder

Post by G1BVI » Mon Apr 15, 2019 12:17 pm

Hi Dick
As you have probably found it is also best to leave power to the LNB ON.

I have low drift but the worst drift is from some transmitters on SSB and then the responding station also drifting and not netted.

I too have all this learning curve to look forward to.

Currently constructing a higher power Amp but struggling to source reasonably priced 90 degree hybrid combiners :(
hear and see you soon on SSB and DATV

73

Nick
G1BVI

g8vpg
Posts: 299
Joined: Fri Oct 11, 2013 9:35 am

Re: Can I use Octagon dual ports for NB and WB transponder

Post by g8vpg » Mon Apr 15, 2019 12:41 pm

Try both ports for ATV - I found that the MER was 1dB higher on one than the other. There is another PLL Octagon twin now available;
https://www.redappledigital.co.uk/produ ... echnology/
I have one here, but haven't had time to try it yet. Be careful, because there is an identical looking and named variant that is cheaper and is not PLL.
73 Shaun.

m1cdq
Posts: 9
Joined: Thu Feb 28, 2019 4:28 pm

Re: Can I use Octagon dual ports for NB and WB transponder

Post by m1cdq » Mon Apr 15, 2019 8:27 pm

i'm using the quad octagon oqslg green hq on WB and NB
I align the dish on bbc arabic

then on Duabi one 12130v 27500 3/4 its a weaker transponder but if you can get a lock on there to have it bang on position
i find my 1m dish is very sensitive.

one port is fed 12v via bias T for vert for NB on my sdrplay.
The 2nd port fed from my minitoiune thats has got a 12/18v switchable lnb supply feed( added it myself )
3 port goes to my sat receiver for Normal Tv
Im receiving ATV signals down to 66ks got a good signal of G7JTT tonight at 66ks

2W0ODS
Posts: 25
Joined: Sun Oct 21, 2018 5:15 pm

Re: Can I use Octagon dual ports for NB and WB transponder

Post by 2W0ODS » Mon Apr 15, 2019 8:39 pm

Yes no problem at all, each output behaves as an individual LNB with H/V and Hi/Low bands selectable independently. In a domestic setting multiple satellite receivers can run on multiple output LNBs.

The exception to this is with Quattro LNB's where each port is one of the following: Hi V, Low V, Hi H, Low H. These do not use tone or voltage switching.
Last edited by 2W0ODS on Mon Apr 15, 2019 9:36 pm, edited 1 time in total.

G1BVI
Posts: 145
Joined: Wed Aug 02, 2017 7:32 am

Re: Can I use Octagon dual ports for NB and WB transponder

Post by G1BVI » Mon Apr 15, 2019 8:44 pm

The Octagon LNB I use is modifier by Darko and Port 1 has a LO of 9.3887 with a stability of 6ppm.

Port 2 has a LO of 10.057529 with a stabiliuty of 2PPM

seems to work very well.

73

Nick

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