I have been using an Octagon successfully to receive Oscar 100 ..Wide and Narrow band
I have been OK with the 1-200KHz drifting as, has been said before it settles down after 30 mins or so.
The Octagon I purchased 3 or 4 years ago is the OTLSO Twin LNB Slim Optima..which I had understood was crystal controlled PLL?
I have just purchased a Red Rocket to 'get the lens' believing it to be a puck LO ..Before I took out the hacksaw I popped it at the focus of the dish
and the received signal was pretty much identical to the Octagon ...The stability however, so far, seems to be at least an order of magnitude better
than the Octagon !
https://cgi.ebay.co.uk/ws/eBayISAPI.dll ... 2641643018
This is what I bought ..delivered from Germany in 3 days.
I leave the reader to draw their own conclusions!
Octagon or Red Rocket?
Re: Octagon or Red Rocket?
Adrian,
I bought a Red Rocket for the lens, but took a hacksaw to it before trying it. I did check on the analyser before and could not see the crystal oscillator spur like you can with the Octagon & Technomate types. Having ruined it, I took it apart this morning and you are correct, it is a PLL type and there is a 25MHz crystal in it. Extracting the board breaks it though and the crystal is on the underside. How does it compare sensitivity wise?
73 Shaun.
I bought a Red Rocket for the lens, but took a hacksaw to it before trying it. I did check on the analyser before and could not see the crystal oscillator spur like you can with the Octagon & Technomate types. Having ruined it, I took it apart this morning and you are correct, it is a PLL type and there is a 25MHz crystal in it. Extracting the board breaks it though and the crystal is on the underside. How does it compare sensitivity wise?
73 Shaun.
Re: Octagon or Red Rocket?
Hi Shaun
Thanks for the info confirming my findings on stability,
The sensitivity of the Rocket is at least as good as the Octagon.
MER of 7 -7.5 on the beacon with 1.2 M dish, new V9 software.
Whilst this is a bit lower than the 8 MER I had on the V8 software on the Octagon, the MER on the Octagon has been a bit low in recent days, possibly
the weather or changes on the satellite?
The stability is so much better than my original Octagon which I think must be DRO ?
Glad I didn't invest in a TCXO!!
Thanks for the info confirming my findings on stability,
The sensitivity of the Rocket is at least as good as the Octagon.
MER of 7 -7.5 on the beacon with 1.2 M dish, new V9 software.
Whilst this is a bit lower than the 8 MER I had on the V8 software on the Octagon, the MER on the Octagon has been a bit low in recent days, possibly
the weather or changes on the satellite?
The stability is so much better than my original Octagon which I think must be DRO ?
Glad I didn't invest in a TCXO!!
Re: Octagon or Red Rocket?
Interesting - I just retrieved mine out of the drawer (minus red cap) and on closer inspection, it doesn't look to have any DRO tuning screws.
The label says black duster which I think I read somewhere means it is PLL - I'll give it a try.
Noel
The label says black duster which I think I read somewhere means it is PLL - I'll give it a try.
Noel
Re: Octagon or Red Rocket?
Hi Noel..it occurs to me that it should be possible to slip the 2,4GHz antenna over the red cap..without the need for all the plumbing!
A
A
Re: Octagon or Red Rocket?
My first ‘Black Buster’ was definitely a DRO type. I recently bought a second one just for the lens and, assuming it was the same, never opened it up.
I have just opened it and it is definitely a PLL type.
So it looks like the design has been updated. It is probably now cheaper to make a PLL type than a DRO type, plus it doesn’t need to be tuned.
I have just opened it and it is definitely a PLL type.
So it looks like the design has been updated. It is probably now cheaper to make a PLL type than a DRO type, plus it doesn’t need to be tuned.
Re: Octagon or Red Rocket?
Yes-ish....
True, the red rocket body is 20.8mm diameter but there is a flange at the end that the red lenses goes on to which is 27mm - you would have to cut that off to get it through the hole and you would need to mount the LNB in the hole somehow...
The major "concern" with most of these LNBs is that the internal diameter of the waveguide is only 18mm which is a bit small for 10GHz (probably OK at 11.5GHz).
It would be really interesting to do a "proper" system at 10.5Ghz - waveguide transition, LNA and down converter - and see what MER difference you get.
73
Noel
True, the red rocket body is 20.8mm diameter but there is a flange at the end that the red lenses goes on to which is 27mm - you would have to cut that off to get it through the hole and you would need to mount the LNB in the hole somehow...
The major "concern" with most of these LNBs is that the internal diameter of the waveguide is only 18mm which is a bit small for 10GHz (probably OK at 11.5GHz).
It would be really interesting to do a "proper" system at 10.5Ghz - waveguide transition, LNA and down converter - and see what MER difference you get.
73
Noel
Re: Octagon or Red Rocket?
By the way, you don’t need to hacksaw the Red rocket to remove the lens. It just unclips from the front of the casting. It takes a bit of force as it is siliconed on but carefully applying pressure sideways will break the seal.
-
radiogareth
- Posts: 1236
- Joined: Wed Jan 06, 2016 9:46 am
Re: Octagon or Red Rocket?
If you soak the red cap in boiling water for a minute or so its a lot easier to get off. The silicon is a water seal, the retention is mechanical, so softening the plastic makes removal easier 
Gareth
Gareth
Re: Octagon or Red Rocket?
Noel
If the ID of the Red Rocket LNB waveguide is 18mm, then the theoretical attenuation at 10.490GHz is about 0.25dB/metre, so no problem!
My recently purchased single Rocket LNB is a PLL model and its sensitivity seems to be similar to that of my first generation dual PLL Octagon. Locking the Rocket is easy using either the Leo Bodnar GPSDO or a 25MHz version of G4HJW's circuit which was in Scatterpoint in 2014 (or do a Google search for "G4HJW lnb locking" ). The latter will probably need to be followed by a simple MMIC amplifier (MAR6 etc) and LPF (see BATC wiki). I have found that locking signal levels do not need to be high, typically -20 to -30dBm in my case. For DATV reception, however, I still get higher values of MER with an unlocked LNB (lower phase noise?)
The 5MHz OCXOs which were on sale at the Cardiff RT are suitable for G4HJW's locking circuit, but note that they have a sine wave output. Output may be taken from either sma connector - terminate the second one in 50R. Connections to the OCXO are (clockwise from pin 1)
pins 1 and 5 NC, pins 2,3 and 7 Gnd, pin 4 +V supply (nominal 20V but will run at 15v), pin 6 EFC.
73
Barry, G8AGN
If the ID of the Red Rocket LNB waveguide is 18mm, then the theoretical attenuation at 10.490GHz is about 0.25dB/metre, so no problem!
My recently purchased single Rocket LNB is a PLL model and its sensitivity seems to be similar to that of my first generation dual PLL Octagon. Locking the Rocket is easy using either the Leo Bodnar GPSDO or a 25MHz version of G4HJW's circuit which was in Scatterpoint in 2014 (or do a Google search for "G4HJW lnb locking" ). The latter will probably need to be followed by a simple MMIC amplifier (MAR6 etc) and LPF (see BATC wiki). I have found that locking signal levels do not need to be high, typically -20 to -30dBm in my case. For DATV reception, however, I still get higher values of MER with an unlocked LNB (lower phase noise?)
The 5MHz OCXOs which were on sale at the Cardiff RT are suitable for G4HJW's locking circuit, but note that they have a sine wave output. Output may be taken from either sma connector - terminate the second one in 50R. Connections to the OCXO are (clockwise from pin 1)
pins 1 and 5 NC, pins 2,3 and 7 Gnd, pin 4 +V supply (nominal 20V but will run at 15v), pin 6 EFC.
73
Barry, G8AGN