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Re: serit tuners ?

Posted: Thu Sep 05, 2019 7:30 am
by g0mjw
Like this. You don't adjust it, you set your IF gain appropriately with amplifiers or attenuators if necessary.
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Mike

Re: serit tuners ?

Posted: Thu Sep 05, 2019 8:48 am
by sean2e0saf
So mike although im trying to get as much signal as possible there is such a thing as to much signal so i have to att the signal... im assuming since i have changed my lnb from a old dro type to a pll one im now getting to much signal..

Re: serit tuners ?

Posted: Thu Sep 05, 2019 9:48 am
by g0mjw
Yes. As long as you are not powering the LNB through the minitioune you can just attenuate the IF. In my case there is a 1:4 splitter so I can attach multiple receivers.

However, the signals from an LNB are not usually that strong, especially after a few metres of satellite TV quality coax. There may be another reason for this. What exactly is the setup?

Mike

Re: serit tuners ?

Posted: Thu Sep 05, 2019 9:56 am
by sean2e0saf
The set up is a 1.5mtr prime focus dish with approx 20mtrs of cable tv virginmedia quality coax maximum. And of course the minitiouner rx.

Lnb is a octogon one i forget the model.

Re: serit tuners ?

Posted: Thu Sep 05, 2019 10:40 am
by g0mjw
You should not be seeing overload then. That's the same as me except my dish is bigger. I do have the splitter though. I would try attenuation and see. The lower LNA gain might not make much difference. If the MER is OK it's probably fine. You should see 9-10 dB on the beacon.

Mike

Re: serit tuners ?

Posted: Thu Sep 05, 2019 11:26 am
by sean2e0saf
About mer 8.1 ish at the moment but i have not finished with lnb i have not fitted the patch antenna for 2.4ghz yet. Im just waiting for a new lnb clamp to come i ordered from satellite superstore

I may need to extend the lnb arms as my initial measurements make the focal point to close to the dish

Re: serit tuners ?

Posted: Thu Sep 05, 2019 7:43 pm
by G8PEF
sean2e0saf wrote:
Thu Sep 05, 2019 9:56 am
The set up is a 1.5mtr prime focus dish with approx 20mtrs of cable tv virginmedia quality coax maximum...
Sean - do you know what type of cable Virgin media use to make the connection between the outdoor termination point and the indoor modem/router? I'm looking to replace and/or extend a length of it, but haven't a clue what the spec is.

73
John

Re: serit tuners ?

Posted: Mon Sep 09, 2019 11:26 pm
by sean2e0saf
hi john to be honest mate i have no idea... the cable im using is the cable that comes in from the street to the brown box on the wall outside.

a local ham here has a large roll of it.. i do believe its commscope cable but no other markings i have looked on net and im sure its this

https://www.commscope.com/catalog/cable ... x?id=25190

exactly how good it is at 10ghz i dont know.

it is coated internally with sticky waterproofing gel

hope this helps

Re: serit tuners ?

Posted: Tue Sep 10, 2019 2:11 pm
by 2W0ODS
sean2e0saf wrote:
Thu Sep 05, 2019 12:45 am
F6DZP wrote:
Wed Mar 06, 2019 6:54 pm
No, it is not a problem if you observe the LNA gain. The best is to have 13dB gain.
This LNA has an AGC so if the signal is too much high, its gain goes down and at the end it acts as an attenuator.
If you see that your LNA gain is less than 3dB or negative (=attenuator), you know that your input signal is too high.

So, Just to observe the LNA gain to know what could be bad on this side.

(Near the LNA gain, I have added an emoticon :( in the version 0.9 to give more advertising about the Input signal when it is too high)

This LNA chip is used by ST Micro in their Professional Demo PCB.

Jean-Pierre F6DZP
jean-pierre

how do i change the lna gain.. i see 0.9db at the moment sad face
I too have the Sad Face, my dish is a 1.2m CM with an Octagon Green Quad, my MER is usually 8-8.1 but at the moment my LNB is not in the right place as I changed to an adjustable bracket and not tightened it up so it moves in the wind :lol:

Re: serit tuners ?

Posted: Tue Sep 10, 2019 5:23 pm
by G8PEF
sean2e0saf wrote:
Mon Sep 09, 2019 11:26 pm
hi john to be honest mate i have no idea... the cable im using is the cable that comes in from the street to the brown box on the wall outside.

a local ham here has a large roll of it.. i do believe its commscope cable but no other markings i have looked on net and im sure its this

https://www.commscope.com/catalog/cable ... x?id=25190

exactly how good it is at 10ghz i dont know.

it is coated internally with sticky waterproofing gel

hope this helps
Thanks, Sean - that's probably the stuff... In previous installations I've had, the outdoor cabling was 'figure 8' zip apart combined coax and telephone cable, but there was no facility for landline phones here when Virgin first came around, so this installation is coax only.
Curiously, I don't have the brown box, either - the coax comes from the cabinet right into the house... Go figure.