Increasing the signal strength for DVB T

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KapitiGeek

4 posts

Wannabe Geek

# 36174 21-Jun-2009 12:35

I have 51% signal strength on a brand new 14db aerial with LOS to Ngarara. I am in the fringe area, but thought I would be okay with the height of the house. When I got the alignment right by GPS I realised I literally could see the transmitter on the horizon. This is despite already having an old hills minilink with 20db gain inside and new RF cable, bar a short length thats old but externally sound.

Should I upgrade to a better aerial (if so what Db)?

Should I now go for a masthead amp instead?

Also the aerial has the option of rotation down from the horizontal, should I use this to point at the middle of the mast, which is slightly below my horizon?

Thanks

cyril7

7056 posts

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# 227129 21-Jun-2009 12:57

Dont worry about signal strength, whats the quality or BER reading, if this is all good then dont worry about signal strength. In the raumati region with LOS a 14dB antenna is more than enough.

The beam width of your antenna is in 10s of degrees, so to play with the elevation will achieve little. Only reason you would need an amplifier is if you had lots of cable or more than 3-4splits.

Edit: I seem to remember I offered to do a free site appraisal with a meter last time, if you still want to know if 51% has a meaningful measurement then I am still happy to measure that for you and make any pointers.

Cheers

Cyril

KapitiGeek

4 posts

Wannabe Geek

# 227151 21-Jun-2009 16:03

Hi Cyril,

You did indeed, but I felt akward about calling you out when I was planning to replace the damaged aerial myself.

The "Quality" is typically 39%, which is all the analysis that I get from Blaze 2.5. It finds the three Signals, but can't get the channel info, or it finds the channel info but reports there are no channels.

There is about 20m of cable, with a hills amp in the middle. There is a 3 way split, with two channels connected (with 1m and 3m tail) both plugged in. Most of the cable is new and satellite quality (foil + brade wrapped), bar the external run which is partially under the gib board, so I have held off replacing this. Visually this is fine, although I have some doubts as this is steel braided, and clearly old wiring.

I have set the tuning to 64QAM, 3/4 code rate, 1/16 Guard, off center frequency 167(default). Transmission mode is not set.

I suspected the aerial was adequate, hene it sounds like an installation problem

steve

cyril7

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# 227154 21-Jun-2009 16:17

Hi Steve, dont feel akward, reason you are on GZ is you are most likely a bit geeky, so I have the expectation that you want to do a bit more DIY than most, I expect that and am happy to assist locals in that situation.

If you have LOS and are only in Raumati then I would suspect you have the ability of good to excellent reception. Therefore I would suspect your cabling (20m is not a lot) and amp setup. Is the amp actually powered?, if remotely is that all in place and operative, whats its watering state (ie has it had a dose).

PM me if you want a bit of my time to sort it.

Cheers
Cyril

KapitiGeek

4 posts

Wannabe Geek

# 227161 21-Jun-2009 17:03

amp has power, fuse intact, the magic smoke still inside the transformer. old cable is dry, but am wondering about rodent damage inside the wall to the one remaining old length. may have to pull some more gib board off. the house has been on cable tv for years, so there's no recent history of the cabling working....

will PM you if I get stuck. More I think about it I think the problem is in the cabling. Had heard that Ngarara was powered down for interference problems, which was causing me confusion.

Thanks