TV1 & TV2 UHF - wont stay tuned in - please help

Hi,

Any advice on resolving this issue would be gratefully received!

I thought i would be the dutiful son and over Christmas i purchased a UHF Aerial for my Dad as a gift.

He lives in Pakuranga, in a dip where there is no direct line of sight to the Waitakeries. Up until now he has been watching Sky digital(via Dish) on TV, which has been fine but the picture quality is no where near as good as Digital HD. He recently bought an new TV (DSE brand) and a Panasonic "My Freeview" hard drive recorder, so It made sense to see if we could get him a better picture for his new TV. So I looked on the Freeview site, put his address in and it said that with a high aerial that it was probable to get Freeview HD.

I purchased a new 93 element high gain UHF 'Yagi' style aerial from Jay Car, new Coax RGB6 Cable and connectors etc (about 15 meters used) and have installed the aerial on a high mast (telescopic) on his flat iron roof. We used a DVB-T signal meter and found that I could only get '50' dBuv (whatever that is?) on the meter, almost regardless of where I pointed the aerial.

The only time the 'meter' went higher than 50, was when a neighbor started their lawnmower (or weedeater), and it shot up to between 60-80 for a brief moment- but this may just be a coincidence?

In the end, I looked at all the neighbors antennas, and pointed Dad's one in the same basic direction (still a solid '50' on the meter). We tried to tune the TV in and it picked up all channels except for TV1 & TV2 (and the '+'1, versions). So we connected the Panasonic My Freeview hard drive as we suspected that it would have a better quality tuner than the DSE TV), and it tuned in all channels, straight away, however it did say that signal quality on TV1 & TV2 were only 7 out of 10, but that strength was 100%.

We noticed that the picture on TV1 and TV2 would sometimes pixulate for a moment or two, but i put that down to the mast moving around. We secured the mast with solid struts and everything was fine for a couple of hours., - all channels crystal clear without pixulation. Yippee i thought!

However, later that night and now, regardless of 'retuning' several times, we can not get Tv1, TV2, TV1+1 or TV2+1. all the other channels seem fine? I don't think the antenna has moved direction (it is up very high and does wobble a little bit in the wind).

I feel a bit rude asking an installer for advice - but wonder if anyone else has experienced this problem and how it was resolved?

I know with my own install (done by a professional) where I live in Karaka, he had to fit a 'Power' injector, however I think that is because my antenna is inside the roof cavity?

Do You think I need something else to make the system work so that it will pick up the signals, or do we need to just try a different type of antenna (maybe phased array).

Any help, pointers or suggestions gratefully received.

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Permalink Reply by Biggles on December 30, 2014 at 14:41

Difficult to say what's wrong without looking at the installation but something is obviously affecting reception of the TVNZ Mux. Is the antenna the same as others in the neighbourhood? It may be that the gain is OK but the capture pattern is too narrow. My son's place in Glenfield is in a gulley well out of sight of Waiataru but we got signals OK about strength 7 - 8 on the TV and Recorder with just a standard 47 element antenna. A masthead amp should definitely help but cannot be guaranteed to assist. It's also possible you may have interference from other electronics in the house. The high strength associated with low quality would indicate interference. Cordless phones can sometimes be a problem. Try turning off all electrics in the house except TV and recorder and try again. There may be a modulator attached to the Sky which is on the TVNZ channel. Turn off Sky and unplug at the wall. Let's know how you get on.

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Permalink Reply by Anthony Barry on December 30, 2014 at 16:16

Hi Biggles, Thanks for the speedy reply !

The antenna looks to be about the same as about 80% of the ones in his street(very long arrow shape), but his house is a bit lower and obscured by a few more BIG trees than most of his neighbors, hence we tried the telescopic mast to gain a bit more height. I will try the 'turning every thing off' and see if makes any difference. I had a look for a 'stand alone' RF modulator, (as i know he has feed the sky from the dish decoder to the other bedroom using cables) but don't think he has one. The cordless phones are worth looking at, and then I might try a 'power injector'. Thanks once again, i will give you an update as soon as we have tried these ideas.

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Permalink Reply by Biggles on December 30, 2014 at 16:46

If he's fed sky to the other rooms then it's most likely via an rf modulator. You should be able to check it's frequency in the Sky setup menu (and change frequency) but turning the Sky box off and unplugging at the wall power socket will certainly disable it.

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Permalink Reply by willis on December 30, 2014 at 23:35

power injector is only used to drive an amplifier

a 15-20 dB one might be helpful

and a rf modulator will have either a scart or red,yellow,white from the sky box going to an aerial lead

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Permalink Reply by Anthony Barry on December 31, 2014 at 8:22

Thanks for your reply and advice, I will be back at his place after new Year so will give it a go then and let you know how we go.

Cheers.

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Permalink Reply by Anthony Barry on January 4, 2015 at 16:00

Hello all,

Well finally got around to my Dad's place this morning, and have tried a number of things without any success - as yet.

1. Using the 'correct compass' bearing (According to the info from 'Matchmaster' website), I re directed the antenna to 269.2Deg. We switched off the 'sky digital' decoder at the wall, and switched off and unplugged all the phones, then re-tuned the channels. The reception was significantly worse - to the point where we lost the TV3 channel.

2. Using the signal meter, we tried several different directions (still not able to get more than '50' on the meter), and re tuned several more times . In the end we settled on 258.0 deg, the result being we have good quality (10) and signal strength on all channels except for the ones we really want (TV1 & TV2). looking at the 'manual tuning' info on the TV, when we select channel 29 (TV1 & TV2?), we get about 50% signal strength, but '0' quality, and the Tuner tells us 'invalid' channel.

So what next?

I can't really make the antenna any higher - as it is now at the maximum height that I can safely secure it. I doubt there is a clear line of sight to Waiataura even with the height of the antenna, as I know there are hills and big trees that will obscure the line of sight.

So what is my best alternative now? - change the 'type' of antenna to a phased array type, or do I stick with the 93 element type i have (Yagi) and look for a mast head amplifier and power injector?

This is starting to turn into a far more expensive Christmas gift for my Dad than I had bargained for - so I need to make sure I find a good quality but affordable solution moving forward.

This is the Antenna we purchased - Jaycar 91 Element UHF antenna

This is the type of meter we are using Jaycar signal meter

We have just over 10 Meters or quality RG6 Coax and the right type of 'F' connections. The Antenna cable runs straight into the tuner (so I have no filter, splitter, amplifiers or anything else that could cause any interference). So any help or advice is welcomed.

Thanks for taking the time ;)

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ZinwellPermalink Reply by Graham Wilson on January 4, 2015 at 16:43

I'm assuming you have the aerial horizontally polarised for Waitarua (rather than vertical for most of the in-fill repeaters) as the wrong polarisation makes a significant difference to the signal strength.

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Permalink Reply by Anthony Barry on January 4, 2015 at 17:08

Hi Graham, Thanks for your reply. The aerial is almost horizontal, slightly raised at the tail which points to Waitarua (about 5-7 degrees maybe). This was the 'first hole on the bracket that secures the frame to the mast.

I could try to re-secure it to be completely horizontal? - would this make enough of a difference do you think?(i.e from not locating the channel 29 to finding it).

Thanks once again for your reply.

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Permalink Reply by Biggles on January 4, 2015 at 18:04

Horizontally polarised is different to being parallel to the ground pointing at Waiatarua. Having the front a bit higher than the back is not a problem.

http://freeviewforum.co.nz/page/antenna-guide#uhf

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Permalink Reply by Anthony Barry on January 5, 2015 at 10:29

Thanks for the info and link. I have done a bit of research and can confirm that it is polarised horizontally.

So I guess the next step would be to change the varity of antenna? From what I have read maybe its time to try a phased array type? The Tri fold antenna says good for fringe (we are about 26 Klm away from Waiatarua), however the description for Phased array says good for overcoming big obsticals.

Any recommendations as to what brand of antenna is likley to give the best result - or in your opinion are they all pretty much the same?

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Permalink Reply by Biggles on January 5, 2015 at 13:59

You may need to try more than one type so I'd recommend getting a Pro Installer with all the right gear. He will be able to select the right antenna for the job and install a masthead amp if needed.

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Permalink Reply by Anthony Barry on January 5, 2015 at 14:17

OK, thanks - this may be the best idea now (even i know when amature hour is over!), as it is not really affordable to purchase several different types of antenna's (and then try to re sell the ones that didn't work).

If anyone has a recomendation for a good installer who works the East Auckland area - please feel free to pass the details on and I will discuss it with the man who's reception is affected.

Thanks for all your help once again!

Cheers.