What type of TV Antenna

[warbo]

I went to a customer site yesterday to do some 3G broadband and they asked me if I knew anything about TV aerials to which I replied not really. However I knew where the two closest transmitters were and that I could try the other one. From one transmitter they could only get SBS OK and ABC not so OK. From the other one they could only get SBS.

They are about 77kms from a transmitter and have some trees in the way close to the house otherwise it would be LOS. They said that in the past they have had reception on all channels.

Their son-in-law installed this antenna. I'm thinking maybe when they had all channels that was analogue.

It's no big deal, I think they are getting VAST installed later in the week. I'm more curious as to what the antenna is?

[ol' boy]

Its a UHF antenna
(Corner Reflector with 3 Yagi or tri boom) Its just a variant of the Yagi.
They are a freaky looking thing. The ones around here had bright orange plastic separators, making look even stranger (Televes made them).

Some guy was installing them in this area, but the local installers didn't like them and pulled most of them out and replaced with a more traditional style UHF antenna
Either single Yagi or phased array.

Loving the 300ohm cable

Not as strange as these VHF/UHF combos...

[ol' boy]

Maybe worth a look in your game warbo, i just check some of the latest catalogues, and they have Antenna like the the one you've mentioned for LTE use.
But for long distance, maybe the dual antenna set up is still the go.

[gordon_s1942]

I went to a customer site yesterday to do some 3G broadband and they asked me if I knew anything about TV aerials to which I replied not really. However I knew where the two closest transmitters were and that I could try the other one. From one transmitter they could only get SBS OK and ABC not so OK. From the other one they could only get SBS.

They are about 77kms from a transmitter and have some trees in the way close to the house otherwise it would be LOS. They said that in the past they have had reception on all channels.

Their son-in-law installed this antenna. I'm thinking maybe when they had all channels that was analogue.

It's no big deal, I think they are getting VAST installed later in the week. I'm more curious as to what the antenna is?

I spotted a similar one near my Daughters at Gosford a few years ago and I have also seen them in use on TV shows made in Europe (Germany)
I saw that one oceanboy posted in a Laceys catalog recently and wondered what the devil how it worked.
I tend to associate those odd looking antennas with those you see in Mail Order catalogs and at Market outlets.

[mtv]

The multi-yagi type antenna is designed particularly for areas where signals are refracted, for example, by hills, buildings or trees.

There are passive and active versions, the latter of which acts like a diversity antenna system.

I've installed them on occasions.

Here's some info.

[stump1100]

Just for info, we often use a phased array receive system on broadcast sites these days - need to suck in every little bit of that signal before its re-transmitted!

[warbo]

The multi-yagi type antenna is designed particularly for areas where signals are refracted, for example, by hills, buildings or trees.

Thanks, sounds like it was a good option.

[hos here]

You have to take sig level readings. Too much gain causes probs too. Now that the mush zone has been eliminated from the Gold Coast I'm finding new issues have arisen. Some folk can not get ABC /SBS. I have found that the amp used to overcome the mush zone now delivers too much sig and has to be taken out of circuite.

Cheers
Hos Here

[gordon_s1942]

Since the retune last week, my ABC is now playing up and is clear during all day, it is literally disappearing from late afternoon until the next morning.
The local TV installer said he took readings from the translator before and after the retune and but while the ABC was the same before and after, all the others (SBS,7,9,10) showed an increase in signal.
Because of how touchy the signal is here, I dont want to hamfistardy fiddle with the antenna unless I have to.

[mickstv]

Since the retune last week, my ABC is now playing up and is clear during all day, it is literally disappearing from late afternoon until the next morning.
The local TV installer said he took readings from the translator before and after the retune and but while the ABC was the same before and after, all the others (SBS,7,9,10) showed an increase in signal.
Because of how touchy the signal is here, I dont want to hamfistardy fiddle with the antenna unless I have to.

Do you have a booster on the antenna ? if so it should have a gain control, reduce the gain.

If the antenna is un-boosted try adding a in-line attenuator to reduce the gain.

[gordon_s1942]

Do you have a booster on the antenna ? if so it should have a gain control, reduce the gain.

If the antenna is un-boosted try adding a in-line attenuator to reduce the gain.

Let me pose this question to you in relation to your first suggestion as I certainly do have MHA's (2 actually) on the 110 metre cable run between the antenna and the TV.

Until last week, all channels were on UHF Band 5 and were working without any loss except in extreme weather variations.
Now, after the 'restack' to Band 4, (Channels 40 to 44) all but the ABC are clear and constant as before and according to my local installer who says he took signal measures both before and after the 'restack', the ABC still reads the same signal strength as before but all the others have increased by 5db I think he said.
Wouldnt that mean that if the MHA's gain was too high, the ABC should still be same BUT the others should be now playing up because of too much signal gain?

What I need to do is get him to come out and do a 'Site Test' and either redirect or replace the antenna (97 element Yagi) if needed.

Digital is a total pain in the arse.

[mtv]

Channels 40 - 45 are all band 5.

Any increase in signal input will have an effect with amps..... so it depends on what they were outputting before any input increase.

It may or may not have caused an issue.

There are numerous factors involved... cable losses, cable integrity, joins, self noise generated from the amps themselves, induced noise, etc, etc.

Yes, overloading signals can cause as many issues as low signals... but it's the signal quality that is the most important factor... BER/MER.... not signal strength alone, as was the case with analogue.

Without accurate measurements... particularly BER/MER along the 'chain' it's impossible to predict with any certainty.

[gordon_s1942]

My apologies regarding the Band 4/5 usage in the recent 'restack' as I thought from previous articles that those with channels on Band 5 were being relocated onto Band 4 and I presumed this area was doing the same.
What in fact has happened is we have gone from using channels 56, 59, 62, 65 & 67 to 40, 41, 42, 43 & 44 but still on Band 5.
This confuses me even more with the ABC formally on 56 to now on 41, is clear until mid afternoon (3.30pm) and is now starting to pixel but still perfectly viewable but give it another hour or 2 and it will gradually degrade until I finally get a Blue screen and the 'No Signal' message until sometime tomorrow morning.
As I said before, for the last 2 years I have had almost no loss of signal on any channel, certainly not the ABC.

[mtv]

Do you have any devices with RF modulators in the house.... VCR, PVR, STB, AV sender, etc?

Possibly you have a device outputting an RF frequency that's interfering with the new TV frequencies.

[gordon_s1942]

Always a thought which I have had similar problems in the past with being in a deep fringe area but again, why does it work until mid afternoon when from a few pixels here and there to by dusk, its just either a scrambled mess to a total No Signal'?

Stupid as it may seem, what about my signal being 'bounced' from an object (remember there aint nuttin' but Trees, sheep, cows and myriads of Kangaroo's' plus a bloody great hill between me and the Translator) that as the temperature changes as the Sun moves, the angle of the 'reflection' changes too?
You could say if it effects one frequency, why not some or all of the others?
In the 50 years I have been here I have had 'Skip' on analog TV from Tasmania, Wagga Wagga and once from NZ during weather variations so today, nothing surprises me with TV reception or anything else for that matter.

I have just checked with my nearest neighbour and he told me that after they retuned their TV's from the 'Restack', they have all the channels so I have to decide to try to re-align the antenna myself or see if the local installer will come out.
I think he has a Digital FSM now which he didnt have before, so I would rather get him to do it using that than my 'Wet Thumb in the Wind' method.

For everyone who has offered any advise, please dont think I am treating it with less than the respect it deserves with my replies as I truly value your assistance, its just that I have to adapt the advise to suit what I can do myself and the area I live in.

[mtv]

Yes, changes in atmospheric conditions (particularly moisture/humidity) can have an effect, especially where signals are marginal.

[gordon_s1942]

Checked both my closest neighbours and at the Pub as he has got one of those weird egg ring type antennas and they all said after retuning, they have all the channels as normal so it looks like its ladder time and gentle touch to move it slightly.

[mtv]

Gordon,

The first thing I'd be looking at is your cabling and joins.

[gordon_s1942]

Gordon,

The first thing I'd be looking at is your cabling and joins.

Only both time and agility have delayed me but I was going to have a look inside the MHA at the antenna end to see if it had any interlopers living in there and check the connections too but I have walked the cable but you cant see anything because its in that garden Polypipe and 3 metres off the ground.
Now while I still have 24/7 access to the ABC either on VAST or Foxtel, this loss is really bugging me after all the time and effort (yours most importantly) done to get the signal.
Here are the readings the local installer took from this translator.
They must be read assuming his meter is accurate and he knows how to read it.

ABC ch 56 now ch41, before 67db, now 67db.
SBS ch 67 now ch40, before 60db, now 68db (gain of 8db)
Prime7 ch 59,now ch42, before 68.4db now 70db (gain of 2db)
WIN9 ch65, now ch43, before 67db, now 72db (gain of 5db)
CAP10 ch62, now ch44, before 69db, now 77db (gain of 8db)

His hand writing is as bad as mine but he shows the MER of all channels is between 29 and 31, and something I think is CN is 40 except for one channel of 37 (SBS)
Also on all is the notation of E 07, whatever that is.

I believe he used a phased array mounted some 5 meters high in an unobstructed totally clear line of sight about 10 kms from the Translator in the maximum signal path of the beam.

I will either drive everyone nuts badgering them to help me or I will do it myself if I can get up the 3 rungs of the damned ladder to reach the antenna.

It does really piss me off at times when you ask and get fobbed off by some trades people and hear them claim there is no work as I asked the local installer for a rough quote to come here, do a site test at least and if he thought it necessary, instal a new antenna but all he did was take my phone number!!
He knows where I live as he took a TV on warranty away for repairs and I made it very clear that any quote he made was NOT binding because of what he might have to do to get it working.

[mtv]

Gordon,

Those readings are excellent, but they mean nothing if they were not made at your place.

Did you investigate my suggestion of RF modulators in your home?

Do you have any equipment that is on a timer? Stray interference (can be electrical, not necessarily RF) can produce the issue you're experiencing.

Poly pipe, when exposed to sun, reaches very high temperatures inside and when it cools, condensation often forms inside, leading to rust/corrosion in connectors/joins.

If you have any air-spaced coax in the line, it is well-known for very poor digital performance.

Ultimately, a single run of RG11 Quadshield is the best for your situation of distance or at least a single run of RG6 Quadshield.

With RG11 being lower loss, you would likely only need a single masthead amp.

Less noise = lower BER/higher MER = reliable reception.