Digital TV Antennae upgrade

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Hi All,

I'm in a difficult reception area here at Salisbury Heights in
Adelaide. I have a ridgeline which shields me from the Mount Lofty TV
transmitter antennas, and a 33KV trunk mains running across in front
of my antenna complex.

I have a two antenna set-up which I installed in 1996. It consists of
a VHF/UHF Tandy 18 element VHF/UHF antenna plus a 12-element UHF
antenna which I bought from K-Mart (I don't remember the brand). The
two aerials  feed into a VHF/UHF Tandy masthead antenna amplifier.
There are also indoor booster amplifiers on the 6 room distribution
system. The antennae system supplies signal to multiple TV's, PVR's,
VCR's, FM radios, & DAB+ radio.

UHF reception of SBS with the K-Mart UHF antenna is excellent, whereas
the Tandy antenna is getting a bit sick up at analogue Channel 10.

Digital TV reception is excellent for Channels 7, 9, 3, and 44 but is
dodgy on Channel 10 and Channel 2. Channel 10 digital is the worst
performing channel.

My Strong PVR gives the following numbers for signal strength/quality
with the Tandy/K-Mart antenna:

(Ch7 83%/95%, Ch9 85%/95%, Ch10 81%/47%, Ch2 73%/50%, Ch44 83%/95%,
Ch28 99%/95%)

The above figures show why digital Channels 2 & 10 are bad performers.
This is so particularly with a north wind which has the 33KV trunk
line producing plenty of impulse noise.

Anyway, I replaced the Tandy UHF/Antenna with a MatchMaster 01M-LP03F
log-periodic antenna. Matchmaster actually recommend the 01MM-DC21A
antenna for my location on their web antenna selection facility.
However, my local Jaycar store had the LP03F in stock and it was only
$79 instead of $149, so I figured I'd give the cheaper antenna a go.
The performance figures seem much the same.

So, I've kept the existing UHF K-mart antenna (which has strong and
excellent performance), and put in the Matchmaster in to replace the
old Tandy UHF/VHF antenna.

I'm only using the UHF performance of the Matchmaster antenna, because
of the old Tandy masthead amplifier requiring separate VHF and UHF
antennas.

My Strong PVR gives the following numbers for signal strength/quality
with the Matchmaster/K-Mart antenna:

(Ch7 90%/95%, Ch9 85%/95%, Ch10 85%/95%, Ch2 82%/95%, Ch44 82%/95%,
Ch28 99%/95%)

So, the Matchmaster log-periodic antenna has improved Channel 2 and
Channel 10 reception to aproximate the Channel 7 and 9 performance
with the old antenna system.

The FM radio signal strength has dropped compared to the old antenna,
but is still quite workable. The DAB+ radio seems to have perfectly
adequate signal strength and is apparently working well as I write
this.

So far I'm jolly pleased with the results. Channel 2 analog even still
works after a fashion, and is quite watchable in an emergency, which I
didn't expect at all., since the Matchmaster is a Channel 6-12
antenna.

I'll be interested to see what happens with a north wind which usually
has the 33KV trunk mains generating plenty of impulse noise. I have a
heat wave/north wind  coming soon, so  I ought know how the new
antenna copes in a week or so.

So far I'm very pleased with the results. :)

Ross



Re: Digital TV Antennae upgrade
Errata

<<<<I'm only using the UHF performance >>>>

Should be "I'm only using the VHF perfornance" of the MatchMaster
antenna.

Ross




On Thu, 29 Dec 2011 02:22:59 GMT, snipped-for-privacy@invalid.invalid (RMD) wrote:

Quoted text here. Click to load it


Re: Digital TV Antennae upgrade-Performance report
Hi All,

We are in a heat wave here and the 33KV trunk main insulators are
breaking down and producing quite severe impulse noise. This is
visible as dashes on the screen from analogue Channel 2 to analogue
SBS, and is breaking through the FM sound too.

The new antenna setup has produced a fairly significant  improvement
in performance of previously susceptible equipment, but hasn't
resolved the problem completely.

I've found for best noise resistance the TV signal needs to be in the
"Goldilocks zone" for any particular piece of equipment. In other
words signal levels need to be "just right".

The only problem is that the Goldilocks zone can differ for different
digital TV devices. I have some Dick Smith variable gain booster
amplifiers and using these to raise/lower the input signal level can
help in finding the aerial signal "sweet spot".

Even given the optimum signal level, then different tuners perform
better than others, and price is no particular pointer in regard to
this tuner performance.

I have a fair idea where particular tuners fit in the performance
heirarchy, but recently I rewired an antenna feed arrangement which
was feeding, amongst quite a few other things, a Telstra T-box. I
think there was possibly a dodgy cable interconnect somewhere in this
particular antenna feed leg.

Anyway, the Telstra T-box is now the best performing tuner in the
house, whereas before it was one of the worst. Other tuners on the
same feed are quite a bit better too, but not by such a lot. Somehow
it happens that signal conditions are now really optimum for the
Telstra T-Box.

I also find high impulse noise levels can produce all sorts of
equipment operational weirdness.

For example, PVR's start recording but don't ever stop recording.
Repeat recording times can suddenly skip a week. Using the remote
control to set PVR's up can result in quite erratic behavior, and
pulling out the aerial feed fixes the problem and  stops the operation
erratic-ness.

In fact, it is easy to think that the dodgy equipment has suddenly
developed an intermittent fault. Except that pulling out the aerial
feed cures the problem.......... And the very next day without high
impulse noise levels about then the equipment is back to being quite
docile and well-behaved again.

Luckily most of this really quite bizarre behaviour only happens quite
rarely on really bad impulse noise days, and these bad days don't
actually happen all that frequently.

There is also a variation in impulse noise during the day. It usually
gets gradually worse as the day progresses, but then gets better
during the evening and often about 8pm or so the impulse noise
completely disappears until about mid-morning the next day.

Anyway, this diurnal effect means much evening viewing works out fine.
Recording things at midday or afternoons is usually the worst time, if
there is going to be trouble.

Anyway, with the new antenna setup, then SBS is the most reliable
feed, followed by Channel 7 and 9. Channel 2 is usually better than
Channel 10, but not always.

If everything performed as well as SBS does then I wouldn't have much
of a problem.

Ross



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