What's wrong with my UHF aerial set up?

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Gradine

77 posts

Master Geek

#110675 14-Oct-2012 12:44

Took down my old UHF/VHF aerial so as to clear roof for a reroofing job. Got an indoor aerial to receive TV in the interim. I am "all digital" - HD freeview set top box (Zinwell - have had for years) and a Panasonic twin freeeview tuner DVD receiver/recorder. TV (LCD) does not have freeview on board - bought it before that bacame the norm.
Have installed a new UHF only aerial on roof - on high pole on bracket strapped to chimney. New RG6 coaxial cable and connections (compression at aerial end and RF input connector into DVD receiver/recorder with loop out to Zinwell. HDMI inputs from both tuners to TV.
Now I get "rubbish" reception from the coax. Only when it rains tho! All is great on fine days. But when it rains then I lose the signal via both tuners - starts pixellating then loses it. Why on earth would that happen??
Aerial is aligned straight at Waiatarua. Transmitter is at about 5/6 kms in a straight line and in line of sight.
My new aerial is a 48 element - 10 4 prong directors, one 4 prong dipole, 2 x 1assy reflectors, = total 48 elements.
Have I gone for "overkill" and installed an aerial that is too powerful given my position in relation to transmitter?
Should there be a relationship between site of home v site of transmitter v type of my cable v my aerial "elements" (do I need all that stuff?).
What might be a simpler set up - aerial wise?
Or should I just get the TV/aerial man in?
Any help or advice appreciated.

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#700947 14-Oct-2012 12:49

Sounds to me either the connetor is not on propoerly or the Balun and or connection are leaking.

Cyril

Gradine

77 posts

Master Geek

#700954 14-Oct-2012 13:05

Thanks Cyril - but the connector at aerial end is a compression fit "make" and has been installed with the appropriate tool. And, the connection is covered with a silde on rubber/synthetic weather sleeve. Water cannot get in. Anyway, the pixellation and signal loss happens instantly - as soon as it rains. For a week since the set up it did not rain. First rain was yesterday and the problem was instant. It's as if the rain on the flat surfaces of the directors triggered the problem - it was that instant!
Any more ideas?

RunningMan

8953 posts

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#700960 14-Oct-2012 13:20

Maybe it's not the actual moisture, but a symptom of a fault elsewhere. If the signal is marginal, then the slight loss from the rain may drop you below a usable signal.

Have you checked the signal strength at the TV when it's fine?

Got the polarity of the new antenna correct?

Gradine

77 posts

Master Geek

#700964 14-Oct-2012 13:38

Thanks "runningman"

How do I check signal strength of UHF aerial? How do I do that on the Panasonic DVD receiver/recorder? How do I do that on the Zinwell HD tuner?

The HD aerial is installed per instructions on box. Really simple to do. By polarity - what do you mean? The aerial can really only be set up one way (I think). Aerial came virtually assembled - just fold out the flat directors, screw the two halves of the main strut together, screw in the coaxial connector to the balun, screw on the entire aerial to the pole. All the "screw ins" are wing nuts and no real tools are required. Suppose one could say "any idiot can do it" - except maybe this one.

Have checked and rechecked all my work and am sure all is set up right.

Only one other bright idea - what if I were to aim the aerial at the Sky Tower instead of Waiatarua? Is the Sky Tower a transmission site for Auckland. That is 11 kms away and in direct line of sight.

Still need any helpful suggestions etc.

Thanks for ideas so far.

Behodar

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#700966 14-Oct-2012 13:45

The "fins" on the aerial should be horizontal for Waiatarua, vertical for Sky Tower.

Edit: Added links to photos.

Jaxson

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#700968 14-Oct-2012 13:47

Do you have the right orientation of your new aerial? ie is it horizontal or vertical as required in your particular area? I'd double check the connections at either end, ensuring none of the shielding is touching the inner core at any stage.

RunningMan

8953 posts

Uber Geek

#700980 14-Oct-2012 14:21

As @Behodar has described - that should sort out that you have the right polarity.

Somewhere in the tuning/setup menu you can normally get a bar graph or some similar indication of signal strength - different receivers will call it something different, but you should be able to use that as a comparison.

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B1GGLZ

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#701018 14-Oct-2012 16:30

Gradine:
How do I check signal strength of UHF aerial? How do I do that on the Panasonic DVD receiver/recorder? How do I do that on the Zinwell HD tuner?

In the Panasonic Menu should be under Setup, Others, Digital TV Tuning, Manual Tuning. Select channel and check strength and quality.
Should be something similar with the Zinwell.

Sounds to me like a faulty connector.

B1GGLZ

1961 posts

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#701027 14-Oct-2012 16:45

Gradine: New RG6 coaxial cable and connections (compression at aerial end and RF input connector into DVD receiver/recorder with loop out to Zinwell. HDMI inputs from both tuners to TV.

Why still using the Zinwell? Seems superfluous. Surely your Panasonic can record up to 2 channels while you watch another?

Gradine

77 posts

Master Geek

#701618 15-Oct-2012 17:07

Thanks folks. Lots to work on.

Seems to boil down to an issue with the connector at the aerial end. Shall try to isolate that as the problem by plasitc wrapping connection and balun so as to waterproof it (as completely as possible). Then to observe before doing anything else. If still pixellating aftre that then may be an issue with the DVD - it's still under warranty.
Use the "old" Zinwell as often do not need to record anything. Might wear out the DVD too???????????eh?
Happy to have kept it as on occasions signal via the Zinwell is not so affected as the DVD (and that on its own may be a pointer to a DVD issue).
And I have other ideas to isolate and get a fix worked out.
Thanks for all help

illicit

553 posts

Ultimate Geek

#701893 16-Oct-2012 08:55

Can you take a photo of the aerial - this will be much easier to diagnose with.

Gradine

77 posts

Master Geek

#702020 16-Oct-2012 12:35

Thanks "illicit".

Can take photo as you ask - but I have never done that for this forum so need some step by step insyructions to do that.

Today - this morning - I have ben on roof and have put a plastic wrap around the balun/box and the coaxial cable below the connector. Hope that has waterproofed this area of the aerial connections.

I noted that, whilst doing wrapping, that there are small slots in the balun/box through which one element of the aerial runs. The slots enable the element to go through the balun box but it seems there is enough gap left for rain/water to gain ingress - especially if it is wind blown.

Now, I have to wait until it rains in Auckland again so as to see whether what I have done has made any difference. Wonder how long I shall have to wait?

PS - re my use of the "old" Zinwell ........ other good reasons for using it are that sometimes I cannot view a third channel whilst two others are being recorded on DVD, and the Zinwel has features such as "storing" two channels and using "Recall" button to move back and forth between them, and the remote for Zinwell has a "Mute" button whereas the Panasonic DVD remote does not have that option - even on the TV "section" of the device.

PPS - have checked signal strength and quality via menu option of remote controller. Both strength and quality are green (which is stated to "good") and on the 0 to 10 scale for both strength and quality the readings are 10 out of 10. And that is the case for all Freeview channels.

So, keep a watch on for this developing saga/soap opera!!

RunningMan

8953 posts

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#702155 16-Oct-2012 16:55

Point the hose at it while you watch the signal meter and see what happens.

Gradine

77 posts

Master Geek

#702216 16-Oct-2012 19:27

Thanks "runningman" - great idea. I'll need to enlist help tho as someone needs to hold and spray the hose on the aerial and balun etc whilst someone else watches the "signal condition" meters.
Think I shall just wait until it rains - as it soon will in Auckland!

Good idea tho!

coffeebaron

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#702236 16-Oct-2012 20:29

Also check the cable hasn't nicked somewhere.

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