How important is it for a Freeview UHF antenna to be exactly aligned with the tower?

Forums › Freeview (DVB-T/DVB-S) › How important is it for a Freeview UHF antenna to be exactly aligned with the tower?

1 | 2

geek4me

843 posts

Ultimate Geek
+1 received by user: 78

Trusted

Lifetime subscriber

#786017 23-Mar-2013 19:18

B1GGLZ:
geek4me:
My original question was can the signal strength be improved by moving the aerial from line of site? Looks like it's not worth the bother trying.

And the answer is - possibly. Depends on too many factors and needs to be trial and error. Usually beneficial only when not in line of sight and signal is low. You may be being overpowered with VHF analogue signal. If the antenna and cable is old they should be replaced. You may have an open circuit feeder? Have you tried an indoor antenna or even just plugging a short length of wire into the TV's antenna socket? I'm about 7km line of sight here in Auckland and can get a useable signal on a short piece of wire on the end of a short co-ax lead. Moving my antenna thru 360 degrees doesn't seem to make any difference to the signal.

As the cable and antenna are old and some connecters look corroded that is the likely cause of the poor signal not the alignment. The VHF overpowering the digital signal will go when it's switched off in future. Don't think I'll bother with an indoor antenna as the house is soon to be sold, I have learned a lot from all the helpful responses given here.

Chrisso43

6 posts

Wannabe Geek

#788145 27-Mar-2013 17:56

Go to www.matchmaster.co.nz and use there antenna selection guide, its awesome. It even gives you a compass bearing, shows you the polarisation on the aerial and a wiring diagram. If you clickon the review transmitter it gived you a google earth map of where you are in relation to the tower and estimated DBuv you should be getting at the antenna.
I would look at your cable network and your connectors including your face plates as these areas are also critical to delivering a good COFDM signal.

geek4me

843 posts

Ultimate Geek
+1 received by user: 78

Trusted

Lifetime subscriber

#788171 27-Mar-2013 18:36

Chrisso43: Go to www.matchmaster.co.nz and use there antenna selection guide, its awesome. It even gives you a compass bearing, shows you the polarisation on the aerial and a wiring diagram. If you clickon the review transmitter it gived you a google earth map of where you are in relation to the tower and estimated DBuv you should be getting at the antenna.

An interesting site. I nearly missed the "Antenna Selection Guide" which looks more like a graphic than a link. Once there it pointed to Fitzherbert with Haywards and Baxters Knob as alternatives under the Review Transmitter link. It did not show the local Stokes Valley transmitter which is halfway up the valley on the hills south of Stokes Valley Road that many newer house aerials are pointing at. Perhaps they don't include all local transmitters in their list or the antenna is not what I and others think it is.

turb

880 posts

Ultimate Geek
+1 received by user: 135

#788374 28-Mar-2013 08:33

That Matchmaster site is excellent!

If it's a cloudy day and you are using a compass to align your antenna, just be aware that True North as used by the site is not quite the same as Magnetic North.

The difference may be enough to be important. you can find out what it is in your location here: http://magnetic-declination.com/.

So for me, the matchmaster site says the bearing to my antenna is 241 Degrees. When I point my compass at it, I'll have to deduct 19.5 Degrees (in Auckland in 2013) to allow for it.

Interests: HTPC, Web App authoring.

Goosey

3016 posts

Uber Geek
+1 received by user: 871

Subscriber

#788389 28-Mar-2013 08:54

Reservations about the quality of data on the matchmaster site regarding the antenna selection tool.
I tapped in a few addresses in our area and the furtherest away from the Christchurch Sugar Loaf transmitter populated with UHF aerials and suburbs a little bit closer populated with Satelite dishes !

My address populated with a satelite dish and our 18 year old UHF is doing pretty well on the freeview TV !

Perhaps matchmaster hasnt fully completed the data input to their tool.

Behodar

11101 posts

Uber Geek
+1 received by user: 6084

Trusted

Lifetime subscriber

#788406 28-Mar-2013 09:25

Gooseybhai: Reservations about the quality of data on the matchmaster site regarding the antenna selection tool.
I tapped in a few addresses in our area and the furtherest away from the Christchurch Sugar Loaf transmitter populated with UHF aerials and suburbs a little bit closer populated with Satelite dishes !

My address populated with a satelite dish and our 18 year old UHF is doing pretty well on the freeview TV !

Perhaps matchmaster hasnt fully completed the data input to their tool.

Similar issues here. I put in my address, which admittedly is in weak coverage, and it suggested a dish. I then put in my parents' address, which is in the green area on the Freeview coverage maps (and they've been using it for years with no issues) and it still suggested a dish.

New World

Shop on-line at New World now for your groceries (affiliate link).

khull

1245 posts

Uber Geek
+1 received by user: 133

#788410 28-Mar-2013 09:33

Our neighbour is an electrical engineer and signal processing - the advice we got was 90 degrees from the transmission tower. what we found was that HD Freeview signal strength is stronger than our previous analog, perfect reception even with an indoors antenna

geek4me

843 posts

Ultimate Geek
+1 received by user: 78

Trusted

Lifetime subscriber

#788438 28-Mar-2013 10:11

Please clarify for me whether the transmitters listed on the Freeview site for e.g. Wellington's Hutt Valley Kaukau, Fitzherbert, Baxters Knob, Haywards are the only transmitters from which a Freeview signal can be received? Am I incorrect to think that there are other local fill-in Freeview transmitters (repeaters) in the area? If they do exist can someone point me to a web site with a complete list showing the location of all local transmitter sites.

knoydart

904 posts

Ultimate Geek
+1 received by user: 154

Trusted

#788458 28-Mar-2013 10:31

There are no "small" repeater transmitters for Freeview. The coverage maps on the FreeviewNZ website for the transmitters listed are the only Freeview terrestrial transmitters here.
This is one of the reasons that Kordia is losing a sizeable amount of income in the coming years with the switch off of all the analogue transmitters.

Edit: poor spelling

B1GGLZ

1961 posts

Uber Geek
+1 received by user: 136

#788582 28-Mar-2013 13:10

knoydart: There are no "small" repeater transmitters for Freeview. The coverage maps on the FreeviewNZ website for the transmitters listed are the only Freeview terrestrial transmitters here.
This is one of the reasons that Kordia is losing a sizeable amount of income in the coming years with the switch off of all the analogue transmitters.

Edit: poor spelling

+1
Have a look here
http://www.freeviewshop.co.nz/information/technical/digital-terrestrial-i-8.html
That's the lot.

geek4me

843 posts

Ultimate Geek
+1 received by user: 78

Trusted

Lifetime subscriber

#788609 28-Mar-2013 13:35

B1GGLZ:
knoydart: There are no "small" repeater transmitters for Freeview. The coverage maps on the FreeviewNZ website for the transmitters listed are the only Freeview terrestrial transmitters here.
This is one of the reasons that Kordia is losing a sizeable amount of income in the coming years with the switch off of all the analogue transmitters.

Edit: poor spelling

+1
Have a look here
http://www.freeviewshop.co.nz/information/technical/digital-terrestrial-i-8.html
That's the lot.

Thanks for these helpful comments. I had seen the freeviewshop list before but could not find Haywards so assumed it was incomplete. Is Haywards "Wellington Infill"?

Mighty Ape

Shop now at Mighty Ape (affiliate link).

geek4me

843 posts

Ultimate Geek
+1 received by user: 78

Trusted

Lifetime subscriber

#788617 28-Mar-2013 13:43

turb: If it's a cloudy day and you are using a compass to align your antenna, just be aware that True North as used by the site is not quite the same as Magnetic North.

To solve this I'll use my mobile phone with a GPS app that shows both magnetic and true north.

turb

880 posts

Ultimate Geek
+1 received by user: 135

#788701 28-Mar-2013 15:21

To solve this I'll use my mobile phone with a GPS app that shows both magnetic and true north.

Oooh this is a tough one: Is it more geekzone to use a compass and maths, or to use an app?

The app is probably more realistic as coffee shakes make the accurate use of a compass difficult....

Interests: HTPC, Web App authoring.

B1GGLZ

1961 posts

Uber Geek
+1 received by user: 136

#788743 28-Mar-2013 15:57

geek4me:

Is Haywards "Wellington Infill"?

Yes.

injuised

256 posts

Ultimate Geek
+1 received by user: 3

#789132 29-Mar-2013 10:31

B1GGLZ:
knoydart: There are no "small" repeater transmitters for Freeview. The coverage maps on the FreeviewNZ website for the transmitters listed are the only Freeview terrestrial transmitters here.
This is one of the reasons that Kordia is losing a sizeable amount of income in the coming years with the switch off of all the analogue transmitters.

Edit: poor spelling

+1
Have a look here
http://www.freeviewshop.co.nz/information/technical/digital-terrestrial-i-8.html
That's the lot.

I don't know where they got their freq from? The only thing they got right for Mt Campbell is the polarity!

1 | 2