[InWaipawa]

After days spent studying this forum, I decided I had to try making a GH, well actually I built 3. The first two where made with 2.4mm aluminium welding wire 1x SBGH and 1x DBGH. After testing both units and having no luck with reception I started again. The latest model uses 8mm aluminium rod for the elements, some 100mm x 50mm PVC spacers and expanded mesh reflector all mounted 8m in the air. Still no digital TV...

I currently have the antenna pointed 41deg towards the closest tower 31.25km away but there is poor line of sight due to the rough topography here. I also tried pointing at 210degrees to the only other transmitter in the area which is 72km away but with better LOS, still no joy.

The channels I wish to get from the closest tower at Mt Erin are:
27v 519.25mhz
31v 551.25mhz
43v 647.25mhz
and I know its outside the ideal range of the GH but I also would like 61v 791.25mhz.

So the biggest question I have is would a masthead amp help? When the antenna is plugged into the digital tuner the scan slows when near the above frequencies but does not find anything. I do however get good VHF reception when plugged into our old TV. I'm hoping at this point it's just the rain affecting the signal.

Any and all advise will be taken into consideration and much appreciated.

 

[ota_canuck]

Ahh!,.. yes, Maybe you should have studied the mounting details more.

I would guess that you're having "no luck with reception" is because you have the antenna mounted sideways. Take it down and mount it vertically and try testing for results again.

 

[Marbles_00]

Rotate the antenna 90 degrees to start. Your elements should run vertically not horizontally. Like this:

You will need a preamp if the cable from the antenna to the TV is in great length, like 60'.

 

[InWaipawa]

I was waiting for that, the reason the antenna is mounted sideways is the signal polarization here is vertical not horizontal like in Canada.

 

[ota_canuck]

I would give it a try vertically anyway! What is the core frequency range for New Zealand digital and analog channels?

 

[InWaipawa]

I did try vertically after I built the DBGH with no difference, the analog channels are being shutdown sometime in the future and the UHF channel range here is 21 to 69. The main goal of this build was to see if was going to waste NZ$150+ for a 91 element antenna, according to the freeview hd website it is unlikely for me to get reception here. So I did a bit of googling that's when I discovered this wealth of knowledge and experience.

 

[stampeder]

InWaipawa, is there a web site for NZ's broadcasting authority that would list the Effective Radiated Power levels of those desired stations?

 

[InWaipawa]

The only site that I have found with any information about transmitter site and frequencies is Lincrad aerials, just did a quick search and found nothing about ERP. Thats the problem with back water countries, not a lot of information is shared with the public.

 

[ota_canuck]

Freeview HD sounds like a marketing ploy to sell equipment. There are many digital converter boxes available globally that are capable of converting UHF digital reception to UHF analog output to your analog TV.

You have a UHF antenna.
You can recieve analog.
You can't get any digital.

If this is the current situation, then you don't have a tuner capable of recieving digtal reception or there are currently no digital broadcasts available in your area. If there is digital broadcasts in your area, then maybe you'll need to upgrade to a newer TV with a built in Digital tuner or purchase a digital/analog converter box.

There is no such thing as a digital antenna or a freeview specific antenna,.. all UHF antennas are capable of UHF reception and the GH will work well within the channel 21-69 range.

If you suspect there is a glitch with the GH antenna design, then make yourself a simple & inexpensive Stealth Hawk antenna and see what transpires.

 

[ota_canuck]

I found some info about FreeviewHD:

Is it possible that the digital OTA signals in New Zealand are encoded broadcasts?

http://www.freeviewnz.tv/images/uploads/pdfs/Freeview_Service_Provider_Code_of_Practice_May10.pdf

 

[ota_canuck]

InWaipawa, is there a web site for NZ's broadcasting authority that would list the Effective Radiated Power levels of those desired stations?

I found this info:

The following is a list of free-to-air digital satellite channels available in New Zealand. Most can be received using the standard 60cm satellite dish that is fitted to many houses, together with a standard blind-scan capable set-top box.
http://en.wikipedia.org/wiki/List_of_free-to-air_TV_channels_in_New_Zealand

Freeview-certified set-top boxes and IDTVs, as well as PVRs, are available at most major New Zealand retailers. Cheaper, uncertified equipment can also be used.
http://en.wikipedia.org/wiki/Freeview_(New_Zealand)

Freeview uses the DVB-T standard for terrestrial transmission, as established in 2001 with NZS6610:2001, to avoid the multipath problem caused by New Zealand's rugged topography. ATSC, a rival standard, cannot handle multipath well, so it was not chosen.[19]

Terrestrial Freeview|HD is broadcast in H.264/MPEG-4 AVC. This meant that people who took part in the Auckland digital trial using terrestrial DVB-T MPEG2 receivers needed to change their receivers to DVB-T MPEG4 in order to receive terrestrial Freeview. DVB-T MPEG4 is also known in some countries as DVB-T HD. MHEG-5 is used for the electronic programming guide.

Freeview Satellite uses the Optus D1 satellite[14] to broadcast, on a transponder, leased from Kordia. The satellite transmissions are in DVB-S MPEG2. Freeview cannot easily move to MPEG4 broadcasting in the future as the codec is unsupported by the installed base of Freeview Satellite receivers. Unlike the terrestrial service, the satellite service broadcasts a traditional EPG alongside the MHEG-5 EPG.

http://en.wikipedia.org/wiki/DVB-T

 

[InWaipawa]

As far as I'm aware the OTA broadcast is not encoded, unless you have Sky pay-tv. We have a HDD recorder and TV with digital terrestrial tuners built in, currently we are using a satellite set top box to receive freeview but it is only 480p vs 1080p on terrestrial freeview hd. Also it negates the use of the HDD recorder twin tuner ability to record two programs while watching a third.

I think an amp is needed, if you look at the PDF below you can see the problems I have with hills. We are located in a white patch surrounded by purple to the left and below the K in kilometers (road above an below). I would mark the exact spot but I do not know how to edit PDF's.

http://www.freeviewnz.tv/images/uploads/pdfs/Mt_Erin_Standalone_Freeview.pdf

I have to install guy wires on the mast when it stops raining, so I may as well buy an amp and fit it while I'm up there.

 

[Marbles_00]

Yeah, I'm curious, since he mentioned freeview HD, I'm wondering if the problem is as simple as you need a converter box distinctly for picking up freeview channels (as advertised on their webpage).

InWaipawa, are you indeed trying to get freeview HD transmissions, or transmissions right from the broadcasters?

Also from the coverage map, your indicating that your on the South East side of Mt. Erin, like around Waimarama, or Ocean Beach...for further South?

 

[InWaipawa]

I am trying to get the OTA freeview HD transmissions broadcast from Mt Erin, we are located SSW of Mt Erin way down by the map scale.

If we lived 1km west of your current location we would easily get reception.

Set top box not required as decoder built into both the TV and HDD recorder.

 

[ota_canuck]

InWaipawa,


You may find some inspiration here from Bullyboxer's results.

This is the info previously provided by an Australian member:

The VHF channel frequencies stretch from 177.5 Mhz to 226.5 Mhz (this is the channel I’d really like to improve as it’s good during the day but drops out very late at night). The UHF channel frequencies are 527.25 Mhz and 548.25 Mhz and it would be good if I could improve their signal strength a little as well.

These are the final results that the Australian member posted:
http://www.digitalhome.ca/forum/showpost.php?p=1118084&postcount=107
http://www.digitalhome.ca/forum/showpost.php?p=1118001&postcount=104
http://www.digitalhome.ca/forum/showthread.php?t=119733

 

[300ohm]

I was waiting for that, the reason the antenna is mounted sideways is the signal polarization here is vertical not horizontal like in Canada.

Sure about that ? According to this, it can be either depending on the station. That can make life a bit more difficult, heh.

The DTT signals will be transmitted within New Zealand on TV Band IV and V (502MHz –
806MHZ). Covering transmission channels TV25 – TV62. The signal could either be horizontal
or vertical polarised depending on the location of the residence to the DTT transmitter.

http://www.freeviewnz.tv/images/uploads/file/freeview_antenna_spec_apr07[1].pdf

The channels I wish to get from the closest tower at Mt Erin are:
27v 519.25mhz
31v 551.25mhz
43v 647.25mhz
and I know its outside the ideal range of the GH

No, those are in the ideal range. With a mountain situation, try aiming the antenna towards the peak of the mountain, by tilting it upwards.


With having both horiz and vert polarization possible, you may want to consider building the Italian Farcarro style antenna (modified double bi-quad), like firimanis X032/X034 found in Area 51. It has a nice round balloon front pattern to it, with a little less gain than a SBGH.

http://www.digitalhome.ca/forum/showthread.php?t=105660&page=3

 

[InWaipawa]

Both local digital transmission towers broadcast uhf with vertical polarization, antenna also has a 3 degree vertical tilt. The rain seems to have eased so I may build a Stealth Hawk after work and try that. Speaking of work, I must go. Thanks for your help guys.

 

[300ohm]

You may have a bad balun, very common.

So the biggest question I have is would a masthead amp help?

Looking at the picture, it looks like you have more than 30 ft of coax, so yes it would help. Look for a quality low noise preamp.

 

[wildwillie]

InWaipawa if you want to make sure you can handle vertical and horzial

take a horztail antenna and rotate it 45 degrees and mount it like that will give you both, you will have some 3db loss, but you will have gain on both V and H

ran a test on the GH6 tilted like so / <--- 45 degres both the antenna and reflector

 

[ota_canuck]

In the Australia/New Zealand market UHF frequencies are 502MHz – 806MHZ. Basically that would represent their channels 21 to 69. He is looking for between 519MHz - 647MHz. The Stealth Hawk seems to work well for both vertical and horizontal in Austrailia. The leg length dimensions should be slightly reduced to shift up the antenna's range within the [channel 21-69] 500-800MHz range.

The Stealth Hawk has low raw gain, so for his application, amplification would be required to boost the weak received signal. Antenna height would be the only cure no matter what antenna he uses in his remote/sparse signal area.

He is in a location that is known to have sparse terrestrial capabilities. His particular area is intended to be serviced through the use of a FTA dish system.

Due to rough terrain, New Zealand is more prone to multpath dilemma than we are used to dealing with, thus the need for both terrestrial and dish systems in order to service the various reception conditions throughout the country.

The use of any high raw gain antenna could result in amplifying those terrain related multipath problems. That may explain why the GH trials have failed in his location. What I'm suggesting is that using a low gain antenna to avoid picking up those stray weak multipath reflections and hopefully only the strongest signals will be seen by the antenna and then amplify that weak but cleaner signal to the tuner.

Everthing in New Zealand is going to come down to avoidance of multipath. That's why they have chosen to use the DVB-T standard for terrestrial transmission and chosen not to use the ATSC standard. Apparently DVB-T standard is better suited for dealing with multipath issues.