Freeview in Co. Louth

MichaelOS

Hi All,
I really enjoyed reading posts on this forum in the past so I've just joined up today.

I recently got the Freesat service installed and while I consider it good value for money I was disappointed that E4/More4 are not available so I was just wondering about Freeview. I live in Dundalk town (on the north side) near the Castletown river. I'm wondering would it be possible to receive a freeview signal from here? Any test I could do before I commit to buying the kit?

Thanks,
Michael.

Ulsterman 1690

Can you get Channel five ?
Its considered a good indicator as to whether freeview is available

Oh and your aeerial needs to be pointed at DIVIS (near Belfast) rather than say Camlough, Newry, Kilkeel etc

Big Dee

I bought a top box for £24 stg yesterday while in Belfast doing some Christmas shopping. I was aware from posts on this site that I didn't stand much chance of getting any reception but I decided to give it a try and if it worked great, if not, re-box it and back to the shop! I live just off the Avenue Road in Dundalk town.
I have very very poor Channel5 reception. In addition my brother, who lives in the UK, took his top-box over about 9 months ago and tried on my tv, but it was useless.
Imagine my surprise last night when I plugged in and scanned with the new top box - an additional 30 channels plus say 15 radio stations - all perfect! BRILLIANT!! Suffice to say, it'll not be going back to the shop!

Richard

MichaelOS wrote:

I recently got the Freesat service installed and while I consider it good value for money I was disappointed that E4/More4 are not available so I was just wondering about Freeview. I live in Dundalk town (on the north side) near the Castletown river. I'm wondering would it be possible to receive a freeview signal from here? Any test I could do before I commit to buying the kit?

You should check to check that you get analogue BBC/ITV/Ch4 from Divis rather than from a relay. So unless you get a good picture on BBC ONE (31), BBC TWO (27), UTV (24) and CH4 (21) then give Freeview a miss.

Presumably too the aerial is horizontally polarised if its Divis you are on.

Ie the rods on it are horizontal (flat sideways ) as opposed to standing up vertical which usually indicates you are on a relay tx.

Aerial if horizontal should be like this



or like this if vertical


Check this site out as it explains it mid way down the page and has more modern looking horizontal aerials than what I pictured above.

watty

Picture above:
There is a "halo", an aerial for Horizontal VHF radio omnidirectional.

(No prizes for guessing WHY it is called a halo!)

I don't know why they are installed:
a) Ireland is almost exclusively Vertical VHF radio
b) UK is mostly "Slant" now to suit cars.
c) It has negative gain!

In Ireland a simple whip will wotk 10 times better for VHF!

Ulsterman 1690

Watty Ive always wondered the same thing so I asked a guy who works for an aerial installer down South and he said "I know theyre not as good as a vertical dipole but the boss says they look good" :rolleyes:

Could this be the same reason for many Southern aerial riggers apparent infatuation with grid/bowtie (Colour Kings) for UHF ?

Ireland is almost exclusively Vertical VHF radio

Some Irish transmitters (mostly on the East coast) use Mixed polorisation but most are Vertical UK transmitters are either Mixed Vertical or slant

lawhec

Could this be the same reason for many Southern aerial riggers apparent infatuation with grid/bowtie (Colour Kings) for UHF ?

I always thought that in and around Munster they were popular because they had a wide front lobe when horizontaly polarized, hence a better chance of getting a main RTÉ transmitter and a local "deflector" with the one aerial rather than needing two?

watty

Ulsterman 1690 wrote:

Watty Ive always wondered the same thing so I asked a guy who works for an aerial installer down South and he said "I know theyre not as good as a vertical dipole but the boss says they look good" :rolleyes:

Could this be the same reason for many Southern aerial riggers apparent infatuation with grid/bowtie (Colour Kings) for UHF ?


Some Irish transmitters (mostly on the East coast) use Mixed polorisation but most are Vertical UK transmitters are either Mixed Vertical or slant

Yes so they all work better with vertical whip or dipole.

The halo has -6dB gain for horizontal, -12dB gain for slant/mixed and around -20dB gain or worse for vertical.


The bowtie is (compared with yagi):
1) Easy to mount.
2) Unobtrusive.
3) Wide band. covers all groups
4) Less directional, accuracy of pointing not so important.
5) Cheap. Of course the really cheap ones are copies that don't have a cable matching unit and and don't work very well.
6) More prone to Ghosting. (pickup of reflections).

Some TV aerials are just copies made by someone who knows nothing about aerials and may leave out vital details to save costs.

A "real one" in a good signal area is fine. A "fake one" may perform worse than a rabbits ear on the top of TV. (I've done tests).

I found that if the top channel or two in a group is weaker or you getting interference pickup against Ch35 to 37 (VHS modulator), the using the next up group of Yagi can work well.

Also using the back mesh of a "bow-tie" aerial tied to the rear reflector of a yagi increases gain slightly and reduces ghosting. If the sides are curved, you make cut to as to bend the top and bottom edges a little more toward MMDS mesh shape.

Most yagi do not have a 75 coax "balun". In this case better matching is obtained by not having the stripped coax to short but having inner and outer dressed in "Y" with 1" / 50mm legs to the terminals.

The "proper" bowties have a plastic box with a printed circuit board balun to match the cable.

CT100 Satellite cable is better than most the TV coax sold.

watty

Northern Correspondent wrote:

I always thought that in and around Munster they were popular because they had a wide front lobe when horizontaly polarized, hence a better chance of getting a main RTÉ transmitter and a local "deflector" with the one aerial rather than needing two?

Possible. Though RLO TV is long gone in Limerick.

Mayo Exile

Bought a Sagem ITD58 freeview box in Argos, Newry for a friend in Dundalk to see if it would work. He lives on St. Mary's Road (town end, near the church). Surprisingly it works! (kind of). There is pixellation/freezing of the picture on BBC1/2, ITV. However the shopping and music channels seem ok.

However when tuning the box for the first time Sky News wasn't there. Is it available on Freeview in Northern Ireland?

lawhec

Mayo Exile wrote:

Bought a Sagem ITD58 freeview box in Argos, Newry for a friend in Dundalk to see if it would work. He lives on St. Mary's Road (town end, near the church). Surprisingly it works! (kind of). There is pixellation/freezing of the picture on BBC1/2, ITV. However the shopping and music channels seem ok.

However when tuning the box for the first time Sky News wasn't there. Is it available on Freeview in Northern Ireland?

The multiplex that Sky News is on (along with UKTV History, Sky Three, Sky Sports News, E4+1 and a few radio channels) is out of band compared to the remaining digital transmissions and analogue services from Divis.

The remedy is to replace the existing aerial with a Group K aerial from a Group A aerial.

Ulsterman 1690

The bowtie is (compared with yagi):
1) Easy to mount.

True

2) Unobtrusive.

Generally yes

3) Wide band. covers all groups

Works quite well on groups B and C/D well but performance on channels below 30 is often inferior to a basic yagi (which makes using them for Divis/Brougher or any on-channel deflectors fed from same rather silly

4) Less directional, accuracy of pointing not so important.

True

5) Cheap..

Probably why their use is so widespread

6) More prone to Ghosting. (pickup of reflections).

Funny one this. They have a wide accepance angle (making them more prone to ghosting from some directions) at least on horizontal polorisation but also a high front/back ratio (making them more immune to ghosting from other directions. In the UK the colourking is actually marketed as an "anti-ghost" aerial

they can be very useful in some situations but are hardly the "near-universal solution" that most Irish installers seam to regard them as

BTW RE: the FM "halos"
1) In the US theyre often reffered to as "turnstile antennas"
2) Ive seen some mounted at a 90 deg angle -presumably in an attempt to make them work in vertical polarity. of course while this will recieve vertically poloriased transmissions (badly) in some directions in other directions the polorisation will be (depending on feedpoint location) a bastardised mixture of horizontal and circular polorisation. Oh and its multipath rejection will be even lower :rolleyes:

watty

A vertically mounted halo a null along axis thrrough loop, (up and down when normally mounted).