Frequencies and channels

bpmurray

Can anyone help: I'm between Drogheda & Dundalk, and on a good day I can get stuff from Divis & from Brougher Mountain. The reason I know this is because these are pre-coded into the software so a scan is a quite trivial point and click.

Now, when I do a general scan, I can't see anything from Clermont Carn. I believe the problem is that the software only scans in steps of 1000 kHz, so it never looks at what's in between. I see a lot of folk referring to channel numbers (and letters) and "mux"es (multiplexers?), but I have no idea how to map these to frequencies. Friends who live in South Dublin use 738000kHz, but that's presumably the other transmitter.

Can anyone tell me the frequency or frequencies I should scan to get the Irish trials?

Mayo Exile

Have a look at this website:

http://www.geocities.com/corkradio/tvch.html

It has a Channel to actual MHz conversion table at the bottom of the page. Clermont Carn's DTT trial is carried on ch. 53 which equates to 727.25 Mhz. There are also blank carrier signals at chs 57 and 60.

watty

Clarmont is using a variable offset. It doesn't work at all on some automatic only tuners. Others it is fine, but you have to rescan when picture vanishes. Some you have to manually tune. Most don't have manual tuning.

lawhec

Clermont Carn's centre frequency will be around 730.000MHz or slightly off it due to an offset. 727.25MHz only refers to the carrier of the luminance if it was an analogue signal being broadcast. DTT frequencies are given for the centre of the multiplex block.

Porter Reekin'

I'm in mid-Kildare. Did a tuning scan with the above list of channels to hand. My wideband aerial is tuned to Kippure (line of sight, about 25 miles away). Without adjusting the aerial, I can get pictures from Mt. Leinster, Cairn Hill and Three Rock.

A few things though-

I can't get RTE2 from Three Rock- any ideas why only this one?.

I appear to get (only) RTE1 from Clermont Carn!!! Is that possible?

Three real oddities-
I'm getting RTE1 (poor picture and sound) on 177.18 mHz (Channel D?).

I'm getting RTE1 (perfect sound, snowy picture) on 366.43 mHz and RTE2 on 414.56 mHz (perfect sound, snowy picture).

Any ideas on any of these- I'm really interested? Thanks in advance.

lawhec

I'm getting RTE1 (perfect sound, snowy picture) on 366.43 mHz and RTE2 on 414.56 mHz (perfect sound, snowy picture).

These two channels would be around the second harmonic of the channels broadcast from Kippure. The reason the picture looks snowy would be down to (a) inneffiency of receiving and transmitting aerials at such frequencies and (b) that suppression of such harmonics should be taking place at Kippure, but are difficult to elimante altogether.

Antenna

Northern Correspondent wrote:

These two channels would be around the second harmonic of the channels broadcast from Kippure. The reason the picture looks snowy would be down to (a) inneffiency of receiving and transmitting aerials at such frequencies and (b) that suppression of such harmonics should be taking place at Kippure, but are difficult to elimante altogether.

They are hardly in the air. Probably the result of non-linearity of a distribution amplifier (or RF loopthrough amplifier in VCR, or satellite receiver with modulator) in 'Porter Reekin's installation.

watty

Agreed. Likely local artifacts from preamp, vhs, tuner etc.

The Sky digibox pass through is particularly prone to intermodulation on strong signals. All my signals improved dramatically with bypassing the box, a 6dB attenuator on input gave same improvement. TV3 went from snowy to crystal clear WITH attenuator! Faint herring bones on all channels dissapeared!

lawhec

Antenna wrote:

They are hardly in the air. Probably the result of non-linearity of a distribution amplifier (or RF loopthrough amplifier in VCR, or satellite receiver with modulator) in 'Porter Reekin's installation.

Probably the most likely reason, but even at Kippure itself these harmonics will be broadcast at a few watts, fairly insignificant once you are a few miles away.

lucernarian

Why do I get a somewhat snowy RTÉ2 on "Channel 10" on a little panasonic TV, with an indoor aerial and then receive an identical picture on Channel 20? It has the exact same interference and all. If I move the aerial, they are still both identical. Something similar happens with RTÉ1, except on different channels (07 and 18).

We have no VCRs at home or any sort of RF modulator. Nearest neighbours are about 100m away.

ethernet

To_be_confirmed wrote:

Why do I get a somewhat snowy RTÉ2 on "Channel 10" on a little panasonic TV, with an indoor aerial and then receive an identical picture on Channel 20? It has the exact same interference and all. If I move the aerial, they are still both identical. Something similar happens with RTÉ1, except on different channels (07 and 18).

We have no VCRs at home or any sort of RF modulator. Nearest neighbours are about 100m away.

Sounds like it's from Maghera. RTÉ 2 is on channel 10 and 20. Don't know about channel 7 and 18 though. Hardly from the UK?

zilog_jones

Is there cable in your area? I can get some faint cable channels on band III even when the TV is nowhere a connection

lucernarian

There is no cable within 20 miles. Navan or Swords would be the nearest places.