Which Masthead amp to use

jack12a

Hi guys,

My location is 60 km N/E of Kippure transmitter which is advised on saorview app, I’m currently using a 10 element C/D aerial fitted on o/s aerial pole, it’s gain I think is around 13db with a 16db masthead amp plus power unit in attic, on my humax terrestrial box meter signal quality is 100% and signal strength is 65 - 70% on ch54 and ch 58.

I need to fit an fm aerial so felt it might be a good idea to change tv aerial as well due to impending channel reshuffle, I purchased a similar wide band aerial ch 21-60 gain 13db,
I’m pretty sure Kippure channels are moving to some where around ch 31 -35,
On reading aerial leaflet I noticed stated gain at ch 29 was down to 9.5db,
My question is as I also have a spare masthead amp with a gain of 25db would I be better using it to improve gain or retaining 16db one ??.

Regards,

The Cush

Kippure will move to UHF 34/35 according to the plan, Group A red-tip aerial.

The mast gets a power boost to 125kW and an increase in height.

The new frequencies officially get switched on Sept 4th, the old and new frequencies will simulcast for 6 months, until next March.

My suggestion would be to hold off with the aerial change until Sept and get the proper in-group UHF aerial, instead of using the 21-60 wideband which will overlap with the future 5G frequencies 49-60. That wideband aerial combined with a masthead amp could cause interference problems in future. With the increase in power and mast height a masthead amp may not be required.

jack12a

Hi Cush,

Thanks for your excellent advice re new aerial it really is a bit of a dark art to get right, when you say transmitter power and height are being increased would you think that would mean a significant gain in signal at my location, I have to put my hands up and admit I have no idea what the difference / affect a 16db or 25db masthead amp would make to signal.

Regards

The Cush

Difficult to know how the transmitter changes will benefit your location at this side of the keyboard but at a guess it might. This is the reason I suggested waiting until Sept when everything is up an running. Only in Sept will you know for sure if a masthead amp is required.

Antenna

The Cush wrote: »

The mast gets a power boost to 125kW

Its a power reduction, not a power boost which is unfortunately happening with the ERP for viewers east of Kippure, which is why a new relay is being built for Wicklow town.

Yes the original poster is best waiting until the new signal is actually on air before trying a new aerial, if current reception is OK

The Cush

Antenna wrote: »

Its a power reduction, not a power boost which is unfortunately happening with the ERP for viewers east of Kippure, which is why a new relay is being built for Wicklow town.

Kippure is currently 63kW max.

Isn't the new Wicklow relay required because of incoming UK interference, must look at the documentation again?

sligojoek

From my experience, you'd be better off waiting till the new transmitter is up and running.

For years I only had a grainy pic from a chimney mounted aerial on account of a ridge of mountains between me and Truskmore. Since they raised the mast, I can now get a perfect picture with the aerial a foot above the back door.

The Cush

Antenna wrote: »

Its a power reduction, not a power boost which is unfortunately happening with the ERP for viewers east of Kippure, which is why a new relay is being built for Wicklow town.

The reasoning for a new transmitter covering Wicklow

In considering the need for two additional sites, at Drogheda and Wicklow, we note that the areas surrounding the Kippure, Greystones, Laragh and Wicklow sites are hilly and that some such areas are not in line of sight of the main Kippure site. That is, even though the Kippure site is at an elevated location relative to the surrounding areas, other nearby hills the block line of sight between Kippure and certain areas while some of those same areas are fully exposed to UK interference (i.e. they are in line of sight of transmissions originating in the UK). Similarly, the two existing fill-in sites, at Laragh and Greystones, also do not have line of sight to all of the affected areas, again due to the hilly nature of the area. Adding an additional site at Wicklow should therefore reduce the number of areas without direct line of sight to a 2rn site, thereby reducing any loss of DTT service in those areas as may result from 700 MHz migration.

2rn on Kippure

“Kippure is a key main station serving the east coast which is the area worst affected by increased interference as a direct result of the 700 MHz migration. In order to repair coverage greater height is needed from Kippure (in line with the original analogue TV transmissions). A new antenna is required approximately 18m higher than the current main UHF antenna at Kippure. The new antenna which is expected to consist of 10 tiers of panels will be installed on a spine at the top of the mast and will be designed for the new frequencies with their associated coordinated radiation patterns. The cost estimate is based on broadly similar installations carried out during the DTT project, but it is expected that the final cost may vary significantly following detailed design and tender. Once this new antenna is in place the existing DTT antenna will be deployed as a back-up. This will allow us to cover a significant part of the coverage area at reduced power during outages arising from faults or maintenance in the main antenna. The existing antenna cannot be operated at full power without breaching coverage restrictions. The coverage given is therefore a useful emergency back-up but no more. This will make working on the new antennas more efficient.

This is the only antenna of this scale being replaced as a direct result of the 700 MHz clearance and is therefore significantly more costly than the other new antennas required.”

Kippure restrictions in the new plan

8dB (1dB HP + 7dBVP) | 010-033 | Darvel (COM)
12dB | 45-90 | Winter Hill (PSB)
8dB | 138-145, 7dB | 146-155 | Huntshaw Cross (COM)