Replacement TV aerial

[u587162]

My existing TV aerial came off its brackets on the chimney recently. It must have been over 40 years old since my parents installed it.

I had it replaced by a company a few days ago. Rather than the larger or existing size aerial, he recommended a periodical aerial which was considerably smaller in size and suggested he attach it to another mast I had on the chimney which held my FM aerial. I agreed after he said that there was no need for a larger one or a new bracket. We tested the signal strength both before (when the old one was dangling off the roof) and after the new one was installed and it showed 16 or 62 (I forget) db reading. The signal quality is near 100%.

My question is whether it was the correct decision to go for this tiny size aerial despite it currently giving a good signal quality. The aerial goes into a signal booster which then splits to other rooms.

Thanks.

 

[Lucid]

Simple answer: Yes, probably.

The way the channels are distributed at each transmitter is changing to make way for the sell off of more of the TV bands for mobile communications. The old idea of having an aerial (correct spelling ) that works well in a narrow band of frequencies is now rarely a valid choice for many. Also, the big wide and high gain aerials are a bit of a con. They aren't "high gain" and "wide band" at the same time. The result is that for transmitters using the lower mux channel numbers then those large aerials are actually quite poor. A Log Periodic aerial is almost actually efficency at low, middle and high frequencies. We say that that is has a relatively flat response. This is ideal where your local transmitter uses a wide spread of mux frequencies or where they they are grouped in the bottom or mid range.

There are of course the odd exception, but as general guidance a Log Periodic is a decent choice for many homes.

 

[Sam Gangee]

A modern log-periodic aerial is actually "narrow band", being designed either for the low "group A" band (21 - 35) or for the new "wide" spectrum (21 - 60) called variously "Group L" or "Group T" or "LTE filtered". You can see this represented graphically here:
http://www.satcure.co.uk/tech/Aerial_Groups.htm

The old "wideband" aerials were designed to cover UHF channels 21 - 68 but the top channels are now allocated to 4G mobile phone transmissions, so you definitely don't want your TV aerial to receive those.

More information about the log-periodic aerial here:
http://www.satcure.co.uk/tech/logperiodic.htm

 

[u587162]

Thanks for the replies. This has given me more confidence in what has been installed. I paid £75 for this work in north London. The aerial itself is only £15 (I checked the model) and he didn't use any other parts as I had an existing mast he tied it to. He did have to climb up a ladder to get onto my flat roof dormer and then fix to the mast on chimney.

 

[Sam Gangee]

£60 for the call-out (fuel, wear & tear, time), plus labour and the skill to choose and fit the correct aerial, seems reasonable - especially for London where traffic and parking can be a nightmare. Put it this way: £60 would get me anywhere near a ladder!