New loft aerial - problems

[Uncle Peter]

All MUXes transmitted from Crystal Palace remain in the Group A range

[Osem]

Originally Posted by Taf

Is this aerial and old analogue one? If so you may have to stump up for a wideband one 'cos the digital signals are spread out a bit more AFAIK.

As for the aerial socket be wary of fine threads of screen shorting it all out.

It's a digital log periodic type aerial. The one shown here:

http://www.toolstation.com/shop/p93127

Will redo the coaxial connection tomorrow when I can see a bit better.

TVM.

[Taf]

I have seen damaged cable cause total loss of signal when both ends of the screen were connected to the plugs/sockets. Internal shorts usually due to them being trampled or bent hard, and especially with air dielectric types.

Come to think of it, this can also cause the screening to become part of the aerial, causing signal fluctuations as you describe.

Looking at the picture, I have to ask how does power get to the masthead amp? And are the unused outlets supplied with loads?

[Osem]

The description is misleading IMHO. The aerial doesn't have a powered masthead amplifier just a metal box (splitter) with a total of 5 f type sockets one of which accepts the short coaxial lead from the aerial itself. The amplifier provided and pictured in the literature has a single outlet to connect it to a single TV via a supplied 1m coaxial cable. It's pictured, in the instructions, plugged into a power outlet adjacent to the TV not connected directly onto the aerial.

Originally Posted by Osem

The description is misleading IMHO. The aerial doesn't have a powered masthead amplifier just a metal box (splitter) with a total of 5 f type sockets one of which accepts the short coaxial lead from the aerial itself. The amplifier provided and pictured in the literature has a single outlet to connect it to a single TV via a supplied 1m coaxial cable. It's pictured, in the instructions, plugged into a power outlet adjacent to the TV not connected directly onto the aerial.

If the kit you have bought is identical to the one you linked above, then it does indeed have a powered mast head amplifier. That's it, mounted right next to the aerial. The box that you plug into the mains in your living room is the power supply for the whole rig. It sends power up the coax to power the masthead amp so that properly boosted signal comes out of all the outlets.

I've never installed one myself so I can't say exactly which wire goes where, but if you get it all plugged in the right way you should have nice, boosted signals on all your tellyboxes.

[Osem]

Aha - that now makes sense. The instructions are rubbish. Will have another look tomorrow. TVM

[Osem]

And as if by diving intervention, the roof aerial appears to have given up the ghost finally so the other TVs in the house have no Freeview. The coaxial cable on the roof's probably broken or been damaged due to all the gusting wind we've been having so I now have the very best possible incentive to get this problem sorted or Mrs Osem will kick my butt! She's having a well deserved lie in right now but as soon as she's up, I'll be in the loft seeing if I can finally wire it all up properly. Fingers crossed...

[Osem]

BINGO!!!!!

Chris's suggestion was bang on. The amplifier is designed to plug into the mains close to one of the TV sets. A short fly lead connects this to the TV and the coaxial cable connects it to the first F socket on the aerial body. This then amplifies all the outlets. I found I had an excellent signal on the first TV so to save time, I connected a second length of PF100 to the aerial body and ran it to the 4 way junction box which connects to the roof aerial and serves the remaining TVs. All that remained was to swap this lead with the roof aerial lead and I'd connected all 3 other sets to the new aerial. Fingers crossed that the amplified signal would be strong enough to be spilt 3 ways, I checked and retuned each TV and found all are working very well indeed.
Hoorah!!!! Can't say how happy I am!!

Sincere thanks to all contributors to this thread, without whom I'd probably have no hair/fingernails left, not to mention Mrs Osem's boot wedged firmly up my backside!!

I think the original cable was a big part of the problem with the reflections so investing in decent PF100 was well worth it. The other thing is that the aerial is only temporarily located in the loft at the moment and needs fixing to the woodwork and orientating towards the transmitter more accurately. No doubt this will improve matters further.

[Osem]

Yes it's a nice feeling. My knees were starting to play up with all that grovelling... lol

A big thanks to everyone who helped.