Loft aerial problems! amp?

There is no comparison between the reception you will get from an aerial in the loft and an aerial on the roof. I think you would be better off getting a professional aerial company to install the aerial on the roof. They also have the correct equipment to measure the signal strength and orientate the aerial for the best reception.

BB

 

using good quality copper shielded coax cable will help, the cheapo stuff is naff.

 

I bought the same one Matt, put it in the bin (like I did coz I was too busy to faff around) or send it back. A bit of coax slung over the roof gives better reception - looking at the connecting box on mine (1) I could see no way that the coax actually made contact with any metal part of the aerial (2) the tread was stripped so was unable to hold it tight anyway. Utter C R A P.

 

It really does sound like it is a duff aerial - can you receive analogue TV at all? Make sure the cable is good quality and make sure no strand of the outer shielding is touching the central core at the connection at either end as this fault would produce exactly the result you describe.
I know this is an unlikely error but are you sure you have the aerial polarised correctly? If you are receiving from a main transmitter it should be horizontally polarised.The opposite is true if you are using one of the lower powered "satellite" transmiters - but you need to check. Details will be on the BBC website.
I have a loft aerial with no amp and I am in a fringe area with low signal strength but I rather surprisingly get good Freeview - the quality of the signal (its freedom from interference) is just as important.If a signal is poor quality amplifing it will just amplify the rubbish as well.
Regards, Hab

 

You really have to take the whole set-up up into the loft with you.

Take the telly/freeview/amplifier/all plugs etc connect it up to the coax that it will be using and move your aerial around the loft to get the right position/height/direction, while the telly is in full view.

One tip, set it all up from your main aerial first, so that you KNOW the channels are set correctly before you start.

Problem with aerials, is that there are specific kinds for specific problems. High gain is not always the best option etc.


I used our old aerial (when we upgraded our rooftop aerial) in the loft, amp at one bedroom TV, and it supplies 2 TVs, 2Freeviews, 2 videos. Perfect reception all round.


Mr. HandyAndy - really

 

On my example, in the connection box there was a small bit of 'circuit board' containing the coax connectors. This board was attached to the dipole by 2 screws - the screws were clearly supposed to make a connection between the dipole and the board - they equally clearly didn't - possibly because the screwholes were too big.

 

Kandy,the circuit board you mentioned is the "Balun" (the balancing transformer).Its used to connect the BAlanced aerial to the UNbalanced co-axial cable.It should be the sign of a good design but the SF example seems very cheap for 48 element aerial.It seems that the detailed design of the aerial has been skipped - a pity as a 48 element aerial should be about as powerful as you can get.Certainly it sounds in the original post as if there is a bad connection or short somewhere , providing the vertical orientation (polarisation) is correct !
Regards, Hab

 

Matlymtyuk,what do you mean by "very high" and "very low".
The Winter Hill multiplexes are transmitted on these channels 56 ,66,68,67,60 and 63 with horizontal polarisation - you may get some programs on 43 and 40 also.If you point your aerial at Winter Hill with the X shaped director elements horizontal do you get all the Freeview programs - there should be about 85 radio and TV.How many can you get?

Regards, Hab

 

ITV muxA and Mux B use a system of coding called "64 QAM" and the others use "16 QAM". The former enables more programs on the multiplex but is more difficult to get so it seems that your signal level is marginal. If you can borrow an amplifier that might work.Other than that you would get better reception by installing the same aerial externally - if that is possible!. Sorry that I cannot be of greater help.
Hab

 

It's not pointing at a cylinder, water tank or pipes is it? There must be something fundamentally wrong if you can rotate it from horizontal to vertical & make no difference, probably a connection. Check at both ends that a strand of wire from the screen has not strayed across to the centre conductor, shorting it out.

 

Outside installation should improve the signal strength considerably.You say that there was no difference if you oriented the aerial horizontally or vertically.Are you sure about this? If the aerial is vertically oriented there should be very little or no signal from the Winter Hill main transmitter.There should be a considerable difference if it is horizontal - what does the signal strength indicator on your box say in both these cases?
You don't seem to be getting the signal that your aerial is capable of so, as "Dormouse" says above,check your connections at both ends and that the circuit board (Balun) at the aerial end is making proper contact with the aerial - a multimeter would help here.
Regards, Hab

 

Hab, I'm working from memory, but on this aerial, is the balun supposed to be in contact with the dipole or does it work entirely on induction?

In the middle of the balun board was an isolated metallic foil 'fat upside down U-shape' with connector for outer coax.

The dipole was in two separate loops and these were apparently connected together by a thin foil strip around the edge of the balun which had the center coax connector attached.

A screw at each corner of the balun board was apparently meant to connect each part of the dipole to each end of the foil strip - but there was no metallic contact. Was that right or wrong?

 

try pointing the aerial to the Wenvoe transmitter and run the coax through a booster before connecting it to the tv.

 

The X-shaped elements should be clipped upright regardless. The whole aerial is then twisted on its axis for hor/ver. It looks very cramped for space there, difficult to get good alignment/sufficient height I would've thought.