TV aerial prob - see pics!

[someonelse]

The house has (had) 3 cables off the aerial serving three locations.

When digital came in we had a guy come round and add a digital aerial (picture below).

While installing he told my partner we needed some extra 'boxes', one outside and one next to the TV, for which, of course there was a charge. I have no idea if these were necessary or even what they do.. (pictures below).

He connected one cable via these and living room TV fine. The others we were not concerned about.

We now want to get one of the other locations working - TV finds 6 or 7 channels only, using the original aerial.

Is it possible (and will it help?) to connect this new location to the 'box' outside?

And do we need another internal one?

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• someonelse
• 4 Sep 2012
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• someonelse
• 4 Sep 2012
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• someonelse
• 4 Sep 2012
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• someonelse
• 4 Sep 2012
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• someonelse
• 4 Sep 2012
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[Ricardus]

Unless I'm very much mistaken what you have is a masthead amplifier (outside box) and its power supply (internal box - sends 12v dc up the coax cable to power the outside amp) - and fairly decent ones too.

Assuming you're in a weak signal area and needed an amp and the installer wasn't flogging you something you didn't need, then for extra TV points first off try some simple aerial splitters off the new, amplified line and see if you still have enough signal to get all your channels reliably.
If that doesn't work then I suggest getting a ladder and taking a closer look at the masthead amp. I've got the same make and once you open the lid you might find it has variable gain or even four amplified outlets.

 

[rjm2k]

Vision do a 4 way amp, so it may be easier to replace the one you have and run the other 2 cables off the same one, that way you aren't adding extra power supplies to plug in etc, though it maybe worth checking which version your fitter used, would be odd to add a single when they could see you have 3 aerials already.

A cheaper way would be to route the output of the 1 you have into the loft and connect the other 2 cables and the original to it using an unpowered splitter.

I'm no expert on these amps but that looks to be a long way from the aerial itself?

 

[daxi]

The only problem with a splitter is that it would insert a significant loss into the system as obviously each output will get a percentage of the output. Plus of course the splitter it's self has an insertion loss.
Average insertion loss if each output is used & allowing for the splitters efficiency at 80 to 90%, would be about 3- 4 dB on a 2-1 splitter & about 7 to 8dB on a 4 to 1 splitter.
Each 3 dB is a 50% loss, so 6dB = 3db at 50% plus another 50% so 6dB =a 75% loss. Thus an 8dB loss is just above a 12.5% efficiency.
So using an un-amplified splitter may be a very poor choice, but that will depend upon the signal level at the splitter.

 

[Sam Gangee]

I suggest getting a ladder and taking a closer look at the masthead amp. I've got the same make and once you open the lid you might find it has variable gain or even four amplified outlets.

I agree. That's the first course of action. Determine the part number like "V20-1127" and then we can advise with some confidence.

If it IS a V20-1127 then replacing with a V20-1420K would be the simplest solution and the same indoor Power Supply Unit (V23-2350G) should be fine.

See http://www.satcure.co.uk/accs/page11c.htm#vision

 

[someonelse]

I'm no expert on these amps but that looks to be a long way from the aerial itself?

Correct. The 'masthead amp' is actually at ground level rather than anywhere near the masthead!

I'll open it up tomorrow (maybe take a picture) and see which version it is.
Thanks all!

 

[Sam Gangee]

The 'masthead amp' is actually at ground level rather than anywhere near the masthead!

That's obviously not ideal because it's amplifying an already-noisy weak signal (made so by the length of drop-cable).

However, whereas that was a major consideration with analogue, with digital it's pretty much all or nothing. So, if it's working OK with 1 output, it should work OK with 4.

You could be a perfectionist and spend time relocating the masthead Amp and cables but the end result (picture quality) would be no different.

BTW I suspect that the other two aerials are perfectly OK and the reason for some channels missing is related to the type and age of the cable. The installer probably added his shiny new aerial just to make more profit. Did we mention that there's no such thing as a "digital" aerial?

http://www.paras.org.uk/02-myths.shtml

The older aerials should be removed to reduce wind resistance.

I would also mention that the cable layout doesn't look very professional. Also, the idea of mounting the amplifier on a drainpipe, whilst ingenious, is probably not a good idea. If the drainpipe ever needs to be replaced, you'll end up with the fitter having to deal with the amplifier.

 

[someonelse]

Opened it up and it is a Vision V21-1127 (picture below). It appears to have one input point and one output only.

(Although Google produced sites saying it has 2 inputs, and another saying 4 outputs!) (http://www.dastechnology.co.uk/shop/masthead-amplifiers/Vision-V201127-Variable-Masthead-Amp-27dB)

So if I buy a Vision V20-1420K:
1) can I simply cut the cable to the 'new' location and connect to a 2nd output point, thus using the same aerial/input as the current one ?
2) is it easy to do?
3) would the unit be better screwed to the wooden soffit rather than the downpipe as at present ?

cheers!

(edit: is it possible to buy the V20-1420K without the power unit and use the existing?)

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• someonelse
• 6 Sep 2012
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• someonelse
• 6 Sep 2012
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[rjm2k]

Looks like the amps and power units are sold seperatly anyway, difficult to tell from their website if your current PSU will work with the 4 way amp but I would guess it probably will.

Probably would be better with the amp on the soffit or wall rather than the pipe, but moving it too far will mean you need to alter the cabling to match, the other aerial output looks like it goes past the amp anyway so should be a matter of cutting those cables, adding f connectors and away you go. Take off the unused aerials/cable if you prefer to not have them up any more. Seems to be very little difference in price between the 1, 2 and 4 output, shame your installer didn't just use a more appropriate on in the first place.

 

[Sam Gangee]

(edit: is it possible to buy the V20-1420K without the power unit and use the existing?)

Yes, I provided the link for you in my first reply.

 

[someonelse]

Anyone know the difference between the Vision V20 1420 4 way masthead amp and

the Vision Optima 4 way masthead amp (http://www.freesatcable.co.uk/masthead%20kit/tv-arial-4-way-masthead-amplifier) ?

 

[Sam Gangee]

http://www.vision-products.co.uk/productpage.asp?productcode=V20-1420&subcategoryid=6

 

[Ricardus]

Personally I wouldn't buy a new amp just yet.

According to Vision's specs the amp you have is adjustable up to 27db gain, and the 4 way version V20-1420 is adjustable gain up to 20db.

As you want to run 3 TVs from one cable then try a couple of 2 way splitters (or a single 3/4 way) and increase the gain on the amp to compensate for the loss caused by the splitters if required.

 

[Sam Gangee]

I've done a bit of searching and found the specification sheets for you:

Optima
http://www.satsol.co.uk/ProductInfo/c44157/c44157.pdf

Vision
http://www.satsol.co.uk/ProductInfo/c12537/c12537.pdf

It seems that the Optima is a low-cost version. It has a significantly higher noise figure, which probably won't matter if your signal is strong. Mind, if your signal is strong, a passive splitter might do (as suggested by Ricardus).