Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Nickbat]

Our existing chimney aerial has lost a few aluminium spokes (from overweight pigeons sitting on them, I expect) and recently, whenever it rains the Freeview signal goes entirely and the analogue picture gets grainy.

I checked around aerial suppliers and found they want more than £200 to fit a new one. OK, I wouldn’t crawl onto a roof for less than two grand as I loathe heights, but I’m in a skinflint mood and Mrs Nickbat eggs me on to do a DIY job.

We live on a hill and sidewall masts are not uncommon, so that's the route I choose. Well, if I’m going to risk life and limb, I may as well splash out on te latest future-proof technology, so a quick check on the internet reveals that the dogs whatsits of TV aerials is the Televes DAT 45 (actually the 75 is the top of the range, but it’s bigger than my house). Off I trot to my nearest discount suppliers and get one of these things for £42, plus a 10ft pole and bracket. The guy there says that I really need an optional Margin Rising Device, for only an extra £9. Does it need power, I ask? No, he says, just clip it on in place of the inferior version already fitted. OK, I bought it.  

Get home, borrow a ladder, and fit the brackets. Drilled five 16mm holes in brickwork high up the wall (remember, I hate heights!). Aerial is big and bulky (but looks high-tech). Nearly fall off the ladder once, but succeed in getting it fixed. Rubbish reception. Try swivelling it, still no joy. In the end, I figure that maybe a nearby house is causing the poor recepton. Choose another less convenient site and go through the whole process again. Finally, I get full power on all Freeview channels…..except CBeebies and a few minor ones. This causes great consternation with my kids. Having spent hours going up and donw the ladder moving this sodding aerial about, I finally discover that the channels I can’t  get (well, I get them , but they break up every couple of minutes) are all put out on Multiplex B at Crystal Palace. Apparently CP is a Group A transmitter, and the Televes is a wideband aerial.  What the...? Haven’t a clue what all this means or what to do next, but then I remember that, in the loft, I have a spare cheapo high-gain aerial that I bought about 15 years ago. I take off the Televes gizmo and stick up this old thing. It's getting late in the day now, so I point it vaguely towards Crystal Palace tighten it up and go indoors and bingo! I get all Freeview channels. Job done.

Moral of the story? Three, actually. First, don’t buy all this high tech aerial stuff. Second, remember what you have in the loft. Finally, don’t listen to the guy behind the counter when he says that the optional Margin Rising Device does not need power (get home to find that it does!).

I now have a Televes DAT 45 plus MRD that appear to be surplus to requirements…        

[sir moanalot]

you will be surprised how little some of these muppets know about their own products, i can never get the right advice nowadays. people always tend to forget about putting ariels in their loft- i did cos .....i diy and dont like hights!!

[Taxi_Driver]

They must charge more in your area.....but thats shocking   £200

Im the same and dont like heights   ....i paid areial shop £130 recently to put up new high gain areial.....worked perfectly on analogue signals.....but not on digital.....freeview with topuptv....then whinged to topuptv.....who in the end managed to update my box....and now it works fine  

But i did have phone bill come the other day.....and it appears topuptv have a high cost number on their customer support.....it cost me over a tenner for calling them    

[DaveL]

Long, long time ago i was an apprentice T.V. engineer working in and around the Fens. A lot of my time was escorting aerials up onto the roof. i had such a job out in the loverly fen's where the wind just goes through you. Tried every thing to get a picture on a customers set with recently fitted aerial. Not a sausage. Phoned my Boss who suggested a cheap :-?er fix. So asked customer if they had any metal knitting needles. They came back with them for me. Then asked for a potato. Puzzled customer goes away and comes back with a potato. :-?  

i cut the potato in half, stuck needles into potato. Bared back the some co-Ax lead. Put centre of co-Ax to one needle, outer to other needle. Connected a co-Ax plug on end of lead and put into Telly. Moved new Aeriel around and Bingo good picture.

Customer delighted. Boss not, as customer told me to take top aeriel off  roof.

Had to call back after a week as picture had been lost. Potato dried out. So new Mk 2 version fitted with potato in small amount of water so did not dry out!!


Who needs to climb on roofs, apart from Santa??
 8-)
DaveL

[Marks DTM Calib]

Never yet seen an engineer fit a tele aerial....seen an aerial fitter do one or two (look up engineer in the dictionary!).

So the muppet who sold you the MRD did not know that it DOES need a power supply....if you cant support this (its phantom powered via the coax so it can be placed behind the tele) then fit the standard pcikup back on....

The DAT45 by the way is a VERY good aerial....

[Nickbat]

Never yet seen an engineer fit a tele aerial....seen an aerial fitter do one or two (look up engineer in the dictionary!).

So the muppet who sold you the MRD did not know that it DOES need a power supply....if you cant support this (its phantom powered via the coax so it can be placed behind the tele) then fit the standard pcikup back on....

The DAT45 by the way is a VERY good aerial....

It does look good, but it's very directonal. And it won't pick up that Multiplex B, which is a mystery to me. Assuming all the multiplexes are sited on the same transmitter tower, why won't it get hold of that one? Mind you, with my luck, I'll probably find out that that was the one day they were working on Multiplex B and it was on reduced power.

[Ghosts in my machine]

When ITV digital was still about (pre-freeview) I bought a box and plugged it in, couldn't pick up any channels. Phoned helpline and they sent out an "engineer" to take a look (this was free at the time). The 17 year old youth went up a ladder, waved a yellow box around for 5 seconds came down and told me I needed a new high gain aerial. and it would need to be fitted on the roof (despite me telling him that local planning restrictions meant I couldn't have it on the roof).

Anyway, told him to P|ss off and decided to send the box back. As a last ditch, had a fiddle with the ancient, bent and rusty aerial in my loft (moved it about 2cm), went downstairs and got all the channels perfectly.

These companies don't employ proper professionals anymore, just a spotty youth off a training scheme (or in the case of British Gas - Ex-cons), give him a two week training course, a bit of health and safety training and stick him in a white van.

Same applies for the so called specialist shops. You get a more accurate spec and desciption in the Argos catalogue, and probably a better job fitting stuff (ie. DIY!).

[Kevin Wood]

These companies don't employ proper professionals anymore, just a spotty youth

Don't get me started..

You need a "digital aerial, mate". What utter cobblers they come out with!

Bit like main dealers, really. Pay the earth to get the job done by a complete gibbon. At least the "advice" was free in this case.

Kevin

[Martin_1962]

None of where I live is allowed an external aerial but we all have them.

I have a large generic wideband which works fine, put the DAT45 for sale on here someone will buy it (think it was BoBo)

[DaveL]

Never yet seen an engineer fit a tele aerial....seen an aerial fitter do one or two (look up engineer in the dictionary!).

i did say in the very distant days, do not know your age but the telly's had valves, ones that glow, and colour telly was a novelty.  

Engineer-- to wangle, contrive, get, obtain, fix, swing and finagle. Not enough telly's around at the time for specialist fitters to put aerials up. Sorry to say that you where probably not around to see them.
 8-)
DaveL

If you where then you have a short memory.

[Marks DTM Calib]

You mean a TV repair man/technician......the engineer would have been the designer (although he might of got bored of his job and then set himself up as a repair man....)

[Nickbat]

Got this response from one of the senior members on the AV forum where I posted my problem:

According to the Wolfbane predictor you'll have an analogue signal of around 64dBuV/m and a digital signal of around 47dBuV/m.

Assuming 80dB as the maximum analogue signal your Freeview tuner will tolerate, that leaves you with 80 - 64 = 16dB to play with.

Amplifying the signals by 16dB gives you 47 + 16 = 63dB of digital which is more than adequate for good reception. The minimum gain you should aim for is 53dBuV for digital, which would require an aerial with a 53 - 47 = 6dB of gain. Basically a piece of wet string!

You should use a low-gain "Group A" aerial. A normal 12dB one would be more than adequate. If you put your postcode in here: http://www.blake-uk.com/  it recommends a DMX10A. Frankly, I think the gain may be a fraction high but the only way to find out is to try it. You might need to fit an attenuator.

The aerial you have at the moment is suitable for Hemel Hempstead, having most of its gain at the higher end of the UHF band. (A wideband aerial doesn't have a flat gain curve - it's worst at the lower "Group A" end. You don't need a lot of gain but it might be pulling in unwanted signals from HH).

 
I need time and a lot of brain power to digest this!

[Kevin Wood]

You mean a TV repair man/technician..

At least they could fault find down to component level. Valves were expensive enough that you didn't just replace all the electronics in the box and hope for the best.

Same with cars. How many "mechanics" know how to change the seals on a brake caliper these days?

I need time and a lot of brain power to digest this!

I think he's saying that, despite what the muppet said, you've got bags of signal and don't need too high a gain antenna for want of overloading the input on your box!

I'd say still get something with plenty of gain but make it a Group A. With gain comes directivity, meaning it'll be less sensitive to reflections and signals arriving from other transmitters. As he says you can always add attenuation if you need to bring the level down.

Kevin

[Nickbat]

Cheers, Kevin. It seems ironic that, at the moment I can't get enough signal and yet, if I get the right Group A aerial I may need an attenuator to reduce the signal. Incidentally, does an attenuator need a power source and where does it attach?

[Marks DTM Calib]

No it doesn't need a power source....it simply fits in line of the coax and idealy as close to the receiver as possible.