Free TV channels for VCR and Sky use!

[ericmark]

I am trying to slot analogue programs from Sky, Freetoair, DVD, VCR, around the existing TV programs picked up by the aerial. I live on top of a hill in North Wales and receive signals from Winter Hill, Moel Y Parc and weak signal from The Wrekin.
This leaves the following channels free 21, 22, 24, 25, 27, 28, 29, 31, 32, 36, 37, 38, 39, 41, 44, 46, 47, 51, 53, and 57. So to add 4 transmit frequencies should not be a problem.
But in practice it seems harmonics are causing a problem and seeing my FTA on channel 37 blocked out Channel 5 on 48. Moving one channel did not help and ended up moving to 57. Now I seem to have lost some multi-plex channels which include BBC1. Constant moving to try to find clear channels is a nightmare, especially with the multi plex channels, which will work at first, then fall over latter as conditions change.
What I can’t work out is it just harmonics which there is nothing I can do about or is it poor rejection on receiver (TV) or poor quality transmitters built into the 4 units.
I have tried my wave meter and I can’t even get it to register the signals are so weak.
Has anyone else experienced the same problems? Am I fighting a losing battle and should I give up or will I win? I have a cable from main TV through booster into loft then splitter 4 ways one to each bed room so the old analogue TV’s can watch either of the sky boxes VCR or DVD. And it does work but picture quality is lacking.
I have considered a lab craft loft box but a lot of money if no better and it seems to only use one LNB connection.
My wife has an upgrade and already has freeview built in, but watches most of the TV using http://www.tvcatchup.com. and catch up TV on PC using TV as just a monitor as freeview is so bad.
This is in spite of being able to see lights of Moel Y Parc through the window.
Before digital we could receive Moel Y Parc using a terminal screwdriver in aerial hole. It all went down hill when Channel 5 came and will still can’t get Channel 5 from Moel Y Parc.
Hence banded aerials pointed to Winter Hill but in spite of using an aerial 4 times the size of original we still can’t get all the multi-plex signals. And Channel 5 is weak.
I have considered getting more FTA boxes but only have a quad LNB so unless I fit second dish I can’t supply all rooms.
I hope others have had same problems and found some answers, Do the DTi do free tests on TV stuff like they use to do for other transmitting equipment?
Eric

 

[ban-all-sheds]

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http://www.avforums.com/forums/index.php
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[electronicsuk]

With careful planning of your channel spacing and the right equipment, it can be done. For starters, there's little sense in trying to broadcast on a channel unless it (and others around it) are free to use, so you will need to limit what's coming in through your aerial. STBs and analogue modulators are also prone to introducing interference as you have discovered.

The solution is of course to use channel pass filters on the RF outputs of every device you want to view in the system. These will pass a specific frequency and then have a steep rolloff on the channels at either side.

You will also need some form of filtering for off-the-air signals from the aerial. As DTV is now so prevelant it becomes more difficult to do this, the easiest option is a group filter specific to your transmission region, but this may not be practical if you need wideband reception to receive all local analogue and digital transmissions. You could also use a set of channel filters, but this means one filter per analogue channel or digital mux. You could easily end up with a bank of 10 or more filters.

Here you start to see the downfall of RF distribution in TV systems. What you want to do can be achieved and in comparison to large MATV installations in hotels and the like is probably fairly tame, but you will still be looking at spending in the hundreds to get a system that works effectively.

EDIT: Missed the bit about the LNB. If you're happy to buy more FTA sat boxes then this seems like the most sensible route to go. You can replace your quad LNB with a quattro LNB, then run four cables from this to a sat multiswitch, which will then feed as many receivers as you like from one dish.

 

[ericmark]

Thank you both.
So if I am reading correctly I need something like the band pass filter I installed to stop 2 meter causing problems but with a tighter band and as all broad cast frequencies are at top of band if I put my units at bottom of band it should work.
Winding coils is not my best work are there any kits for sale the make the band pass filters.
I am sure there will be something in next radio rally but that's not until November.

 

[electronicsuk]

Ericmark, try www.taylorbros.co.uk (click the union jack to load the PDF of their catalogue) and take a look at pages 30-35.

The filter/leveller on page 31 would be an ideal start for feeding the inputs from your DVD/VCR/STB/CCTV/etc into, especially as it is available in configurations with multiple inputs and one output. However, you would need to plan your channels carefully, as you need to specify the filter frequencies at time of ordering.

If you check page 24 you will see they also sell an agile unit - the filter frequencies can be easily adjusted at any time, although you will have to pay a little more for it. It is also limited to three inputs, so a better choice for filtering off-the-air signals from your antenna.

I expect you will find the group filters in the catalogue too, although I haven't looked for you as it's a general PITA to navigate through such a large PDF file.

I also strongly recommend you read this excellent article on Wrights Aerials.

Oh, and finally, if you get stuck with the Taylor catalogue then I also know that a company called CDI-UK stock these filters (albeit at an increased price), a Johansson also produce a range of programmable agile filters similar to those on page 24.

 

[Markey]

you may also find http://www.kat5.tv/taboo_guide.html useful

 

[ericmark]

Thank you electronicsuk and Markey with the +5 and +9 rules I have reduced what frequencies I can used and one that was set it became apparent there was a fault with the Mercury ILS102 Universal RF Modulator I used on the DVD, it seems when the two DVD were not running it auto shut down which I didn't realise so as far as I knew it was switched on and not EMC problem. Switching on DVD which was not connected directly to it however activated it.
As a result I had been chasing my tail looking for EMC with the two satellite boxes and VCR when they were not the real problem but for some reason they were activating the Mercury ILS102 Universal RF Modulator unit.
Switched it off all now works. Slight problem in I can't find how to change frequency on VCR but only used once in blue moon anyway.
The DVD having no RF output is a little bit of a upset but easy enough to set up DVD in bed room anyway.
The Mercury ILS102 Universal RF Modulator was first bought as I could not find how to move frequency on Sky receiver but now I can move frequency on sky no real need for Mercury ILS102 Universal RF Modulator
Thanks to all Eric

 

[Markey]

Cant you now use your rf modulator on your dvd player?

 

[ericmark]

The RF modulator does work but it kills some of the multi-plex outputs from freeview receivers down stream of it.
So it I have something I want to watch I will need to lean over the TV and switch on but I will not leave it on if not required.
It was cheap now I know why.

 

[radioredcat]

I think the problem your describing is cross modulation (signal overload) as you said you can see moel-y-parc so if that is the case then you need to attenuate the signal from there,best with a variable attenuator.
Are you using two aerials for for winter hill and moel-y-parc?

For the sky box i would use CH69 not used for tv to do this press services-401-select then you will enter installers menu change to CH69 and go to save settings at the bottom press back to exit.

Depending on how strong the wrekins signals are if you attenuate the signal they to a low level so you might be able to use some of the channels lower down the band.

You say that you have a splitter to split the signal from the aerial is it an amplified splitter (needs a power supply)or a passive splitter.
You will need to attenuate the signal before the splitter.

Also for every transmitter there is five analogue and six digital so where i live i get winter hill,storeton,moel-y-parc,the wrekin, sutton coldfield,emley moor so iv'e no chance for anything esle other than my sky box which is on 69


andy

 

[ericmark]

You are of course correct.
I have all aerials pointed at Winter Hill although born in Wales I am not a Welsh speaker so I have 21 signals as no Channel 5 from Moel-y-parc.
I have already moved the Sky box output and the FTA box output but until I found the fault I was still getting cross channel interference.
What I had done was first switched on the Mercury ILS102 Universal RF Modulator that was connected to DVD and check there were no problems but I had not switched DVD on at this point. Then sky and again OK and the FTA at which point I had problems so I spent ages moving the output channel of the FTA box.
But it transpired it was the Mercury ILS102 Universal RF Modulator which was causing the problem but until it receives an input it does not transmit and switching on the FTA was causing the Mercury ILS102 Universal RF Modulator to start transmitting.
Hence why I couldn't find the problem.
My only remaining problem is the VCR could do with going up one channel and I can't find out how to change channels but as yet not really looked to hard. There does not seem to be any screw so I would assume software method to move.
Problem is one can see an analogue signal and easy to avoid but the digital signal is harder to locate the TV also has no signal strength meter so I can see if I have a good 5 and 9 only the FTA and sky box have these built in so one does not really know if one is just receiving freeview or if it's booming in.
Next is to play with aerials I think I can really reduce size if I use a Log-periodic instead of a yagi but can't even buy banded yagi now in local shops one has to send off for them.
As for a green TV aerial and you get daft comments like we only stock silver ones! seems no one has heard of colour coded bands.

 

[radioredcat]

If you post the model of the video i'll see if i can find any info but usually you have to go into the setup menu,But some like toshibas you have press eject for more than 3 secs i have one the only problem is it only tunes from 52-68 hopeless where i live.

Log periodic aerials have a slightly lower gain than a conventional yagi but the signal is good then thats the best aerial to use.
The aerial groups are usually identified with a coloured bung in the ends of the boom see the table below.
For winter hill you would ask for a group c/d aerial and that will be the same after DSO but moel-y-parc won't after it's group B at the moment but after DSO it will require a wideband aerial.
I don't know if you want to receive moel-y-parc but if the signal is coming off beam (ie: from the side ) then a log will reject that signal better than a conventional yagi.

Group UHF Band Colour
A 21-37 Red
B 35-53 Yellow
CD 48-68 Green
E 35-68 Brown
K 21-48 Grey
W (Wideband) 21-68 Black

The site below will give details of all the transmitter channels.

http://www.ukfree.tv/txlist.php

And this site will tell you all you need to know about aerials and they also test what they sell.

http://www.aerialsandtv.com/aerials.html

I have an aerial 10 foot off the ground on the east side of the house so i can reduce moel-y-parc transmissions.
Hills are good if you do dx ing like i do.

Digital channels look noisier than and blank channel and if tune a video to a digital channel the picture will look very noisy.

andy

 

[ericmark]

Thank you again all received and understood (QSL) not so sure about hills being good for DX unless you want to collect peaks on air contacts.
When I lived is Suffolk we had some great Isotropic propagation I got right into Scandinavia. And sporadic E was something else. But although great for hobby it played havoc with TV reception with the inversion layer being above us but below the aerial on the broadcast mast.
However it was often still above the Dutch transmitter aerials and so the Dutch stations came in better than our own. Pity we could not get sound and vision.

73 Eric GW7MGW Ex VR2ZEP and VP8BKM

 

[radioredcat]

I don't know if your interested but received a tv amature from le havre,france and i put it up on you tube and he replied to me after 18 years.

http://www.youtube.com/watch?v=u9SJ4dM4VVM

And i received several times at 295 miles.

andy

 

[ericmark]

I ran the QLS bureau on the Falklands for about 2 years and I dealt with 100's of short wave listeners cards. Many over 10 years old but 18 years is going some. I was more into Packet Radio myself I have wondered if I got the old Amiga dusted off what Packet would be like now.
Seems unbelievable it ran on 1200 baud and down to 300 baud on HF.
Are you a short wave listener then? Or do you hold an amateur licence?
On the Falklands I once thought I was picking up the Argentine but then when after playing with aerials I got it a little better I realised I was picking up a TV 4 doors away who was playing a video with the aerial still connected to his TV.
At that time only used TV for spectrum computer. There was no local broadcast.
But when it started a local got a wind charger and old video machine and a amp and received the SSTV and re-broadcast it into Stanley it worked quite well until the SSTV people found out.
That was some real DIY and then people tried to say they were thick. I could not have done that with what they had. It took me 4 attempts to make a wind charger that could take gusts of 110 mph never mind the rest.