Loftbox messing up my digital reception?

almighty1

Hi,

When I plug my UHF aerial directly into my TV I get near 100% signal however when I diasy-chain it through my TV system I get next to no signal.

Here is my setup

Aerial (RF45)-> Modulator (RF32) -> FTA Box (RF69) -> DVD Player (RF41) -> Sky+ (RF61)-> Loftbox -> TVs

Most connections between devices are direct, except between FTA Box and DVD Player which has two seperate F-Connector connections.

It looks like the problem is either

1) A connection problem between Modulator and Sky+ box as the Sky_ works great on all tellys but the FTA and Modulator signals arent brilliant.
2) The loftbox is killing my UHF DTT signal.

Any ideas anybody?

STB

almighty1 wrote: »

Hi,

Aerial (RF45)-> Modulator (RF32) -> FTA Box (RF69) -> DVD Player (RF41) -> Sky+ (RF61)-> Loftbox -> TVs

That is your problem! The signal and PQ cant be worth much after that amount of modulation!

You dont make things simple do you. One of those boxes is not passing the signal on in the chain - possibly a sleep type function or doesnt work in standby mode. Also the amount of RF frequencies is madness and could be wiping out any possibility of RF reception at the end point.

watty

Use a passive 4-way splitter as a combiner.
That looping is crazy.

Also ALL modulators use up the next lowest channel as they are double sideband AM, not vistigial Sideband. Most modulators also create interference on other channels also.

To have that many modulators needs VERY careful choice of channel, a channel wide helical filter for the channel to block interference and then use a combiner to add them all.


As specified, it's rubbish.
channels used
31, 32
68, 69
40, 41
60, 61

Channels likely to have varying degrees of interference
27, 28, 30, 32, 33, 37, 38
62, 63, 67
35, 36, 39, 42, 45, 46
55, 56, 59, 62

almighty1

Thanks guys, I know its a bit crazy but I do like being able to give as many choices as possible to each room

The second device in the daisy chain (Media Player Mod) displays fine in all rooms but the third device (FTA Box) shows interference. Anyway I guess that I really have to work out my channel arrangements.

Is this even a possibility to have all these devices at the same time?
if so, given the only constant in DTT on RF45, what RF channels could I set the other devices to maximise quality and minimise interference?

I vaguely recall seeing a post here about a UHF channel calculator but I cant find it now

Should I introduce the DTT Aerial at a later stage in the chain?

watty

Don't have a chain!

    _
21-| |
27-| |
61-| |       _
67-|_|------| |__  Out
  aerial ---|_|

use a 4 way splitter as a combiner (if not available use 2 x 2 way and a 2 way to combine them)
add in aerial last with a 2 way splitter

You need a filter on output of each modulator. But try channels below

Try 21, 27, 61, 67 for Modulators.

almighty1

Thanks Watty. I forgot the the analogue terrestrial is also in the mix. Although the reception is bad Im sure thats not going to help either.
I dont recall what channels analog TV3 and TnaG display at on Mt Leinster.

Anyway I'll give your channel arrangement a shot, I can take the DVD player out of the mix as the Modulator (for the Media Player) has taken over that.

21 Mod/Media Player
27 FTA
45 DTT
67 Sky+

I have a F Connector Splitter/Combiner like this. Would this suffice?

watty

should do

almighty1

Thanks Watty,

Ive confirmed something on my Sky+ box is messing up UHF signal. I tried RF channels 57-68 but it makes little difference on DTT SQ.
Is it possible that the RF-IN is faulty on my Sky+ box?

Antenna

you could try using an aerial diplexer such as the 4046 here (before trying more expensive measures ) :

http://www.televes.com/hojastecnicas/103793.pdf

You do not therefore loop aerial through modulators, though the modulators are still chained

your aerial goes to input 1, (covers all your analogue and DTT)

your modulator chain goes to input 2, and have all modulator channels at Ch 55 and above

almighty1 wrote: »

I dont recall what channels analog TV3 and TnaG display at on Mt Leinster.

26 and 23.
RTE1,2 at VHF band 3. The "UHF 1" (lower channels) input of those diplexers also pass VHF

watty

almighty1 wrote: »

Thanks Watty,

Ive confirmed something on my Sky+ box is messing up UHF signal. I tried RF channels 57-68 but it makes little difference on DTT SQ.
Is it possible that the RF-IN is faulty on my Sky+ box?

Don't put an aerial into sky box or loop via it. The modulators on them are very noisey .