Confused connecting a modulator

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MarkM536

309 posts

Ultimate Geek

#273256 12-Aug-2020 20:17

This one is driving me up the walls at the moment.

I have a Lenking branded HDMI to DVB-T and I'm struggling to 'inject' the signal into my TV aerial wiring.

The main issue is down to my antenna amplifier being a 'masthead' unit. It receives power from a power supply in another room and through the amp's output wire.

This diagram below is the wiring untouched:

Click to see full size

When I first started looking into adding a modulator I thought there would be a device known as a 'combiner'. I didn't have any luck finding one labelled as such.

Later I emailed MatchMaster and a person said that it is a standard to use a splitter in reverse.

So I tried using a splitter with power pass through capabilities.

First off was trying without going through the power supply:

Click to see full size

This worked as expected, all TV channels and modulator could be viewed.

However, the problem lies with my test of the power pass through:

The Modulator's signal was received and I presume the aerial signal would also be received. However I could not power up the amplifier. Even though this was using the power pass through of these splitters.

My best guess is that there is a diode inside of this splitter.

So this disrupts my idea of having the 'combiner' placed after the amplifier.

Click to see full size

I've tried combining into the UHF input of the amplifier. Problem is my modulator set at lowest output of -34dB seems to be too powerful.

Any ideas on wiring this modulator? Sorry as well for more posts on modulators, this forum seems to be very popular with them.

webwat

2036 posts

Uber Geek

Trusted

#2573124 23-Sep-2020 23:21

Why not change your main splitter to a 4-way unit? If the masthead amp isn't powerful enough then use a "multi-switch" something like this one, your modulator goes into the "backfeed" port and you can adjust the amount of amplification for satellite signal.

www.matchmaster.co.nz/multiswitch-systems/21mm-mds-a-4switch

Time to find a new industry!

Rentakill

82 posts

Master Geek

#2573168 24-Sep-2020 07:58

Hi there.

Best bet - If Possible. Relocate your Power Injector to be inline with your Masthead Amp.

At least then your injector is out of the way and not tangled up behind your TV like most.

My Distribution is identical to yours, I have my Injector in line with the Amp but Terminated into the Ant Input of the Splitter and works fine.

My Modulator just Backfeeds into one of the Tappings.

The One thing i did have to make sure of was to Balance the Modulators Output levels to that of my DTT Signal Levels.

Cheers:

MarkM536

309 posts

Ultimate Geek

#2573696 24-Sep-2020 18:19

webwat:

Why not change your main splitter to a 4-way unit? If the masthead amp isn't powerful enough then use a "multi-switch" something like this one, your modulator goes into the "backfeed" port and you can adjust the amount of amplification for satellite signal.

www.matchmaster.co.nz/multiswitch-systems/21mm-mds-a-4switch

Currently the aerial splitting between 3 rooms is 2 2-way splitters snaking off each other. I’m happy to replace this with a better 3/4-way splitter. But can you back feed into a splitter?

When I first got the modulator, I tried back feeding and other TV’s in the house got a signal, although it has heavy interference.

But this ‘Multi-switch’ looks promising. Aside from what you’ve mentioned for connection; would I be able to directly connect the UHF aerial to (what looks like) the antenna input?

Ideally this could be an all in one unit to save needing the current masthead amplifier and power supply.

I’ll enquire with Match Master over this product for my needs.

MarkM536

309 posts

Ultimate Geek

#2573697 24-Sep-2020 18:22

Rentakill:

Hi there.

Best bet - If Possible. Relocate your Power Injector to be inline with your Masthead Amp.

At least then your injector is out of the way and not tangled up behind your TV like most.

My Distribution is identical to yours, I have my Injector in line with the Amp but Terminated into the Ant Input of the Splitter and works fine.

My Modulator just Backfeeds into one of the Tappings.

The One thing i did have to make sure of was to Balance the Modulators Output levels to that of my DTT Signal Levels.

Ideally, I won’t relocate the power injector into the roof space. Considering how old it is, I don’t want to risk it having a problem up there. I have mentioned above that a new device would be okay.

I do not have any Satellite connection. My current system is a VHF and UHF aerial. Now that analogue TV has been discontinued the UHF is only in use for Freeview (I think it's UHF).

Mentioning about moving the masthead amplifier power supply does give me an idea. I could move it to another TV’s power point. I’d need to switch the cables around for the power pass direction.

Here’s the splitters in use right now. [They probably need replacing anyway]:

The idea I can think of is to place the ‘combiner’ in the chain so two of the main TV’s will receive the signal. The master bedroom TV would now have the masthead amplifier power supply. This means the ‘combiner’ isn’t in line for power passing.

But as you can see, it’s probably best to replace all these rusted devices anyway.

Rentakill

82 posts

Master Geek

#2574696 26-Sep-2020 16:19

Hi Mark.

Looking at your Pictures.. my first recommendation would be to illiminate or remove those Splitters.. The insertion loss that they would be introducing would be Colossal.

Replace them with some good Quality F Type Splitters and you'll probably find all comes right.

Those Original splitters were total crap in the day of analogue, plus the overall condition of them in your pictures is not what i would call flash.

Your cabling looks to be RG59U Type cable - which is expected for that time and will be fine for UHF DTT.

You can get RG59 F Connectors to Crimp or Terminate to the end of your RG50 Cable ends.

So - Id recommend a 6 or 8 way F type Splitter with Power pass and you should be away. It will Tidy everything up nicely.

Cheers:

MarkM536

309 posts

Ultimate Geek

#2574759 26-Sep-2020 20:40

Rentakill:

Hi Mark.

Looking at your Pictures.. my first recommendation would be to illiminate or remove those Splitters.. The insertion loss that they would be introducing would be Colossal.

Replace them with some good Quality F Type Splitters and you'll probably find all comes right.

Those Original splitters were total crap in the day of analogue, plus the overall condition of them in your pictures is not what i would call flash.

Your cabling looks to be RG59U Type cable - which is expected for that time and will be fine for UHF DTT.

You can get RG59 F Connectors to Crimp or Terminate to the end of your RG50 Cable ends.

So - Id recommend a 6 or 8 way F type Splitter with Power pass and you should be away. It will Tidy everything up nicely.

Cheers:

RG59 / RG50. Dam it. I bought some more RG6 F connectors...

I haven't had anything come back from MatchMaster yet with my inquiry.

But I might as well start looking at a new 4-way splitter. Hopefully one with a back feed.

MarkM536

309 posts

Ultimate Geek

#2603540 13-Nov-2020 20:33

webwat:

Why not change your main splitter to a 4-way unit? If the masthead amp isn't powerful enough then use a "multi-switch" something like this one, your modulator goes into the "backfeed" port and you can adjust the amount of amplification for satellite signal.

www.matchmaster.co.nz/multiswitch-systems/21mm-mds-a-4switch

I've had a look around at these MatchMaster branded devices with back feed. I was thinking towards the one suggested which is a multi-switch.

In the end I got this one [10MM-DDA24], I decided for this one since it could be a standalone amplifier. It can output 14v to the terrestrial amp if needed but I plan for standalone.

I did get the 'remote' powering with a DC inserter, so the power supply will remain behind the lounge TV.

Looks to be a very nice device. I'm looking forward to ripping out the old splitters and amp to replace with this.

Having a look back at photos I took; The wiring currently in use does look to be RG6, just some RG59 in the background that is disconnected in a coil. A friend has given me a compression tool and F-connectors.

I will let you know how it goes. I'm likely to get it setup next week once I'm free.

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webwat

2036 posts

Uber Geek

Trusted

#2612454 28-Nov-2020 19:44

So how did the multiswitch go?

Time to find a new industry!

MarkM536

309 posts

Ultimate Geek

#2612660 29-Nov-2020 14:44

webwat:

So how did the multiswitch go?

Its alright. I still haven't got my modulator to output to each TV yet.

Although the new amplifier gets a clearer image and the TVs show 'HD TV'.

I used some inline joiners because the lounge and kitchen cables were very short and because they were stranded RG59. This went from RG59 to RG6.

The TV antenna and bedroom cable is RG6, although it has a very thick outer insulation. I couldn't get compression fittings to work with it, so I just used twist-ons. The new RG6 from the modulator worked with compression connectors.

All TVs know that the modulators channel is there. Two TVs (main ones) have distortion issues with the image. Kitchen one has coloured bars at the bottom and the lounge one has half an image to the left side.

When the modulator has a signal (HDMI) is flicks to 1080p (from 720p 'no signal screen'). The lounge TV completely blacks out and the kitchen one still has its coloured bars.

Weirdly though, if I plug a smaller TV in (bedroom) into either outlet it gets a perfect signal.

I've got a feeling that I need to consult the modulators manual to get the right broadcast settings. The modulator worked to each TV directly so I don't know what has happened.