I need to block a UHF channel but not sure how to do it

[dicky96]

Hi guys
I couldn't really find a section on the forum for this question so I guess I will put it here

I do a lot of work in one of the local apartment hotels (an apart-hotel they call them here)

Mostly I am maintaining the equipment in the 'TV' room or at the pool bar

Anyway, I have a problem with the system in the TV room - most of this was a system I 'inherited' off the previous technician who no longer lives on the island

Basically they have (see pic it probably explains it better) the following system. The UHF cabling is daisy chained through all the modulators/transmodulators adding more DVB-T MUXes to the incoming Aerial Signal like so:

*Incoming DVB-T (Spanish TV) from TV Aerial (numerous MUXes)

* UHF Antenna Mast Head Amplifier

*Incoming UK TV from satellite 27.5W + 19.2E, 4 receivers connected to quad input DVB-T modulator outputs 1x DVBT Mux

* Incoming UK TV (19.2E), plus 3x IPTV (Sweden, Norway, Finland) connected to quad input DVB-T modulator outputs 1x DVBT Mux

* Dual Transmodulator German satellite TV 19.2E, outputs 2x DVB-T Mux

* Dual Transmodulator French satellite TV 19.2E, outputs 2x DVB-T Mux

* Quad Transmodulator German satellite TC 19.2E + Italy satellite TV 13E, outputs 4x DVB-T Mux

* Dual Transmodulator German satellite TV 19.2E, outputs 2x DVB-T Mux

* UHF Power Amplifer outputs all MUXes combined (approx 75 TV Channels to 120 apartments over 5 floors plus communal areas/restaurant/pool bar, via 'Cab boxes' on each floor


So all this was working fine..... until it seems there is a new terrestrial TV service on the same frequency (or adjacent frequency) as one of the MUXes on the Quad Transmodulator, causing four German TV channels to continually glitch/break up. I can prove this by disconnecting the TV aerial and the German channels are all OK then but obviously I have no Spanish TV.

So I can see two ways of fixing this - but both have their disadvantages

1: Retune the affected MUX to another channel frequency. The problem with this is that someone then has to go to all 120 apartments and re-scan the TVs. This means waiting for the apartments to be free so as not to disturb guests. Also this would most likely cause more channels to be added from the Spanish TV Aerial (assuming a new transmission caused the problem) which affects the channel order / channel numbers which then means having to reprint all the TV channel lists that go in a welcome folder in each apartment. Assuming it takes 15 minutes to visit each apartment, turn on the TV, re-tune it, change the channel listings in the folder, turn off the TV - then it is going to take 30 hours or more to complete the job. That's wages and time.

2. Fit a blocker or filter between the Aerial and the first DVBT Modulator (before or after the UHF Mast Head Amp) that removes the signal on that RF channel. This should work fine but I tried to google for such an item but the problem is I can't seem to find what I need, possibly due to not knowing exactly what to search for. Preferably something I can choose to select and block 1 UHF channel (channels 22-69)

3. Some other good idea I didn't think of?

Hopefully the attached pic shows better how this all works

Cheers
Rich

[stj]

Re: I need to block a UHF channel but not sure how to do it

a notch filter may do it,
but frankly all that crap is unreal.
i would have just used a pair of dishes and a bank of 16way distribution units
put a sat reciever in each room.

the only downside is each room needs it's own feeder from the switch

[dicky96]

Re: I need to block a UHF channel but not sure how to do it

a notch filter may do it,
but frankly all that crap is unreal.
i would have just used a pair of dishes and a bank of 16way distribution units
put a sat reciever in each room.

the only downside is each room needs it's own feeder from the switch

@stj
What you say does not make a whole lot of sense because:

The Spanish channels are terrestrial (yes could also be received on satellite at 19E or 30W but would then require even more DVB-S -> DVB-T transmodulators and they are expensive.)

Three of the UK channels are on a satellite at 27.5W (needs special BISS decoders to unscramble them) and a 1.8m dish to reliably receive the signal

The other two UK channels are on 28.2E (Sky TV pay channels requiring two official receivers and subscription cards) plus a 3m dish

German, Italian, French are all FTA but needs two dishes, one on 19.2E (80cm) with quatro LNB and the other on 13E (1.5m) with single LNB

Norway, Denmark, Finland TV are impossible to receive here on any size dish so required an IPTV solution


So what you say just wouldn't work I guess you just didn't appreciate the complexities involved

Having said that where can I buy a suitable notch filter to get rid of the troublesome terrestrial interference? Ifound this o nAmazon but it does not seem to be available

https://www.amazon.com/Tunable-Filte.../dp/B072K6BNP1

[stj]

Re: I need to block a UHF channel but not sure how to do it

i have no idea, you need to know the exact center frequency, and how wide you have to block without clipping surrounding muxes.

[sam_sam_sam]

Re: I need to block a UHF channel but not sure how to do it

Take a look at this website link page

https://fado168.com/us/merchant/B07H...-f-connectors/

I would try to get in touch with them and see if they can help you to getting one

support@fado168.com