Choosing an RF out channel

Hi, as part of some troubleshooting I want to change my older sky hd boxes RF out channel for my magic eye setup but am just wondering what channel I should select for my area (Shropshire)?

Its currently set to channel 68 but I'm not sure which would be the theoretically cleanest channel to select for my area (ignoring local interference of course).

Any pointers would be great, thanks.

Channel 68 should be clear of Freeview tv transmissions in most if not all areas. Highest frequency from the Wrekin TV transmitter that serves Shropshire is 682.000 MHz (UHF channel 47).

Are you getting interference? It is possible that 4G mobile phone signals in the 800Mhz band could be interfering with TV RF reception try dropping the RF2 frequency to find a clear frequency but don't drop lower than UHF channel 50 to avoid interference from Freeview signals.

Thanks, yes I do suspect 4G interference so want to avoid the higher channels (this area has good 4G coverage).

Aren't there any lower channels I could select as the cables that run to the other rooms are long and not the best quality with poor screening, I was hoping a lower frequency would help with that too.

I've come across this chart of the channels in use for my area and it looks like the mid 30's might be a safe bet.

Attachment 6513

Do TV channels overlap at all like with wifi? How many channels should I keep between my selected channel and what's shown in the image?

Thanks again.

Edit: Odd, I have no idea why the image has become so small but here are the channels in use.
C23
C26
C30
C41
C44
C47
C53
C57
C60

Channels don't overlap but TV tuners rf frequency characteristics will allow reception of strong signals from adjacent channels. It is partly for this reason that Freeview transmitters leave at least two clear channels each side of their transmit frequencies. With that in mind you should restrict RF2 frequency selection to between channels 33 and 38 when using the range you suggest.

Thanks, when you say "between channels 33 and 38" do you mean those two channels in particular or anything starting from 33 all the way up to 38?

Any channel between including 33 and 38.
Are you having problems with interference or is it some other problem that you are trouble shooting?

Intermittent and seemingly random interference, changing the RF out channel to 34 seems to have done the trick so far but only time will tell. I also re-did some of the coax cable couplers as they had gone high resistance and intermittent.

I guess I'll report back after leaving it for a few days but now I'm thinking it might be combination of interference and poor connections. I also tracked down a burnt out neon indicator on an extension cord that could have been tying to re strike so I cut that out too.

With the analogue service two types of interference was possible: adjacent channel which Seawright has mentioned and co-channel. to avoid the latter your chosen output channel should not be a multiple of 3 or 5 away from a used channel. In theory, with the advent of digital these issues should have gone away but they haven't as the carrier is still analogue with digital modulation. Using your supplied channel your best channel(s) would be: 33, 34, 37, 63, 64, 67 68. As you were having problems with 68 chances are the interference wasn't either of the two transmission ones. Unavailable channels are known as "Taboo" channels.

Update: Haven't watched a whole lot of TV recently but it does seem to be fixed (touch wood). Currently running on channel 34.

Come to think of it the inference did get really bad one time during a family gathering at our house, that could well have been several smart phones switching to 4G since not everyone had connected to our routers wifi.

Thanks again and I will update if the interference returns.

You might want to look at all the details provided by the the government agency set up for the 4g/freeview interference problems called a800.
https://at800.tv/

Taken from their FAQ;

Quote:

---

Since the digital switchover, channels 61 to 69 have been reserved for 4G mobile signals

https://at800.tv/faq/what-is-happening-and-why/

---