[mythtv-users] OT: Moved aerial & lost one mux (UK Freeview)

Simon Hobson linux at thehobsons.co.uk
Mon Oct 16 20:16:16 UTC 2017

Slightly OT but I suspect there's a few people here with more RF/antenna knowledge than I have ...

We've just moved, and no aerial on the new house - prev owner used Sky and I don't have any sat equipment.

Until I get round to having a decent one put up outside, I've put one in the loft for now. When I was testing with the aerial in the lounge (didn't want to miss Red Dwarf !) I did a full scan on the TV and got all 5 muxes I should. Now I've moved it to the loft, pointing in the same direction, but with a longer cable (WC100/WF100) - I can't get anything on one mux.

The other 4 muxes are fine, plenty of signal, just the Com6/ArqB mux on C22+ (482.2MHz) is "missing". It's almost as though there's a notch filter in place - connected direct to the TV it gives "no signal" but just occasionally flickers a bit of pixellated picture and a "click" of sound.

Anyone come across this effect before, got any suggestions as to the cause ?

It's the same for the TV, and both my tuner cards (HVR1350 IIRC). Transmitter is Lancaster (Gp A, Vertical pol), Wolfbane says I have a clear LoS and should be OK with a Hi-Gain antenna (50dBµV/m), and the aerial I'm using at the moment is a Gp A XB10 http://aerialsandtv.com/gaincurves.html#Agroups. All connections are F type, except for the TV which is the old Belling Lee "UHF" plug. Roof is slate on timber rafters & battens.
I'll be putting a Yagi 18A up when I get round to calling the installer in.

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