interference on the freq.

[magpienja]

Hi guys very often when having a listen to my local N/W airfield on my scanner in my dinner hour, I hear pilots complain of interference on the freq, I have never heard any of this interference when flying my microlight but don't get to fly that often,

But I wonder to myself if this is somebody with a hand held icom being a silly bugger or some other prob, but on the said freq I do hear a lady talking on what sounds a PMR business radio in FM rather than AM at various locations that I maybe, I know this maybe just the poor quality of my scanner but do you guys ever get to the bottom of these problems.

Nick.

[MNT]

Yes in the UK complaints of interference are investigated by NATS in conjunction OFOM. Where traced to illegal transmission sources (e.g. Pirates) or use of illegal equipment confiscation and or prosecution can follow. Other sources such as Industrial or Scientific sources can be closed down.

[JustaFew]

If it's traffic into Liverpool which you're hearing commenting on interference, yes, it is logged and details passed to OFCOM for investigation.
It varies in where it occurs, and the type can differ. Usually, it's over NE Wales to Ellesmere Port, from @10 000ft down to 2500ft. Heard by pilots but not ATC.

[atcomarkingtime]

We get alot of interferance on frequencies....the tower gets alot of breakthrough from the tower in Amsterdam....and another radar freq gets breakthrough from Calais Approach...depends how high the pressure is!!

[ATCO Fred]

Not forgetting that annoying little tone whenever someone with a mobile phone on in the cockpit/aerpolane transmits!! (okay - mainly GA!)

Although was useful the other day when the aircraft at the holding point phoned the Twr to return to the apron with RT failure!!

Fred

[K.Whyjelly]

Was NOTAM'd a while back to report frequency breakthrough in the vicinity of Dean Cross. Must admit to having reported interference in the form of a morse signal and also talking of a non aeronautical variety in the DCS area

[chevvron]

At home listening to 102.2 we often hear aircraft calling Bournemouth on 119.475.

[merlinxx]

Same for me on DAB, but not on steam FM just outside M25 N of LGW

[chevvron]

Ah Merlin, that puts you close to two transmitting stations, Riegate Hill and Warlingham.

[vintage ATCO]

The barbers I use in Luton has a trannie in the corner with Radio 1 on it (:yuk:), this picks up acft calling London on 121.275! :)

Many things can cause interference on aviation freqs. Duff thermostats are one, and then there was the famous case of a certain brand of baby alarm; one was found in a house 6nm final for Luton's rwy 26. CAA/Ofcom had to persuade Toys R Us to withdraw them from sale.

[Spitoon]

Forgive me vintage, but surely thesedays you should be frequenting barbers that have Radio 2 on. How can you expect a good haircut with that cacophony in the background?

Still, at least it means that you've still got your hair - it doesn't look like I'll be needing the services of a barber much longer!

[FantomZorbin]

Many, many years ago (about 40!) at a radar unit in Yorkshire the local GPO telecomms engineers turned up to check all our transmitters as a local resident had complained about hearing our ATCspeak on his TV.

After the engineer had confirmed that all our kit was 'in spec' we enquired "what now ...?" The engineer said that he would now visit the complainant and explain that as our kit was OK it must be his TV at fault.

The engineer said that he would instruct the luckless TV viewer to get his set repaired/scrapped and issue him with a summons for listening in to our transmissions without a licence:sad:

Any way isn't it all to do with Harmonics and the Appleton Layer?:}

[threemiles]

On standard trannies without a proper preselector for "mirror frequency surpression" all Air Band frequencies can be heard at (freq - 21.4) MHz, as this is double of the Intermediate Frequency of the radio (10.7) and called "mirror frequency". FM demods usually demodulate AM well enough to get a good understanding.

[HEATHROW DIRECTOR]

<<The engineer said that he would instruct the luckless TV viewer to get his set repaired/scrapped >>

I am a radio amateur and when I first became licenced in the mid-70s visits by the Radio Inspectors was commonplace. It was always the fault of the neighbours' hi-fi, radio, TV, deaf-aid, or whatever simply because they were designed to be as cheap as possible - basically junk. Sadly RIs are now very rare - I haven't seen one for about 20 years; hence the little kiddiwinks can go into any radio dealer or pilot shop and buy an airband radio and play at being pilots or air traffic controllers. There's simply no policing of the radio spectrum any more..

[vintage ATCO]

Forgive me vintage, but surely thesedays you should be frequenting barbers that have Radio 2 on. How can you expect a good haircut with that cacophony in the background?

It's cheap. :) The 'hair stylist' up the road charged me 15 quid and I don't have that much hair!

[PositiveClimbGearUp]

"On standard trannies without a proper preselector for "mirror frequency surpression" all Air Band frequencies can be heard at (freq - 21.4) MHz, as this is double of the Intermediate Frequency of the radio (10.7) and called "mirror frequency". FM demods usually demodulate AM well enough to get a good understanding."

Thanks, threemiles - that's interesting! But does it explain why I occasionally pick up Classic FM on 119.7 and/or 121.725 (EGNT Tower and Ground frquencies), while listening on an air band radio?

[threemiles]

That seems to be a different sort of interference, possibly cross modulation or reflection.