UHF Radio's

[Brian]

Can anyone help here?My problem is that lately for some reason, the mike in my helmet is picking up mostly noise from the engine, sounds mechanical. My voice has now become extremely hard to near impossible to hear.The system DID work very very well before.I have installed a new aerial, new UHF,new mike in helmet plus had the helmet checked by a expert and tried a new hand mike as well. At low engine revs the radio sounds perfect but as the revs build up the background noise just gets louder and louder. I can hear perfectly!!Now, I'm just not sure when the problem has occured or if its been a gradual thing cause I dont get to hear how I sound till the other day when my wife recorded my transmission[shock ,horror]I have had in the last few months had Tim put a new cam belt on,installed new spark plugs [have resistor built in ]had all fuel hoses renewed. I did back in early December have a slight accident when refuelling when the hose came out of the tank and sprayed the dash with a lot of fuel which melted part of my windscreen however, all gauges work normally and nothing seems worse for wear .I have checked plug leads and they show resistance although the reading is diferent for each side. I tried a 12 volt battery and put the power to UHF off it to no effect to noise. Has anyone any ideas ??You never know how far you can go, till you get there !

[birdy]

I'm blam'n the present position of Pluto in relation to the earth.Coz thats the only thing that has changed since both me VHF and UHF decided to never talk to other radios.IOW,I'v got the identical problems you have and have tryed everything imaginable,including smash'n the f%$^&$g things with a sledge,but nothing will improve the transmitions.The most frustrating thing bout it is that they both used to work perfectly.If anybody has the answer I'd gladly like to know too.[the sled hammer trick is git'n a bit expencive]Ignorance is bliss............but only till you realise you were.

[asra]

Well i'm glad it wasnt just mine that i was gettin the sh*ts with too..Mark

[asra]

my uhf has become very nois!y the only thing i thought it might be wind noise w drewery

[birdy]

I reckon its wind/engine noise,but why do they not pick it up when you first install the setup??I'v tryed useing noise canceling mikes,rally tested mikes,the origional hand held mike that cums with the unit,and they all seem to suffer the same problem.It seems to be worst when the pressure is on,we can cr*p on bout the footy,weather,our wives all morning with no problems,but when the sh*t starts hit'n the fan and you NEED to comunicate the radio sh*ts itself.[wunder if its got anything to do with the four letter expleatives used in times of crisis,might be a new age PC thing.]Ignorance is bliss............but only till you realise you were.

[Brian]

Nope, its most definately something thats happened in the last month.I have had verification by at least 3 people now so its not imagination and all of those people stated that my transmissions used to be clear as !!I have to agree with you Birdy, it does sound like wind /engine noise but why has it suddenly become so loud and drowned our voices out ??I'm going to try a thing strapped to the throat that's supposed to stop all this noise thing so will let you know the results as soon as its been tested. Seeing its a similiar problem for a few of us, it would be worth finding out if the yanks have thrown some wizz bang sat up thats doing odd stuff. Would be worth asking on the US forum if anyone there is having the same problems. Would you ask Birdy ? I havent woorked out how to post new topics there yet. You never know how far you can go, till you get there !

[asra]

It could be to do with solar flares, altrhough they don't usually affect UHF. I have noticed that the reception of the VHF weather station has deteriorated during the last couple of weeks. When I was an active amature radio operator we used to take a lot of interest in the 11 year sunspot cycles.I still hold my amature radio ticket so that I can have a hobby when I am too old to fly!!!! Geeeez, maybe I should start refreshing the radio bit now!!!! LOLAussie Paul.[]www.firebirdgyros.com

[asra]

Pretty close Birdy. I don't think it's Pluto but it may well be your Earths. Just a slight build up of corrosion on your connectors/lugs can do horrible things to communications and instruments - particularly at high revs when the impulse levels are high. Up to a point your UHF/VHF can filter out this noise quite well but after that it is amplified like genuine mic audio and transmitted.I'd be cleaning all my connectors/lugs thoroughly first, then I'd beat the cr*p out of it.

[birdy]

Bit late for that,I'v already flogged the cr*p outa it longa go.Honistly tho,I'v virtualy giv'n up on f$%$#@g radios,they'r only make'n me age prematuraly.I'v tryed rewire'n the hole radio direct to the battery with new wire,new coax,new airials moov'n airials,different supposedly yu'beaut headsets,different radios streight out of a bullcatcher that was work'n perfectly...........everything.They just refuse to &*^$@#%^$ work in me gyros,both F&%^$$%&^ gyros.I'm not go'n to ask the yanks coz I'v had "experts" actualy work'n on me ferel try'n to figure why they don't work,and they hav'nt fixed it.The only sucsess I'v had was use'n a 20 year old VHF that don't have the tone sencitivity built in,only trouble with that is the new tone sencitive pices of sh&t wont receve its signal properly.It keeps stutter'n.I see the only solution is to try to find some GOOD 20 YO radios and only use them,at least they don't mind a bit o swear'n now n then.If it isn't obvious,I don't like talk'n bout radios,it's a sencitive subject here,so I'll just lurk this thread now,sorry.Ignorance is bliss............but only till you realise you were.

[asra]

Brian,If everything used to work "very very well" then at least you can have confidence that your electrical layout is sound - unless you since modified it or added a new piece of gear incorrectly.Your electrical integrity may be sus though. Corrosion may not be visible but can still wreak havoc. (battery -ve to block, single point earth at battery -ve etc) Continuity checks may all look good but they won't reveal the effects of a loose piece of co-ax braid rubbing on the frame somewhere or a connector that is vibration sensitive. Little things make all the difference.When you tried a separate 12V battery, was the whole UHF system isolated? ie Did you isolate your ptt button, aerial and headset from the rest of the aircraft as well?There is always a logical reason for these things happening but finding it can be excruciatingly frustrating. The last time something similar happened to me I just had to admit defeat because of time constraints (and a low IQ) and built in a cheap fix instead.A heavy-duty low pass line filter placed right at the input to the unit, in series with the +ve and gnd leads, killed the noise problem outright.You haven't got it so bad really though. I once had a 240V 3KW room heater/radiator that played the local radio station. In winter I couldn't sleep for months. With the heater on I was warm but the radio reception kept me awake. With it off, I got too cold to sleep.Unfortunately it did not receive UHF so I would not rush out and buy a room heater to solve your problem.David

[Brian]

Thanks David for the advice, gives me something to play with for a while.No, I didnt isolate the rest of the UHF system when I tried a seperate 12 volt battery.I will clean all connections first, particularly the conncter at the edge of my seat where the helmet lead plugs into as it would have gotten a good spray of petrol when the hose came out of the seat tank while refuelling.Have heard of electrical appliances doing all sorts of crazy stuff but a heater playing the local radio station .........still, I rely very heavily on being able to communicate with the ground crew in a clear fashion seeing I have a tendency to mumble, unwanted noise isnt appreciated.You never know how far you can go, till you get there !

[birdy]

Well well well,[three ols ina ground], My radio works.Duno why I didn't try it 9 years ago, just call the broken ill mob and ask for a ed set. Bingo, fixed.The only down side to me new Rosco unit is I havn't figured how I'm guna spit, without spray'n me wind screen.Coz on a -6c morn'n and sport'n a lergy, I'll av more'n a mouthfull after a couple o hours.Ignorance is bliss............but only till you realise you were.Ingratitude stinks.......be generous carefully.

[Brian]

Great to hear that you are now back on air !!! Nothing those BH guys cant do.Yep, spitting is out and even sneezing with a cold aint good either !!!!BrianYou never know how far you can go, till you get there !