RB & Scanner Interferance

[jonjorobb]

I have my supplied RB antenna on the window ledge outside, and my scanner inside. i pick up MACC & LAC Swanwick controllers of the Preston transmitter, but they are quite faint. when i use my RB, i get lots of interferance that drowns out the controllers. is there away to prevent this? is it the Radio itself or the Radio antenna that is "alergic" to the RB?

Thanks,
Jonjo

[davjhedges]

hi jonjo.i have 2 external aerials onthe same 12 foot mast on the side of the house,one for rb, one for airband.with both the rb and scanner on i ,like you ,am getting bad interference on certain controller frequencies.with the rb switched off or using the supplied antenna,controller reception is fine.conclusion,these aerials need to be some distance apart,probably have to erect another  mast.if you are satisfied with your rb performance with the default antenna,try an external airband aerial ,and get it as high as possible.

[CoastGuardJon]

Hi Dave, what sort of distance have you got between the antennas? I thought the RB was a totally passive device - could this be computer noise?, are you using any sort of pre-amp to cause some interaction?

[davjhedges]

hi CoastGuardJon,eitherside at the top of mast, eg very close together.watson 125 preamp on airband line.

heres a pic
http://img25.imageshack.us/img25/1323/house004.jpg.

Regards,

davh

[jonjorobb]

ive noticed my Radio, (DJ-X30) has a built in Attenuator, would this help? or would the controller once again be unheared. also, putting the Radio furthest away from RB does not give good reception.

[CoastGuardJon]

Hi Dave, it may be that the cause is the fact that they are so close together.   It would be worth temporarily separating them by a metre or so, and see if that cures the interaction, and if it does, erect another pole, with the RB one slightly higher as well as to the side.   Being so close together there must also be a fair few degrees of blind spot caused to the RB antenna?   What's your polar diagram like?

[davjhedges]

hi,CoastGuardJon.thx for that,polar diagram is not too bad at all,especially to the north,seeing plenty of ads-b only flights at any one time,30 -50 odd,but i take on board what you said,when i have got time will split them,putting the airband aerial on a J mast on the fasia board.if that is successful will invest in another mast. cheers davj h.

[davjhedges]

hi JonjoRobb,when i use my attenuator,it makes the strong signals fainter,so i donot use it on the airband,recommend you get a better aerial,preferably external and purchase a pre amplifier,which makes fainter signals stronger.if you can hear the controllers the improvement will be noticable.regards davjh.

[jonjorobb]

Thanks davjhedges, I will try that. can you reccomend a good pre amp?

Thanks for all your replies,
Jonjo

[davjhedges]

hi JonjoRob.i have watson wrp-125 preamp,about 34 quid from airband -online.
regards davjh

[tailplane]

I recommend to try changing usb-cable which is well shielded.
Then, I solved.

[Blackthorn]

The problem with pre-amps is they also amplifly the noise.