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FILTER
- Thread starter ray
- Start date
You didn't say what kind of antenna - or any other gear you are using - either.
It would help out a lot to know all of the equipment you are using.
*Put the antenna as high as is safely possible. 50 ft to the feed point would help. Some antennas are notorious for giving off 'TVI'. Shakespeare 'Big Stick', Antron A99, and even the Imax 2000 can throw off TVI. Especially if they don't have any ground plane on the antenna.
*Put a low pass filter on between the radio and antenna. These are relatively cheap and are not a cure-all. But they can help.
*Don't run a radio with a clipped out AM Limiter. If you are an AMer/radio operator; then make sure the AM limiter hasn't been disabled in the radio. The modulation will be waaay over 100% and you are probably splattering across several channels too. The second you exceed 100% modulation and above; the radio will begin to transmit nasty harmonics which will bleed over - even into your toaster.
*Don't run more than 100% modulation. Keep it a 95% and be sure it doesn't go over that. An in-line meter will help keep an eye on it.
*Don't run a linear amp. If you run any linear amp and live in a residential neighborhood, then you are asking for trouble. The FCC doesn't come out until someone complains. If you give your neighbors a reason to complain by creating interference by the use of a linear amp; the FCC may well come out and possibly cite/fine you.
*Ground everything. Make sure the antenna mast, your radio, and possible power supply are all hooked up to the same house ground.
It would help out a lot to know all of the equipment you are using.
*Put the antenna as high as is safely possible. 50 ft to the feed point would help. Some antennas are notorious for giving off 'TVI'. Shakespeare 'Big Stick', Antron A99, and even the Imax 2000 can throw off TVI. Especially if they don't have any ground plane on the antenna.
*Put a low pass filter on between the radio and antenna. These are relatively cheap and are not a cure-all. But they can help.
*Don't run a radio with a clipped out AM Limiter. If you are an AMer/radio operator; then make sure the AM limiter hasn't been disabled in the radio. The modulation will be waaay over 100% and you are probably splattering across several channels too. The second you exceed 100% modulation and above; the radio will begin to transmit nasty harmonics which will bleed over - even into your toaster.
*Don't run more than 100% modulation. Keep it a 95% and be sure it doesn't go over that. An in-line meter will help keep an eye on it.
*Don't run a linear amp. If you run any linear amp and live in a residential neighborhood, then you are asking for trouble. The FCC doesn't come out until someone complains. If you give your neighbors a reason to complain by creating interference by the use of a linear amp; the FCC may well come out and possibly cite/fine you.
*Ground everything. Make sure the antenna mast, your radio, and possible power supply are all hooked up to the same house ground.
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Your going to have to start with a good grounded (Lowpass) filter just remember that sometimes theres nothing you can do other than get that antenna up high and sometimes depending on neighbors electronics quality there is noway out of the issue. If you are running a power mic and basting audio that will add to this mess.
Back down on power and audio also Ide atleast find something else to do when mass is going on
Back down on power and audio also Ide atleast find something else to do when mass is going on
Sorry ROB.Iam running a 2000 hooked to a UNIDEN WASHINGTON.
the imax2000 is notourious for bleedover even with a stock cb
id ground it at the mounting plate using 1 mounting bolt .
use #6 or 8 bare copper wire and a 8 or 9 foot grounding rod
all advailable at lowes or homedepot.next is coax i try to
use double shielded coax like lmr-400 .i switched from rat shack rg8
to lmr 400 and it did help me didnt cure all but helped.id also
try the gpk for the imax 2000 i didnt try this cause i got tried
of my imax but could help.and then get a filter i put that last
cause i bought a 80 dollar filter it did absolutely NOTHING to help
also if ya have a good cb shop around make sure your audio limiter isnt cut /disabled
if using a power mic try turning down mic gain on radio may help
wish ya the best of luck
A low pass filter on your end is worthless because it's your fundamental signal that is getting picked up by wiring like an antenna, and then it gets rectified by the first P/N junction it comes across. After that it gets amplified as an audio signal and ends up across some speaker terminals as annoying interference.
The problem is not on your end, rather the fault lies with the equipment erroneously receiving your signal. Your only hope is to eliminate it before it can get rectified and amplified. Once it does, you're powerless to do anything about it. Obviously, the more power you run, the more interference you generate.
Go buy yourself a bag of .1uf disk caps and put them everywhere. Across the phone lines - even across the actual microphone and speaker elements if you can open the handsets. On the church P.A. system, put caps across each speaker lead, and from each lead to chassis. Do the same with the microphones.
For the TV (obviously an old analog set), you need a high pass filter on the antenna, and possibly caps on the speaker. If the radio has separate speakers, 3 more caps on each left and right channel. If it's a small portable radio, you're basically screwed and are better off buying a replacement for them. Of course, you'll have to test them out first.
Other than that, you're only choice is to reduce power.
The problem is not on your end, rather the fault lies with the equipment erroneously receiving your signal. Your only hope is to eliminate it before it can get rectified and amplified. Once it does, you're powerless to do anything about it. Obviously, the more power you run, the more interference you generate.
Go buy yourself a bag of .1uf disk caps and put them everywhere. Across the phone lines - even across the actual microphone and speaker elements if you can open the handsets. On the church P.A. system, put caps across each speaker lead, and from each lead to chassis. Do the same with the microphones.
For the TV (obviously an old analog set), you need a high pass filter on the antenna, and possibly caps on the speaker. If the radio has separate speakers, 3 more caps on each left and right channel. If it's a small portable radio, you're basically screwed and are better off buying a replacement for them. Of course, you'll have to test them out first.
Other than that, you're only choice is to reduce power.
Then go buy some heavy duty aluminum foil and make a hat. Sit in closet that has the most shoes in it. and wait till the world ends. Youll be just fine.
Actually no. Other then a reality check for you Cro. You are actually suggesting this individual to go out and purchase a crap load .01 mircofrad caps and knock on peoples doors so they can install them.
Seriously he gave his radio and his antenna that he is running. Its been said that his antenna is prone to the issues he is describing.
However you sir did not provide any relavant information that was not practal to his situation.
Id like to see an individual knock on my door and say I need to install a shit load of capacitors to your electronic equipment so I can talk on my radio!
Actually I said .1uf, not .01uf. There's a difference. Although, at 11M .01uf may work, just not as well.
Seriously he gave his radio and his antenna that he is running. Its been said that his antenna is prone to the issues he is describing.
However you sir did not provide any relavant information that was not practal to his situation.
Id like to see an individual knock on my door and say I need to install a shit load of capacitors to your electronic equipment so I can talk on my radio!
The problem here is you you have absolutely no clue what they're talking about, yet that doesn't seem to stop you from posting your so-called ideas. Everybody has an opinion, except some are right and others are crap. Guess which ones yours are. So, you think that wrapping his coax around some sewer pipe or pounding in a ground rod will fix the problem? Yeah, right. Better save that tin foil for yourself.
The problem here is not that Ray is sending out some spurious signal that can be filtered out on his end. On the contrary, he's sending out a beautiful and powerful 27MHz AM fundamental signal that his neighbor's cheap-ass appliances aren't equipped to deal with. So that's where you have to filter it out.
Back in the 1980s, after I graduated from the state university with a electrical engineering degree and then passed all 4 elements to receive my FCC First Class Radio Telephone License, I interned at a local AM broadcast station. So I know a little bit about this subject. Checking transmitter function took up about 10 minutes of my day. RFI occupied the other 7 hours and 50 minutes, plus overtime. We had to filter just about every house within a mile of the towers, and some even further. We worked with telco and cable tv, but we also used to handle service calls ourselves. Many times we could add filters (free of charge, or course), but sometimes we just gave the resident a new radio or whatever just for public relations.
Ray can dick around with his antenna raising it up or moving it to a different location, and he may get some results because, due to the inverse-square law, distance is your friend. But he's really not going to achieve much success until he starts applying filters to the crappy electronics that are happily sucking up his RF. And that's the problem, Ray's RF. His choices are either eliminate it at the source by not transmitting, or eliminate at the destination with filters.
So, yes, his choice may very well come down to knocking on doors and saying "I need to install a shit load of capacitors to your electronic equipment so I can talk on my radio." I've done it many times.
Ray, pick up a copy of the Radio Amateur's Handbook. It has an extensive chapter on RFI that will teach you what exactly causes it and what you have to do to eliminate it. And not necessarily a new copy, either. I still use my 53rd Edition published in 1976 as a reference, and it has saved my ass dozens of times over the years.
And Superidgit - you might want to pick up a copy for yourself.
Some good points made by all, even sitting in the closet with a tin foil hat on, as long as you can't reach your CB anymore, lol.
What you can do at your end is remove the Imax and get a ground plane antenna, add a coax or ferrite choke to prevent any CMC's, which could be causing a problem, add a low pass filter and get the antenna up higher if you can, higher up is further away from the equipment suffering RFI, which can help.
Unfortunately, even after doing everything you can to your station to prevent RFI, ultimately it is down to the equipment receiving the RFI, being cheaply made, poorly designed and with a poor immunity to RF that it is not supposed to receive and it is the equipment being effected that needs the help and not your station. Try telling your neighbours that it is their cheap ass TV or w/e that is the problem, and you will be met with numerous different responses, lol, Diplomacy is the order of the day.......
What you can do at your end is remove the Imax and get a ground plane antenna, add a coax or ferrite choke to prevent any CMC's, which could be causing a problem, add a low pass filter and get the antenna up higher if you can, higher up is further away from the equipment suffering RFI, which can help.
Unfortunately, even after doing everything you can to your station to prevent RFI, ultimately it is down to the equipment receiving the RFI, being cheaply made, poorly designed and with a poor immunity to RF that it is not supposed to receive and it is the equipment being effected that needs the help and not your station. Try telling your neighbours that it is their cheap ass TV or w/e that is the problem, and you will be met with numerous different responses, lol, Diplomacy is the order of the day.......
So you are suggesting (just trying to make sure here) that this individual with the question at hand. Go up knock on folks door make modifications to electrical equipment they paid for, just so the individual with the question can play radio?
And you have done this?
So theoretically you are saying if I want to play radio, if I cause interferrence its not my problem but yours.
Thats kinda pathetic.
I do not need a book to see that is a morale problem and nothing scientific about it.
And the fact that you have done this. Makes me wonder about your psyche and even if one should trust anything you say.
Might be cheaper still to buy the ground plane kit for the Imax - rather than trashing it altogether. After putting a ground plane kit on the Imax; doing the ferrite treatment or winding an RF choke ('ugly balun') below the antenna feedpoint would accomplish much the same . . .
Much if not most of the time it is the equipment that is receiving the bad interference that is at fault. That means that the only way to fix the problem is to either filter at the devices in question (which would be inside your neighboring homes and businesses) or to replace them altogether. CroMagnum is correct as far as his replies that I've read. If your neighbors equipment is experiencing difficulties due to interference, the best (and often the only) way to fix it is to go to the device and add filtration there. In order to do that without catching a B&E case, you might want to ask the neighbor first BEFORE you enter their house/business.
To most people, your act of offering to install caps and filters on their equipment will seem like a very nice, generous thing to do. It's all in how you present it to them
.