Looking for a bleed over fix?

[kidx]

Well I found this and was wondering, If this is against the law. I would like channel 18 to stop bleeding over into 19. So i can hear truckers and the traffic. Also talk to my Cb Club members on channel 10 it is getting annoying when they bleed over. Well here is a solution I found is this legal i think no but what is your opinion and is there any channel guards out there i can get? Or any thing legal.

Channel Guard Bleedover Filter for CB Radios

 

[teufler]

looks like it should help. Not to be a smart Axx, but that was a reason that many of us became ham operators. Too much power on the db bands and the radios just could not handle the over power signals. Perhaps other CB Club Members would like to become hams. I am sure there are some clubs in Windsor that would help you get licensed and move away from the interference.

 

[kidx]

True but the law should stop this yea or people should help make a channel gaurd for this. Yea lets clean up CB Radio guys really come on now.

 

[prcguy]

There are a couple of things that would cause bleedover, the spectral purity of the offending transmitter and the selectivity of your receiver plus the close proximity of the offending transmitter.

In the case of a transmitter that is causing bleedover due to splattering because someone clipped out the modulation limiter and is overdriving the transmit audio stages with some stupid noise making mic, there is little to nothing you can due because some of his transmitter energy is actually on the channel you want to hear. Improving your receiver selectivity will have little effect on the problem.

In the case of a poorly designed receiver or cheap radio, adding more or narrower IF filters does improve things, if the offending transmitters are not causing out of band emissions.

Even if your receiver is of reasonable quality and has good selectivity, close proximity to the offending station will cause its own problems. If your receiver has a certain spec of so many dB down at 5 or 10KHz away, that might be fine with weak to moderate signal levels, but when the guy is next door his signal might 50dB (grabbed that number out of the air) higher than expected and his out of band signals that are within spec are still there and 50dB higher to you because he's next door.

In that case a receiver filter upgrade may help or maybe not. All transmitters make noise outside their allotted transmit band width and even if its 60dB down 10KHz away its still there and if your right next door you will pick it up and it cant be filtered out because its on your receive frequency.

Back in the 1970s when I worked for Pace Communications, I used to add ceramic filters to most of my CB radios so I had two in series and it made a slightly noticeable improvement in the receiving experience. It adds a tiny bit of loss in the receiver IF but tightens up the skirts a lot to improve adjacent channel interference as long as they are not transmitting out of band garbage. You usually have to diddle any IF transformers before or after the ceramic filters to make sure the IF passband has the right response.
prcguy

 

[KC4RAF]

KIDX, out of curiosity;

1. What brand of radio are you using?
2. Any idea as to distance, direction from you to the offending transmitter?
3. What type of antenna are you using.

Some transceivers are slightly better than others against bleed-over, not by much tho.
If the offending transceiver is kind of close, say a couple of miles or so, you might know who it is.
How many channels is he/she bleeding over to?
If you had a Yagi antenna, you could reduce some of the offending signal; but if you were trying to communicate with somebody in-line with the bleed-over, you're s-o-l.
I agree with you about stopping this type of problem, but there's really no solution, (well you could spike, the cable, etc., but THAT could get you into serious trouble.)
Hope you can find a solution,
73s

 

[TheSpaceMann]

I had an issue with a station causing bleed over way back when My solution was to put up a beam antenna and turn it away from the offending station!

 

[kidx]

i have a cobra 18 wxst II C yes and the radio is amazing so far yup. I hope more people can enlighten us to a problem solver here lets keep this thread open once this is solved then CB will be amazing. Also the guy is a street or 2 over yup.

 

[gewecke]

i have a cobra 18 wxst II C yes and the radio is amazing so far yup. I hope more people can enlighten us to a problem solver here lets keep this thread open once this is solved then CB will be amazing. Also the guy is a street or 2 over yup.

Study to get your ham license kid. Your problem will be solved. . 73, n9zas

 

[mule1075]

Study to get your ham license kid. Your problem will be solved. . 73, n9zas

And again a post not relevant to the question asked.

Sent from my Z750C using Tapatalk

 

[gewecke]

And again a post not relevant to the question asked.

Sent from my Z750C using Tapatalk

That's your opinion. Considering the fact that it would help solve his issue, it Is relevant. . 73, n9zas

 

[cmdrwill]

Well I found this and was wondering, If this is against the law.

No, a better receiver IF filter would NOT "be against the law". What IS against the law is a splattering transmitter. And anyone who modifies a CB transmitter IS violating the law.

Unfortunately most CB radios do not have really good receivers, the cost would price them right out of the CB market.

 

[gewecke]

i have a cobra 18 wxst II C yes and the radio is amazing so far yup. I hope more people can enlighten us to a problem solver here lets keep this thread open once this is solved then CB will be amazing. Also the guy is a street or 2 over yup.

Also if you wish to stay with cb, Try to find a cb that has a RF Gain control on it. This will allow you to decrease your receiver sensitivity enough that some of your bleedover can be dealt with. 73, n9zas

 

[kidx]

Also if you wish to stay with cb, Try to find a cb that has a RF Gain control on it. This will allow you to decrease your receiver sensitivity enough that some of your bleedover can be dealt with. 73, n9zas

Thanks for everything man.

 

[KD8DVR]

Well I found this and was wondering, If this is against the law. I would like channel 18 to stop bleeding over into 19. So i can hear truckers and the traffic. Also talk to my Cb Club members on channel 10 it is getting annoying when they bleed over. Well here is a solution I found is this legal i think no but what is your opinion and is there any channel guards out there i can get? Or any thing legal.

Channel Guard Bleedover Filter for CB Radios

Well, if you are dealing with those idiots who turn their radios up to over 100% modulation.... nothing you do will help. Their signal is going outside the 10 khz channel space and going into adjacent frequencies.

Now, if you add one of those illegal and cheap Class C (incorrectly called linear amplifiers) "Cb amplifiers" to the mix, it becomes more insane.

Add thopse people who illegally try to contact others over the 250 KM range,it becomes unbearable.

This is what has caused CB to become ineffective as a communications service.

 

[kidx]

Sad thing is there are really cool Americans in USA i talk to and some cool Canadians as well yup.

 

[JayMojave]

Hello Kidx: Yeah that web site showing the "Channel Guard Filter" works at improving the receivers selectivity some what. I installed the Channel Guard IF Filter in a older Cobra 148 GTL radio many years ago and was impressed in the receivers improvement.

This mod is not for the unexperienced solderer type green guy.

There are also U-Tube videos showing the difference from older CB Radios to newer radios in the IF Filter used, as the newer radios don't have a narrow filters as the newer radios had. And I know there have been modifications that install a better IF Crystal Filter in some AM and SSB CB Radios.

But there is more to a receivers circuit considerations than just IF Filters. Your Cobra 18 radio is one of the cheapest radios available. And we know CB radios are mass produced using the cheapest parts around. So be advised. Top notch receiver design is not included. My Icom 746 works great rejecting unwanted near by interference, and now I hear the Icom 7300 is even more better and has shinier knobs.

The Ham Radio Lic is a good call allowing even more contacts to be made on different bands. A lot of CB stations use the good ham radios for CB as they have a much better receiver with much less interference and the ability to reject close by stations bleed over quit impressively. Yaesu inside guys told me back in the early 1980's that approx. 30 to 40 percent of there radios went to CB use. Many of the ham radios have a "Pass Band" Tuning function that is the good stuff. With new digital technology the radios just keep getting better.

One thing that can be done in a cheap radio is to use the RF Gain, adjusting the receiver sensitivity down this also allows the IF Filter to work better in rejecting bleedover interference. But the Cobra 18 doesn't have a RF Gain, back to the cheap radio again. Another way is if u want to play one must pay.

Good Luck.

Jay in the Great Mojave Desert... NO International Airport as promised by the Restate Lady, no freeway off ramp yet, no paved roads yet, but we did get a price break on Ammo, must be an election year. Spelling and punction is good enough for whos it 4.

 

[kidx]

Why has some one not made a better RF Gain filer adapter that plugs on to your coax or a include in a SWR Meter?

 

[jassing]

the cbc filter hasn't been available for years, good luck finding one. LesComm is rumoured to have his own version, but haven't seen it . The cbc filter was really good, but they say there wasn't enough interest to keep it going. Turning RF gain down will help but it's not the same as the filter.

 

[kidx]

the cbc filter hasn't been available for years, good luck finding one. LesComm is rumoured to have his own version, but haven't seen it . The cbc filter was really good, but they say there wasn't enough interest to keep it going. Turning RF gain down will help but it's not the same as the filter.

I I would like is to have a CB Filter for RF Gain that would be in the center of both the antenna and CB Radio and it would be way better to have that and have it on a CB cause it can do more and be of more Quality. Maybe working with some one who can do this would be cool. Also why not make a channel guard and RF Gain or something all in one filter?

 

[prcguy]

The filters being discussed go in the receiver IF path, which is at a different frequency than CB and usually down at 455KHz, you can't put that in line with the antenna like an SWR meter. Same with RF Gain, that controls the gain of a receiver stage or two and is part of the inner workings of a receiver, can't put that external without also cutting your transmit power down with it. Its also impossible to make an external filter at 27MHz that will allow only one channel to pass through to reduce bleedover. Making a single channel width filter at 455KHz is possible and there are literally hundreds available off the shelf.

It would be easy to incorporate an RF Gain in an IF filter assembly and it could be a simple PIN diode attenuator that is controlled with an additional pot. But you would be cutting into the receiver IF path on a circuit board and inserting the whole thing there.
prcguy

I I would like is to have a CB Filter for RF Gain that would be in the center of both the antenna and CB Radio and it would be way better to have that and have it on a CB cause it can do more and be of more Quality. Maybe working with some one who can do this would be cool. Also why not make a channel guard and RF Gain or something all in one filter?