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DF3000 3KW Low Pass Filter Question?

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#1
When using the DF3000 3KW Low Pass Tvi Rf Filter, It makes my signal strength low. Does it have to be grounded? Also can i have it sit by my desk? in my house. If i can how would I go about that?
 
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#2
When using the DF3000 3KW Low Pass Tvi Rf Filter, It makes my signal strength low. Does it have to be grounded? Also can i have it sit by my desk? in my house. If i can how would I go about that?

Please explain by what you mean "It makes my signal strength low". Have you actually measured the input power and output power to make this statement?

A low pas filter is designed to let the low frequency signals through and attenuates the high frequency signals. Not having spent the time to look up where that filter rolls off, I can't tell you where the signals will start to be effected. My guess is that the roll off is about 30 MHz. Above that the signals will be attenuated.
 
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#3
Well would that be good for CB Radio? I am not picking much up with it and wondering why. My bro got it to stop the interference to other electronics, Also him But when he hooked it up outside. His WX channels on his cobra went out. But I told him this is not to enhance the weather channels nor for that but he gets mad at me when i say the weather channels going it is no big deal. he says the filter is crap and stops all the signals from coming in. All in all i have stress, So much from arguing it feels like my high blood pressure is high. From arguing due to the fact this don't degrade signal at all just stops interference, That the weather channels going out does not matter cause this is for CB radio not WX weather.
 
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#4
A low pass filter allows the lower frequencies to pass, but blocks the higher ones. This is so emissions outside the CB band are blocked (or at least greatly reduced) to avoid interfering with neighbors TV reception.

Since the "cut off frequency" for these low pass filters is somewhere above CB and usually below TV Channel 2, (54MHz and up) they will block the weather channels. This would be considered normal operation for the low pass filter and some indication that it is working correctly.

Without having some test equipment, it would be difficult to know for sure if the low pass filter was working correctly. It could be damaged. Looking at the reviews for this device, it looks like it's not one of the best out there.

It's hard to tell you if it's working correctly. It would be expected that these would introduce a slight amount of additional loss in the path, but usually not very noticeable.

Unless you have a specific issue where your CB is interfering with others TV reception, remove it. If you are running legal power levels and haven't done any tweaking on the radio, you shouldn't need it. On the other hand, if you are running an amplifier or have had someone "peak and tune" your radio, then, yeah, you probably need it.
 
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#6
Several people have explained what the filter is and what it does. In my experience I have never seen a filter like this cure any TV interference from a stock CB on the lower TV channels like 2 through 5 where CBs could have a tendency to affect the TV. If you are running an amplifier then the filter might help reduce interference on TV channels 2 through 5.

What the filter will not do is cure interference to stereo's, PA systems, doorbells, telephones or any other device. My suggestion is to not use it if you have a stock CB.
prcguy



Well would that be good for CB Radio? I am not picking much up with it and wondering why. My bro got it to stop the interference to other electronics, Also him But when he hooked it up outside. His WX channels on his cobra went out. But I told him this is not to enhance the weather channels nor for that but he gets mad at me when i say the weather channels going it is no big deal. he says the filter is crap and stops all the signals from coming in. All in all i have stress, So much from arguing it feels like my high blood pressure is high. From arguing due to the fact this don't degrade signal at all just stops interference, That the weather channels going out does not matter cause this is for CB radio not WX weather.
 
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1158 W. Valley Circle, Ash Fork, AZ 86320-482
#8
Also here is another reason I am using this Dino will explain in a video.

https://www.youtube.com/watch?v=ajhxxFv5YsU

Well in other terms I use this, To keep the bad stuff out. Also to keep me out of others electronics, I know people who use it and its fine and people who don't and fine I guess to each there own.
So far you haven't presented a credible reason to need a low pass filter.

What bad stuff do you have and what electronics are you getting into? Are you getting complaints from others in your house, or your neighbors?

Unless you are generating interference, that can be directly traced to harmonic radiation, you don't need a low pass filter. If you are simply overloading some electronics, the low pass filter is not the fix.

I have been a ham for 50 years and have never needed a low pass filter, even operating on 10 meters.

Martin - K7MEM
 
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Aug 27, 2016
Messages
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Location
Windsor, Ontario, Canada
#9
well it works fine here and better with it on due to the face it stops interference from other interfering with me. Specially on a indoor antenna and yes others ion my house were complaining cb radios interfere with 400 watt speakers and stuff.
 
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So Cal - Richardson, TX - Tewksbury, MA
#12
The guy in the video is basically clueless and all the info he gives is wrong or worthless. The only thing your low pass filter might do is keep the 2nd, 3rd and higher harmonics of 27Mhz from getting into nearby TVs on channel 2 through about 5. I know your in Canada and I'm not familiar with your TV services but in the US TV channels 2 though 5 have been eliminated in all but a few areas and the TV transmitters have moved to UHF where they will never get interference from a CB.

Bottom line is if you have a stock CB the low pass filter will not do anything for you in keeping your CB transmissions out of other equipment nor will it keep anything out of your CB that you will ever notice. Interference into stereos and audio equipment is not due to harmonics that the low pass filter is designed to address and the low pass filter will do nothing for that kind of interference.

Every CB has a low pass filter built into it that addresses harmonic radiation and they allow the CB to meet pretty tight specs on harmonic radiation anyway. If you remove the DF3000 low pass filter from your radio you'll get your weather channels back and your radio will work as its supposed too. If the filter causes any degradation in your regular CB transmission or reception, then that particular low pass filter is broken and not working to specs.

I don't think I can spell it out any simpler than that.
prcguy



Also here is another reason I am using this Dino will explain in a video.

https://www.youtube.com/watch?v=ajhxxFv5YsU

Well in other terms I use this, To keep the bad stuff out. Also to keep me out of others electronics, I know people who use it and its fine and people who don't and fine I guess to each there own.
 
Joined
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PA
#13
The filter is probably a waste of money. If the CB is bleeding over into speakers and such, it is because the speakers are not robustly RF shielded, and RF on any frequency is going to cause problems. The only way it could possibly help anything is if you were running a cheap crappy power amp that was outputting harmonics above the 27MHz CB band, or if you lived next to a TV station that was interfering with your reception. Any other "benefit" you might be seeing is because the filter is attenuating your output from 4 watts to maybe 1 or 2, which is going to cause other problems. Like nobody else being able to hear your TX.

If your CB is in the house, you need to have an outdoor antenna with good shielded coax between radio and antenna so that your RF is being emitted outside the house away from speakers and such. That will solve things way better than any filter.
 
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Messages
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Location
Windsor, Ontario, Canada
#14
Actually is cause I have 400 watt speakers up a 1000 watt antennas but prolly. Also this box works well for what the guy said plus he has good rep any how thanks for the replies ill be keeping it on since its better for me and nothing in my house has been bothering me so yeah I don't need weather channels my brother was complaining not me.
 
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#16
So are you saying your speakers have a 400 watt rating or does your stereo amplifier put out 400 watts? Is your antenna rated at 1,000 watts or are you actually transmitting with 1,000 watts into your antenna? Big difference in both cases but if you are using a stock CB into an antenna rated for 1,000 watts, you are still using a stock CB and the DF3000 is doing nothing for you.

I also watched a few videos from your buddy Challenger in Missouri. All I can say is if you take advise from him you deserve all the problems you have and the fact that your IQ is going backwards from watching that guy. People like that are one of the reasons the CB hobby is full of senseless BS that stupid people make up and propagate through the hobby as technical facts. What a blithering idiot.
prcguy



Actually is cause I have 400 watt speakers up a 1000 watt antennas but prolly. Also this box works well for what the guy said plus he has good rep any how thanks for the replies ill be keeping it on since its better for me and nothing in my house has been bothering me so yeah I don't need weather channels my brother was complaining not me.
 
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