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Chris
| | Posted on Saturday, November 16, 2002 - 6:10 am: | 
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First of all, Im running a Cobra 25 LTD Classic with a 102" whip mounted behind the cab. My SWR's are 1.3,1.4 to 1 across all 40 channels.
Why is it when I pass through a intersection, I pick up a lot of static? I have my rig powered and grounded to the battery. Which brings up another ?
Have any of yall heard of running coax directly to the battery for your power supply and ground?? I also have the radio grounded from the casing to a ground under the dash..
I tried this the other day, and it seems to be working fine. So let me know if im nutz...
73's
Chris in AZ |
Alsworld
| | Posted on Saturday, November 16, 2002 - 10:39 am: |
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Chris,
glad to see you were successful with the whip and SWR's. Sounds great!
Many intersections will cause static on a lot of mobiles so you are not alone there. Sometimes it is power lines that cross. Flourescent lights from gas stations (or similar type corner stores), especially at night can cause the static. Lots of noise makers out there that cause static, but I've noticed the same condition at certain locations in various states, and I have local friends here that experience the same (I run a K-40, one friend runs a whip, the other runs a Wilson 1000). I would have to say I seriously doubt it is anything from your rig being wrong, just outside interference beyond your control.
I am not sure about the coax question you asked but maybe someone else may know that answer. Sounds like you've got it set up good. Great job!
Alsworld |
Stepchild
| | Posted on Saturday, November 16, 2002 - 4:55 pm: |
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Alsworld,I've had about the same problem.I have a Chevy Silverado w/ the electric fuel pump in the tank and it puts a strong whine in my receive on my galaxy and superstar but, not hardly at all on my 2950.Why is that and, what can I do about it? |
Alsworld
| | Posted on Saturday, November 16, 2002 - 7:39 pm: |
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Stepchild, I wish I had the cure. I also have a Chevy Silvarado with what appears alternator whine. I did install a Pyramid 10amp filter inline with the radio power line, and have run RF chokes on my positive and negative lines but the reduction of noise was minimal. Interesting about your 2950 except...
If I run my Lincoln in the truck, the Noise Blanker completely eliminates the whine. I must assume that your 2950 and my Lincoln have more effective NB filters installed. Honestly that is just a guess but I can see the difference in my setup (same power wires and quick disconnects). And obviously you have seen the difference.
Anybody have other ideas?
Sorry Stepchild, that's the best I can do. Just for comparison, do you run a mag mount? (I do, just looking for common denominators). Additional grounding maybe?
Alsworld |
Dx431
| | Posted on Saturday, November 16, 2002 - 8:35 pm: |
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Stepcild, Chevy's are notorious for fuel pump noise. Here's a suggestion. Buy a good noise filter and install it inline with the fuel pump, NOT the radio. You want to stop the noise from entering your radio, so you must go to the source.
My .02 worth
431 |
Ironmask
| | Posted on Saturday, November 16, 2002 - 9:22 pm: |
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Alsworld, Just coourious. Where do you get your power from. By this I mean do you go directly to the battery or are you hooking into the fuse panel?
Do you notice a difference in whine with different fuel levels?
1. I would suggest hooking direct to battery with both positive and Negative.
2. Magnum makes an inline filter that is very effective [ I use one]
3. The choke you speak of should go as close to the source [at the fuel tank] as possible. Not near the radio because by then it is too late. Yes, different radios have better or worse NBers.
Just my thoughts from past experience |
Kirk
| | Posted on Saturday, November 16, 2002 - 9:43 pm: |
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Fellas.....one word....FERRITE!! Get some nice cores, not Rad Shacks! Wrap them up on your DC. If it doesn't help, try coax also. |
Bigbob
| | Posted on Saturday, November 16, 2002 - 9:53 pm: |
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Using rg-8 is ok if you're running stock watts(shield attached to ground connections,center attached to pos.connections)otherwise use 6or8 gauge cable.Find the hot and grnd for fuel pump close to tank,attach a .3mfd.automotive style filter cap,then attach a 3-amp diode reverse biased,that should kill 90% of the noise. |
Bigbob
| | Posted on Saturday, November 16, 2002 - 9:59 pm: |
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Look guys the noise is comming in on the antenna not the power leads,the fuel pump is turning the elec. system into a huge antenna,another truck parks next to me,I shut off my engine I can still pick up his fuel pump,so there. |
Alsworld
| | Posted on Saturday, November 16, 2002 - 10:22 pm: |
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Ironmask,
I run the power straight from the battery via 8 gauge wire to power distribution blocks. From there it it branches to the radio filter and other things.
I have a cheap AM only radio installed in that truck. Most of my talking is done from my base. As said earlier, the Lincoln is great in there but it's only installed for long road trips.
For me, my setup really sound like alternator noise (varies with rpm's) than fuel pump noise.
Kirk,
What is your best website for good ferrites? I have many of the ham catalogs here at home. I currently have the R/S ferrite chokes around the +/- (1 each) but realize that is probably not enough. Around where I live, zero ham shops, and CB shops are "chop" shops. Great guys but it's like "what's a ferrite???" Internet is my best option besides R/S.
If I talked more mobile, I would be more serious about correcting the problem. 99% of my QSO's are from the base.
Alsworld |
Stepchild
| | Posted on Saturday, November 16, 2002 - 10:45 pm: |
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Alsworld,At the moment I'm running a top loaded wilson 3' fiberglass but I'm going to change over to my 4' Stryker(made and sold by a tech in Oklahoma City)in the morning.I've had real good luck out of it mounted on the mirror of my big rig but,may not do so well on the rail behind the cab since it's not top loaded.Also does it not hurt the filter to get wet? |
john
| | Posted on Saturday, November 16, 2002 - 10:58 pm: |
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will the chokes that Copper carries work on coax? |
Stepchild
| | Posted on Sunday, November 17, 2002 - 2:28 am: |
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Hey,does anyone know of a good web site of classifieds for ham/cb stuff.I need a rotor and control for a moonraker 4 ... cheap! Also is a cd45II big enough for the MR4? |
quickshot
| | Posted on Sunday, November 17, 2002 - 7:53 am: |
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I asked about the rfi in intersections. I talked to a city engineer and he told my that it was most probly from the traffic lights!! The are real "dirty" as far as rfi!! |
Dx431
| | Posted on Sunday, November 17, 2002 - 1:25 pm: |
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If anyone has MSN Messenger, give me a click....fantom84@hotmail.com
431 |
Stepchild
| | Posted on Sunday, November 17, 2002 - 8:08 pm: |
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This question is for any and all.How much is to much swing?I mean if your deadkey is 3w and you swing to 15w pep,Is that to much input to the amp?I've just heard so many story's.I was told that a Texastar 350HDV will take 10w min. 20w max to drive it and you could swing whatever you want.Same go's for a low drive except for the drive.(2-4w)But on the other hand I've been told that to much swing is bad on the finals or it can make it go poof!!!WHATS THE DEAL!!Stepchild |
Tech671
| | Posted on Monday, November 18, 2002 - 5:42 am: |
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Part 1.
Traffic lights did not always interfere with radio. It's been since the change to L.E.D. traffic lights that emit horrible hash for CBs.
Part 2.
Each amplifier will take different carrier (dead key) and swing (pep). Some are common to each other and some not. On the Texas 350s I've found it best to run 1-2w carrier input, and you can run as much as 50w pep input. |
bruce
| | Posted on Monday, November 18, 2002 - 10:00 am: |
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Here in Pinellas Park fla they use a low band VHF link to control the lights it can be heard from CB to 2 meters DIRTY O'Boy. Its SO bad it will swamp the reciver frount end on 29.6 MHZ on several radios i use if you have a preamp on. Well it has been there for many years and an't going anywhere soon so we put up with it. Now back in the early 60's i remember CH 23 was the control channel for the New York City lights we all remember the BEEP ! BEEP ! BEEP ! then a pause. Lots of control signals were on the RC channels like 19a and 22a some are still there. |
dale
| | Posted on Wednesday, November 20, 2002 - 1:50 pm: |
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step child as far as having too much swing that sounds crazy unless they mean overmodulated thats caused by cutting limiters.so i would no never to much swing as long as your limiter stays in place thats my personal opion none of my radios have cut limiters thats very dumb |
Stepchild
| | Posted on Thursday, November 21, 2002 - 12:33 am: |
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Thanks Dale,I don't know that much about radio vs amp so I usualy just take them to a cb shop that I've used for several years and let them match them together.This has worked well in the past.I bought a Galaxy DX99V in'98 and had it converted,peaked and,tuned and then about 6 mo later took it back and had it matched to a Silver Eagle 200.This has worked very well from what I've been told.Thanks again 73 |
Chris
| | Posted on Thursday, November 21, 2002 - 2:32 am: |
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Thanks everyone for the input. So pretty much Im going to have to live with the static around the intersections... Thanks fine...
Back to the second question?? Have any of all heard of running coax for your power supply? I heard it from a "ol" time Ham user and thought I would try it. It seems to be working good.
Thanks again for the input.....
Chris in AZ |
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