Jeep - Noise from H3ll

Discussion in 'Mobile Radio Systems' started by NG7E, Apr 22, 2011.

Thread Status:
Not open for further replies.
ad: L-HROutlet
ad: l-rl
ad: Subscribe
ad: Left-2
ad: L-MFJ
ad: abrind-2
ad: Left-3
  1. NG7E

    NG7E Ham Member QRZ Page

    This past week, i purchased an FT-857D which has been installed in my 2001 Jeep Wrangler. I've been battling the worst noise i've heard over a radio, which makes for wanting to NOT have a radio in the Jeep.

    With the Jeep off, the S meter is S1, with the Jeep on, the S meter jumps to S9 or S9+. I've ensured that the engine, tailpipe, tub, hood, doors are all bonded to the frame, yet the noise is still there. I have noticed that the noise only appears with the Jeep on, not when the accessorie(s) are on, and not the first few seconds when the fuel pump would come on, but only when the Jeep is on.

    I also found that if i unhook the coax from the back of the radio, the sound goes away, yet when the coax is hooked up, the sound is back.

    I'm stumped!!! I tried different spark plugs but the sound seemed to get worst, even with the NB on, i still had an S9, where as with the old plugs, the NB contained the noise down to an S7.

    Based on this info, anyone have any ideas? I'd hate to abandon the thought of an HF rig in the Jeep, and buying a new Jeep isn't an option.

    O.c. - W6OCL
  2. M0GVZ

    M0GVZ Ham Member QRZ Page

    My friends FT-857 is the same in his Vauxhall Astra. My Kenwood in his Astra doesn't have the same problem. Likewise his old Murphy 3000 CB doesn't have an issue either but his other CBs do.
  3. K0RGR

    K0RGR Premium Subscriber QRZ Page

    Have you been to k0BG's web site yet? He has lots of advice on curing ignition noise and other mobile noise sources.

    In general, you need to ensure that everything is bonded to everything else - the hood, the tailgate, the tailpipe, and the engine block need to be firmly bonded to ground. Alan has advice on suppressing noise from the newer ignition setups, too. There are other potential sources of this noise - fuel pumps are the worst, fuel injectors can be bad too.
  4. K7CJ

    K7CJ Ham Member QRZ Page

    Just for grins, can you try a different power source? Are you connecting directly to your battery?
  5. WD5GWY

    WD5GWY Ham Member QRZ Page

    Is it a pulsing noise? Or a whining? If it's a pulsing noise, and you have electronic fuel injection, the injectors could be the source.
    (more so, if after you switched spark plugs) One of my trucker, ham friends had the same problem (I do too on the same engine)
    and he wrapped the wiring to the injectors with copper foil (hobby shops like Hobby Lobby are a good source) and soldered a braid
    between them and then grounded that to the frame of the truck and it eliminated the noise. That idea could possibly work with
    noise generated from the computer module if your jeep has one.
    Another idea presented here is to try a different radio (if you have a friend who will let you try theirs) and see if the Noise Blanker
    and other noise limiting features are able to get rid of the noise or at least suppress it more than the radio you are currently using.
  6. NG7E

    NG7E Ham Member QRZ Page

    W7DSS - yes, connnected directly to the battery for both + and -. I will be trying a stand by battery in the back of the jeep tomorrow. Will post updates

    WD5GWY - I do have my base radio that i can try in my jeep, will update on that too. I did buy a new set of "resistor" plugs last night and after installing them, the noise got worse, i promptly restored the original plugs and will go spend more than $1.99 on plugs today. Also, the jeep doesn't have the conventional wires, so it isn't easy to wrap.

    ONe thing i did find today is that while i was running my A/C, while the compressor was engaged, the S meter dropped from S7 to S1. When the compressor disengaged, the noise went back up to S7.

    The new S7 while jeep is on as opposed to the original S9 is due to replacing my original mount. For some reason this made a difference. I also scraped some paint off of the places where my ground straps were placed.. i'm sure this too helped!!
  7. KE5PPH

    KE5PPH Ham Member QRZ Page

    do you have the coil on plug packs?? those can some times be as bad as the injectors. In a Jeep, the ECM is a MAJOR noise source. It's possible, that you need to shield the buss connections Like the above mentioned Injector fix.
  8. K7CJ

    K7CJ Ham Member QRZ Page

    W6OCL, so I am in a similar position as you. I bought my FT-857D about 2 months ago and am planning to use it in my 2003 Durango. I did a test install over the weekend. I also have a S7 noise (plus alternator whine when revving the engine) but the NB will get rid of it. You have to adjust the NB to 100. Also, I tried a 2nd, separate battery and the noise still remained. I brought out my portable SW radio and sure enough, the engine compartment was full of RFI. There was a 4-5ft circle around the front where the RFI was picked up. I have a 3/8x24 mount that is near my driver's side door just in front near the hood. My 20m hamstick is likely picking up the RFI from the compartment. I also have a Wilson 5000 10m mag-mount antenna. I've used this antenna with an Icom 7000 and didn't notice this noise -- but I didn't use it with the front mount. I have a feeling that if I buy a K400 mount and put that on the hatchback -- which is a good 5-7ft away -- the new location will hopefully relieve most of the RFI.

    Either way, the NB did remove it. It definitely is annoying on AM or SSB. (BTW, it was only bad on 40m. I didn't seem to have much RFI on 20m.)

    As KE5PPH mentioned, my Dodge uses the non-standard plugs which make replacing them and the wires rather tedious. My PCM is located on the passenger side and thankfully I didn't hear any RFI from it.
  9. NG7E

    NG7E Ham Member QRZ Page

    W7DSS, thanks for responding. I found that most all of the bands, expect 160 is full of noise for me. My antenna is in the rear passenger side, yet the noise is there.

    I have set the NB to 100, but my noise still varies from S4-S7, only a few times does my noise go down to like S1 and that's when the A/C clutch kicks in. Hopefully over the next few days i can do a bit more work to it and document my work so as to pass it onto others.

    I did also replace my old Champion spark plugs with new Platinum Champion plugs, but that didn't work. I'm considering wrapping the COP rail with wire and grounding it to see if that helps.
  10. KA1FFO

    KA1FFO Ham Member QRZ Page

    I run a jeep. Take a run of coax with a small load/antenna on the end and with the jeep on, but not running, walk around the jeep and touch parts to try to locat the noise source. if no luck, then with the jeep running, do the same . Take your time and be very careful when doing this. moving motor parts. Once you find the noise source , then work a cure for it. It could be a fuel pump. Thats an easy fix. on my ford, I put in line eletric caps to ground, no noise.

    I spent 40 hours plus making sure of good ground for all of the radio system was made right. if you want to talk more.
    Good luck. AL KA1FFO
Thread Status:
Not open for further replies.

Share This Page