Proper Installation:

You must have a good install to eliminate the most common problems. 
You will get rid of most of your poor reception, RFI, and low power 
problems with proper installation.

Mount your radio in a good stable position where you can access the 
rear of the radio, coax, power lines and etc without having to un-install 
the radio. 

After mounting the radio, run a good ground to the radio (I know the 
radio already has a ground going to it, and that the coax also is a 
ground, just do it anyway.)

Make sure that there are fuses in both the hot and ground power leads. 
Then twist them as tightly as you can, twist, twist, twist. I know that 
getting your radio mounted as close as you can to the power source is 
only possible if you have a remote mountable control head, do what you 
can to keep your power leads short. Please hook up only to the battery, 
and only the battery. Resist the urge to go under the dash and hook up 
to power supplying your fuse/breaker box. Going to the battery box will 
help you eliminate noise, if you go to the breaker/fuse box you will be 
getting noise from other things that are running thru that main power 
line. In other words, your battery will act somewhat as a noise filter. 
Don't have any weak or loose connections, everything has to be tight or 
you will get noise.

Start your vehicle, turn on your radio, before attaching a coax, turn 
on your pre-amp and listen for noise and RFI on all the bands. Now shut 
down your truck and see if there is a difference. If there is then your 
noise is coming thru your power lines. You can solve those problems by 
installing inline filters that are available at Radio Shack, or you can 
wrap your power lines with ferrite. The more turns, the better.

Everything else that you hook up to your radio will need ferrite. I put 
ferrite at both ends of every lead. Example: Extension speakers, I put 
ferrite right next to the speaker, and also right next to where it 
plugs into the radio. This may seem a bit like overkill, but doing all this 
during installation will certainly eliminate the headaches, and weeks 
of searching for for RFI later on. You will certainly be taking steps 
that are not necessary, and may not be appropriate for your installation, 
but by doing everything in excess, you will be able to operate well, 
and actually hear the far off and weak stations without having to shut 
down your truck to hear people.

OK, now for the coax. Use the best coax that you can find. I use RG213 
it is double shielded, and completely insulated. I can run all the 
power that I want without the center conductor melting into the braid,  
and it is fairly flexible, so bends in the install are possible. Make sure 
to have good connectors on both ends, and for the end that goes outside 
paint it up with waterproof goop, or liquid electric tape. If you 
aren't using a connector, but you are using a split, make sure that you have 
good soldered connectors, and again paint your outside connections to 
insulate from the elements. Now, start your truck again, turn on your 
radio, and listen for noise. (you will get some atmospheric noise now, 
maybe even hear people talking on your favorite frequency, but RFI should 
be hopefully non-existent) If you are getting RFI, perhaps you have run 
your coax alongside other wires that run fans, motors, etc., but that 
shouldn't be an issue if you used good coax, and quality connectors. I 
still put ferrite on both ends of the coax, near the radio, and near the 
antenna. The ferrite will not take away any signal, but will steal RFI 
from the coax braid.

Mount your antenna as far from noise makers on your truck as you can. 
My ECM is (everybody's)on the left side, so I get less noise from 
the screwdriver on the right side of the truck and I do from the 
screwdriver on the left side. Also, if you have loud tires, a fender mount may 
not be your best move. Mounting your antenna behind the cab is NOT an 
option, your trailer will block and absorb your signal. Having your 
antenna on the side of your truck is an option if you can get it away from 
the cab some. I have one fender mounted on the right, and mirror 
mounted on the left. I run a Kenwood TS 480, and a Henry SS-750 amp. The 
radio has it's own antenna switch, but I use a manual switch so that I can 
use the power thru the amp on either antenna.

Grounding the antenna, This is where the fun begins. The more grounds 
that you have, the bigger your signal will be. You will know when you 
have enough grounds (the point of no gains) by tuning your radio to a low 
band frequency on 75 or 160 meters while Bobtail. Then hook up to a 
trailer. If you don't have to retune your antenna, you probably have 
enough ground. Your ground (just like a dipole) is 1/2 of your signal. If 
you run a braid to the bottom of your antenna, the braid needs a short 
run to the frame. I also walked around my truck with a multi-tester, and 
checked everything under the hood, and under the sleeper of the truck. 
Anything that didn't have continuity to the frame got a braided ground 
strap. This quieted the truck as well as increased the size of my 

Build a Sniffer:

We are all truckers, and we all have old CB radio coax. Just cut one of 
the connectors off, expose the center conductor by peeling back the 
braid an inch or more. Then dip the conductor in liquid electric tape 
(the last thing you want to do is allow your conductor to touch something 
while you are sniffing, you could zap your radio, so insulating it will 
fix that).

After building your sniffer, get some 20ft or longer headphone cords to 
plug into your radio, start your truck, wear your headphones, walk 
around your truck probing with your sniffer. You will be able to hear 
everything that makes noise thru your headphones. Your sniffer is now 
your antenna, it is small, and won't hear much unless it is close to the 
noise maker. Once you have found the source of the noise, you can work 
on eliminating it.

Most noises can be eliminate by grounding, shielding, the use of 
ferrites, and capacitors. If you do a proper installation, have good grounds, 
good coax, get your antenna away from noise, you have a head start. 
Good Luck, Jim K6TEX

Any questions email Jim:


Some Other Proven Solutions for Noise Suppression

ECM NOISE -     For 60 Series Detroit Engine

Install a minimum of two snap-on ferrites over the 8 wires on the ECM line going to the back of the block to the injectors. Some drivers have installed as many as 6 snap-on ferrites. The ECM is on the left side of your engine as indicated in the picture on the left. You can see the white wires coming out of the front at the top of the ECM and curving up and back then goes inside the black plastic cover. The plastic cover is split so it is normally easy to access the wires anywhere along the block. Dave, KB9IOT and I only used (2) of the Radio Shack Data Line Filters (ferrites) and they run about $5.00 each.  However, you can buy them a little cheaper if you order them in quantity from Palomar Engineers or buy at a hamfest.
Leece-Neville Alternator Noise -

Install (3) .01mf capacitors and daisy chain them from the POS to NEG on the Alternator, then NEG to the Frame's Ground then the Frame's Ground to POS.

Grounding Most Important - Install Ground Straps from the bottom of your antenna to the frame (short as possible). Tarheel says no more than 1-foot long.  Also, grounding all your equipment to the Frame Ground helps reduce noise.
On Your Power Line to Radio - W3IZ says to install a large Capacitor (350Mf or larger at 50v) will eliminate AC noise on DC power cables. 
Surge Protection - for Radio - Install an MOV (Metal Oxide Varistor) between your Hot and Ground on your Power Lead. (very inexpensive) The ARRL Antenna Handbook says: An MOV should be installed between the two leads of the equipment power cord.  A GE MOV (V36ZA80) is recommended for this application.  This MOV provides the lowest measured clamping voltage (170V) and is low in cost.

If you have any solutions that has made a difference with your installation, noise reduction of your mobile HF antenna, please send them to me and I will add them to this page.

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