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[digitalanalog]

o.k., i am sure this has happened to others, but how do i get rid of the Heater motor interference out of my scanner.

Must be some type of filter i would guess.

Have my scanner power cord plugged into the cig lighter, and when the car's heater is on high (i live in ohio so it's on high allot during this time of the year) it kills my reception.

ideas?
Thanks

 

[Bucko]

If the noise is coming though the power source not the antenna then powering though your vehicles accessory should yield better results.

 

[digitalanalog]

I kinda figured that would be an option, i'll have to get another plug for the back of the scanner, don't really want to cut the factory cigarette adapter from the scanner.

Infact maybe running it straight to the battery might work better.....

Thanks

 

[N1508J]

Tell us more!

If the noise is coming though the power source not the antenna then powering though your vehicles accessory should yield better results.

Try unpluging the antenna first as an easy test to see if the racket is being radiated into the antenna...unlikely. If not, and more difficult than installing filters, try SHEILDED 2 wire cable attached directly to the battery. Remember, this direct hook-up also utilizes the battery as a FILTER believe it or not! Ground the shield at one end as close to the radio as possible. The shielded cable prevents radiated noise from entering the radio. Do not let the shield of the other end touch anything near the battery and it's best to insulate that end. Yeah, I know you will have to turn the radio off and on with the on-off switch. If you don't like this idea, then you will have to go with filtering the +12V side to your rig. You might get away with the old time method of using a audio output transformer secondary in series with the +12V source as a choke. Otherwise, get fancy with a fat toriod wound with as many turns of wire as will fit and hook that to your +12V suppy and radio. You may use in-line coaxial capacitors or other store bought noise filters that may greatly reduce your noise problem as well.:wink:

 

[betta]

noise from fan motor

You should route your power cord direct to the battery. The battery will help filter the
noise. Keep the power cable close to the body or metal part of your vehicle. You have
conducted noise, through the electrical system. A direct path through to the battery is the
easiest and cheapest way to cure the noise. It is the noise from the brushes in the motor
causing this problem. Nothing wrong with the motor.

 

[digitalanalog]

I've got some Belden 24/2 shielded cable from work, i think i will try that with an inline fuse and go straight to the battery, Thanks folks, all great help..
Thanks

 

[N1508J]

Location of fuse

I've got some Belden 24/2 shielded cable from work, i think i will try that with an inline fuse and go straight to the battery, Thanks folks, all great help..
Thanks

You most likely know, however, put a slightly higher rated fuse than you need in the + side of your supply line close to the battery terminal...perhaps an amp more. Then use the rated fuse value near the rig. That way if the coax accidently gets smashed you won't have a fire cuz the larger rated fuse will open at the battery. :wink:

 

[kb2vxa]

The age old cure is to install a .01uF disc ceramic capacitor with leads as short as possible, one to the B+ lead and the other to the motor frame under the nut holding it to the blower housing. FYI, the cigarette lighter is the noisiest part of the entire electrical system making it the worst place to tap power for a receiver. The accessory lug on the fuse block isn't much better so a two prong approach is called for, install the cap and draw power directly from the battery terminals, both of them, not using the frame as ground return because every noise maker is connected to it. Don't forget to put a fuse in the B+ lead AT THE BATTERY, you want it to blow and prevent a fire should the wire chafe and short to the frame. One of those Max fuses in an in line holder is great, it's completely enclosed and impervious to dirt, oil and moisture. You'd be surprised how the battery acts like a filter, it's the quietest spot in the system.

On the other hand you can put an external horn speaker behind the grille and work the blower motor like a siren. (;->)