Need antenna help....not Marshall Mod

[Monsta]

I would like to improve my AM reception if possible. There are places where I cannot get the AM stations that I can in my trucks. Improving FM reception is a welcome addition although I can get all the stations that my trucks can.

 

The Marshall mod confuses me a bit as i don't get all the lingo and the bases and stuff... (Just what the hell is a PL259?? He references it but makes no mention of it in the parts list...)

 

Anyway...I don't need a folding bases. I have a metal grommet in my cover that the antenna slips through. I was very proud of that mod and don't want it to be wasted by going with a fold down bases. My base doesn't fold down now anyway due to "oldness".

 

So...what IS the best antenna to use and what base would I use? And is there anything else I can do to improve my AM reception.

 

Stupid questions but...can I run TWO antennas for improved reception to the radio? I do not use the CB antenna and have actually taken it and the entire holder off. (We don't use CB's here or rather, when I tried nobody answered me.) Is it possible to split the AM & FM signals to different antennas without having some sort of Radio Engineering degree and a thousand bucks. Or even run two AM/FM antennas or is two not better in this situation?

[Freebird]

The Marshall mod will not help at all with AM reception. The PL259 is a coaxial type connector for CB antennas, nothing to do with your AM/FM antenna. I never listen to AM so can't tell you how well mine picks up but I do know that it can be hard to improve. I would go to a local radio shack or someplace similar and see if they have an AM signal booster. I know that there are some available and would bet that Radio Shack has them. You could replace the antenna but it likely won't help a lot. If you decide to try, it would be easy to do. Simply remove the old antenna and replace it with one that will fit through the hole on the bracket. I don't remember for sure but don't think the antenna cable unplugs from the stock antenna, if I remember correctly, it is soldered in. I may be wrong though. If it is, just cut it off close to where it goes into the bottom of the antenna. You will probably be able to get enough slack to install a new male connector on the end and just plug it in.

[Bummer]

Is there anything actually wrong with your existing antenna? The antenna booster I found in a quick google plugs into the radio, then the antenna wire plugs into that. I haven't checked the Venture radio but I'm expecting the antenna wire to plug into it like automotive radios. If not it'd just be a $3 trip to the local mom and pop electronics parts shop for a set of solder in Motorola Plugs and some shrink tubing.

 

The wire is crimp/soldered into the antenna.

 

Am/fm antennas are not the same length as cb antennas so using one would be a compromise.

 

Replacement antennas come with a wire attached.

 

There's only one antenna input to the am/fm radio. I know of nothing commercially available to usefully split to two am/fm antennas. I can think of an outside possibility, but it'd be a $75 experiment which could easily fail due to a directional or frequency specific problem.

 

I'd try the plug in booster first.

[GeorgeS]

About all you can do is mount a Seperate AM/FM Antenna for the Radio.

 

Use the CB antenna only for the CB, presently there is a unit called a " Duplexer " that splits the signal ( for lack of a better term ) to feed the CB and receive signal for the AM/FM

( this is a comprimise, at best for AM reception )

 

Even if you were to install better CB antenna, you would still have marginal AM

 

About all you can do is purchace a high quality Automobile AM antenna and mount it in a seperate location.

 

These antenna's come with cable attached, ( It is not RG-58/u coax as used for the Cb antenna. Its a special cable )

 

Do, not cut the cable that comes with the antenna, or it will not work right. You must install what comes with the antenna. It will have whats known as an " RCA " plug, this is the type of connecter on your AM/FM.

A car antenna should give resonable results.

 

However, Without haveing all the Metal, of a car body, its not going to function as well, as if mounted on a car.

 

There are some small dipole type replacement auto antennas for mounting inside of windshields, sold in most autoparts store's. some have an amplifier built in. ( this has a seperate wire that hooks to 12V)

I was thinking of trying this myself, and mounting it in the top of th Trunk lid. ( cost about $20 )

 

I simply put a Short ( 13 inch ) auto replacement and mounted inside the trunk. It works, but not very good for AM , considerable worse then the Stock set up. Seems OK on FM though

[Guest cdvogan]

Hey Monsta

 

When I was a kid and FM was just starting out, we used to listen exclusively to AM radio and anytime I changed radio's in the car I thought I did some radio tuning (adjustments) to make the reception better.... Now I can't say for sure that there is a place on the radio for this but here is what I found on a google search that just might help....

 

Cliff

 

The real trick to good AM reception is to tune the radio to the

antenna. Most all car radios have a "peaking" capacitor somewhere

accessible from the outside that is designed to tune the antenna and

feedline to resonance. Some are accessible through the front panel

but most are on the rear or bottom of the radio near the antenna

connector. most of the time it will be labeled "peak". What you

want to do is to get between stations near the center of the band

and then tweak the peaking adjustment with a non-metallic tuning

screwdriver (from radio shack) until you get the most background

noise. Then tune in a distant station and make a minor adjustment

to make it as strong as possible. it must be a distant station. A

nearby station will be on the automatic level control and you won't

be able to hear any difference. Tune for maximum noise first to

make sure the ALC isn't active. IF what you're interested in

listening is mostly on one end of the band or the other, then tune

there instead of in the center.

[Freebird]

George,

That was a great explanation for a first gen but we are talking about the second gen. It already has separate antennas and therefore no duplexer.

[arhayes]

Monsta,

In my opinion, you can, and will never, get the same AM reception on a bike that you get in your truck because of the way antennas work. Your truck provides a huge ground plane or the counterpoise required for effective antenna operation. This is also true for FM and CB. All effective antennas operate as dipoles, meaning that there must be two "halves" to the antenna system. On a vehicle system, one half is provided by the "vertical" portion (what you think of as the antenna), and the balance is provided by the vehicle itself. On a motorcycle, there is not enough conductive mass to equal the mass of an automobile or truck.

 

Bottom line, in my opinion, you're wasting your time. Others may disagree.

You don't have to be a mathematician (though antenna theory is best expressed with mathematics). Good luck!

[Monsta]

Hmmm...interesting. I hate wasting time...and money! I can deal with spending the $15 for the booster but even that has a 50/50 shot based on the 6 reviews.

 

That's good info you posted and I certainly understand it, however, my Excursion gets worse reception as my Avalanche. My Excursion has more metal since it is much larger and the Avalanche is mostly covered in plastic (not sure if that matters). My Mazda 5 gets the best and it is less than half the size of the Excursion and has an antenna that is about 7" long.

 

Should I take into account the actual power from the radio as well? I don't understand this electronic signal stuff...I just wanna listen to talk radio.

[arhayes]

Good radio reception, be it AM, FM or CB is definitely impacted by both the capability of the antenna system and the radio itself. With experience, those interested in radio transmission and reception usually learn to spend 75% of their time and effort in the antenna system (which includes the antenna, connectors, and feedline (cables), and 25% on the radio itself. The difference between your two automobiles' reception may be impacted by either one or both.

 

I'd make sure all of the connections of your antenna system at both the antenna itself, and the radio, are clean, solid and secure. Past that, you're on your own at this point!