i had a cb radio with dual k40 antennas...im replacing the cb with a scanner radio and antennas....my question is, is it better having one or two antennas for the scanner and what is the difference in the lengths ( 3ft, 4ft,) im installing whips...thanks

 

What freqs will you mostly be scanning?

 

Depends on how far you are tryin to reach (scan local or next counties). I am running a bearcat trunk tracker with a glass mount whip on my rear window and perfroms good. Im set up to add a second ant when my box is on my truck and is a 3ft whip which increases my range by approx 30 to 40 miles range. The guy who does the radio installs for my Fire Co. suggested this to me, set up pretty well. Just make sure if you do duals to keep them at least 3" apart. I bought my antennas at radio shack cheaper than buying commercial whips,straight whip is not going to work to well you will need the load in the center of the whip to receive effeciently. Hope this helps

 

well im running two 4ft firestik scanner antennas pretuned for the 30-1200 mhz...just the standard kind....im running them off my toolbox and have the rg 59 coax cable....the one i ran before was just the glass mount one from radio shack and it picked up ok...i thought going with two trucker style 4ft i would pick up alot better...

oh by the way...when you say having the load in the center...what do you mean? like a base on a magnetic?? i just have the line from the scanner to the whips...i dont have the box or load like i did with the glass mount...

 

I could not find the model you are talking about. Which firestick antennas are these?

http://www.firestik.com/index.htm

Are you using them for CB too or are you just using a scanner?



As I asked you before what band of frequencies you use should help you decide which antenna to use. It does not mean that it won't work for other frequencies just that it will be tuned to recieve in a certain range better than others.




Antennas are really just lenghts of wire. Different frequencies have different wave lengths. The best CB antenna (27mhz) is the 102" whip with a spring (bringing it to 108") that means its 1/4 of the size of the frequencies "wave" the 860mhz 1/4 wave antenna is around 4" inches.

Center loaded (or "bottom" or "top" loaded) refers to a technuique manufacturers use to get more wire into a shorter backage.


This is a "center loaded" antenna:




(actually its a "dual loaded" antenna as there is a coil in the base also)



All that refers to is where they put the "coil" (its just what it sounds like the antenna at the coil is wrapped to keep the lenght the same but to shorten the overall length).....



The biggest effect is on transmit and significantly to almost unnoticable IMO on recieve in a mobile setup.

 

i got these but havent put them on...i got them in 4ft...

http://cgi.ebay.com/FIRESTIK-Scanner...QQcmdZViewItem

 

Ahh ok.... That will do you fine. Stick with one. two would be a waste IMO unless you are scanning real far distances and want to use a specific tuned antenna. Even then in a mobile the difference would be minimal.

 

I agree 2 sometimes overides one another and also will get you the distance. I have since deleted one of mine due to picking unwanted signals I didnt really care for listening to. Nice choice of ant.

 

ok so could i run one of my current k40's and one scanner antenna to the scanner since i have a cb channel built in to the scanner...if so would i have to get that cb antenna re-tuned since im eliminating one of them...thanks for te input!!

 

are you just scanning or also transmit? I never had anything like that before. I would assume if your scan ant freqs reah as low as CB freqs I dont think you would need it as long as you werent trying to transmit.