Scanner Antenna





Introduction: Scanner Antenna

This is a simple but sensitive Home Made J-Pole Antenna that works great when You are limited as to a place to mount an external antenna !
What You Will need:
1( 48 1/4 " twin lead wire
2( Measuring tape
3( Exacto knife or similar cutting tool
4( electrical tape
5( short lenght of coax cable
6( antenna connector for scanner

Step 1: Step 1

cut a 481/4 " length of the twin lead and remove 1/4" of the insulation on 1 end exposing 1/4"
of each side of the twin lead wire

Step 2: Cut the Notch

measure up 12" from the insulation and cut a
1/4" notch through the insulation and 1 of the twin leads.

Step 3: Attatch Cable or Coax

Attach the braided wire from your coax to the notched side of the exposed twin lead and tape
Attatch the center wire of coax to the non notched side and tape securely
Attach the connector for your scanner to the other end
of the coax using what ever lenght is apprioapate
Use as short a lenght of coax as pratical to achieve
best reception.

Step 4: Mount the Antenna

Tape the antenna horizontally in a window or exterior wall,plug it up to your scanner and you are ready to listen.
I routinely receive crystal clear reception on all frequencies within a 75 mile radius of my home.



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    16 Discussions


    10 years ago

    Hey, this is a great instructable and is very informative. Just one thing is missing... pictures! It really helps a lot when trying to follow directions so you should consider taking some photographs. Once you do that and leave me a message when you have so that we can publish your work. Thanks! Thanks for the cool instructable and we hope to publish this soon!

    3 replies

    Hey my friend...i have completly redone the instructable including adding pictures. Please review and publish as you find appriopate..if you feel it needs additional work please let me know...thanks Randy

    thanks for you comments admin....this is my 1st attempt at an Instructable and I appreciate your critique...I will follow up with pix as recommended !

    Just put one together today and it is amazing! Loved the idea and after a quick trip to the big box store I was on my way home with the supplies needed for the build. I added a few additional inches and placed the assembly inside a PVC pipe sealed at both ends for outdoor mounting. Geeting signals I was not with my old scanner antenna. Using only for receive. Thanks for the inspiration! ~GOD BLESS~ john

    is there anything that would stop me from building one out of steel and wiring it to the scanner?

    a definite big improvement over the pull up telescopic antenna. A lot less white background noise and now hearing more than before!

    I found this antenna to be extremely easy to fabricate. It's true that this "J-pole" type antenna has great wide band characteristics. I found that placing it in a length of Panduit wiremold (rectangular ABS clamshell conduit that is hinged along one side and snaps closed on the other) with a chunk of foam every 8 inches or so to hold it flat and in place was a great way to protect it and make it easy to install. I soldered a standard threaded panel mount BNC female on the business end and secured the conduit's end cap at the top with silicon adhesive/caulking to make it watertight. Don't use antistatic or conductive foam - it may affect the antenna's performance. Overall it by far outperforms the rubber duckie on my handheld on every band.

    indeed this is a real "Instructable",crystal clear and easy to follow btw,is a dual band antenna or just for 2m or 70 cm?

    1 reply

     If you move the notch up to 30" inches and twis  or solder the 2 wires at the top together, you will receive better on the VHF low band (below 50 MHz).

    This antenna is actually called a "J-Pole" antenna. No idea what frequency it's cut for, but they are a great antenna! Though I don't suggest mounting it to the wall as shown! The J-Pole is very sensitive to solid objects and likes to be as far away as possible! Get a piece of 3/4" white PVC pipe and some end caps and mount the antenna inside the pipe. Leave yourself a long enough end to reach your radio and mount the thing on your roof. It will make a world of difference!

    I am planning to build this one for my realistic pro-2022. Would it give me a decent performance? also: when you cut the notch, do you cut through the wire, or just strip it from its insulation? and would it matter if I used thicker twin-lead wire with the leads closer together (like speakerwire or something?) If this works I think I will shove it in a pvc tube so you have a plastic antenna.

    1 reply

    Cut the notch thru the wire..I havent tried the better insulated type twin lead so Im not sure if it would effect the performance....putting this into a piece of pvc tube is an excellent idea !

    Great instructions.... clear, concise, easy to understand. Definitley do-able.