FM Radio antenna - successful DIY?

[Guest]

I want to kludge an external antenna to pick up 94.5 FM. Our cabin window’s facing away from the Owen Sound transmitter. What I have on hand (here in the bush)...

• coaxial cable. ~50 feet. BNC male coupling on one end, make cablevision-type male connector at other end.
• spools of speaker wire (for Shortwave pickup).
• duct tape, gorilla tape.
• rudimentary tools. No soldering iron.

I’ll do a google search too; however, I want to see whether my e-community have plans that worked! Thanks in advance, eh.

 

 

[mariushm]

Get some think solid core wire and bend it like it looks on these products, just guess the diameter as close as possible:

 

1byone Outdoor Radio Antenna, High Gain Omnidirectional FM Reception Antenna with Round Dipole Design- FM Antenna

https://www.amazon.com/dp/B01HE9R1HE/

 

Black stuff is insulator, and note the top circle is screwed directly to the metal bar on one end, the other is insulated.

 

 

Another design, potentially easy to fabricate by yourself:

ViewTV VT-FM20 Outdoor Omnidirectional DAB/FM Antenna - 80 Miles Range

https://www.amazon.com/dp/B075LK18P5/

 

the wires from coax get screws in that black stuff, the ends of the thick circle thingie.

 

Then you only need some coaxial cable or some cable that behaves the same way (some core inside, shielded by some mesh wire on the outside) ... 50 ohm coax would work fine, but I don't think you really *need* 50 ohm.

[Scheer]

In the past I've used speaker wire for an antenna. Run it straight up a wall, then split the two wires apart going opposite directions horizontally for about 6' on each of them. Then turn the radio onto the station you really want and snip off a few inches at a time from each side until it comes in clearly. Its hit or miss if it works due to the enviroment... but speaker wire is dirt cheap, worth a try.

 

You could do the math for the length of the leads... but its easier to just slap it up and cut away at it

 

[bob345]

if you want a simple antenna, just connect a wire roughly 30 inches or 75 cm long to the center pin. That should be adequate for a simple quarter wave antenna. Double those lengths for a half wave antenna and a bit more gain. FM signals tend to be pretty strong so it shouldn't take much unless you are in the middle of nowhere. If that's the case i would look into building a simple yagi antenna. Yagi's are highly directional so you need to know what direction your source is, but you wont get much better for a simple diy antenna when it come to gain. Lots of tutorials online on how to put one together. Also, dont worry about impedance too much, matching 50 ohms isn't super important if you are just using a receiver as there will never be any reflected power.

[Guest]

On 2018-07-23 at 4:17 PM, mariushm said:

Get some think solid core wire and bend it like it looks on these products, just guess the diameter as close as possible:

 

1byone Outdoor Radio Antenna, High Gain Omnidirectional FM Reception Antenna with Round Dipole Design- FM Antenna

https://www.amazon.com/dp/B01HE9R1HE/

 

Black stuff is insulator, and note the top circle is screwed directly to the metal bar on one end, the other is insulated.

 

 

Another design, potentially easy to fabricate by yourself:

ViewTV VT-FM20 Outdoor Omnidirectional DAB/FM Antenna - 80 Miles Range

https://www.amazon.com/dp/B075LK18P5/

 

the wires from coax get screws in that black stuff, the ends of the thick circle thingie.

 

Then you only need some coaxial cable or some cable that behaves the same way (some core inside, shielded by some mesh wire on the outside) ... 50 ohm coax would work fine, but I don't think you really *need* 50 ohm.

@mariushm ... I regret the late reply. My Grundig radio’s an odd beast. My FM port uses a BNC coupling & cable... my brother-in-law left a tangle of it. It might be 50 ohm cabling... who knows! Those images intrigue me. Thanks, eh.

On 2018-07-24 at 4:47 PM, Scheer said:

In the past I've used speaker wire for an antenna. Run it straight up a wall, then split the two wires apart going opposite directions horizontally for about 6' on each of them. Then turn the radio onto the station you really want and snip off a few inches at a time from each side until it comes in clearly. Its hit or miss if it works due to the enviroment... but speaker wire is dirt cheap, worth a try.

 

You could do the math for the length of the leads... but its easier to just slap it up and cut away at it

 

@Scheer ... I like it. Raw, cheap.

 

I’ll try the math (x cm ... t-junction ... y cm) approach first. Take apart one end of a coax cable... core soldered to y ... outer metal sheilding soldered to x cm). I’ve gathered there’s an equation one uses. Desired frequency range .... overall x + y length.

On 2018-07-24 at 10:01 PM, bob345 said:

if you want a simple antenna, just connect a wire roughly 30 inches or 75 cm long to the center pin. That should be adequate for a simple quarter wave antenna. Double those lengths for a half wave antenna and a bit more gain. FM signals tend to be pretty strong so it shouldn't take much unless you are in the middle of nowhere. If that's the case i would look into building a simple yagi antenna. Yagi's are highly directional so you need to know what direction your source is, but you wont get much better for a simple diy antenna when it come to gain. Lots of tutorials online on how to put one together. Also, dont worry about impedance too much, matching 50 ohms isn't super important if you are just using a receiver as there will never be any reflected power.

@bob345 ... Indeed, I’m in the hinterlands. Re: yagi. I already have one pointed at our nearest cell tower (so our Chinese-made über-bööster can give us more reliable LTE & G service).

If I understand your advice, I don’t have to ferret out 50ohm-rated cable. I’ll see what scraps I have.

75 cm wire (horizontal to horizon?) soldered to the Coaxial’s metal core, right? What about the metal cladding?

 

Thanks for ALL of your ideas, eh. Time to start kludging!