CB antenna help

[Warpt762x39]

I'm trying to find an antenna for my Radioshack handheld CB radio. I have an external magnet mount antenna to use but it's not exactly portable.

My CB doesn't have the BNC mount it has the older 3/8"x24 female thread mount. The only website I have found (wearecb.com) that sells them doesn't take my credit card from my credit union.

Anybody know of any websites that sell that style antenna? I don't want a 102" whip antenna as that would be less portable than the one I have.

I'm just looking for a black rubber antenna. Simple, cheap and with the 3/8"x24 threads on it.

If not, is there anywhere I can get an adapter to use a BNC antenna with the threaded mount on mine?

Any help would be great as I'd like to get this CB up and running soon.

[Vig]

I'm trying to find an antenna for my Radioshack handheld CB radio. I have an external magnet mount antenna to use but it's not exactly portable.

My CB doesn't have the BNC mount it has the older 3/8"x24 female thread mount. The only website I have found (wearecb.com) that sells them doesn't take my credit card from my credit union.

Anybody know of any websites that sell that style antenna? I don't want a 102" whip antenna as that would be less portable than the one I have.

I'm just looking for a black rubber antenna. Simple, cheap and with the 3/8"x24 threads on it.

If not, is there anywhere I can get an adapter to use a BNC antenna with the threaded mount on mine?

Any help would be great as I'd like to get this CB up and running soon.

I'll take some pics of the CB antenna I have downstairs. I think it matches your requirements, and if so, you can just have the thing.

[Snert]

Try here..


www.scannerworld.com

Snert..

[Exbiker]

The problem is if it`s a full power CB and you don`t get the SWR`s close you could burn out the finals in the set.

[Warpt762x39]

The problem is if it`s a full power CB and you don`t get the SWR`s close you could burn out the finals in the set.

Even if it blows itself into tiny pieces, I'm only out $1.25

It's just a start to my SHTF communications gear. I have an old Cobra handheld that is the size of a pretty good size hardback book but it's somewhere in storage.

I found a decent handheld on Amazon for $31.

http://www.amazon.com/Midland-75-785...777210&sr=1-68

If I can get the one I have right now working it would be great. It's a decent radio it's just missing an antenna and the power cables. I just run it on the 10 AA batteries right now. I'll find some rechargeable ones to keep with it. But it works for now.

[PA Rifleman]

...

My CB doesn't have the BNC mount it has the older 3/8"x24 female thread mount. The only website I have found (wearecb.com) that sells them doesn't take my credit card from my credit union.

3/8x24? That's usually the antenna stalk thread on an antenna mount, not the chassis connector. Is this what you have?

SO-239 (chassis) connector


PL-259 coaxial cable connector
If so, it's called an SO-239.

Anybody know of any websites that sell that style antenna? I don't want a 102" whip antenna as that would be less portable than the one I have.

I'm just looking for a black rubber antenna. Simple, cheap and with the 3/8"x24 threads on it.

I'm unclear on a point...does your radio have a connector on the back, or a pigtail lead that connects directly to the antenna?

Or is this discussion about an antenna mount?

If the connector on your antenna feedline (coax) is different from the connector on your radio, you have two basic options:

1. Purchase an adapter. This will add a little feedline loss, but at 5 watts @ 27 MHz max, this will likely be negligible. It will add a potential disconnect point if it loosens over time.
2. (my choice) Replace the connector on the feedline to match your radio. Obviously you'll need to positively identify the connector on your radio first.

If not, is there anywhere I can get an adapter to use a BNC antenna with the threaded mount on mine?

Another option: get the antenna and mount you want, and switch the connector on the back of the radio to match the antenna. As long as everything's 50 ohms impedance, it won't care. Coaxial cable is available pre-cut with PL-259 connectors if you don't have the tools to install your own conenctors.

Also, do you have some means of measuring standing wave ratio (SWR), or return loss?

Am I the only person that noticed this?
http://www.wearecb.com/products/antenna/cb_antennas.htm

The coil is where the signal comes from.

If you look at all CB antennas, you will notice a tight coil of wire somewhere on them. The location of this coil is important because this is where the signal radiates from. When the coil is higher up, the angle of radiation is lower, and the signal will travel farther. So a top loaded antenna will preform better than a center loaded antenna, and a center loaded antenna will preform better than a top loaded antenna.

I don't think so, chief. Toploading = capacitive loading, not inductive. Inductive is best bottom-loaded, sometimes center-loaded

Oh wait, he's talking about "preform" antennas. I though they meant perform. Silly me.

...
It's just a start to my SHTF communications gear. I have an old Cobra handheld that is the size of a pretty good size hardback book but it's somewhere in storage....

Kudos to you, someone finally realizes the need for commo!

[ehidle]

Electrically short antennas are capacitive, so a coil will move their impedance closer to the origin on a smith chart, but the radiation pattern still won't be that great.

The radiation pattern of an antenna depends on the currents in the wire (it's basically the 3D spatial fourier transform of the surface current). A capacitance hat, as they're called, allows for a more uniform current distribution on an electrically short antenna.

Taking the same antenna wavelength, it is always better to top load than to base load. It'll still be necessary to tune the antenna, because any loaded antenna will have a narrower bandwidth and probably not be wide enough to cover the entire band. The more an antenna is loaded, i.e. the larger the equivalent lumped elements are, the higher the Q and narrower the bandwidth.

You want all of your energy radiated and none of it stored, but as soon as you make your antenna reactive (by making it too long or too short) and compensate with another reactive component to cancel, you've just made a series resonant circuit that will store energy instead of radiating it.

Anyhoo, I forget where I was going with this... oh yeah... rubber duckie CB antennae. I've never seen a Radioshack handheld CB with anything other than a BNC connector on it. What model do you have? SO-239s are usually reserved for higher power and/or higher frequency applications that use some kind of coax transmission line (like RG8/9 or RG58/9).

I have, however, seen a PL-259 to BNC adapter that will screw into an SO-239, which would allow you to use any common BNC rubber ducky antenna - and not worry about all this malarkey about loading...

[Warpt762x39]

The top of my CB has the FEMALE side of the 3/8x24 mount. It's not BNC and it doesn't have serrations in it like the one showed above. I tried taking a pic but it won't come out.

The SIDE of my CB has an input for an external antenna. It has the plug that looks like an RCA jack.

I have a seperate antenna that you would mount to a CB in your truck that plugs into the side. I need one that goes right on top of the CB that mounts directly to the CB.

The mount looks like a bolt would go right in. The bottom of the hole is solid. No serrations. No plugs. Nothing. Just a flat solid bottom.

This is the kind of antenna that will fit. I can't order from the site it's on because they don't take credit cards from my credit union.

[PA Rifleman]

The top of my CB has the FEMALE side of the 3/8x24 mount. It's not BNC and it doesn't have serrations in it like the one showed above. I tried taking a pic but it won't come out.

The SIDE of my CB has an input for an external antenna. It has the plug that looks like an RCA jack.
...

I must be dense today.

No problem, you need to go to Radio Shack (link) and order a replacement antenna. Model number, please?

Example:



Radio Shack still sells several CB walkie-talkie models (example) that appear to have the 3/8x24 antenna mount. If true, order an antenna for one of these newer models. All that matters is the impedance matches (50 ohms)

If you find a RCA-to-SO239 adapter for the side antenna port, you can use external antennas. In the case of hiking, this means attaching a larger, more efficient antenna to your pack frame. The result is more range with the same input power.


SO-239 to RCA adapter

[Warpt762x39]

I must be dense today.

No problem, you need to go to Radio Shack (link) and order a replacement antenna. Model number, please?

Example:



Radio Shack still sells several CB walkie-talkie models (example) that appear to have the 3/8x24 antenna mount. If true, order an antenna for one of these newer models. All that matters is the impedance matches (50 ohms)

If you find a RCA-to-SO239 adapter for the side antenna port, you can use external antennas. In the case of hiking, this means attaching a larger, more efficient antenna to your pack frame. The result is more range with the same input power.


SO-239 to RCA adapter

I've checked the website. I can't find the model I have one there. The model number is TRC-225.

All the handhelds I have found on the site and in the store all have BNC mounts for the antenna.

I do have the adapter for the RCA plug in the side. It's how I have my magnet mount antenna plugged in.