CB radio antenna

[jrose]

Ok its been a long time since I took a HAM radio class. But CB is the 11meter band right? I wonder if anyone has pics and a brief rundown of some simple antennae they have made.I have done some reading about 1/4 wave setups but is loading an antenna a bad idea or useless? I have a SWR meter and have been experimenting. My next question (understanding the regulations of output power) how can a person make an amplifier or booster of low wattage.

[Terryl]

Yes 11 meters is CB band.

11811 divided by the frequency in megahertz (example, 27.405) will give you a full wavelength in inches, divide that by 12 and you have it in feet. Divide that by 2 and you have a 1/2 wave length, a half wave length dipole is the best to start with.

And you can't use an external RF power amp on CB frequencies; you’re stuck with 4 watts.

However there are ways to get more ERP (Effective Radiated Power) then a ½ wave antenna and that is to use a 5/8 wave dipole, (about +3 dB) or a multi element beam antenna, the more elements the higher the gain (over a dipole), a 4 element beam will give you about 5 dB, a 7 element will give you about 11 dB.

So theoretically 4 watts (RF output of the transmitter) = 36 dBm, add 11 dB (antenna gain) to that and your ERP is about 40 watts, (46 dBm) and all that power is going one direction not like an omni directional antenna like a dipole.

Actually your not going to get 40 watts as there is loss in the coax, so using the best coax you can (RG-9914) will cut down on this loss.

[jrose]

RG9914? ok I will look into that. Yah the math part makes sense, Im kinda restricted by height but will fine tune something. Yah your right amplifiers are like binfiles...thats bad!

[Terryl]

Look into making a "J" pole antenna, it makes a "J" bend at the bottom and can save some room, you can make it out of 1/2 inch copper pipe.

Here is a good place to start.


http://www.dxzone.com/catalog/Antennas/J-Pole/

[publicraven]

I made my 11 elemenet beam out of Stainless, and a free Gamma Match from CUshcraft, works great aswell..

[brotherstores]

Yes 11 meters is CB band.

11811 divided by the frequency in megahertz (example, 27.405) will give you a full wavelength in inches, divide that by 12 and you have it in feet. Divide that by 2 and you have a 1/2 wave length, a half wave length dipole is the best to start with.

And you can't use an external RF power amp on CB frequencies; you’re stuck with 4 watts.

However there are ways to get more ERP (Effective Radiated Power) then a ½ wave antenna and that is to use a 5/8 wave dipole, (about +3 dB) or a multi element beam antenna, the more elements the higher the gain (over a dipole), a 4 element beam will give you about 5 dB, a 7 element will give you about 11 dB.

So theoretically 4 watts (RF output of the transmitter) = 36 dBm, add 11 dB (antenna gain) to that and your ERP is about 40 watts, (46 dBm) and all that power is going one direction not like an omni directional antenna like a dipole.

Actually your not going to get 40 watts as there is loss in the coax, so using the best coax you can (RG-9914) will cut down on this loss.

eh?

Can't use as in they are not available or illegal?

[Terryl]

Illegal as all heck here in the States for use on chicken band, and all the HF amps for Ham radio have to be modified by the end user (a Ham) for 10 meters as they (the manufactures) can't sell them setup for that band. (it's too easy to down tune them to CB freq's)


All the CB amp's out there now are made illegally and sold on the black market (sometimes E-bay) most of the Ham amps take a minimum of 50 watts to drive them, that's so you cant use them directly with a CB radio.

[Terryl]

This is a link to the biggest beam antenna for 11 meters, it's a big one.


http://kollmanradio.com/maco-shooting-star-switchable-element-beam-p-6637.html

[brotherstores]

Illegal as all heck here in the States for use on chicken band, and all the HF amps for Ham radio have to be modified by the end user (a Ham) for 10 meters as they (the manufactures) can't sell them setup for that band. (it's too easy to down tune them to CB freq's)


All the CB amp's out there now are made illegally and sold on the black market (sometimes E-bay) most of the Ham amps take a minimum of 50 watts to drive them, that's so you cant use them directly with a CB radio.

huh....

I guess it has been a while since I was into that hobby.

My father used to have a 200W amp for the base station, and a 50W mobile. Too bad all of that stuff got sold at his estate auction after his death....might be worth something now.

I can remember talking to folks in South Africa on SSB using that 200W amp, our beams, and a good night of skip.

[publicraven]

I was a night/dusk skiper long ago... I had a Uniden Hr2510 opened up with a Tri-star push pull 250 amp so I could drive my Sig down to the US boys.. was a great time when the skip was good, and mad alot of contacts.. I have a Hf rig here now that hardly ever gets turned on, and my 2m aswell...most have gone to the way side..shame..

[brotherstores]

I was a night/dusk skiper long ago... I had a Uniden Hr2510 opened up with a Tri-star push pull 250 amp so I could drive my Sig down to the US boys.. was a great time when the skip was good, and mad alot of contacts.. I have a Hf rig here now that hardly ever gets turned on, and my 2m aswell...most have gone to the way side..shame..

That name rings a bell.....was the case anodized blue aluminum? Wouldn't happen to have a picture would ya?

[publicraven]

Negitive, no pics left...packed away somewhere..lol where ever the boss put it...I think it was a black case, and some loud relay's when you keyed the mic you could hear the click, and hummmmm...lol

[grub]

I was a night/dusk skiper long ago... I had a Uniden Hr2510 opened up with a Tri-star push pull 250 amp so I could drive my Sig down to the US boys.. was a great time when the skip was good, and mad alot of contacts.. I have a Hf rig here now that hardly ever gets turned on, and my 2m aswell...most have gone to the way side..shame..

Those were certainly the good old days.
I can still remember my first contact with Cuba, South Africa, East and West Germany and Russia, but my most valuable was with china and japan using a Relastic ssb radio 100w huricane amp and antron 99 omni ant. transmitting from Montego bay jamaica.

Still have all of those qsl cards

[rickw]

Ahh,,,QSL cards..I remember them well..Mine had the RCA logo,, with the dog peeing into the horn..His collar had "skip" printed on it and the caption underneath read "10-9?? You were drowned out by skip"...:sun:

[nor]

huh....

I guess it has been a while since I was into that hobby.

My father used to have a 200W amp for the base station, and a 50W mobile. Too bad all of that stuff got sold at his estate auction after his death....might be worth something now.

I can remember talking to folks in South Africa on SSB using that 200W amp, our beams, and a good night of skip. Hope your father had a ham licence if he used that much power.

[RONSAT]

Thanks for keeping CB legal.

[Nostradamus]

Hope your father had a ham licence if he used that much power.

hell that was baby stuff, I had 500 on the base and 250 mobile and never hadd a ham ticket, had a ham transmitter though;)