A reader’s question
I wanted to post a readers CB antenna question and my response. So here goes…
“I have my 70cm/2m Diamond antenna on my roof for my TYT 9800 and it works great, but I want to string a separate CB/SSB field antenna up into the very large trees in my yard to get the best reception I can get.
I live on a hill, 600ft MSL but between me and the closest city. 15-20 miles away is a hill that is 760ft MSL. I have “cobra heads” and resistors, 50’ of 12GA Solid copper clad PE jacketed wire and a 42’ Beldon 8340 50 Ohm RG-58/U BNC Male to UHF male PL259 cable.
Using these items (and others if I need to get them) what is the best field antenna I can construct that will give me the best utilization of my Uniden Bearcat 980SSB CB radio, (4 watt CB/ 12 Watt SSB) ? vertical end fed? vertical dipole , ?? 1/4 wave, 1/2 wave, ?? Any input would be appreciated. Thank you!”
Sorry for delay, I just wanted to go back through and re-think every thing.
Goals in mind: Minimal kit, easy to field deploy, easy to repair, highly configurable.
Frankly, it’s going to be hard to beat the resonant horizontal dipole or Jungle Antenna depending on how you are able to string it up. Also it can give you some directionality if you bring the dipole ends into a sloping V towards the direction you want to transmit and receive. See here for an example.
Either cut it for CB channel 18/19 (middle of the frequencies 8′, 7.3″) or channel 38 (middle of SSB, 8′ 6.6″) but as you see there is only 1-2″ difference so anywhere in there is good enough.
Height of Antenna
With it being 11 meter, you’ll get some ionosphere bounce (sky wave) as well. Internet searches seem to be all over on horizontal or vertical for best skip, etc., so real life testing is in order. A rule of thumb is, the higher the antenna ( > 1 wavelength or 18′) the better it is for a lower take off angle to the horizon, so potentially longer skips.
Making the antenna closer to the ground ( < 1 wavelength or 18′) sends take off angle very high, so shorter skips. Also a chance of loosing a lot of signal from the maximum useable frequency (MUF) depending on the season, time of day, and the displeasure of the signal gods. An option if you want to limit distance.
What about the Half-wave End Fed Antenna?
I looked again, and the Half-wave End Fed Antenna will need a 9:1 UNUN at the antenna to get it matched to the coax for best performance. A bit more equipment but easier to deploy as the coax is at the bottom (versus a vertical dipole where the coax will have to come out the side for 10-20 feet for best performance). I think performance will be a bit less than the dipole, but I doubt you be able to notice without test equipment.
Horizontal and Vertical Polarization
Another consideration is horizontal vs vertical polarization. If you want to have more of a “private conversation” (whatever that means with radio) then I think most CB antennas are in a vertical placement, so they won’t pick up the signal as well from a horizontally aligned antenna. The remote stations in your group will need to be setup the same way. I would also use SSB since you have that capability.
However, if you wanted to talk people outside your group, then the end-fed antenna would be the easiest to deploy, then the Jungle Antenna has the most flexibility (can be dipole, directional sloping dipole, or a jungle antenna). Much harder to rig a vertical dipole with the coax coming out the side.
The Best Antenna
Just remember, the best antenna is the one that works.
Here’s some inspiration for a field antenna kit: http://www.n6cc.com/field-antenna-kit/.
Here’s a low power portable 9:1 UNUN for a Half-Wave End-Fed Antenna that might interest you: https://qrpguys.com/qrpguys-end-fed-wire-antenna
I do have antenna parts and accessories at my shop and are adding more all the time.
Hope this helps!
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