Antenna
Antenna
Post by Phaze91460 »
If you have a all band radio like the one Col is selling, What kind of antenna would you run. For 11 meter you have an antenna with a specific length which you tune physically to the correct length with an SWR meter.
With a radio that operated on so many frequency's, what antenna would you use or would you use several ? How would you tune them/it? How would you set them up if multiple?
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I would guess that SWR readings would differ per different band, how much I can't say.
If the difference in SWR,is minute I would think you could get away with it.
If the difference is in excess you may have to run a separate antenna for a different band.
This is all a guess.
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Post by bullet »
Post by PA629 »
True enough, but it's an option. You could always just go with a multi-band setup with paralleled half-wave dipoles connected to a common feed line. Or perhaps mono-band yagis interlaced on a single boom for 25, 15, and 10 meters. Lots of ways to go depending.......bullet wrote:A antenna tuner will work, but you lose alot of power. A number of antenna is the best way to go with the antenna tuner. You can get the best power output with the right antenna set up and the tuner can help on the extremes of the band. This is my 2 cents. I am no antenna expert, but this is what makes since to me. I guess we will both learn something.
Post by linx »
There are some that do require antenna tuners. Long wires/Balun's require antenna tuners as well. Antenna tuners will definatly throw you out of budget if your setting up a ham shack on a budget. A basic antenna tuner that will handle 100 watts of power is not a bad price, and some radios like most Kenwoods have built in automatic antenna tuners. When ya get into wattage, and want to run legal limit of power (1500 watts) then that's where the money starts to play a factor. A antenna tuner that will cover 1500 watts will cost as much, if not more, then the amplifier. So you're probably looking in the 600-700 dollar range for a good one, if not higher. If you plan on running a antenna tuner that requires a antenna tuner, I think the best thing is to buy the radio with it built in.
Also there are automatic antenna tuners and manual antenna tuners. Ya gotta be good to use a manual antenna tuner, and you gotta check your SWR's a dozen times to get it right for each band you plan to talk on.
Post by Punkin Head »
this is a link to a screwdriver antenna.
http://www.thescrewdriver.com/
Post by linx »
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Post by 231 »
Phaze to hopefully answer your questions in a nutshell, most Hams tune their antennas for resonant performance from the get go. There are a few designs that really aren't resonant on any band...but with a tuner still work very well. The Cobra Ultra-Lite Sr. is one of them that comes to mind. For me though, resonant antennas are what I prefer to run (for now). Their performance is fairly predictable and decent. I'm considering a Cushcraft multiband vertical...but verticals can be extremely noisy and expensive if bought new. With the homebew dipole designs I've built they are very quiet by comparison...and still perform as well (better I think) than a standard wire dipole.
As far as tuners go, nothing says a person has to buy a new tuner. Decent older tuners can be had cheap...and that is exactly what I did until someday I can afford a Palstar. Mine was a fraction of the cost of my amp, but loafs along at full limit...and it'll tune a door knob if I want! :D
So building a station can be done on the cheap, but it takes time and alot more energy to do it. Frankly, I've enjoyed building my own stuff when I can. I'm not overly skilled in alot of areas (including thing one) and there are tons of good guys willing to help.
I hope that helps some...and maybe adds a little to what has already been shared.
Post by DX_MONKEY »
I missed what radio the Col. is selling but we'll assume it's an HF rig.
Needed information is: Is the new owner going to use it base or mobile? Completely different antennas will be called for.
Here's a series of statements not necessarily in any order.
Practically all HF operations below CB (27mhz) is DX, or talking long distance. Fully resonant partial wavelength vertical antennas don't exist (typical homeowner) for the lower HF bands as they are too long. Here's an example. The good ol' 102" CB whip is a fully resonant partial wavelength vertical. Or in other words, a 1/4 wave ground plane. You can do a 1/4 GP on CB frequencies because it comes to only about 9 feet long (102"). That's a length that we can deal with even on a mobile. But a similar 1/4 vertical ground plane down on say 80 meters would be about 62 feet long or tall. Now you see one the problem. It is not easy to construct a 62 foot tall vertical antenna out in your yard!
Now go down further to the AM Broadcast band. Look at WSB 750 AM in Atlanta. A 1/4 wave vertical ground plane on 750khz becomes a whopping 312 feet tall !
234 / f mhz = 1/4 wavelength
So did ya'll realize that the towers you see up at AM radio stations ARE the antennas. It's not a tower with an antenna on top of it.....the tower IS the antenna and they are isolated from the ground by a large a large ceramic platform.
Back to ham. Most HF operations below CB are DX. Most DX signals twist and turn around in the atmosphere before coming back down. So it largely doesn't matter much with DX whether you transmit vertically or horizontally, you will frequently get the same results.
Horizontal beams have been the preference for hams. They're somewhat easier to handle and install. Practically all wire antennas are are put up horizontally because they end up being LONG to cover the LONG wavelengths of the lower HF bands....where most of the activity is.
There are several advantages to using wire for base antennas for the lower bands. The whole antenna is cheap to buy and easy to make and install. And because with just a typically sized yard and a tree or two for supports, you can put up a long enough wire for it to be resonant at some point and maybe even see some gain. Like a simple dipole. They are 1/2 wave, have some gain and are fully resonant for a frequency range they're made for so you do not need a tuner. A Loop is another type of wire antenna that has many resonant points on different bands, has some gain, and will not necessarily need a tuner.
It is always best if possible to use a resonant antenna for any operation. That's very easy to accomplish with CB because you've got only the 40 channels to cover. That's not very much bandwidth and any antenna, made for the CB range and properly constructed and working, will easily give you that 1:1 flat line match....no SWR.
So now you have a radio with all of the lower ham bands. What would be nice is ONE antenna that covers all of the bands and WORKS WELL too. That's where the problem comes in. There aren't too many choices. There is the off-center fed dipole type which is also known as a Carolina Windom and a.k.a. G5RV. There are variations in each but the 3 are about the same. This is a simple wire antenna that will tune up and work on all bands as long as you make to for the LOWEST band that you desire to transmit on. There is no antenna that will work EFFECTIVELY on a band is below the one it is make for. You will not get an antenna made for 40 meters at 7 mhz to work on 80 meters at 3.5 mhz. You MIGHT get such an antenna to "load up" on 80 by tricking the heck out of the electronic factors using an antenna tuner...but it won't work well or radiate much signal. The tuner is simply creating an electronic match for your radio's circuits to see.
The G5RV described above will have resonant points on all bands above the one it is made for. So if you put a long one that covers 80 meters, it will also work on 40, 20,15 and 10~11 also. But this type of antenna has no gain anywhere. It will work....but no gain. That's called a "compromise" antenna. You're compromising any gain in exchange for having ONE antenna that works on many different bands.
Another choice is the one I use and that is a horizontal Loop antenna. It is a simple piece of wire that goes out and comes back around. They can be made in any convenient shape. A square shape is usually chosen as it's not that hard to come up with 4 tie-off points in a yard. Loops are the only full-wave design I know of. Loops have gain above the bottom band or band that it's made for, and start increasing in gain as you increase in frequency. My loop is made for 80 meters so it works on 80,40,20,15,10~11 and even up on 6 meters at 50mhz. There is no gain on 80 meters but it still works very well even without any gain there. It has natural resonance points on all of these bands but......
....no multiband antenna like this is resonant all of the way across all of the band portions and will REQUIRE an antenna tuner to "spread out the ends" so you can cover the whole band.
Properly used, an antenna tuner is your friend. Practically every ham with a home station and who moves around and uses all of the bands has one. If antenna tuners were no good, then hams would not use them. Period. The only other alternative is to have a resonant antenna for every band. Well that is all fine and good but if you talk on 8 different bands then you are going to have to maybe 8 or even more different antennas, like dipoles, up in your trees. Few people have room for or even feel like messing with a separate antenna for every band. It's just too much stuff!
There is NO NOTICEABLE LOSS incurred in using an antenna tuner as long as you are correcting a MINOR mismatch to extend the range of a resonant antenna. Yes....if you "force" an antenna to work using a tuner onto a frequency that the antenna was not designed to work on, then a much greater portion of your signal will be "lost" as heat inside the tuner. But this is clearly not the purpose of an antenna tuner. So we're back to always trying to select an antenna that is resonant in the first place....one that is designed and made to suit your transmitting purposes.
Mobiles. Mobiles you're stuck pretty much with vertical types. For HF, all mobile antennas are tuned compromise antennas. Something is done, whether by winding a big coil, or using a tuner, to make up for all of that long length that the lower frequencies require. Some of these HF mobile antennas are simple like a Hamstick. They are cheap wire wound jobs looking like a CB Firestick, and tuned precisely for one band. So if you're on a long trip and want to talk on many different bands, then you're going to have to carry along one antenna for each band and stop and change it out every time you want to go do a different band. And even these single-band antennas will not cover an entire ham band any more than base antennas will.....so you may have to have a ant. tuner in the vehicle to "extend the range" of the antenna's bandwidth ends to be able to use the whole band and not just one little piece of it.
Then there are the mechanically tunable types like the screwdrivers and such. They are still shortened-compromise antennas, they just have a built-in mechanical~electrical tuning device so you can hit a switch in the vehicle and change bands without stopping and getting out and doing anything to the antenna to change frequencies. These antennas work but are expensive due to all of the extra parts and features.
So there are many choices out there for multiband operation. It's worth investigating them all and just go with what you operating needs REALLY are versus the thickness of your wallet and how much you are willing to spend on stuff.
We can count our blessings that CB is in the HF spectrum where it is. Where are near the top of the HF area. A 1/4 wavelength is only 102" at our band so we can easily make good working and resonant antennas with gain. We got lucky there.
Sorry for going on so long. Hope some of this helps!!!
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Post by preacherman »
that is adjustable by band...you move a external wire to various taps
and you use your auto-tuner within the band. The real purpose of
tuners is twofold...you can improve your recieve...just try listening
to short wave through a tuner and then play with the settings and
you can get the load to where the transmitter is happier...but you
won't increase the ability to transmit...you'll just shunt off the extra power
into the tuner.
preacherman
Post by DX_MONKEY »
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Post by 80 meter man »
Thanks to 22-0 for license plate art work
EM²
Fear the spinning Fish!!!
II Chronicles chapter 7 vs. 14
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Post by Circuit Breaker »
Post by Jester »
Secondly, I'd recommend a tuner. The MFJ 949 is tops in the ham game, and both this tuner AND the G5RV will work for 11 meters. Most antenna tuners and their respective antennas can be tuned for just about anything from 160 (in most cases, 80 in nearly all cases) to 10 with no problems. Ive had a 949 for a few years now and I can recommend it without any hesitation.
Ham radio is a LOT of fun. Despite what the old farts say, you can have your cake and eat it too- play CB AND amateur radio. I do it all the time without any problems. Getting your tech license is easy, and I recommend any die-hard radio fan to check it out!
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Post by Night Crawler »
for less than $50 and it will cover 80 thru 10 meters.
www.njqrp.org/n2cxantennas/halfer/index.html
www.wr6wr.com/newSite/article ... wp899.html
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