Antenna Questions from a Noob: Scanner and CB

[Nagant]

I'm just starting to get into radio gear as part of my survival plans. Currently I only have a Radio Shack Pro-94 scanner which I programmed with police, fire, ems, road crews, and a few others for my entire tri-county area. Right now I am probably getting at least 15 miles on it using the rubber duck antenna, but I want to increase my range.

I have been looking into various homebuilt antennas, ranging from 1/2 wavelength vertical dipoles, 1/4 wavelength ground planes, and J-poles. All of these seem to require the antenna to be tuned for a particular frequency. The problem being is that I listen to a wide range of frequencies, so is there a multi frequency antenna I can build to accomodate this? What style works best with scanners? Dipoles, Ground planes? J-Poles?

Additionally, I will also be adding a CB radio as well. Tuning the antenna is not my concern here, but rather, what style seems to work the best? Dipoles? Ground planes? J-poles? I am a little tight on money, so I would rather have this be a homebuilt project so I can save some cash.

I plan to mount the antenna(s) to my house, because it is at least 30 feet high (old Victorian style from the 1880s). I would like to hide the antennas, so could they be placed in the attic and not have their performance impeded?

Thanks for putting up with a radio noob!

[crypto]

tuned antennas are mainly for transmitting, you can use pretty much any really long wire for a receive-only antenna. Just get a BNC connector to attach to your scanner and solder a really long piece of wire to the center conductor, and you're set.

Most EMS/fire/police radios are either VHF (1xx MHz) or UHF (4xx MHz) with the exception of some state patrols that use HF radios.

Making a serious CB antenna is a pain in the ass, because 11m is so big. A J-pole would have to be 25 feet tall. Most people ( I think) make a folded dipole for 10 and 11-meter, but I dont know. Since a lot of CB operators aren't the most technical people in the world, you may find you have better luck adjusting 10m amateur designs to 11m dimensions.

[thelight]

Although I do not have direct experience with wide band receive antennas (aside from a rubber duck on a cheap scanner), I had read in numerous places that a discone antenna works well for fixed scanner operation. Invest in a quality feed line to ensure minimal noise gain from that. After all, a feed line is just a shielded antenna.

As for your CB, I would be a bit more worried. If you do not have a proper antenna you can fry the amplifier in your CB. If you are looking to design your own antenna to save some money you should pick up any of these books from the ARRL. Check out this site for some very useful info on CB antennas.

Also, start studying for your amateur radio license! It will give you great amounts of flexibility.

73's
-D

[rpc]

As others have pointed out, tuning the antenna is not particularly important for receiving. The most important factor for VHF and UHF is the height of the antenna above the nearby terrain. If you simply took the scanner to your roof, along with the rubber antenna, this would give much better reception that having the scanner and antenna in the basement. But since that's generally impractical, the next best way is to put something on the roof.

They're not used too often, but I think the discone antenna would be very good for transmitting, since it served as a tuned antenna for many different frequencies. While it would probably give you some advantage for receiving, it's probably not worth the bother.

I'm a ham, and what I use for transmitting on 2 meters is very simple. I have a PVC mast, which I use mostly to hold up my HF antennas. Pretty much as an afterthought, I wanted to put up something for 2 meter FM. What I did is simply run a piece of coaxial cable to the top. At the top, I unzipped it, so that the braid runs 19 inches in one direction, and the center conductor runs 19 inches in the other direction. I'm sure a "real" antenna would be somewhat more efficient, but this serves my needs. I use it for transmitting on 2 meters, 220 MHz, and 432 MHz, and for receiving on many VHF and UHF frequencies. Since the height is the most critical factor, it does a very good job.

Almost everything you will want to listen to on VHF is vertically polarized--that is, the transmitting antennas are vertical. Therefore, you should also orient this type of antenna vertically. In my case, I simply taped it to the PVC mast.

If you want to tweak it for best reception on one particular frequency, then use the formual 234/F, where F is the frequency in MHz, which will give you the length in feet. In my case, I wanted it to work best on 146 MHz, which gave me 1.6 feet, or 19 inches, which is the length of each leg. But again, for receiving, the length is not critical. Just get it up as high as possible, and as far away as possible from metal objects. If you have an attic, such an antenna inside the attic usually performs well.

[Nagant]

My next question concerns the type of CB and the SWR meter. Looking through Radio Shack and Walmart, CBs run from $30 to $160, and SWR meters are up to $50. In terms of cost effectiveness, I could buy a lower end CB for $30-$60 and the SWR meter for a total of $80 to $110. Or else, I could buy a Cobra Model 29 WX NW ST for $99 at Walmart, which has an SWR meter built in. Would it be advisable to keep the two units seperate or together? With all things being equal, what would the difference in performance be, let's say, between a low end CB like a Midland Compact:

http://www.radioshack.com/product/index ... age=family

or a higher end Cobra model 29 or similiar style?

[crypto]

I'd get a separate SWR meter, so when you get a amateur license you can use it on ham antennae too. I wouldn't pay $30 for one though, specially not your first one. Check google for when the next ham radio swap meet is in your area and pick up a used SWR for $5 like I did, they're all over the place.

The high-end CB's usually have some stuff that the lower-end units dont, but it's mostly audio tuning and effects. Truckers like to have an echo on their voice, or tone control for the mic, or use a compressor/limiter to make them sound louder on the radio. If you need to sound like a big dude when you yell BREAKER BREAKER ONE NINE then you'll need the Cobra or another unit covered in chrome and knobs. The only feature I've ever seen on these units that interested me was SSB operation, but in order to use a side-band you'd have to have another CB radio that did it, and be talking to someone who wanted to switch over to it.

Now, here are the things you REALLY should look for:

5-watt Output
Built in wx (weather band) reception

If you're going to use it on a vehicle, having an emergency traffic alert band on it can be nice, it will alert you to hazardous traffic conditions near you.
Having a built-in SWR can be useful if you're using it in a vehicle, because it lets you see if your antenna/feed line has been damaged due to the elements, and your RF isn't making it into the antenna. Thats definitely a convenience item though, and I wouldn't lose any sleep over it.