ky5u
04-24-2008, 06:20 PM
There are many antenna experst on QRZ.COM I am sure, but if you're a newbee, perhaps this will answer a few questions.
Best and most simple antenna for a newbee
Dipole and a tuner rated at the power of your transceiver. If you have a built in tuner, then you're ok unless your antenna dimensions are WAY off. If your dipole is cut to the frequency you plan to use, within 2:1 SWR either side of that center frequency you probably don't need a tuner.
Disclaimer: Yadda yadda, yeah the experts never need a tuner, yadda yadda, this that and the other. This advise is for the newbee who isn't an expert like you.
Antenna basics
The most basic thing about antennas is that for every desired frequency there are two (yadda yadda yes there are many more) important components. There is resonance and there is impedence. Many newbees want shorter antennas to use on 80M and above. When you cut these antennas for resonance, the impedence often is not 50 ohms. Short verticals tend to have an impedence in the neighborhood of 12 ohms. Most noobs would slap a tuner at the transceiver end and tune away.
Just be advised thet a 4:1 balun can be used to bring thei impedence to close to 50 ohms. On longwires the impedence can be 200 ohms or better. A 4:1 balun can be used on a vertical to bring the 12 ohms to near 50ohms or the 200 ohms down to 50 ohms. Just reverse the direction of the balun/unun.
Also be advised that on a vertical you can use something called a UNUN instead of a Balun. Here's a review I did for eHam on one type of (http://www.eham.net/reviews/detail/6765?cookietest=1) UNUN. I am in no way associated with the company mentioned. A vertical is an unbalanced antenna and your 50 ohm coax is umbalanced. So a UNUN is a UNbalanced to UNbalanced match.
With a 50 ohm match at the antenna, your 50 ohm cable will deliver full power to a resonant antenna and no tuner is needed. You'll love the results.
Hocus Pocus Antennas
Be wary of hocus pocus antennas. While a G5RV will work pretty good, you really can do better with a simple dipole. If a G5RV is all you can find then use it. I use an ISOTRON-80 antenna in my attic and it works for the limited use I need. As an overall antenna it is hocus pocus.
Beware of the "no ground radials needed" antennas that are not top fed/loaded. A Hustler vertical, or a Hy-Gain vertical can be mounted on an MFJ 2' by 2' mounting plate and the radial length is drastically reduced (25' for 80M). The $400 Comet vertical is basically a dummy load with a radiating mast on it. Yes it works but a dipole would work better.
Before you invest in magical antennas, get the ARRL antenna book and bone up on theory. Until you do, stick to a dipole or a simple vertical. Store bought GAP antennas work well off the shelf.
Disclaimer: Yadda yadda, your Poopsie Plane Vertical voo doo antenna works great...yadda yadda G5RV's are the bomb....yadda yadda. This again is trying to simplify things for the noob.
Don't be confused by voo doo and marketing. Until you learn about antennas, keep it simple. String up the wire dipole you can get away with, run it through a tuner, and look at it on an MFJ antenna tester. Adding or subtracting a little wire may get you resonant where you need to be on the band you need. Or, stick up 18' of aluminum radiating mast series fed (with a tap) through an open coil of 24 turns at the base of the antenna (see the MFJ 18AVS) and it will resonate on 80-10M. Mount it on a 2X2 plate and string 10 each 25' radials and feed it through a UNUN and you'll be AMAZED at the performance all for about 200 bucks no tuner needed. Remember.... resonance and impedence.
Every Ham thinks his antenna is the bomb. I complement them on pride of ownership, but for a newbee who is unshcooled in antennas, you can waste ALOT of money fast. Now let's sit back and watch the experts comment.... :rolleyes:
Best and most simple antenna for a newbee
Dipole and a tuner rated at the power of your transceiver. If you have a built in tuner, then you're ok unless your antenna dimensions are WAY off. If your dipole is cut to the frequency you plan to use, within 2:1 SWR either side of that center frequency you probably don't need a tuner.
Disclaimer: Yadda yadda, yeah the experts never need a tuner, yadda yadda, this that and the other. This advise is for the newbee who isn't an expert like you.
Antenna basics
The most basic thing about antennas is that for every desired frequency there are two (yadda yadda yes there are many more) important components. There is resonance and there is impedence. Many newbees want shorter antennas to use on 80M and above. When you cut these antennas for resonance, the impedence often is not 50 ohms. Short verticals tend to have an impedence in the neighborhood of 12 ohms. Most noobs would slap a tuner at the transceiver end and tune away.
Just be advised thet a 4:1 balun can be used to bring thei impedence to close to 50 ohms. On longwires the impedence can be 200 ohms or better. A 4:1 balun can be used on a vertical to bring the 12 ohms to near 50ohms or the 200 ohms down to 50 ohms. Just reverse the direction of the balun/unun.
Also be advised that on a vertical you can use something called a UNUN instead of a Balun. Here's a review I did for eHam on one type of (http://www.eham.net/reviews/detail/6765?cookietest=1) UNUN. I am in no way associated with the company mentioned. A vertical is an unbalanced antenna and your 50 ohm coax is umbalanced. So a UNUN is a UNbalanced to UNbalanced match.
With a 50 ohm match at the antenna, your 50 ohm cable will deliver full power to a resonant antenna and no tuner is needed. You'll love the results.
Hocus Pocus Antennas
Be wary of hocus pocus antennas. While a G5RV will work pretty good, you really can do better with a simple dipole. If a G5RV is all you can find then use it. I use an ISOTRON-80 antenna in my attic and it works for the limited use I need. As an overall antenna it is hocus pocus.
Beware of the "no ground radials needed" antennas that are not top fed/loaded. A Hustler vertical, or a Hy-Gain vertical can be mounted on an MFJ 2' by 2' mounting plate and the radial length is drastically reduced (25' for 80M). The $400 Comet vertical is basically a dummy load with a radiating mast on it. Yes it works but a dipole would work better.
Before you invest in magical antennas, get the ARRL antenna book and bone up on theory. Until you do, stick to a dipole or a simple vertical. Store bought GAP antennas work well off the shelf.
Disclaimer: Yadda yadda, your Poopsie Plane Vertical voo doo antenna works great...yadda yadda G5RV's are the bomb....yadda yadda. This again is trying to simplify things for the noob.
Don't be confused by voo doo and marketing. Until you learn about antennas, keep it simple. String up the wire dipole you can get away with, run it through a tuner, and look at it on an MFJ antenna tester. Adding or subtracting a little wire may get you resonant where you need to be on the band you need. Or, stick up 18' of aluminum radiating mast series fed (with a tap) through an open coil of 24 turns at the base of the antenna (see the MFJ 18AVS) and it will resonate on 80-10M. Mount it on a 2X2 plate and string 10 each 25' radials and feed it through a UNUN and you'll be AMAZED at the performance all for about 200 bucks no tuner needed. Remember.... resonance and impedence.
Every Ham thinks his antenna is the bomb. I complement them on pride of ownership, but for a newbee who is unshcooled in antennas, you can waste ALOT of money fast. Now let's sit back and watch the experts comment.... :rolleyes: