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Author Topic: looking for a good antenna  (Read 482 times)
RI126
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Posts: 9




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« on: January 12, 2005, 07:57:13 AM »

I am looking for a good antenna that will cover 26-30 mhz. I don't have room for a beam so it must be vertical. I am looking at SOLARCON I-MAX 2000, What do you think
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WB2WIK
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Posts: 20542




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« Reply #1 on: January 12, 2005, 10:07:54 AM »

It's a very popular, well-selling, extremely inexpensive (available for $39 retail) antenna.   It's just not a very good one.  Technically, a crappy design.

WB2WIK/6



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DROLLTROLL
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Posts: 265




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« Reply #2 on: January 12, 2005, 11:54:47 AM »

I don't understand Steve's answer? A bumblebee is also a "technically crappy design", engineers are still trying to explain how it flies.

Does the antenna radiate well but has poor materials or construction? Does it not radiate well? High angle? Poor/no gain? Lossy? Dummy load?
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WB2WIK
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« Reply #3 on: January 12, 2005, 03:07:21 PM »

Crappy design in many ways.

Lightweight, very thin wall fibreglas won't survive winter storms in many environments.

The radiator is a single piece of solid hookup wire inside the tubing: There's room for something far more substantial, but hookup wire it is!

The matching section at the base of the antenna is the same hookup wire plus a fixed value capacitor.  The wire is air wound on a very small diameter and is pretty lossy, I was able to get one so hot it melted the soldered connection by applying 150W or so (FM) for a few minutes.

There is zero attempt at decoupling the line from the antenna, as is required for an end-fed half-wave.  As a result, in most installations, the outer conductor of the coax line becomes part of the antenna.  Might actually help in some cases, but usually it won't.  The supporting pipe or mast also becomes part of the antenna for the same reason, so performance varies with the length and material of the supporting mast.

WB2WIK/6
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RI126
Member

Posts: 9




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« Reply #4 on: January 12, 2005, 08:27:44 PM »

so can anybody recommend a good fairly inexpensive antenna.Like I stated earlier it has to be a vertical antenna and able to go from 26-30 mhz. I live in Virginia so the weather is not so bad. I appreciate all the tech. stuff I am learning, but you need to keep it simple for me I am new at this hobby
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WB2WIK
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Posts: 20542




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« Reply #5 on: January 13, 2005, 02:16:39 PM »

The "26-30 MHz" requirement makes it a bit tougher, as broadband antennas are always a compromise.  A 10m vertical antenna only needs to cover 28-29.7 MHz, and since you really only *need* a vertical for FM work, and FM is only authorized above 29 MHz, a *GOOD* vertical for 10m really only needs to cover 29.0-29.7 MHz.  That makes for a MUCH better antenna!

Why the "26-30 MHz" requirement?  Trying to use the same antenna for CB and 10m?  If so, don't be embarrassed -- it just makes it tougher to find a decent antenna, if you need it to work across such a broad piece of spectrum without re-tuning as you change frequency.

One good, fairly broadband and very high-performance vertical antenna with more than normal bandwidth is the folded element ground plane.  This uses a folded monopole radiator to achieve better bandwidth, along with conventional radials (3 or 4 radials, typically), all integrated into a single antenna.  A good one really can cover just about 26-30 MHz, if you tune it to the center of that area (28 MHz).

Problem is, they're not cheap!  These are commercial grade antennas, and normally in the $250-$300 range.  But they are good, they are broadband, and they do work well -- one will "blow away" the IMAX 2000 design, easily.

WB2WIK/6
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RI126
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Posts: 9




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« Reply #6 on: January 13, 2005, 03:39:02 PM »

thanks for your help,this was very helpful hope to be on the air soon.i have a president lincoln that i got from 1 stop electronics it has been worked on thats why 26-29mhz, let me ask another question.am i better off using lets say an I-MAX for 10m and cb and then get anothor for 29mhz and above
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KF4EYR
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Posts: 14




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« Reply #7 on: January 13, 2005, 06:29:21 PM »

are you licensed for 10 meter radio band? and using president lincoln on citizens band is definatly illegal,,,soooo what you need is just a 102 whip with a legal cb radio, or get your ham license and be right in what you are wanting
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K0RFD
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Posts: 1368




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« Reply #8 on: January 30, 2005, 07:37:42 PM »

The IMax 2000 is actually designed better than Solarcon's other antenna, the A-99.  However, even my A-99 makes contacts.  And it certainly was cheap, at about half the price of the Imax.  No it's not the world's best antenna.  It's not even a good one, as verticals go.  However it got me on the air when it was all I could afford.  I know enough now to build my own antennas; back then I didn't, or at least I didn't think I did.  Anything that helps you get on the air and learn something is worth looking at.

Any antenna is better than no antenna.  And any antenna you can afford is better than one you can't.
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