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Author Topic: Antenna for confined spaces  (Read 4556 times)
VE3DKT
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« on: August 12, 2011, 06:47:52 AM »

I am looking for any experience with the Isotron4080 antennas, ar ethey as good as they say
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AC4RD
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« Reply #1 on: August 12, 2011, 09:01:21 AM »

Take a look in the "Reviews" forum here on eHam--I'm pretty sure I've seen a lot of discussion of them. 
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KQ6Q
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« Reply #2 on: August 12, 2011, 02:53:14 PM »

I had an Isotron for 40m, and can report that I get better results on 40 with either a horizontal hamstick dipole, or a Hustler 54" mast and 40m resonator on a triple magmount with counterpoises. On 80m I use a magmount setup as on 40. Both are better than the Isotron was. You might try the MFJ-1788 tunable loop to get on 40 and above if space is your main constraint. For 40 or 80, a hamstick dipole mounted vertically could work, at about $100 per band.
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KG4RUL
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« Reply #3 on: August 12, 2011, 04:39:00 PM »

An Isotron radiates as well as the coax connected to it.   Roll Eyes
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K1CJS
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« Reply #4 on: August 17, 2011, 04:42:51 PM »

An Isotron radiates as well as the coax connected to it.   Roll Eyes

I have to agree with that.  I had a 20/40 Isotron setup, and the only thing I could say about them is that they were slightly better than no antenna at all.  You may well be better off with a light bulb on the end of 100 feet of coax, mounted on a fence post.
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K5LXP
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« Reply #5 on: August 18, 2011, 09:01:59 AM »

are they as good as they say

If "they" are the folks that realized their coax wasn't connected or the antenna switch was in the dummy load position before trying the Isotron, then they're right.  Compared to an open circuit or a resistive load they work great.

I have a 40M Isotron and I have not yet experienced an antenna that's less effective.   Maybe I should use longer coax...


Mark K5LXP
Albuquerque, NM
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WB2WIK
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« Reply #6 on: August 18, 2011, 02:25:37 PM »

are they as good as they say

If "they" are the folks that realized their coax wasn't connected or the antenna switch was in the dummy load position before trying the Isotron, then they're right.  Compared to an open circuit or a resistive load they work great.

I have a 40M Isotron and I have not yet experienced an antenna that's less effective.   Maybe I should use longer coax...


Mark K5LXP
Albuquerque, NM


Mark you must have missed the instruction recommending you install the antenna very close to the station you want to contact.  It helps a lot. Smiley
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KI4SDY
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« Reply #7 on: August 18, 2011, 05:07:17 PM »

I was too smart to buy one! If the antenna looks like it defies the law of physics, it probably does!  Wink
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AA4HA
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« Reply #8 on: August 18, 2011, 05:41:57 PM »

 Wink Isn't the word Isotron Latin for "dummy load"?

I had a friend who was a bit of a speed freak (fast driving), ironically he was also a police officer. He asked for my help to evaluate a "radar jammer" that he wanted to put in his car. It was supposed to work in conjunction with his CB radio.

It was a 4' long fluorescent light bulb wrapped with about 50 feet of #16 wire from end to end with the wire ends connecting to the pins at the end of the bulb. Then there was a "special" piece of coax that connected the center pin to one end of the bulb and the shield to the other end of the bulb.

The idea being that if you saw a police car and he had is radar gun pointed at your car you would grab your CB mic and key it on and off in fast succession. The disruptive RF energy would be converted to microwave jamming signals by the bulb and the police car would not be able to keep a lock on your car (this was way back before the days of instant on radar).

Incidentally he was pulled over for speeding, the officer who stopped him also said that the flashing fluorescent bulb on the dashboard drew his attention to that particular car.

I tried and tried to explain it to him that this was a crazy idea but he had it in his head that it had to work because it was the most convoluted design ever seen.

This reminds me of the Isotron antenna.
« Last Edit: August 18, 2011, 05:50:41 PM by AA4HA » Logged

Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
AC4RD
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Posts: 1235




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« Reply #9 on: August 19, 2011, 09:19:17 AM »

help to evaluate a "radar jammer" that he wanted to put in his car. It was supposed to work in conjunction with his CB radio.   It was a 4' long fluorescent light bulb wrapped with about 50 feet of #16 wire

When THAT didn't work, you should have sold him some "magic beans."  Someone who would pay money for the 'radar jammer' would probably be willing to pay top price for some Radar-Avoidance Magic Beans.  :-)
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