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ISOTRON AM BROADCAST ANTENNA WITH AM MAX II

 
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ISOTRON AM BROADCAST ANTENNA WITH AM MAX II
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Robert Dillon
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Post ISOTRON AM BROADCAST ANTENNA WITH AM MAX II Reply with quote
Thank you for your prompt response. Good PCS Tech-Support!
As you can see I am one of the first proud owner of the AM MAX II. I saw that you recommended the Isotron Antenna for this Transmitter. Does this antenna require any tuning or is it just connect and forget? I can invest in this Antenna providing it works.

How far apart can it be connected by Coaxial cable? In my case I want to mount this Antenna at 60' above ground.

Is there any provision or modification for Tuning an Antenna in the TX. circuitry? What is the purpose of INTEGRATION INTERVAL?
Sat Jun 26, 2004 6:40 pm View user's profile Send private message Visit poster's website
Transmitter Man
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Post Reply with quote
Robert,

The Isotrons for medium wave come pretuned to your proposed operating frequency from the factory. However, there is fine-tuning adjustment on the antenna to allow set resonance +/- 30KHz.

If you're intending to mount the antenna that 60ft above ground I don't need to tell you to use at the very least a good grade of RG213 / URM67 coaxial cable.

Phil
Transmitters 'R' Us
Sat Jul 03, 2004 4:38 pm View user's profile Send private message
Black_Hawk
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Post LOOP ANTENNA IDEAS Reply with quote
...Part 15 FCC requirements dictate the final stage of the transmitter be located as close as possible to the loop terminals.(HOW IMPRATICAL FOR THE AVERAGE LAZY JOE DOE) This constraint posses no major difficulty since the stage can be constructed on a small circuit board and mounted within the same weather-proof enclosure as the matching transformer and resonating capacitor bank. This also isolates the more expensive exciter components from the possibility of damage from a nearby lightening hit. The power can be supplied with low-cost small gauge wire since the current is under 50ma. Additionally, the power can be supplied via the coax signal line by inserting isolation transformers at both ends.






http://www.thepittsfieldinn.com/Bill/
Sat Jul 10, 2004 6:40 am View user's profile Send private message
erobertg
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Post New price for Isotron... Reply with quote
I see the price has been lowered on the AM broadcast Isotron Antenna. I ordered mined today. This should be interesting seeing what Antenna under 10' long should do for range.
Mon Nov 22, 2004 10:34 pm View user's profile Send private message
erobertg
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Post French Isotron Reply with quote
Naturally this site is translated from French so the lingo will be a little off. Whorls are turns etc. Has a table from 10 mhz and up but the data can also be used for approximately taylored for lowered frequencies by scale. An interesting note, they use (2) metal disks and the ground disk is used on top. For 10 mHz they use between 130-200 mm diameter and recommend 300 mm disk for 40 meter band.

A lot of constuction tips for compact Isotrons and EH antennas...

http://216.239.37.104/translate_c?hl=en&u=http://f5ixu.wathy.com/&prev=/search%3Fq%3Disotron%2B73%26start%3D80%26hl%3Den%26lr%3D%26sa%3DN
Sun Nov 28, 2004 5:24 pm View user's profile Send private message
erobertg
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Post Cut and Paste... Reply with quote
The above address has to be manually cut and pasted into your browser for proper French/English translation...
Sun Nov 28, 2004 5:35 pm View user's profile Send private message
Sir Nigel
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Post Reply with quote
That's funny, that guy is holding his dog in that picture. L'homme et le chien. Yeah, I'm currently learning French.

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Sun Nov 28, 2004 9:35 pm View user's profile Send private message Visit poster's website
Antler
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Post Reply with quote
Now that the price seems to be more reasonable I may interested in the Isotron.

Question, has anyone bought one of these and if so, DOES it work well? If you have one of these, please give specifics. If you tried other antennas first please make comparisons if you can.

Regards, A-man
Tue Dec 07, 2004 2:15 pm View user's profile Send private message
erobertg
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Post Reply with quote
Isotron showed be here friday. I'll keep you posted after this weekend...
Tue Dec 07, 2004 5:32 pm View user's profile Send private message
erobertg
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Post Got My Isotron Antenna... Reply with quote
Got my Isotron yesterday and assembled it last night. Would't you know, it rained today. Well, I braved the elements and stated tuning the unit for 1640 kHz, very touchy. Mounted the unit on a section of 10ft. mast lying against the deck at about a 45 degree angle for tune up. Must have spent a couple of hours farting around with the tuning rod. For some reason I disconnected the audio to the xmtr when I finally arrived at a SWR 1.5:1 which I thought was good enough. I reconnected the audio and my SWR went up to way over 3:1...Well into the red. I already have a good ground on the transmitter end so I don't know what's the matter.

Well, I turned up the unit and checked back later and I got an SWR 1.7:1 WITH my audio connected. An hour later the SWR is over 2:1. The SWR does seem to jump around. I'd like to get Isotron mounted vertically on a 30' telescoping mast but I'm afraid I'll lose my tuning. Does anyone have any ideas?
Sat Dec 11, 2004 2:31 am View user's profile Send private message
Antler
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Post Reply with quote
An antenna analyser would be handy if you know someone who has one. I have the cheap MFJ and I know that Autek http://www.autekresearch.com/ makes one for under a $100.

Re the SWR, the one thing I have noticed in the past is that the enviroment can come into play and throw your antenna out of resonance. You might try hoisting it on up and see if that gives you different or better readings.

Good luck,
Sat Dec 11, 2004 3:15 am View user's profile Send private message
erobertg
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Post Thanks For The Tip... Reply with quote
Thanks for the tip Antler, that RF analyzer sounds like a good item to get. I read that Isotrons usually display about 30 Ohm impedance compared to a 50 ohm transmitter impedance. So I'm finally getting a steady 1.8:1 SWR with the audio turned on, not bad. The antenna shows quite a load, I'm showing about 14 watts +/- 5% meter reading which is a really good for 19 volt supply.

Well, I'll get the unit hoisted up when the weather clears. Right now, I'm getting out about 2 miles with in the tune up position and I'm sure it will vastly improve once I'm fully operational.
Sat Dec 11, 2004 4:30 pm View user's profile Send private message
Antler
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Post Reply with quote
How is going? Have been able to do anything more over the last couple of days?

Antler
Mon Dec 13, 2004 7:32 pm View user's profile Send private message
erobertg
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Post No not lately... Reply with quote
I talked to a guy named Ralph today who makes the Isotron. He said to tune my transmitter up and down to find the lowest SWR. I currently have the antenna mounted horizontally on a 10' mast and the lowest point is about 5' above ground, the SWR is 1.4:1. On either side of 1640 kHz the SWR quickly goes up, so I'm confident the I've found resonance. I currently putting out a go clean signal all things considered.

Tomorrow is going to be cold, but I'm taking a trip up to Lowes and get their 30' telescoping mast fo $45. Going to see what hardware I'm going to need to do the job right. Keep you posted.
Tue Dec 14, 2004 12:19 am View user's profile Send private message
sealerman
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Post Reply with quote
can I ask what kind of range you are getting with this setup. and iwhat kind of range are you getting with a portable radio versus a car stereo?

Thanks
Terry
Fri May 12, 2006 6:51 pm View user's profile Send private message
static-radio
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Post Isotron 400 Reply with quote
I have been looking at the Isotron 400, they are $600 dollars i the states and Canada, i see xxxxx are charging £695!!
is there any other company that does supply them?
Tue Aug 19, 2008 3:06 pm View user's profile Send private message Visit poster's website
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