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eHam Forums / Amplifiers / RE: new al 80b not working
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on: February 15, 2013, 05:54:35 PM
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Is the the f101 fuse visible from the top as I can not find it in circuit diagram. As stated the 10 amp fuse is fine and the 20 for 110 operation is not needed but also fine. Will find the resistor mentioned in the manual and check and then resolder the straps on the power strip. Hopefully ameritron answers their phones on saturdays. Tnx for help guys. Bob
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32
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eHam Forums / Amplifiers / new al 80b not working
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on: February 15, 2013, 04:21:03 PM
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Out of the box, wired for the 230 volts, put the two straps on as per directions. Put a 12/3 plug on the wire. Turn it on, micro second later a little click sound , no smoke, no power, very slight smell. Fuses all good, 230v at lines inside the cab with power on and top off, interesting. Any thoughts ? Bob
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33
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eHam Forums / Elmers / RE: 40M vertical, help desperately needed, u may need coffee (just saying)
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on: February 12, 2013, 03:42:21 PM
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No way am I gonna handle all the points you raise but a few can be addressed. If your radials are on the ground, so should your vertical be, forget the 2in to 30in constraint. just a few inches up at the feedpoint will be the usual approach. The copper pipe idea is not worth the effort or expense, at 35 ft a wire on a fiberglass pole will be better and more durable. Making a 40 vertical efficent on the upper bands will need a remote tuner and mucho radials, and will not be something to write home about due to the various patterns developed and of course the major mismatch the tuner is cooking toast with. You feed a vertical very simply, center conductor to the vertical, coax braid to the common point of all the radials. Also, lose the modeling approach, I have built many advanced verticals, phased, 4 squares etc. the only thing a modeling program can supply is some inkling of pattern and impedance. Others will respond with further info but the basics are presented and I suggest you hit some books like the ARRL antenna books etc, open up a whole new world. Build it then see what happens. Bob
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35
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eHam Forums / Antennas and Towers and more / RE: Wire beam for 20m band
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on: February 11, 2013, 04:22:09 PM
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I use a 20 meter phased pair of dipoles with good gain and front to back, reversable. Both are equal length at 34 ft and seperated by 16 ft, 1/4 wl, with correct phase lines, a great beam antenna with wide beamwidth and bandwidth. Mine is at 40 ft supported by trees and competes very nicely with tower beams. 40 version on my qrz page. Bob
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eHam Forums / Antennas and Towers and more / RE: Construction Q/Concrete for Mast Support/Cold Weather
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on: February 08, 2013, 06:20:46 PM
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I've used 4x4 pt poles for years to hold up 50 ft rohn push ups and other types of poles with no failures. As long as the hole is deep enough and post holed, there really is no need for any sackrete or other bag goods unless you are sure it will be permenant installation. If gravel or small rocks are jammed/ tamped in to the small space around the the pole your good to go, it will take an 80 +mph sustained wind to break a 4x4, if 1/3 of the length of the 4x4 is in the hole. Bob
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40
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eHam Forums / Elmers / RE: antenna help2
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on: January 31, 2013, 09:07:21 AM
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If your stuck with ground mounting, I would raise the radials by tying them off a few feet up and away frome the vertical wire with a piece of string, like a gullwing, and pull out straight from there. Make them 180 degrees, opposite, from each other. The radials can be lengthened to achieve around a 1.4 to one swr by careful measurement. Be advised the radials are gonna be high voltage at the ends, so tie off with insulator to non conductive support. Lastly, put a 1 to 1 current balun at the feedpoint and try to keep feedline from running parallel under either radial. Good luck, Bob
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eHam Forums / Amplifiers / 572b Reasonable Life Expectancy
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on: January 25, 2013, 04:08:44 PM
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I use an 811h amp with the W8JI, 572b conversion. My usual time on air with amp on is 3 to 4 hours a day almost every day. How many hours can one expect before the tubes will show some deteriation in output or other type problems? Bob
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