[AMRadio] Re: new antenna...

Craig C. Heaton wd8kdg at worldnet.att.net
Tue Feb 6 10:33:33 EST 2007

Hi Brett,

I've played with loading coils on a 40 meter dipole feed with 600 ohm open
wire trying to get it on 3.870 MHz. Transmitter was a Johnson 500, about 350
watts of carrier.

The short answer is use "large" diameter wire for the coils & wide spacing.
My loading coils arced with the 500 in the tune position and tripped the
overload relay in the PA circuit. I did get it so I could whisper into the
mic at low power (not a good impedance match for the mod tranny) at about
50% modulation of the carrier. Anything more and the overload relay tripped.
Receive was as good as my 75 meter full wave loop.

Where on the dipole the coils are going to be placed will be important,
running 600 watts of carrier could mean "strapping" coils.


-----Original Message-----
From: amradio-bounces at mailman.qth.net
[mailto:amradio-bounces at mailman.qth.net]On Behalf Of Brett gazdzinski
Sent: Tuesday, February 06, 2007 5:52 AM
To: 'Discussion of AM Radio in the Amateur Service'
Subject: RE: [AMRadio] Re: new antenna...

after a while on full power (600 watts carrier), which
is likely normal, its not hot...

The question is: Does a resonant antenna work better on

AThe antenna is 100 feet long now, and the ends are right up
against the trees, but I could add loading coils to make
the antenna resonant at say 3880.
Would that improve receive any?

What do you guys think would happen if I added loading coils?


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