[AMRadio] low band am


Brett gazdzinski brett.gazdzinski at verizonbusiness.com
Thu Mar 8 22:09:30 EST 2007


>From what I have found out over the years, working with
no towers, a small lot, electric wires, etc:

Try to get as much wire up as you can...if you want to operate
80 meters, try to get 120 feet up (60 feet each side).
If you only have 100 feet, you can make a homebrew G5RV
and feed it into a tuner, that is what I have now, and it seems
to work well on 80 and 40, WITH a tuner.
I had to trim the open wire line length to get away from a
voltage point.

You can go through trees, bend the antenna up some, etc.

Try to get the antenna up as high as possible.

Try to keep the antenna away from power lines, cable TV
lines, and away from the house as much as possible, I have
3 antennas up right now, the G5RV at 45 feet right angles
to the house and power lines, about 100 foot flat top, 35
feet of home made open wire line, then into about 20 feet
of RG214 to the tuner...seems to work very well.

An alpha delta dx-dd, its 82 feet long, and has loading coils
at about 32 feet from center, resonant on 80 and 40 meters,
its at 40 feet lengthwise over the house and at right angles
to the G5RV, works ok on 40 meters but is ALWAYS noisy
as hell. Because its over the house I suppose.
Noise levels seem to run 10db higher then the G5RV.
I interfere with stuff in the house with this antenna.


Butternut vertical 80 and 40 meter version, about
32 feet tall, generally a very poor performer, better on
40 meters where its almost full size, but poor even
there 90% of the time.

Trap antennas can burn up with 100 watts of AM,
the B+W broadband folded dipole is very poor and
is not good for much AM power.

I have not tried a loop antenna, I don't have good supports
away from the power lines and house, many recommend them.

If you can go balanced with open wire line into a balanced
tuner, that makes the best all band antenna.

I plan on taking the G5RV and the dx-dd down soon and putting
an 80-40 meter dipole up where the g5rv is, running the 80 meter
dipole through the trees and down, to give 120 feet,
with a 40 meter dipole suspended below off the same coax.
Hopefully I will not need a tuner, which I find to be a real
pain in the butt.

Depending on band conditions, many times 100 watts on 40
meters will result in a very strong signal all over the east coast
and into Canada. 40 has been kind of poor lately, with lots less
activity then there used to be.
Used to be 3 QSO's with 6 to 10 people in each on weekend
mornings till the broadcast rolls in.
People ran all sorts of old rigs, dx60's, globe scouts,
multi elmac and gonset stuff, along with the usual dx100 
and Johnson gear, homebrew little rigs, etc.

As far as a receiver goes, depends on what you want
it to do. I always liked the R390 or R390a with
audio off the detector.
I find most of the collins stuff poor on AM and way over priced.
The NC300 or NC303 are good, maybe some of the RME receivers,
the older receivers like the SX17 or SX28, and other 1940
era radios had great audio but poor frequency resolution.

The TS 140 is a poor AM receiver I would guess,
noisy, distorted, even with outboard audio.
I have not found a modern receiver I would want to 
use as a main station receiver for AM.

If I did not build my own, I would pick an R390 for each 
band I used regularly, say one for 80 and one for 40.
Add one for 160 if you operate there.
Take the audio out to a nice hi fi amp and speaker.
They have gotten real expensive (as has everything vintage).

Brett
N2DTS 
 

  
> 
> im gettin the am bug again...maybe this time it will come to
> fruition....
> 
> with that said i have
> 
> a 40 meter half wave dipole available.  i do not have a lot of real
> estate nor 100 ft towers.  so what is the best way to hang the dipole
> for 40/80m am?  nvis stile, horizontal at n ft, or as a sloper off
> another mast?
> 
> also what is a good receiver, tube type?  i am using a 
> kenwood 140s for
> both xmit n receive...the xmit is ok puts out 40 watts am but the
> receive is too much hash and frying eggs noise so liiking for a good
> receiver.
> 
> enjoying 75m ops on 3880 in mornings lately....
> 
> 
> 
> 
>  
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