[AMRadio] AM on 160m


Jim Wilhite w5jo at brightok.net
Thu Jun 5 12:20:29 EDT 2008


Hi Ken,

How much space do you have?  If your tower is 50-60 ft. could you 
possibly install an Inverted L?  Say 55 ft vertical (the more the 
better) with the rest horizontal out to about 160-170 ft and the end 
as high as possible.  Feed that with 50 ohm coax and use a series 
cap in the center of 100-300 pico farads.  If you will do that, you 
will be able to tune the thing on all bands with a good tuner at the 
transmitter.  The downside is that it will be a better antenna for 
long distant communications and not as good for distances out to 500 
miles.  I have 44 ft. vertical and the rest horizontal and it works 
on 160 both close in and at a distance (as many radials as you can 
put in).

On 75 meters, however it is distance dependent.  Close in stations 
are weak, stations out over 500 miles do well.  As for power, the DX 
40 will have trouble on 160 and 75 on AM in the evening.  However on 
40 and above you will make adequate contacts.  On CW you will do 
fine on 75-10 and ok on 160.  I have a 40/75 meter dipole (the poles 
support the ends as high as the center), the inverted L plus a 5 
band beam for the upper bands.  I find the L works fine on the upper 
bands.

For transmitters I use a B&W 5100B for SSB, a B&W 5100 , Globe 
Champion 300A and a Globe King 500A.  On the upper bands, power is 
not that important, but on 75, especially at night, it is.  CW is 
much more forgiving than AM so take that into consideration.  The 
more work you put into the antenna the better the payoff no matter 
what the transmitter.

73

Jim/W5JO


----- Original Message ----- 
From: "Ken Zuercher" <


> Jim, If I had a little more land, I'd put up dipoles
> also. I am however using half slopers on 40,20, and 10
> meters. the longest is only 32 feet. The 40 meter unit
> tunes well on 15 also. i haven't worked anyone on 15
> as I haven't been around when the band is open. I am
> just about able to put up a 75 meter half sloper to a
> point on a tree from the tower. What do you use to
> tickle the dipoles? I have a Heath DX-40 which is more
> than enough for any cw contact but I haven't done more
> than test on AM. Do you think the higher bands will go
> with the lower power on AM?
> Thanks for the advice in advance!
> Ken KC8QO
>



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