On Wednesday, February 3, 2016 at 10:18:57 AM UTC-6, Joe from Kokomo wrote:
On 2/3/2016 10:47 AM, Michael Wilson wrote:
What is the best antenna for general shortwave listening? I was thinking of building a fan dipole but I wanted to check to see if there is a better alternative. Thanks!
For your "general shortwave listening", a random length long wire
antenna should be just fine. A fan dipole is nice, but more complex to
build -- and you have to cut each dipole for the band of interest; if
you wanted to listen to 4 different bands, you would have eight ends of
the dipoles to mount.
Depending on your receiver and how deeply you are into the hobby, you
would probably not notice much difference between a fan dipole and a
long wire.
P.S. For those not familiar with a fan dipole, it consists of multiple
dipoles with one common center insulator fed with a single coax.
Typically used by frugal hams that want an 80 and 40 meter antennas and
want to use a single coax feed line.
Good luck and let us know what you end up with.
On 2/3/2016 1:19 PM, Michael wrote:
I'm thinking using this guy's approach to making one for the 40-20-15-10 bands. Would the length of wire he uses be appropriate for SWL, or should I do more research on this issue?
Thanks!
https://www.youtube.com/watch?v=8KHzsKYsZL0
Yes, time for a bit more research. The length of the wire is dependent
on the frequency. If you want to listen on 40-20-15-10, his lengths are
fine -- as those lengths he calls out are for those specific ham bands.
If you are listening to the SWL bands, you will need different lengths,
one for each SWL band of interest. The formula is wavelength = 300
divided by the frequency in Megahertz. Also remember that this is a
half-wave dipole, which means you divide the figure you got above by 2.
Or just use this site to calculate the half wave length of the
frequencies you are interested in.
http://w6dek.com/dipole.html
As stated in my response above, the fan dipole is a bit more complicated
to make than a random length wire for general purpose short wave
listening -- and you probably won't notice any difference between the
two types of antenna.