MK,

Good Ideas... But You are thinking with your Amateur/HAM Hat On.

Think like a SWLer who whats a Receive ONLY Antenna that will
work well for all directions on All Bands from 500kHz to 30 MHz.

The Dipole is a Great Frequency Specific Directional Antenna
for use by Amateurs/HAMs for Transmitting.

IMHO: The Random Wire Antenna configured as an Inverted "L"
Antenna using the Low Noise design concepts as popularized by
the writings of John Doty. Would serve a SWLer better for a
Receive ONLY SWL Antenna.
http://groups.yahoo.com/group/SWL-AM...na/message/374


iane ~ RHF
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= = = (Mark Keith)
= = = wrote in message . com...
"JEFF UK" wrote in message ...
Just wondering...........

What would be best for my next receiving antenna.

1) A long wire , coax feed (no balun ) about 80 feet,
( earthed coax braid)
15mtrs from house.

or

2) A Long dipole, about 80 feet each side.

Noisy here at times.

What do you reckon?

Best Regards

Jeff

I'd rather have the dipole I think, but it really doesn't have to be
that large to work well. Would be nice for the lower bands though.
Overall, the dipole will probably give you the best s/n ratios being
it's usually fairly easy to decouple. I'd use a good 1:1 balun or a
coax choke or ferrite beads. If you used a 160 ft 1/2 wave dipole, it
would be resonant at 5.8 mhz as a half wave. 11.6 mhz as two half
waves in phase which is a hi-z feed. About 17.4 mhz as a 1.5 wl
dipole, which is a low Z feed. Other bands will vary... It would work
pretty well on most all the higher bands. The pattern on the upper hf
bands would be multi lobed, and fairly omnidirectional overall. The
mismatch using coax to feed one of these is not worth worrying about
for receiving. The coax loss on any HF band is not enough to lower the
s/n ratio. Not even close unless you have a dead radio or dead coax.
All bands will still have plenty of signal level. But you could use
twin lead and a tuner if you were worried about feedline loss. Another
advantage to the dipole, is you then really have three antennas. The
dipole fed normally. Or you could feed one conducter, "usually the
center pin, by unscrewing the shield and letting ground float" as a
random wire. Or you can tie the center pin to shield at the shack ,
and feed as a single conductor T vertical. Good for 160m, MW, LW,
etc..Myself, I parallel dipoles on the same feedline. Right now, I
have a 80m turnstile, and a 40 dipole on the same coax feed. It's a
good SWL antenna anywhere in the HF spectrum. Sometimes I have
80/40/20. Sometimes 160/80/40. Just depends on the time of the year,
and what I'm working the most. I didn't use a 160 dipole this year, as
I usually prefer my top loaded vertical.
MK
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