Eh? A 40m dipole is pretty close to resonance on 15m already, so how can you
avoid that. In fact, all dipoles are resonant at odd multiples of half waves,
so this is impossible to avoid.
Could you clarify the issue here?
wunder
K6WRU
CM87wj
http://observer.wunderwood.org/
On Sep 13, 2014, at
Fan dipoles depend on the relatively high impedance on the fan
pieces that are for other bands to send most of the energy into
the tuned fan. If you are using fans for 40 and 15, the energy
will be split between them on 15M which isn't what you want.
BTW - My combination of a 160M dipole
Don -
Did you mean 80 meters and 30 meters? 40 meters and 30 meters should
be OK, even if the frequency separation is not optimal.
- Jim, KL7CC
On 9/13/2014 9:31 PM, Don Wilhelm wrote:
I failed to mention another point with regard to fan dipoles. Do not
mix 3rd harmonic radiators on
: Antenna ideas for a cheap ham
Don -
Did you mean 80 meters and 30 meters? 40 meters and 30 meters should
be OK, even if the frequency separation is not optimal.
- Jim, KL7CC
On 9/13/2014 9:31 PM, Don Wilhelm wrote:
I failed to mention another point with regard to fan dipoles. Do not mix
I don't have a tower but I am using a 10-20m cobweb antenna in my
attic. It's non-directional and feeds with a single coax. It gets out
pretty well on all five bands. Recently worked aZL station on 17m with
less than 2 watts (this is the requisite anecdotal information... but
true.) I'd love to
Correction:
Make that 'don't mix 80 meters and 30 meters on the same coax'
73,
Don W3FPR
---
I failed to mention another point with regard to fan dipoles. Do not
mix 3rd harmonic radiators on the same coax. In other words, stay away
from
The reason that the 80/40/15 combo does not work well is that the 40 resonates
pretty well on 15 because it is 3/4 wave. I have had a lot of difficulty with
80/40/20 and have never had one work well. My current fan is an Alpha-Delta
80/40 with a 75 meter wire fanned. It is the magic formula
Thanks for the suggestions.
We considered shortening the vertical from 36 to 50 MHz, but there is
almost no local activity on 6m so probably of more use to him with a
Tech License as a 10m vertical - just has to add aluminum tubing of
the correct diameter (the antenna has existing section the
: Antenna ideas for a cheap ham
I don't have a tower but I am using a 10-20m cobweb antenna in my
attic. It's non-directional and feeds with a single coax. It gets out
pretty well on all five bands. Recently worked aZL station on 17m with
less than 2 watts (this is the requisite anecdotal information
Right. That makes sense.
Though the worst case would be a 2:1 SWR if both are resonant, because the feed
point impedance would be 1/2 what is expected. Not the end of the world.
A 40m dipole isn’t quite resonant on 15m anyway, so having both might make for
more broadband 15m behavior with
I sent this to the reflector last Tuesday but it never posted on the
reflector; here it is again:
Date: Tue, 09 Sep 2014 09:03:13 -0800
To: Elecraft Reflector
From: Edward R Cole kl...@acsalaska.net
Subject: OT: Antenna ideas for a cheap ham
This might be considered an offshoot of the OT R8
Ed,
Since he does not want a beam, I would suggest 3 dipole antennas
supported from his 80 ft. tower - OK, really 8 dipoles, but 3
feedlines. All of them would be inverted VEE type.
One of them is a fan dipole for 10/15/20 meters. Position that one to
favor his preferred DX locations.
The
One other comment regarding fan dipoles.
They really work well, but if one attempts to put more than 3 bands on a
fan dipole, the interaction can become frustrating to tune them all,
been there, done that, and have all the scars.
I separate the radiators in my fan dipoles by about 1 foot
If he has a long coax run, he should consider a remote antenna
switch. I have one to keep the coax in the house to the YL's
tolerance level. If he can locate it close enough to the feed
points, he may be able to avoid multiple common mode chokes.
73 Bill AE6JV
On 9/13/14 at 4:47 PM,
On Sat,9/13/2014 5:01 PM, Don Wilhelm wrote:
One other comment regarding fan dipoles.
They really work well, but if one attempts to put more than 3 bands on
a fan dipole, the interaction can become frustrating to tune them all,
been there, done that, and have all the scars.
Strongly agree.
I failed to mention another point with regard to fan dipoles. Do not
mix 3rd harmonic radiators on the same coax. In other words, stay away
from combinations of 40 meters and 15 meters, and also 40 meters and 30
meters. They may work, but tuning problems are 'iffy'.
73,
Don W3FPR
On
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