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[K4BDA]

A local ham uses this wire antenna to work 80, 40, 20, and 15 I think.

- It is a dipole with each leg 47.5 feet long.
- It is center fed with 300 ohm twin lead with no balun.
- The 300 ohm twin lead goes directly to his antenna tuner.

I'm wondering what the name of the antenna is as he said it is widely used.

Thanks.

[WA5VGO]

It’s a doublet. Since it’s fed with 300 ohm twinlead, feedline losses are low. It’s a little short for 80 meters, but I’d guess the radiation efficiency on that band is still around 95%. It’s a much better antenna than many of the voodoo antennas out there.

[K2TL]

It is close to a Cebik Dipole.  W4RNL designed it as an 88 foot doublet fed with balanced line.  I use one myself and have for maybe 30 years now.  It does work 80-6 but a bit compromised on 80 ( not much ).  Almost a resonant dipole on 60.  Performance is excellent.  I believe he selected 88 feet for the improved radiation pattern as a multiband antenna.  You can Google Cebik Dipole or 88 foot doublet and read to you hearts content.  Cebik was an amazing antenna guru and is now SK, but his legacy is still availble online.

[WB6BYU]

Doublets of just about any length can be fed with twinlead
or open wire line and made to work.  The length affects the
efficiency and radiation patterns, as well as the impedance
that the tuner has to match on each band.  Just a matter
of choosing a convenient combination that fits your available
space and meets your needs.

Besides W4RNL's 88' doublet (the length of which was chosen
so the radiation pattern is broadside to the antenna on 80m
through 20m), another doublet of similar length is the ZS6BKW,
where the dimensions were chosen to give a relatively low
SWR on 40, 20, 17, 12, and 10m.

Note that in either case, both the length of the antenna
and the feedline affect the impedance that the tuner has
to match.  Sometimes you end up with a combination that
doesn't match easily on one or more bands, in which case
changing the feedline length by a few feet may fix it.

[N7EKU]

Note that in either case, both the length of the antenna
and the feedline affect the impedance that the tuner has
to match.  Sometimes you end up with a combination that
doesn't match easily on one or more bands, in which case
changing the feedline length by a few feet may fix it.

Hi,

I think that should read, "in all cases" because even on the OP's antenna, the total length of the antenna arms and feedline length matter as far as making sure your tuner has an easier time of matching.  Like you said, if your tuner has a hard time finding a match, just change the feedline length a bit.  Better still, is if you have or can borrow and analyzer or do modeling, then you can have a better idea.

73

[WA3SKN]

It's called a dipole.
You can feed a dipole with coax or with a balanced line.
With a tuner you can load it to just about any band.  AND... it works!

-Mike.

[AI5BC]

It's called a dipole.

Agree nothingt mor or less, just a dipole. All the other names are just CB/ham foolery.

[VE7RF]

It's called a dipole.

Agree nothingt mor or less, just a dipole. All the other names are just CB/ham foolery.

Doublet =  dipole.  I call it a dipole.  I have noticed over the years that the infamous 102' long G5RV  is always down from folks using a full sized dipole..when on 75m ssb.  But the 102' G5RV was never a multiband dipole.   It's  a  4.67 mhz dipole, operating on it's 3rd harmonic on 14 mhz.  It's a 20m ant.   No different than using a 40m dipole on 15m. 

[W9IQ]

'Doublet' and 'G5RV' are designations for an antenna system. Both use a dipole in their construction.

The term 'doublet' refers to a multiband, center fed dipole fed with a balanced transmission line. The balanced line is used to minimize transmission line losses.The length of a doublet antenna can be varied to suit target bands or radiation patterns. Thus the length of the doublet antenna is often specified.

The G5RV antenna bears a strong resemblance to a doublet but it deviates due to the coaxial transmission line that is mated with the balanced  transmission line. The original G5RV antenna was also a specific length, center fed dipole.

So while these antennas are both broadly classified as dipoles, it is helpful to have these antenna system names to reference them with brevity.

- Glenn W9IQ

[WA3SKN]

A dipole is simply two equal length conductors.  Dr. Kraus was kind enough to show it's various characteristics as he ran it from zero to infinity length in his famous "Antennas" book of 1950.
An interesting read.
G5RVs are dipoles.  OCF dipoles are NOT dipoles.  And dipoles do NOT have to be 1/2 wavelength.  We use 1/2 wavelength because it is easy to get the power transferred into the antenna.

-Mike.

[WA3SKN]

Oh... and 47.5 ft is the length used for 30 meters if you don't subscribe to the "468" formula for dipoles.  It is closer to the correct number than 468.

-Mike.