[FARC] The best antenna for a new ham

[Kirk Talbott]

Tnx Joe for the great antenna info.  It's good to know what works and I'd 
like to relate for the benefit of others what I've tried that doesn't.

Beware the "shortened" dipole.  I don't have a lot of tall trees or the yard 
space for a very a long dipole antenna. The plethora of ham magazines that 
arrive in the mail are full of ads and ideas for "shortened" dipoles or wire 
antennas much shorter in length than the standard length of a dipole for a 
particular band.

I took the bait and bought a 20 meter "shortened" dipole which is 20 ft. 
long with two small coils.  This particular antenna carries the label of QRP 
antenna and the instructions indicate that it is for use with 150 watts or 
less.  From a diagram in a book, I assembled my dipole in a "sloper" 
configuration, the high point attached to my TV tower about 12 feet up.  Per 
the diagram in the book, the low end of the sloper is attached to a 1 foot 
wooden stake hammered in the ground.  The dipole is center fed with RG-8X 
coax at a 90 degree angle to the wire, or nearly so.

This was an easy, neat, and compact antenna installation project.  The only 
problem is that it doesn't work. I would say it works marginally on PSK and 
RTTY because it is actually cut for the CW portion of the 20 meter band. I 
have made a few contacts with it.  It doesn't work at all on 20 meter SSB 
phone and I've made no contacts with it. The instructions did indicate that 
an antenna analyzer would probably show that it would need trimming to 
operate higher in SSB phone portion of the 20 meter band, however, since it 
didn't work very well with PSK or RTTY for which the dipole was originally 
cut, trimming it couldn't possibly have made it better.

So, the moral of the story is an old one.  The antenna was $39 plus shipping 
and it looked too good to be true.  It wasn't.

73
KB3ONM
Kirk


----- Original Message ----- 
From: "Joseph M. Durnal" <joseph.durnal at gmail.com>
To: "Frederick, Maryland ARC" <farc at mailman.qth.net>
Cc: "MADXRA's Friends&Members" <madxra at madxra.org>
Sent: Tuesday, July 17, 2007 11:26 AM
Subject: [FARC] The best antenna for a new ham


> Short answer: A 40 meter dipole
>
> Short why: Because it works great on 15 meters too
>
> When I ordered my Elecraft K1 2 band Transceiver kit, I had to decide
> which two bands I wanted it to come with.  After a lot of thought, I
> decided on 40 & 15 meters, for two reasons.  First, 21 MHz is the
> third harmonic of 7 MHz, making a 1/2 wave dipole for 40 meters a 1
> 1/2 wave dipole on 15 meters, a 50 ohm match that will even have a
> little bit of gain.  Second, the propagation properties of 40 & 15
> meters complement each other.  While 40 is great for local and
> regional communications, 15 is a great DX band, but that doesn't mean
> that you can't work DX on 40, or work state side contacts on 15.  I
> also thought about the 11 year sunspot cycle, and sadly, right now,
> there are few sunspots, which isn't so good for 15 meters, but it is
> rare for the maximum usable frequency not to get up above 7 MHz.
>
> I've been asked by a few hams new to HF about what they should do for
> their first antenna.  I often answered generically, "it depends on
> what you want to do".  But often new hams don't have a predefined idea
> of what they want to do, but want to try different things.  After the
> long hours of deciding the bands I wanted in the K1, I figure I could
> apply the same logic to a first antenna recommendation for a new ham.
>
> Building a 40 meter dipole (on the cheap):
>
> 68 feet of wire (14 ga +/- is fine, copper is best, no insulation 
> required)
> 3 insulators
> length of light rope
> length of coax
>
> 1.  Locate two supports at least 70 feet apart
> 2.  Cut wire in two equal lengths
> 3.  Attach one end of each leg to the center insulator
> 4.  Solder the coax center conductor to one leg of the dipole and the
> shield to the other. It is also advisable to provide some strain
> relief which can be accomplished by wrapping the feedline once around
> the center insulator and securing with a cable tie-wrap.
> 5.  The connection can be weather proofed with silicone sealant
> 6.  Attach the other end of each leg to an end insulator, each leg
> should be about 33 feet, the excess wire can be folded back and
> wrapped around the leg and/or trimmed.
> 7.  Attach a length of light rope to each end insulator and tie to
> supports located in step one.
>
> Some notes:
> - Dipole legs don't need to be perfectly straight or horizontal.
> - Do not put any part of the antenna system over, across or near
> electric lines.
> - Keep the ends of the antenna at least 8 feet above ground to prevent
> it from being a hazard to those walking by.
> - Insulators can be made out of just about anything that doesn't
> conduct electricity.
> - A commercially made 40 meter dipole can be bought for $35 or so,
> most will require a little trimming to make them resonate.
>
> Please save this note and pass it on to anyone seeking advice on a
> good first antenna, feel free to improve it in any way you wish.
>
> 73 de Joe NE3R
> _______________________________________________
> FARC mailing list
> FARC at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/farc
>