[FARC] Re: FARC Digest, Vol 37, Issue 9

Sat Jul 21 08:05:27 EDT 2007

Thanks Howard, but it is not necessary.  I raised the short end of the 20m 
dipole from 1 foot to 7 feet and it works a little better now, especially 
for PSK31.  It's a temporary set up though because my wife hates it and it 
looks a little rickety, kind of like a sagging clothesline.  The center 
feedpoint sags because it is heavy, and no amount of tension helps it.

I'll have to make a more neat installation after I prove that it is actually 
working to my satisfaction.  Either the antenna still isn't working properly 
or digital communications are a "nine-to-five" operation, as I can't find 
many early-birds or night-owls on PSK31 or RTTY.  After raising the antenna 
though, last evening around 7:00 p.m. there were so many signals on the 
PSK31 waterfall that I couldn't find a place to transmit. This morning at 
8:00 a.m. there are none.

When I do see signals on PSK31, I see a lot of DX stations calling one 
another and communicating in their native languages, and I never saw this 
until I raised the dipole.

73
KB3ONM
Kirk

----- Original Message ----- 
From: "Howard W3CQH" <hsgorden at comcast.net>
To: <farc at mailman.qth.net>
Sent: Friday, July 20, 2007 8:47 PM
Subject: [FARC] Re: FARC Digest, Vol 37, Issue 9

> > Message: 2
> > Date: Wed, 18 Jul 2007 17:37:25 -0400
> > From: "Kirk Talbott" <KirkTal7237 at msn.com>
> > Subject: Re: [FARC] The best antenna for a new ham
> > To: "Frederick, Maryland ARC" <farc at mailman.qth.net>
> > Message-ID: <BAY101-DAV767ADFA9FAA8D432ED2A8A6FA0 at phx.gbl>
> > Content-Type: text/plain; charset="iso-8859-1"
> >
> > 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
>
> =============
> Kirk - If you are still having problems with the dipole - I will loan you 
> my
> 6 band 80m - 6m, Mobile antenna system, that you can mount on a pole.  The
> only thing that you will have to do is make a small harness to feed it 
> with
> RG58u cable and some PL259 connectors...
> 73's de Howard W3CQH
> 1-240-793-6736 - cell
>
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