[HCARC] 80 meter short distance comm & Field Day

Sun Feb 9 23:06:48 EST 2014

Harvey:

Sounds like the "double bazooka" antenna. Google it and see if that was what
you were using. The original QST article by W8TV is from July 1968, p. 38.

It reportedly is broadbanded. However, the broadbanding appears to be due to
several factors, including resistive losses in the coaxial stubs - see
Technical Correspondence, QST Sept. 1976, p. 29, for an analysis by W2DU. So
you may lower the SWR but at the expense of also lowering the net power
radiated by the antenna.

73,

Dale - K4DG

PS: I have .pdf copies of both the above QST articles. Anyone who is
interested can email me privately to get a copy.

-----Original Message-----
From: hcarc-bounces at mailman.qth.net [mailto:hcarc-bounces at mailman.qth.net]
On Behalf Of Harvey N. Vordenbaum
Sent: Sunday, February 09, 2014 8:36 PM
To: 'Dale Gaudier'; 'H - Reflector'
Subject: Re: [HCARC] 80 meter short distance comm & Field Day

There was an 80 M broad banded antenna design in QST years ago that worked
pretty well.  Some parts of it were pieces of coax as well as wires. If I
recall correctly SWR was below 2:1 over the whole band. It was coax fed and
you need a pretty good sized center connection with a coax connector for the
coax feed line. I had it up until a deer tore down one end of it 15 years
ago.
I'd have to do a search for the article since I don't seem to have a copy of
it.
Hv

-----Original Message-----
From: hcarc-bounces at mailman.qth.net [mailto:hcarc-bounces at mailman.qth.net]
On Behalf Of Dale Gaudier
Sent: Sunday, February 09, 2014 9:42 AM
To: 'H - Reflector'
Subject: Re: [HCARC] 80 meter short distance comm & Field Day

All:

Thought I'd chime in here, since I'm scheduled to demo my 80m broadbanded
antenna design at the May club meeting.

I think the idea of doing a test of 80m NVIS communications during Field Day
is a good one. As I recall, one of the purposes was to see if we could reach
the NWS station, so we would likely want to try making an hourly sked with
them to check on the communication path. And we should consider using
different modes - SSB, CW, PSK31, etc. to see which, if any work the best.

As far as antennas go, the 80m antenna design I will present to the club in
May can be used, but offers no advantages over a simple dipole cut for the
part of 80m you prefer. Its advantage lies in its broadbanded nature - it
can cover almost the entire 80m band with a VSWR of 2:1 or less at an input
impedance of 50 ohms, meaning it can be directly fed with coax and not need
a tuner. This design uses a parasitic element spaced apart from the driven
dipole element, which makes it bulkier than a simple dipole. It also is
designed solely for use on 80m.

Now, if you're looking for a truly portable 80m antenna for the field or
emergency use that is easily stored and set up, easily tunable and can also
be used on all the higher HF bands, plus 6m, then you should look at my
"yo-yo" dipole. Those of you who have sat through my Tech license class will
know the antenna design I am talking about. Email me if you want a more
detailed description. 

73,

Dale - K4DG

-----Original Message-----
From: hcarc-bounces at mailman.qth.net [mailto:hcarc-bounces at mailman.qth.net]
On Behalf Of Harvey N. Vordenbaum
Sent: Sunday, February 09, 2014 7:26 AM
To: 'Gary J - N5BAA'; 'SARA SANDSTROM'; 'H - Reflector'
Subject: Re: [HCARC] 80 meter short distance comm & Field Day

During our "in-house" Field Day at the RC radio room several years ago Bob
Richie traveled to Sonora and put up a 80 M antenna and contacted n5hr here.
Hv

-----Original Message-----
From: hcarc-bounces at mailman.qth.net [mailto:hcarc-bounces at mailman.qth.net]
On Behalf Of Gary J - N5BAA
Sent: Saturday, February 08, 2014 8:10 PM
To: SARA SANDSTROM; H - Reflector
Subject: Re: [HCARC] 80 meter short distance comm & Field Day

>From my recollection, I heard about the 80M experiment in a conversation
with Dr Jim concerning Field Day.  He was the one who had suggested to me
(not necessarily the first one to suggest it overall) as an experiment
during Field Day.  Dr Jim's thinking I surmise was connected with Bob
Ritchie's scheduling Dale Gaudier to talk about his wide band 80 meter
dipole as the presentation for the May meeting with a follow-up "build the
antenna session" scheduled for the Saturday following.  Newly built NVIS
Dipole antennas and the chance to utilize them in June seemed a natural
progression.  My idea for Field Day is the more antennas the merrier.

I have been working to identify enough of the 4 foot military surplus mast
sections to be able to put up 7-8 40 foot support masts to string antennas
from.  At this point I have identified 72 four foot sections, 50 of which
are the stronger aluminum ones.  We had a problem last Field Day with the
fiberglass ones splitting (principally mine which weren't reinforced - you
know what I am talking about if you have the mast sections).  I have since
replaced these mast sections with the aluminum ones and have donated the
fiberglass ones to the club.  They will work fine, but need one of the metal
hose clamps on each joint to reinforce them.  Since they will only be used
once a year or so, the extra effort to reinforce them is doable.  IF YOU
HAVE MAST SECTIONS AND ARE WILLING TO USE THEM AT FIELD DAY, PLEASE ROGER
UP.  The more masts we can erect the better and it frees us from being
dependent on finding a location that not only has sufficient covered
pavilion space, but also adequate tall trees, etc.  It would be wonderful to
get to the point where holding Field Day is purely a matter of finding
sufficient ground to build antenna mast on, far enough apart for the
antennas.

I also have access to a couple of these "portable garages" if they are
needed. 
http://www.harborfreight.com/10-ft-x-17-ft-portable-garage-69039.html

Gary J
N5BAA
HCARC Secretary 201314
2014 Field Day Coordinator

-----Original Message-----
From: SARA SANDSTROM
Sent: Saturday, February 8, 2014 5:44 PM
To: H - Reflector
Subject: [HCARC] 80 meter short distance comm

I'm not sure who in the club is working the short range 80 meter question.

For everyone's info, here is a list of 80 meter contacts that covered 100
miles or less.  My station consists of an ~70 Watt transmitter and a
Butternut HF2V vertical.  The vertical is not a good choice for a short
range antenna, a low dipole should do better.  Of the dozen contacts, 11
were in the even ing after dark  and 1 was in the morning before sunrise. 
None were pre-arranged.  Two were good CW signals but would probably not
have been useful for SSB, 3 would probably have been marginal for SSB and
the remaining 7 would have produced useful SSB signals. All would have been
adequate for PSK.

The contacts included Junction, Salado, Georgetown (2), Austin (4), Liberty
Hill, Dripping Springs, Round Rock and Selma.  The stations on the other end

were using between 40 and 100 Watts with  verticals, inverted vees, or loop
antennas.The contact with Junction is possibly ground wave.  The contact
with Dripping Springs I believe had both ground wave and sky wave components

do to the fading and multipath echo on the signal.

The problem with using random signals is, except for contests, there is very

little activity (actually none!) on 80 meters in this area during the
daytime.  However, I am convinced that Austin and closer is easily workable
on 80 meter CW using 100 W and almost any antenna at anytime with the
exception of during the day if there is a stro ng X-ray flare on the sun.  I

also believe that the same area can be worked using SSB if low dipoles and
100 W are used.  My experience has been that QRN is lower in the summer
during the day than at night.  I hope that th e club is able to conduct the
80 meter experiment  for Field D ay.  If I 'm available, I certainly plan on

listening for all the rov ers and perhaps I'll get a dipole up for
comparison with my vertical.

Kerry
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