This note is relative to the "field day" portion of the subject line. The
NVIS portion has been discussed previously.
The Jan 2022 Winter Field Day rules are available at www.winterfieldday.com.
Portable, outdoor and home stations are allowed.
73,
Henry - K4TMC
On Fri, Dec 17, 2021 at 9:14 AM
A couple of historical references on the current topic:
https://www.mpoweruk.com/papers/Radcom_NVIS.pdf
https://www.mpoweruk.com/papers/Arnhem_NVIS.pdf
Interesting articles. Lore notwithstanding!
Merry Christmas to all.
AG6CX
Sent from my iPhone
> On Dec 23, 2021, at 8:23 PM, Bill Parso
Dean Straw's December 2005 NVIS article with color graphics appears to be a
public access document and archived at the ARRL website at:
http://www.arrl.org/files/file/QST%20Binaries/Straw1205.pdf
The version retrieved in the standard ARRL members only archives accessed
at the Technology tab Period
Thanks to Bill Parsons-AF6AE for the tip on the QST December-2005
article. Pulled it out and scanned it over (will read more thoroughly
later) but interestingly showed how 80/40m coverage varied by time of
day (which was demonstrated real-time in the 1980's on the Iditarod
trail working into A
Thanks Jim.
I was glad that Dean deviated from the usual zero dB reference style of
many ARRL antenna patterns and addressed NVIS propagation for the EmComm
(Emergency Communications) audience with signal levels over geographic
regions and graphs with your style of everything plotted on the same g
Take a look at Dean Straws NVIS article (with color graphics) in the
December 2005 issue of QST for a discussion of optimizing antenna height
for NVIS based on signal to noise ratio and region you wish to cover. Most
if not all of that article appears in the 23rd and 24th editions of the
ARRL Ante
You're correct - it hasn't been stated anywhere but that won't stop some
from refuting it as if it were ;-)
John AE5X
https://ae5x.blogspot.com
>I’ve scanned back through this thread and I don’t see where anyone said
that their signal got stronger by lowering their antenna. Maybe I missed it
some
I agree. I never said, believed or thought an NVIS antenna HAD to be low, I
just said it COULD be low.
In fact I was banking on the fact that making it low would make distant signals
weaker. ;-)
73,
Dave - N5DCH
> On Dec 18, 2021, at 4:18 PM, Jim Brown wrote:
>
> On 12/18/2021 2:31 PM,
On 12/18/2021 2:31 PM, David Herring wrote:
Putting a dipole at about 10 feet (plus or minus, I don’t recall the exact
height) accomplished everything I wanted. I worked, on a daily basis, hams at
all points along the length of the State of Hawaii, I experienced reduced band
noise, and I did n
I’ve scanned back through this thread and I don’t see where anyone said that
their signal got stronger by lowering their antenna. Maybe I missed it
somewhere?
To be clear, in my specific case, I was crafting a purpose-driven antenna. I
wanted an antenna that would provide reliable, continuous
Just a comment on low dipoles:
On the Iditarod Dog Sled Race (Alaska) we had ham stations located in
remote located checkpoints (total bush-no telephone or other utilities).
We used 80m and 40m to communicate with race HQ in Anchorage over
paths of a couple hundred miles to 600 miles, or so.
NVIS information is almost always anecdotal and a myth, more than science!
As I have told many participants in many presentations, "If you think
lowering your antenna will make your signal stronger, expect your QSL cards
to arrive on a unicorn." How many of you looked at Jim's, K9YC,
explanation?
I'm about 25 km LOS from W7RN. W7RN is 30 over S9 here on 160, 10 over
on 80, about S7 on 40 anytime. I can barely see it on the P3 [and it's
QRK2 in the noise on the headphones] on 20, and missing above 20. K2RD
in SW Reno is a bit closer, but the same prevails for the ground wave
for Ira.
but having a low antenna goes a long
way toward limiting the contacts you make to NVIS propagation.
I suspect you could accomplish the same result simply by reducing
transmitter power.
A dipole 1/4 wavelength high has a nearly identical radiation pattern to
one close to the ground. It just
>You might want to consider doing this within the Winter Field Day event.
That's a great suggestion.
Those are correct who say that an antenna (dipole) doesn't have to be low
to the ground to make use of NVIS - but having a low antenna goes a long
way toward limiting the contacts you make to NVIS
For 80M NVIS I put up a 'improved' extended double Zepp (315' long
designed by N6LF) at 30' with a wire reflector 5% longer buried an inch
in the ground. There is a 4:1 balun at the center with a coax feedline
to the shack. Covers entire band under 2:1 SWR. Email for more details
if desired.
I put up an NVIS antenna for 80m a number of years ago. It works great
for local 80m nets.
It is a full wave length loop (more square) mounted about 10' above the
ground.
It is feed with 450 ohm ladderline from a 1:1 current balun at the ATU.
EZNEC shows the radiation is UP.
It also shows gain
On 12/18/2021 1:09 AM, Ken WA8JXM wrote:
Some people may be
confusing groundwave (usually up to 25 miles) with NVIS.
Yes, AND groundwave weakens drastically with increasing frequency. With
average soil, a station operating on 550 kHz will be 21 dB stronger at
100 miles than a station running
--- "In Hawaii, 40 meters worked great for NVIS probably 11 out of 12
months a year. Someone else who knows can comment, but I got the impression
that 40 meters almost never works for NVIS in the mainland US. If this is
true, an Elecraft NVIS field day might be limited to those who either have
roo
It is absolutely true that antennas intended for NVIS use do not have to be
hung low. But they CAN be. And there are instances where doing so can be
desirable.
When I lived in Hawaii, we used NVIS for reliable statewide HF communications
to very good effect. When I hung my dipole up about 30
Wait, why would people think verticals are good for NVIS? Isn't a
vertical's radiation pattern pretty much "sideways but not up", and NVIS'
desired radiation pattern "up but not sideways"?
On Fri, Dec 17, 2021, 12:54 Jim Brown wrote:
> On 12/17/2021 6:12 AM, Greg Herman wrote:
> > What if there
On 12/17/2021 6:12 AM, Greg Herman wrote:
What if there was the annual event called the The Elecraft
NVIS field day?
There is a major myth regarding NVIS that antennas must be low. This is
totally false. The facts are that vertical antennas are terrible for
NVIS, and that horizontal antennas
Greg,
You might want to consider doing this within the Winter Field Day event.
There are 'indoor', 'outdoor' and 'home' categories. The next event is Jan
29-30, 2022. See www.winterfieldday.com for details.
I had fun operating the event in Jan 2021 from a portable beach house site
using a K3/10
This is just a suggestion and forgive me if I’m not aware of something that
already exists. What if there was the annual event called the The Elecraft
NVIS field day?
As we all know Elecraft plays well with others, and along that theme
everybody would be welcome to participate in such a field day
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