You need to calibrate your coax SOL at the far end, so your readings look
like your antenna is at the vna and not some distance away.9
On Mon, Mar 31, 2025, 12:58 AG6CX via groups.io <edwmccann=
[email protected]> wrote:
Maynard and others:
You and we were most fortunate to be initiated with one of the most robust
sunspot cycles of modern times in 1957!!
Same story at pre-Nano VNA KN1CJO in southern Maine. Worked all over the
place, including all TV sets in the neighborhood.
Antenna was classic Windom, usual length, but fed with 300 feet of single
wire to bannana plug into the DX-20 antenna port, me serving as T-R relay.
We are equally fortunate to still be able to remember all that, and be
alive to write about
Ed McCann
AG6CX
Sausalito
On Mar 31, 2025, at 8:45?AM, Maynard Wright, P. E., W6PAP via groups.io
<ma.wright@...> wrote:
?I got my Novice license in 1957 and used a single wire routed out the
window and up to the brick chimney and then across the yard about 100 feet
to a pole. It worked fine, with my best DX using a Knight Kit 50 watt
(input) transmitter being an Argentine station in Antarctica. I worked a
few Japanese stations and some South Americans from my QTH in Northern
California, never realizing that my antenna was really awful.
When I upgraded from Novice to Conditional in 1958, I used a 100TH with
the same antenna to work folks on AM and CW. With either transmitter, I
had to stand up and throw a knife switch on the wall to go from receive to
transmit.
I also still have a bunch of QSL cards from that era that bring back
nice memories.
The important thing was that my Knight Kit with a pi-network and my
100TH with a swinging link coupler didn't care much about the SWR. I
simply tuned for about a 10% drop in plate current and no red glow from the
100TH and everything worked fine. With a modern transmitter that wants
something approximating 50 ohms, such an antenna would require a tuner and
the losses in the tuner might use up a lot of the generated RF energy.
My most modern rigs here still use pi-networks, which is why I can get
away with using a wire in the attic draped over air conditioning ducts and
water pipes and work DX, not like a real DXer would want, but enough for a
casual guy.
73,
Maynard
W6PAP
On 3/31/25 08:07, Jon via groups.io wrote:
Joe,
I got licensed a decade after you and did not have a chance to use a
balun
or 50 ohms coax then. My 40 and 80m dipoles were fed by 75 ohms TV
cable. I
did not have an SWR meter either. Still I could work a lot of DX
including
a few W land stations with my homebrew 3 x 807 radio, 120W CW and
straight
key. I still have a couple of W land QSL cards in my precious
collection.
73
Jon, VU2JO
On Mon, Mar 31, 2025 at 7:50?PM Joe WB9SBD via groups.io <nss=
[email protected]> wrote:
Yup!
The Balun Craze is a new Generation thing. Got licensed in 1975, Never
ever heard of a Balun.
All my dipoles were direct feed.
Only till recently has the myth of a dipole without a balun will not
work.
just like a 40 meter Dipole will not work on 15 meters!
tell that to all the Novices that got their license in the 70's.
Joe WB9SBD
On 3/31/2025 8:53 AM, Zack Widup via groups.io wrote:
I have never seen a problem feeding a dipole directly with an
unbalanced
feedline. The last dipoles I had up (which were for 40 and 30 meters)
were
just fed by connecting the two leads of the coax directly to the
antenna
wires attached to an insulator at the center of the antenna. SWR in
both
cases, when the antenna was trimmed, were around 1.05:1. And I worked
180
countries on 40 m CW with that antenna and Japan fairly often on 30 m
CW.
Zack W9SZ
<
Virus-free.www.avg.com
<
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
On Mon, Mar 31, 2025 at 7:59?AM Bob Ecclestone VK2ZRE via groups.io
<becclest@...> wrote:
Hello Hobride,
Unfortunately you have not supplied a photo of your test setup.
A dipole is balanced at the feedpoint, your VNA is unbalanced.
I suspect your problem is that you do not have a balun or choke at
the
antenna feedpoint to prevent the feeder from affecting the
measurement.
I won't make any guess as to why the VSWR appears lowest at 513MHz,
but
I do suggest you use a balun or choke at the antenna.
HTH...Bob VK2ZRE
On 31/03/2025 11:25 pm, Milton Engle via groups.io wrote:
You did not indicate the range of your sweep.
Try setting the sweep range to 150MHz to 190MHz, recalibrate
open/short/load, then measure.
I suspect that you will find the lowest VSWR near 171MHz, indicating
that the element lengths are a bit long.
The third harmonic of 171 is 513
Milt
N3LTQ
On Mar 31, 2025, at 03:51, hobride via groups.io <hobride=
[email protected]> wrote:
?Hello everyone,
I have bought a NANO VNA H4 to build simple dipole antennas.
Now I have made a simple dipole antenna for testing. This should be
tuned for 172 MHz. The total length is ~83 cm (2,72 feet), one leg is
~41.5
cm (1,36 feet).
When I now connect this antenna and try to measure it, the result
is a
lowest SWR (1.15) at 513 MHz.
Can this be possible? I am not a radio specialist. I am an IT guy.
I have flashed the NANO VNA H4 to the latest firmware (tried
DiSlord
and Hugen) and also calibrated it.
Perhaps I need to make further settings after flashing?
