Re: Help reading Antenna plots
This is the antenna when it its wound to the 14m markers so even shorter than the 7m marker on the wires.
This position gives good readings for the 40, 15, and 6m bands i think i will leave it here for now not sure why i don't get the 14m band when the antenna is on the 14m marker but i suppose that could be the effects of how low it is to the ground perhaps.
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Re: New firmware from DiSlord 1.0.39
Hi all,
Where do I get the latest DiSlord firmware download for my Nanovna H-4?
I¡¯m using windows 10 on my computer and have never tried DiSlord firmware on my nanovna as yet.
Any help gratefully received.
Regards Chris
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Re: Help reading Antenna plots
Kind of weird its now stretch out as long as at it can be and it seems to be acting as though i shortened it i would have expected it to move lower. There are a lot of areas under 3:1 but they line up with the HF bands. If i read it right I almost think it was better at the 7Mhz markers but i could be wrong. I really need to figure out a way to get one end up 25 feet on the back of my house next although I am gonna take a 12 foot piece of ABS pipe i have out there tommorow and push the centre with the balun up high like a short inverted V
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Re: Help reading Antenna plots
I like data modes and i am a night owl so I think i am more interested in getting the 80m band I am gonna test it down the other side of the house i have 123.5 feet between the fences along that line although i am not sure the gypsy is actually that long. Then test it a gain since I am really learning how to get the most out of the nanovna and interested in seeing where the graphs move with it stretched out the max. If i search around the web it points me to a 9:1 balun if i go to an end fed configuration.
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Thank You Martin
Just what I needed right now.
Easy to follow and understand even for an old fart like myself. It does in seconds what used to take hours with pen and paper or XL spreadsheets and smith charts.
Can't wait for delivery of my NanoVNA H4 with the 4" screen.
Cheers Bob
--
No good deed goes unpunished.
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Re: Help reading Antenna plots
The choke you built is good for center fed doublets - equal lengths of wire
either side of the center insulator. More or less turns on your choke
will not change the resonant points of the wires. If you want to transmit
on 20-meters, you need to shorten the wires appropriately.. The receive
function is not nearly as critical as the transmit properties of an
antenna. You may receive well with a random length of wire, but the SWR is
not low enough to keep the transmitter happy. In receive your are dealing
with microwatts. In transmit, you are dealing with 10's of watts.
Microwatts will not burn out much of anything. 10's of watts can burn out
expensive devices.
Dave - W?LEV
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On Sat, Nov 7, 2020 at 1:35 AM <deadman1966@...> wrote: Dave,
Yes it's nicely under 3:1 on 40 and 15 meters for sure and if i had
equipment for 6m its good there as well so i guess if the markers say this
setting is for 7m then would it be right to say it is tuned for 7.0 Mhz or
what the markers say it should be?
Can this be tuned further via custom measurements and tweeking the choke
turns and or core?
I do have to say that despite it being over 3:1 at 14.230 i certainly hear
a ton of stuff there i didn't hear before at s9+10 earlier. What happens
with the kenwood if you try and tune with a match over 3:1 does it give
some kind of warning, lol. I just got this radio a few weeks ago. Have one
cleaned up but still need to clean the gunk from the vco circuit and fix
the key bounce on the other one.
I do have room to make the wires longer so i suppose if i wanted to get
down to 3Mhz it may be possible i think i might experiment with that
tomorrow or later tonight since I am a night owl.
One question on the choke i created, this works great for this ant which
is centre fed. What would I do if i used a single wire instead of this
setup and fed it from one end which is more likely going to be the only way
i can get this thing higher on my property.
--
*Dave - W?LEV*
*Just Let Darwin Work*
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Re: Help reading Antenna plots
Dave,
Yes it's nicely under 3:1 on 40 and 15 meters for sure and if i had equipment for 6m its good there as well so i guess if the markers say this setting is for 7m then would it be right to say it is tuned for 7.0 Mhz or what the markers say it should be?
Can this be tuned further via custom measurements and tweeking the choke turns and or core?
I do have to say that despite it being over 3:1 at 14.230 i certainly hear a ton of stuff there i didn't hear before at s9+10 earlier. What happens with the kenwood if you try and tune with a match over 3:1 does it give some kind of warning, lol. I just got this radio a few weeks ago. Have one cleaned up but still need to clean the gunk from the vco circuit and fix the key bounce on the other one.
I do have room to make the wires longer so i suppose if i wanted to get down to 3Mhz it may be possible i think i might experiment with that tomorrow or later tonight since I am a night owl.
One question on the choke i created, this works great for this ant which is centre fed. What would I do if i used a single wire instead of this setup and fed it from one end which is more likely going to be the only way i can get this thing higher on my property.
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Re: RETURN LOSS TO SWR CHART
David,
Good reference material. I downloaded and printed out the pdf chart from the link at the bottom of the page.
Roger
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Martin:
I believe on page 8 with respect to blue trace (R) and green trace (X), the scale is 20 ohms ¡°per VERTICAL division,¡± versus ¡°per HORIZONTAL division.¡±
Thanks for you effort and contribution to our great hobby.
Ed McCann
AG6CX
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For those who wish to dwell more in the return loss world instead of the
SWR world, or to gain a link between the two, here is a nice online chart
that converts between the two measurements.
--
*Dave - W?LEV*
*Just Let Darwin Work*
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Re: Help reading Antenna plots
Re: your open wire fed doublet,
1. do you attach the Twin lead through a banana plug adapter into the VNA
port 0 and measure directly?
No. If you are referring to the data in the Word write-up, the banana
plugs are terminated with the noted loads - good non-inductive carbon comp
resistors. The VNA is connected to the SO-239. The cal is done at the end
of the cable connecting to that SO-239. The measurement plane is the
SO-239.
When measuring the antenna through the choke, yes, the banana plugs are
connected to the open wire feeder in the shack and the SO-239 is connected
to the VNA. Again, the measurement plane is the SO-239.
2. If so. Do you calibrate the input plane at the plug, (OSL).
The cal is done at the end of the cable that connects to the SO-239 so the
measurement plane is at the input of the choke, SO-239. The cal is done
with HP precision OSL cal standards.
What do use as load? 50 ohms? Or 450 ohms? (Assuring feed Zo = 450 ohms)
In the write-up carbon comp resistors are used at the noted resistances.
In that write-up I am evaluating only the performance of the choke over the
noted frequency range with the noted resistive loads. All cals are done
in a 50-ohm system using the HP precision cal standards. The measurements
are all made using the HP 8753C with the associated S-parameter test set
and the HP precision cal standards.
3. If you attached a 9:1 balun between the trim lead and the VNA, wouldn¡¯t
you calibrate OSL with 50 ohms at VNA input?\\
I do not use or believe in good balun performance with an impedance
transformation. I've measured too many. Many of these on the amateur
market are not baluns, but transformers. Transformers are miserable
performers as a balun, especially with reactive loads and resistive loads
much removed from their design impedance. I do not deal with 9:1
'transformers'. I take what the antenna gives me at the shack end of the
open wire feeders, then propagate that through the CM choke(s), through the
L-Network matching network, and into a final CM choke on the 50-ohm port of
the matching network. The network is designed to take whatever the
antenna/feedline/CM choke delivers to its input and transforms that to 50 ¡À
J0. I do not deal with transformers and/or 'baluns' that include an
impedance transformation. Any impedance modulations in the system are the
job of the L-Network.
Consider my notation of S11 as port 0 on the NANOVNA's and are single-port
reflection measurements. All the measurements from the past are made with
the HP gear only.
Dave - W?LEV
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On Fri, Nov 6, 2020 at 9:55 PM AG6CX <edwmccann@...> wrote: David:
Re: your open wire fed doublet,
1. do you attach the Twin lead through a banana plug adapter into the VNA
port 0 and measure directly?
2. If so. Do you calibrate the input plane at the plug, (OSL).
What do use as load? 50 ohms? Or 450 ohms? (Assuring feed Zo = 450 ohms)
3. If you attached a 9:1 balun between the trim lead and the VNA, wouldn¡¯t
you calibrate OSL with 50 ohms at VNA input?
Thanks for the clarification.
Ed McCann
AG6CX
--
*Dave - W?LEV*
*Just Let Darwin Work*
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Re: Help reading Antenna plots
Baluns
What is a balun really? Something which converts a balanced load, antenna etc to an unbalanced source, a transmitter a VNA etc.
If your antenna is not balanced (a dipole) then you don't need a balun.
A 1:1 balun is really just a choke to reduce common mode currents and prevent RF from traveling on the outside of the coax feed-line which you won't need if you feed it from the 2nd floor straight into your ATU. Feeding the wire from the other end via coax would be better for radiating but then you would have to deal with coax losses and how to ground the braid of the coax at the feed point. Very messy.
These 9:1 "baluns" which are sold with end fed "long-wires" or off center fed dipole antennas are an attempt to bring a random relatively high impedance closer to 50 Ohms or at least within the range of your tuner and allow the antenna to radiate some power. So it's a RF transformer not a balun.
I use a 450Ohm to 50Ohm homebrew balun to feed my balanced & terminated wide-band folded dipole with 50Ohm coaxial cable. The terminating resistor is 450Ohms so I needed to convert from balanced to unbalanced and a RF transformer to go from 450Ohms to 50Ohms.
You don't need a balun, you may need a Impedance transformer IF your tuner can't tune the random wire against whatever ground you can find.
Good luck
73 Bob vk2byf
--
No good deed goes unpunished.
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Re: Help reading Antenna plots
I can't comment on your VNA measurements as I have no experience with VNAs. Mine hasn't been delivered yet but I do know about antennas. Your predicament is not going to get solved with VNA graphs & smith charts.
Were I in your situation, I would certainly feed the antenna from the high (altitude) end and keep the other end of the wire as far away from any metal as possible. I would somehow find a ground from either a water pipe assuming it's not plastic, or at least use the earth wire from your AC mains connection. Feed this via an ATU. My old TS-440 has a tuner built in and drives a 40m full wave loop antenna at 20 feet or so above ground. It works on 80m, 40m, 17m & 15m. Let's say it loads up and radiates. My 10Watt WSPR beacon has been heard all over the world with this setup.
I have used some pretty weird antennas in the past when portable. Fences, disused telephone aerial telephone cables, Power pole strainer wires coming out of the ground. Metal rainwater drain pipes, a 40m dipole laying on the roof of heritage steam train carriage while under way. All good fun and educational.
As we say in VK land , suck it and see. Experiment.
73 Bob
--
No good deed ever goes unpunished.
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Re: Help reading Antenna plots
David:
Re: your open wire fed doublet,
1. do you attach the Twin lead through a banana plug adapter into the VNA port 0 and measure directly?
2. If so. Do you calibrate the input plane at the plug, (OSL).
What do use as load? 50 ohms? Or 450 ohms? (Assuring feed Zo = 450 ohms)
3. If you attached a 9:1 balun between the trim lead and the VNA, wouldn¡¯t you calibrate OSL with 50 ohms at VNA input?
Thanks for the clarification.
Ed McCann
AG6CX
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Re: Help reading Antenna plots
At the very end of your plot, you might squeeze in 50 MHz, 6-meters, as
well where you should not need a tuner.
Dave
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On Fri, Nov 6, 2020 at 9:25 PM David Eckhardt <davearea51a@...> wrote: You're certainly looking good at 40 and 15 meters. Also at 36 MHz where
we don't have an allocation. Looks very good!
Now, you might zero in on both 40 and 15 meters and do a measurement of
those bands to assure you are less than 3:1 over the whole band. Set up to
scan 7.000 to 7.300 MHz (40-meters) and 21.000 to 21.350 MHz (15-metes).
That will tell you whether the internal tuner in the Kenwood will correct
for SWR. I have the TS-2000X and its internal tuner will properly match up
to and including 3"1 SWR, but not much more. Most of the internal tuners
stop at 3:1.
On your return loss plot, only these two amateur bands show less than 6 dB
which is an SWR of 3:1. So, you are limited to those bands.
Dave - W?LEV
On Fri, Nov 6, 2020 at 8:48 PM <deadman1966@...> wrote:
I have the antenna spooled out to exactly the 7Mhz silver markers on the
wire here is the readings on the antenna with my homemade choke on it. Not
sure what other improvements i can make yet. Based on the readings are
there frequencies i should not transmit on I really don't know how the AT
unit works in the kenwood and how much range it has to correct SWR.
--
*Dave - W?LEV*
*Just Let Darwin Work*
--
*Dave - W?LEV*
*Just Let Darwin Work*
|
Re: Help reading Antenna plots
You're certainly looking good at 40 and 15 meters. Also at 36 MHz where we
don't have an allocation. Looks very good!
Now, you might zero in on both 40 and 15 meters and do a measurement of
those bands to assure you are less than 3:1 over the whole band. Set up to
scan 7.000 to 7.300 MHz (40-meters) and 21.000 to 21.350 MHz (15-metes).
That will tell you whether the internal tuner in the Kenwood will correct
for SWR. I have the TS-2000X and its internal tuner will properly match up
to and including 3"1 SWR, but not much more. Most of the internal tuners
stop at 3:1.
On your return loss plot, only these two amateur bands show less than 6 dB
which is an SWR of 3:1. So, you are limited to those bands.
Dave - W?LEV
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Show quoted text
On Fri, Nov 6, 2020 at 8:48 PM <deadman1966@...> wrote: I have the antenna spooled out to exactly the 7Mhz silver markers on the
wire here is the readings on the antenna with my homemade choke on it. Not
sure what other improvements i can make yet. Based on the readings are
there frequencies i should not transmit on I really don't know how the AT
unit works in the kenwood and how much range it has to correct SWR.
--
*Dave - W?LEV*
*Just Let Darwin Work*
|
Re: Help reading Antenna plots
I have the antenna spooled out to exactly the 7Mhz silver markers on the wire here is the readings on the antenna with my homemade choke on it. Not sure what other improvements i can make yet. Based on the readings are there frequencies i should not transmit on I really don't know how the AT unit works in the kenwood and how much range it has to correct SWR.
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That sounds like an excellent idea!
Roy
WA0YMH
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On Fri, Nov 6, 2020, 1:36 PM n5kzw <n5kzw@...> wrote: Dental floss is a good way to cut through the adhesive, and it doesn't
stress the LCD.
Ed - n5kzw
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Re: Help reading Antenna plots
To measure the total inductance, or more importantly, the +jX of the
windings: Short both conductors together at both ends so the choke forming
a single conductor consisting of two paralleled conductors on the core.
This is for test purposes, only. Then connect one end to the S11 center
pin and the other to the S11 backshell. Then, on the Smith Chart using the
cursors, you can measure the total inductance and +jX of the windings on
the core. To provide adequate choking, the total +jX should be at least 5
times the system impedance (some state 10X). For a 50-ohm system
impedance, this, of course would be +j250, ideally at the lowest frequency
of interest. If you don't want 160-meters, that requirement becomes much
easier to reach.
With my doublet fed with open wire transmission line, I measure (from 1.8
through 29.5 MHz) : real: 25 to 5 ohms ¡ÀjX: -200 to +80
So I have read data to address with my choke designs. You might make the
same measurements of your antenna to properly design your CM choke as I
have. No single solution fits all applications. Fortunately, with the
advent of the NANOVNA's, we now have the tools to measure and to design to
what we have installed as an antenna.
Dave - W?LEV
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On Fri, Nov 6, 2020 at 6:03 PM AG6CX <edwmccann@...> wrote: Martin:
Re:
If you wish to examine the common mode impedance of chokes like this,
connect the VNA across the windings between both wires of the Balun
connected together at the input and output of the choke.
Could be a bit more specific about the connections,? Can¡¯t quite figure
out your suggested wiring.
Thanks.
Ed McCann
AG6CX
--
*Dave - W?LEV*
*Just Let Darwin Work*
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Dental floss is a good way to cut through the adhesive, and it doesn't stress the LCD.
Ed - n5kzw
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Chris
Bob
Roger Need
