REMARKS and software for Radioamatør Antenne Analysator

UPDATE latest: 20.02.2018

Latest version of software for the analyser with AD8307 Detector is available here:

Latest version is always on the top of the list, and all earlyer versins is included in the latest...

NEWS: Battery has arrived...

What to do...

REMARK, all softwarefiles is stored as TXT-files - MARK the whole file - COPY and PASTE into ARDUINO IDE on your PC. IDE will ask where it should create directory for the file, and you have to reply, and then save the file as an .INO-file.

Furthermore, it should be noted that there are a number of libraries mentioned at the start of the programtext and that there are links to the sites on the web where libraries can be retrieved, but my experience tells me that these files can be updated over time and Thus, it will work with a different functionality, so I have downloaded the working files and thay can be downloaded from the DOWNLOAD page.

All files must be downloaded and extracted in the Arduino IDE Librarie, which will be default as follows:

Once the files are in place, Arduino IDE can be started and Antenne_Analysator1.18.x.ino can be downloaded and UPLOADES to the Antenna Analyzer.


                               The compleated Antenna Analyzer

Software-version 2.18.8 - Codenavn: Charge the Battery

This version is added a testroutine to check the batterylevel.

If the battery voltage goes under 8 Volt, the tekst in the picture:

Charge the Battery!

You have to go into the OPTION and start TEST BATTERY, for details.


Software-version 1.18.7 -
Now you can move the frequency in this image by turning the Rotator.

The frequency moves 10,000 Hz per click, one way or the other, and the measurements are measured immediately and appear in accordance with. SWR and RTL.

In this way, a resonance point can be determined, with precise measurement.

See also the DEMO Video, which deals with all previous changes and additions.

2018.2.19: Added surveillance of the battery in this picture, so if the battery comes under 8 volts, it will be written at the bottom of the image, 

"Charge the Battery!". 

Furthermore, the background color is changed to BLACK in this picture, to avoid too much Flikker.

Software-version 1.18.6a -
Codenavn: SERIAL
The SERIAL function under OPTION is enabled in this version.

The antenna analyzer is connected to the USB connection to the computer, and ARDUINO IDE is started and the latest software version LOADES into IDE and UPLOADES.

Serial Monitor is activated at 9600 baud speed.

The Rotary Encoder button selects the file to be DUMPT, and the image to the left is displayed.

Pressing the Encoder button starts DUMPING.

DATA can then be marked in Serial Monitor and copied to, for example, a .CSV file that can be saved, or imported to EXCEL spreadsheet where they can be further processed.

In this way, DATA can easily be saved in a file on the computer, or ported to, for example, an EXCEL Spreadsheet, and as shown below, there will be no difference in the graphics.

Next best method is to remove the SD and insert the card into your computer.

Software-version 1.18.6 - codenavn: Batterytest

The new Software version 1.18.6 is equipped with a new OPTIONS for battery voltage testing.

For this reason, 3 resistors should be added, as shown in the picture. This can be done while the PCB is in its built-in box, simply lifting the display.

3S 10A Li-ion Lithium 18650 Battery Cell Charger 
BMS Protection PCB Board 12.6V

This can be found on this address:

... and is precisely made to cope with this task ...

The 2 resistors on the left are 13 K Ohm, in series = 26 K Ohm.
All resistors are at least 5% resistors or better.

The resistance to the right is 4.7 K Ohm, and is mounted in extension with the first 2, and is wired to a frame terminal on the right side of the image.

It could also have been connected to the voltage regulator leg straight
under the 2 resistances that form the reverse V.

The focal point between the 26 K Ohm and 4.7 K Ohm, is led to Analog
pin 15 (counted from the left in the top double row, PIN No. 8, and most
To the left of the image, the resistor is soldered to the voltage regulator
input terminal.

In this way, a voltage divider has been created so that the construction
can be supplied with a MAX voltage up to 15 volts without the MEGA 2560's analog port is printed more than 5 volts, which the MAX can withstand.

The following pictures show addition and operation. When the voltage is below 8 Volts, the text "Charge the Battery !!!" with flashing white color. RED text is not seen too well.

The red BAR does NOT mean that the antenna analyzer no longer works - it continues to work until the voltage is below 6 Volt or lower, but from 7.5 to 7.0 Volts, the measurement is changed to a 75 Ohm LOAD, which shows 

SWR = 1: 1.5, to 
= 1: 1.4, with the same calibration.

If you want to measure and only have 7 volts available, a new calibration must be made and if calibrated at 7 volts, the result will be OK.

Nevertheless, do not wait to
mount the battery for charging when YELLOW BAR apears, or until it change to RED BAR.

Batterys has arrived from China

... and also battery charger-distributors, which will protect the batteries against

Here is a double-sided foam tape mounted and connected to the charger (BLACK / RED cord. 

The battery charger distributor works in such a way that when the battery is full charged, the battery and power supply will be disconnected from charging the battery and it works just fine.

In order to be able to charge the battery, an alternative input must be added
den udvendige strømforsyning.

This is done by installing an additional port, which connects directly to
Batteri-Charger +/- in the left side of picture.
In this way, the battery can be recharged without switching on
ON/OFF-Switz on the Antenna Analyzer.

In addition, a 3-pole switch must be installed to switch OFF the connection to the 3 voltages 4.2, 8.4 and 12.6 volts under normal Use.

With AA, it is meant that power can be drawn by the Antenna Analyzer. With the switch in "CHARGE", a power supply can be connected MAX delivers 1,625 Amp. and 12.6 - 13.5 Volt to make the batteries full charged. 

As mentioned above, the controller-print interrupts the connection between power and batteries when fully charged and protects hence the batteries for overcharging.

PANASONIC prescribes that these batteries can be recharged to full power with 1625 mA for 4 hours, which should give a voltage to MAX = 12.6 Volt.

Here you can see that the power limiter is active (the red lamp) and has pulled the voltage down to 11.6 volts, to hold the 1.61 Amp. like MAX. power and I can see that the tension is slightly increasing as well charging takes place ...

When charging reaches the end, it can turn on and off some times before it is finally extinguished, which is clearly apparent power consumption of the supply.

Here is a diagram of charger and how
The batteries are connected to a 3-pole switch,
to switch between usage and charging.

The Batterys is in order...

Now the final batteries from Holland are awaited, 3.7 * 3 = 11.1 Volt as a starting point, with a capacity of 3350 mA, and could probably provide 8 to 9 hours of operation - ... and then they can be in the box. I have ordered the batteries equipped with soldering flaps so that they can be serially connected by soldering and thay can be ordered, on link to in the picture below.

This page describes a bit about the performance of these batteries:

If you use batteries other than the above, specifications may be
be different, as some batteries of the same type 18650 are
specified as 3.7 volts, others like 4.2 volts, ie as min and max,
and why that difference can be in pure marketing and probably not
something with lifetime or charging time to do.

Software-version 1.18.5 - codenavn: Calibration

This is the first version of the software for the Antenna Analyzer, which is rebuilt to use an AD8307 as a detector. 

The principle of measurement with AD8307 is that, as a rule, FORWARD power is not measured
by making a calibration table stored in EEPROM on ATMEGA 2560.

Next, only the reflected effect is measured with AD8307, and the difference between the FORWARD of the table and the measured REFLECT, both in dBm, gives the result in RETURN LOSS. Return loss can then be converted by calculating the Reflection coefficient, which is added to the general SWR calculation. 

Therefore, it is also seen that by measuring on a frequency (3rd image) including RETURNLOSS as part of the result, along with VSWR.

START Calibration

While this image is on ( for 3 seconds), press the Rotary Encoder button and held down until the image disappears.

This will start calibration of the antenna analyzer, which must be without DUT.

This calibration is, in principle, only necessary the first time the analyzer is started or if it is operating under high temperature fluctuations, such as outdoors in winter.

The calibration traverses the entire range from 600 KHz to 29990 KHz, with 200 KHz jumps, and stores data in EEPROM in ADMEGA 2560.

The calibration notes the FORWARD signal in a table and is necessary because the output of the generator (oscillator) decreases at increasing frequency and therefore is not the same at all frequencies.

The FORWARD signal is called again when the program needs to use them when calculating VSWR and Returnloss.

By looking at calibration data while calibration is running, DATA is seen as a Negative Number.

The oscillator is measured with unloaded DUT - result is noted in the table, and an antenna connected to DUT will reflect the part of the signal it applied for, like RETURNLOSS in dBm.

The calibration numbers represent the sensitivity of the unloaded DUT on AD8307 at the given frequency, and in the example, -84.66 is expressed in dBm.

For a measurement of eg an antenna, take a corresponding measurement, for example, -70.72 dBm, the difference is as follows:

  (-84.66) - (-70.72) = -13.94, which is dBm RETURNLOSS

 which can be converted into: 

               VSWR approx. = 1: 1.50 

... corresponding to a LOAD of 33/75 Ohm.    

The measurement method described here is extremely precise.


The Sweep image has come to look like this with the new colors.

The RED cross in the RESONANS point is the frequency at the top of the image.

Here are the new colors in the tape chart,
with the best SWR on the 60 meter band as 1: 1.00.