ICOM AH-4 tuning aid with any radio

 Somehow, you end up into an ICOM HF eco-system.

You have an IC-7300 or 7100 or 7000 or anything else; a radio that can do HF and you also have an IC-AH-4 the "wonder ATU" from ICOM.

You mod it to be more modular and portable as I did, ready for field use.

Maybe you want to use some other radios on the same antenna system or you want to go portable with a Xiegu G90 and you said to yourself: "I could put that AH-4 to good work but the ATU will not work with anything but ICOM radios".

Well, you may be wrong!

The AH-4 can and should be used with other radios because it is a small gem! But how?

A small independent control box can be used with other radios to tune various antennas, from wires to loop antennas and this is what I done recently.

It is in a crude form, maybe I will make it with the help of a microcontroller or maybe I will leave like it is now because, it is working well!

What do you need?

-ICOM AT connector;

-One Red and one Green LEDs

-Two PCF817 or similar optocouplers;

-Two 1N4148 or 1N4001 diodes (not mandatory);

-Three resistors between 1.2 KOhm and 2.2 KOhm (these values where tested);

-a temporary SPST push button;

-a small test PCB or any other solution to mechanically fix all together.

The schematic:

How this is working?

Power up the box. The Green LED will lit.

START and KEY have 5V (UP).

Set the radio to 5W in carrier mode (AM, FM, CW) and press PTT or CW Key.

Momentary press the button TUNE. The RED LED will lit.

The START line (from radio to ATU) will go down; the ATU will respond with KEY going down for the tuning cycle (request for carrier). Side note: if you didn't press the PTT or the CW Key before pressing TUNE, now it's the moment to do that!

During the tuning cycle, the AH-4 will request from the radio (which is not connected to the control lines) to transmitt a 5 W carrier. 

Thus the IC-1 LED will lit and the corresponding transistor will keep START line down as long as the tuner need for the tuning cycle. Keep PTT or CW Key pressed on the transmitter.

When the RED LED is going off, the tuning solution is achieved.

Note: there are situations when the tuner will not find a solution for the antenna; the RED LED will go off and will lit again, the tuner will start a second sequence then will go in bypass mode.

I suggest using a small SWR meter between the radio and the ATU or watching the built in SWR meter to be sure a tuning solution was aquired.

This is my version:

The LDO is not used, it is for "further developments and upgrade"!

Yes, I know, it's ugly! I don't care about at this stage. 

It is temporary and it's working. 

The next version will be with a nice MCU, WiFi and Bluetooth controll and probably with RF sensing for auto-tuning!

Kidding but why not trying something like that? 

Are you a brave ham?

73 de Adrian YO3HJV

ICOM AH-4 Automatic Antenna Tuner modification for RVSU

The Spring is here full power so is the war just North of Romania so our Emergency Communication Team (RVSU) is preparing for... field day!

Our standard in HF EmComms are ICOM radios and ATU's; we are using IC-7100 as our main HF radio paired with T2FD antennas for NVIS and AH-4 with verticals and wires for various Long Range HF.

In this post I will briefly show one modification for the AH-4 Automatic Antenna Tuner (one of the best in my opinion, for 100W output power).

It consist in changing the way the Coaxial RF cable and the Control cable are connected.

Because our concept is based on modular kits, the AH-4 must be able to be installed quick, reliable and we must have provisions to modify the setup if the field conditions required so and this must be done by operators with minimal training.

The standard ICOM AH-4 box include, among other things, a 10m LMR coaxial cable and 10m of 4 wire control cable terminated with the infamous MOLEX connector present in ICOM HF radios.

The way those cable connect to the Tuner box is pretty against "field use" principles therefore, a solution must be found.

After a few years of playing with my own AH-4, I concluded that it is not acceptable to open the case of the tuner anytime the cable must be connected or disconnected.

Another problem is the fixed lenght of the cables. Just 10m might not be enough in certain scenarios and while another coaxial can be added with the help of a female-female adapter, require intimate knowledge from the field operator and present some fatal risks for the integrity of the radio or the ATU if the wires are connected in the wrong way. 

So, another solution must be found!

We are not using the ATU in permanent setup so, some measure originally designed to prevent the water or moisture ingress can be reduced in order to accomodate some that can give more simplicity in installation and use.

First, the RF connector must be moved from inside the ATU to the outer case. 

The SO-239 (UHF-female connector) will be seated just where the cable clamp was. 

The connector is a good quality one, from Amphenol.

Unfortunately, the plastic will not support the mechanichal stress  of the connector so a small plate was cut from a piece of Aluminium.

Then, the ATU's case was prepared to accomodate the SO-239; the backplate was threaded for 3mm screws for better electrical contact.

Everything fits.

The lower left screw is longer. This is because there will be the Ground connection for the small piece of coaxial cable from SO-239 to the ATU's PCB.

This coaxial patch was made from some cable left from GSM sites and I know it can handle easy 100 W up to 100 MHz. So, I prepared it to be used here.

I removed the original piece of metal with the old SO239 and make some scratches on the Ground pad to install the coaxial patch.

I found a little piece of metal, soldered it onto a metal shield and put some heat shrink tube on it to fix the coaxial patch firmly in place:

Looks good and it is the time to take it to the next level: the control cable.

A few words about choosing the right cable:

In the field you need various lenghts of cables. Often those cables are cut, lost, or even forgotten at the base.

The ATU is drawing less than 1 Amp, typical around 200 mA. The control signals are at TTL logical level (5V) and the "protocol" is nothing more than pulling to ground or to +5V so nothing special with this cable must be observed.

Can be a cheap cable and it is desirable to be found easy. Long story short: what if I could use a FTP cable? Well, on my balcony I have an AH-4 which is connected to the radio with this kind of cable and for 2 years performed extremely well.

The problem with my AH-4 is that i modified it very ugly; the female RJ-45 connector is placed on a cut into the case and, believe me, it looks bad! 

In this case, I decided to use something that I already have in my junk box from a never-finished project. A RJ-45 female-male patch cable designed for panel mounting.

I was a little bit nervous because I thought the lenght of the patch cable was not enough to go from the upper case of the ATU to the PCB...

Checked and it was just the right lenght! So, I could start making the square hole from the round one!

... it fits now:

And this how it is. I put some hot glue to seal the holes but I forgot to take pictures...

At the other end of the control cable, a wall RJ-45 connector was tied to a MOLEX ATU connector. Fortunately, I bought some kits a long time ago so I could make it fast.

This is the electrical diagram for the RJ-45-MOLEX adapter:

... and this is how it looks:

Yes, I know, it's horrible but this is what I found at nearest store to me. I promise I will search for other solution but this is it, for now.

Now we can use (almost) any lenght of network UTP cable and (almost) any lenght of coaxial changing them in the field. And, if there is need for the network cable to our applications and no need for HF, we can use the cable for that purpose.

I hope this is an usefull ideea and will inspire other "brave hams"...

Some notes:

73 de YO3HJV, Adrian.

CW and Voice memory keyer for ICOM IC-7300

After a long time I decided to came back to CW.

Just for fun and to use the Pandemia holiday I thought will be interesting to have a little remote for the Voice and CW memory.
While the Voice memory callback is relatively simple with CI-V protocol, for CW memory there are no commands provided by ICOM.
Therefore, the keyer will store the preset messages (10 messages) and send them using a 4 x 4 keypad.
The uC of choice is an Arduino with Atmega 328 on UNO platform.
The keypad is also used to Power On and OFF the radio and TUNE the ATU (I use an AH-4).

The 4 x 4 keypad is able to send: -In CW, 10 preprogrammed CW messages, each of 128 bytes; -in SSB, AM, FM, 8 prerecorded voice messages -"A" is Power ON -"B" is Power OFF -"C" is TUNE

Here is a small video on youtube about this


Here is the code

Arduino Energy-meter

A few days ago I was contemplating a little device from a hobby store. It was a smart power gauge meter for tracking the charge and discharge of a battery.
I was wondering if I cannot do it by myself with a Arduino Uno board and some current sensor.
As I'm not a code-freak dude, I did a little research and found a nice start for my project, right here.
I do have a ACS-712 for 5 Amps and also for 30 Amps.

I decided to start with the little one as my project is designated for my portable HF backpack based on ICOM IC-703.

As the Arduino ADC input cannot accept more than 5V, a voltage divider has to be used.
Is the classic one, in wich I used a 10 kOhm from A4 to ground and a 100 kOhm from A4 to the probe. I used SMD resistors but after I measured the ratio I found that the real ratio is not 10 to 1 but somewhere around 10.93:1.
It is important as this ratio will be used to calculate the voltage into the Arduino code.
I modified the code from Instructables because it had some major measurement errors inside as it was written for ACS715 and I do have some problems here with the libraries since I tried to do some tests with I2C LCDs... Also, I found a lot of discussions about how that code is not working properly.

So, below  is my version of the code of the Energy meter with ACS-712-05T.



The code is heavily commented so, I believe is easy to understand what is about.






#include <Arduino.h>
#include <Wire.h>
#include <LCD.h>
#include <LiquidCrystal.h>

/* This sketch describes how to connect a ACS712 - Bidirectional Current Sense Carrier
to the Arduino, and read current flowing through the sensor.

*/

LiquidCrystal lcd(8, 9, 4, 5, 6, 7); // Easy to connect the LCD Shield

/*

Vcc on carrier board to Arduino +5v
GND on carrier board to Arduino GND
OUT on carrier board to Arduino A0

Insert the power lugs into the loads positive lead circuit,
arrow on carrier board points to load, other lug connects to
power supply positive

*/

  int batMonPin = A4;           // input pin for the voltage divider
  int batVal = 0;                     // variable for the A/D value
  float pinVoltage = 0;           // variable to hold the calculated voltage
  float batteryVoltage = 0;

  int analogInPin = A0;          // Analog input pin that the carrier board OUT is connected to
  int sensorValue = 0;            // value read from the carrier board
  int outputValue = 0;            // output in milliamps
  unsigned long msec = 0;
  float time = 0.0;
  int sample = 0;
  float totalCharge = 0.0;
  float averageAmps = 0.0;
  float ampSeconds = 0.0;
  float ampHours = 0.0;
  float wattHours = 0.0;
  float amps = 0.0;


void setup()
{
                                               // initialize serial communications at 9600 bps:
  Serial.begin(9600);
  lcd.begin(20, 4);
}



void loop()

{
 
  int sampleBVal = 0;
  int avgBVal = 0; 
  int sampleAmpVal = 0;
  int avgSAV = 0;
 
      for (int x = 0; x < 20; x++)                 // run through loop 20x


                 {
                                                                                        // read the analog in value:
        sensorValue = analogRead(analogInPin);  
        sampleAmpVal = sampleAmpVal + sensorValue;       // add samples together

        batVal = analogRead(batMonPin);                           // read the voltage on the divider
        sampleBVal = sampleBVal + batVal;                        // add samples together
 
      delay (10);                                                                // let ADC settle before next sample

                   }

   avgSAV = sampleAmpVal / 20;

                                                                                      // convert to milli amps
   outputValue = (((long)avgSAV * 4980 / 1024) - 2485 ) * 1000 / 130;  
 
/*
Modified by Adrian YO3HJV for real life ACS712-05A

Sensor outputs about 2.485 V at rest.
Analog read produces a value of 0-1023, equating to 0v to 5v.
"((long)sensorValue * 5000 / 1024)" is the voltage on the sensor's output in millivolts.
"5000"mV is ideal value, my board has 4.985 V measured with a precision Voltmeter
Therefore, we have a 2485mv offset to subtract.
The unit produces 185 mv per amp of current, so divide by 0.185 to convert mV to mA.
The documentation said that the ACS has 185mV/Amp but I measured 130 mV/ Amp.
         
*/


  avgBVal = sampleBVal / 20;                       //divide by 20 (number of samples) to get a steady reading

  pinVoltage = (avgBVal * 5.0) / 1024;      
 
                                //  Calculate the voltage on the A/D pin
                                /*  A reading of 1 for the A/D = 0.0048mV
                                    if we multiply the A/D reading by 0.00488 then
                                    we get the voltage on the pin.                                 
                                   It is a good practice to measure the Vcc with a good voltmeter and
                                   to adjust the 5.0 V to the measured value.                                  
                                    Also, depending on wiring and where voltage is being read, under
                                    heavy loads voltage displayed can be  well under voltage at supply. monitor
                                    at load or supply and decide.
*/


  batteryVoltage = pinVoltage * 10.93;    /* 10.93 is the voltage divider ratio
                                          measured with a voltmeter.
                                          First, measure the input voltage (ex. 12V)
                                          Then, measure the voltage at pin A4 (V input).
                                          Then make the ratio between and write it here.
                                          */
                                         
                                           
  amps = (float) outputValue / 1000;
  float watts = amps * batteryVoltage;
   
                                          //Here we print the data output to serial port.
                                          //Usefull for some data logging onto PC
  Serial.print("Volts = " );                      
  Serial.print(batteryVoltage);     
  Serial.print("\t Current (amps) = ");     
  Serial.print(amps); 
  Serial.print("\t Power (Watts) = ");  
  Serial.print(watts);  
 
   
  sample = sample + 1; 
  msec = millis();
 
 
 
   time = (float) msec / 1000.0;
   totalCharge = totalCharge + amps; 
   averageAmps = totalCharge / sample; 
   ampSeconds = averageAmps*time;
   ampHours = ampSeconds/3600; 
   wattHours = batteryVoltage * ampHours;
 

  Serial.print("\t Time (hours) = ");
  Serial.print(time/3600);
 
  Serial.print("\t Amp Hours (ah) = ");
  Serial.print(ampHours);
  Serial.print("\t Watt Hours (wh) = ");
  Serial.println(wattHours);
 

  lcd.setCursor(0, 0);
    lcd.print(batteryVoltage, 2);
    lcd.print(" V ");
  lcd.setCursor(11, 0);
    lcd.print(amps, 2);
  lcd.setCursor(16, 0);
    lcd.print(" A ");
 
  lcd.setCursor(0, 1);
    lcd.print(watts, 2 );
  lcd.setCursor(7, 1);
     lcd.print(" W ");
  lcd.setCursor(11, 1);
    lcd.print(time/3600);
  lcd.setCursor(16, 1);
    lcd.print(" H ");
 
  lcd.setCursor(0, 2);
    lcd.print(ampHours, 2);
    lcd.print(" Ah ");
  lcd.setCursor(11, 2);
    lcd.print(wattHours, 2);
    lcd.print(" Wh ");
 

  lcd.setCursor(0, 3);
  lcd.print("Ch/Dsc: ");
  lcd.print(totalCharge, 0);
  lcd.print("mA");
 // lcd.print(avgBVal);
 


  // wait 10 milliseconds before the next loop
  // for the analog-to-digital converter to settle
  // after the last reading:
 
  delay(10);                    
}
//END of void loop ()




 I have some plans to develop even further this project... I think is suitable for a smart monitor for my holiday house...

73 de Adrian

My Dream "GO-BOX" for emergency communications. Or just for fun!

Well, I sibscribed recently to a FB group dedicated to emergency communications. Its a very nice group.
I do not believe in the FB because it's like the sand. You write something or find something but soon it's hard to find it again.
I like very much to have the possibility to go somewhere and try to make some QSO's. I am not a contester and I appreciate a nice chat with a fellow ham from here or anywhere. Therefore, I realise i really need a "GO-BOX" or a "GO-KIT" able to work all mode, all frequencies from HF to UHF.
Also the kit will be good for RVSU which is a network of hams involved in emergency communications for various NGO's here.
I will tell you my secret: My GO-BOX is on wheels!
It's a Nissan X-Trail "doped" with a lot of ham-stuff.

The main radio is a ICOM IC-7000 mounted in the trunk and the front panel remote. I finally made the permanent setup; the radio is under the trunk hood, bolted with the optional DC filter (OPC-639) and on the HF side I put a choke Balun  to reduce the common mode currents from the Codan antenna (or any  othe HF antenna) because the IC-7000 remote head is very sensitive to that issue.

The remote head is under the radio; i put it in place with the help of some industrial 3M velcro. In the left side is a small loudspeaker connected to the remote head. I use that velcro also for phones, portable radios etc...


The main attractions is the Codan 9350 auto-tuning antenna. Bulky but with outstanding performance, it's definetly a magnet for everyone's eyes, in march or in parking lot!

I wrote in other post about the custom mount for this antenna and about the connection with ICOM IC-7000 radio.

What I did lately was to put all the important wires in a protection harness.

 The main 12V DC is in harness, the RG58 and the command cable for the ATU antenna is in the harness also. Was a little tricky but the final result is amazing!



For VHF and UHF I use quarter wave antennas. I found that if I put a quarter wave on VHF, the same antenna is resonant also in UHF! A MMANA-GAL simulation showed that the UHF angles are somehow elevated but still a +2db at 0-15 deg. over the horizont so the antenna can be used well.

I preffer NMO (New Motorola Mount) for my mobile antennas. This is a special designed mount to accomodate proffessional antennas ant to whitstand to all the special conditions on a  mobile setup in full run. Do not ignore that! And also, keep in mind that a fixed mount is BETTER than any magnetic mount.

Here it is a NMO mount, VHF quarter wave antenna.

Now, for really serious things like emergency comms., I have a little toolbox with a 35 Ah SLA battery.
I was looking for a good battery eliminator but the price was too high and had to buy it from overseas! Hey, I think a little here and I know how to use a solder iron. Or solder station. Or something like that, you figure out...

So I made a very very simple "battery eliminator" or "separator", whatever, from a Schottky power diode. It was a bulky one, I don't know at what current is rated but did'nt burned at 14-16 Amps so must be better than that. In the little Hammond box I put a little 5 LED voltmeter to quick view the main battery status.
The later addition was a little digital voltmeter on a "Y" cable to view the voltage. Both of them are usefull.
The battery have two fuses, one for plus and one for minus.
Some hams think that if they put a single fuse, on the plus side, is enough!
Well, what if you make a shortcircuit between minus cable and the "plus" pole?

That toolbox cand accomodate the ICOM IC-7000 or anything else. In this setup made for Ciucas Trail Running (a 100 km mountain marathon) I have two Motorola mobile radios.

The lower is a GM360 VHF radio to talk to Salvamont (Mountain Rescue) teams and the upper is a DM3600 to use it with the Radioamateurs in the RVSU network (Radioamateurs for Emergency
Communications).
In order to be able to use a single antenna, a diplexer is used. Is a Diamond 2000 with modified RF cables. The original ones was too bulky and used PL and N connectors.
A lot of hams use amateur equipments for frequencies above the 146 or 148 MHz. They tend to ignore that out of the regular amateur bands, the radios are very ineffective!
I measured a lot of radios and they seems to loose power after 150 MHz and become very insensitive over 155 MHz. That's how they are made...  So, in a emergency network I found a little stupid to use deaf and mute radios! Therefore, I will go with proffessional radios for that particular case and the choice is Motorola!

A completion to my HF setup is a AH4 ATU with a collection of wires. I use two lenghts, 8,5 m and 4 m as they are not half-wave, as reccomended by ICOM to use them with AH-4.
The trick here is that I made two lenght of control cable and RF cable (tied together) so I can use 5m or 10m from radio to AH4.
The AH4 can be used for tuning a horizontal antenna (dipole) or a vertical one (erected on a fishpole stick) using 2 equal wires or 4 counterpoises with a vertical radiator. That's why there are 5 cables at the same lenght...


Well, this is my GO-BOX!

4 wheels and radios!


For final, here it is with a strange VHF antenna on the rooftop!

YOFF HF Mobile activation

Well, tomorrow morning (April 18th)  I will be enroute to Petrimanu, a remote place in Parang Mountains, near Voineasa.
I will be there until April 21st.
I will be there with Sorin YO3DLW and Bob YO8RNI.
According to INMH, the weather condition will be bad, with a lot of rain, fog and low temperature.
We will try to work from mobile in YOFF-420 (LOTARITA) and YOFF-006 (COZIA), both in Natural Protected Areas .
I will use my ICOM IC-7000 with CODAN 9360 Autotune antenna and, if conditions will permit, an AH-4 ATU with a dipole.

Tomorrow  I will try to be active on the road from mobile on this frequencies:

3791.0 kHz
7185.5 kHz
14342.5 kHz
18157.5 kHz
21437.5 kHz
24977.5 kHz
28327.5 kHz

73 de Adrian, yo3hjv