Category Archives: Radio Ham

Widow Maker Plug Top

I was given a 13.8v Power Supply Unit at a local radio rally so thought I’d check it out, first job was the plug top, this is what I found;

20160502_111900 (Small)

I rewired the plug and used the optional extra strain relief, this was the before picture.

20160502_112541 (Small) 20160502_112548 (Small)

It was only after I put the plug back  and inspected it, that I noticed the condition of the outside of the plug and the lethal exposed conductor.

Once a new plug was fitted the PSU worked fine, just a cautionary tale, always double check everything from a rally.

Mast Automation Proximity Sensors

This Blog post went into detail on the sensors used for the mast position, I have found reasonably priced ferrous metal inductive proximity switched, these are non contact devices with a detection range of 5mm which is perfect for my application of securing pin detection, feeding into the masts PLC logic controller.

2016-04-09 17.11.08 (Medium)

Sensor mounted below bottom mast securing pin hole, the sensor was fixed the mast by drilling and tapping a 6BA hole, the HSS drill size of 2.3mm for a 6BA tap cost 99p for 10 from Hong Kong.

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Test position for alignment and operation checking.

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Lower pin sensor finished with a three pin male Superseal waterproof connection, the female will break out of the 10mm convoluted conduit via a hinged tee piece.

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Top mast securing pin sensor being fitted, this pin stops the mast from tilting down (Luffing), the output from this sensor, like the bottom pin detector will influence the functions available in the PLC controller, for example, if the mast is elevated and the top pin is removed, the mast will not lower as this is an unsafe condition.


The next stage is the mounting of the controller cabinet and wiring, keep a watch out for this.

Orbitron & PST Rotator Interface with Easy Rotor Control

This blog is an update of this – Pan & Tilt Orbitron Interface post as I’ve added some pictures of the kit used and I have finally got round to putting the Rotorcards in a decent enclosure.

The main controller is a ERC-M USB kit which interfaces with the PC and programs which are running , the Rotorcard relays  are controlled by the ERC-M, the Rotorcard also provides a positional feedback to the ERC-M.

Front panel of the Desktop housing for the ERC-M, the front panel has manual buttons for up/down tilt & left/right pan, LED's also show when internal relays are operated.

Front panel of the Desktop housing for the ERC-M, the front panel has manual buttons for up/down tilt & left/right pan, LED’s also show when a signal is sent to the Rotorcard relays.

The two yellow LEDs on the left hand side indicate the signal to the auxiliary relay.

The LCD display is showing the position in degrees, the number after Az or El is the feedback from the Pan & Tilt head, the numbers on the other side of the > are the output from the software, the ERC-M compares the two values and energises the appropriate relays which in turn operate the motors in order to keep the values aligned.2016-04-01 12.04.05 (Medium)

The ERC-M kit is the top left PCB, the desktop housing is also a kit comprising of the LCD display and front panel buttons.

2016-04-01 12.04.33 (Medium)

The PCB mounted inside the desktop housing is the 13.8v to 10v voltage regulator which provides a stabilized supply to the Pan & Tilt heads positional potentiometers.

An external 13.8v supply is required in order to drive the high current motors of the Pan & Tilt head.

2016-04-01 11.37.03 (Medium)

The two Rotorcards (one for Pan the other Tilt, or more correctly Azimuth and Elevation respectively) are enclosed, 13.8v can be fed to the relays here or at the desktop housing.

2016-04-01 12.01.25 (Medium)The three outputs from the ERC-M enter on the right hand side to the Rotorcards, the middle connector is the 13.8v – 0v – 10v supply.

The top Rotorcard relays operate for clockwise or anticlockwise supply to the Azimuth motor, the third relay is not used (auxiliary relay) as the Pan & Tilt head does not have an electro-mechanical brake fitted, if it did, relay three would operate in advance of the motor supply relays.

The bottom Rotorcard is for elevation, Up & Down.

On my version, the ERC-M is connected to a PC via a USB connection to Com Port 6, the position of the heads has already been calibrated using the provided software from Easy Rotor Control.

To start tracking satellites, the first step is to open Orbitron.

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This is a free download program, each time it is ran, check that the TLE files have been updated then select the satellite of interest from the right hand list, once this is done, click on the satellites on screen icon.

On the bottom tabs, select rotator and click DDE a small box should now open on the screen with live positional data of the selected satellite showing,  (a separate download is needed for the DDE function).

Open PST Rotator program:

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Using the PST Rotator settings configure the program to respond to Comm Port 6, use Orbitron as the controlling program, that the type of head ouput is GS-232 and Az/El is selected.

When the program is set to ‘Track’ as the above image, the displays show the actual position of the Pan & Tilt head by a black line with the green line showing where the head needs to move to, the green line is controlled via DDE from Orbitron.

A further setting I have enable is the link to weather information, this allows the mast to rotate into the wind when a trigger speed has been reached, this reduces wind loading on the mast and antenna.

2016-04-01 11.36.20 (Medium)This is a Dennard CCTV Pan & Tilt head and operates at 24v, 13.8v works it just fine with a maximum current draw of 600mA, I have commoned the potetiometers supply, so the minimum number or wire cores is 8:

2 – Pan Motor

2 – Tilt Motor

2 – 10v supply across positional potentiometers

1 – Signal feedback from Pan

1 – Signal feedback from Tilt

The next stage is to get some decent antennas for satellite reception.

4m band dipole finally fitted

My local area has quite an active 4m band, and recently Andy (G6OHM) has gained an NoV for a 4m simplex parrot which is working well.

Kevin (2E0OPU)kindly gave me a 4m band dipole as he knew I had an Icom 7100 and no antenna, so I finally got round to installing it.

I did a temporary setup at ground level and got the VSWR to 1.0:1, mounting the antenna in it’s fixed location would not allow me to get the VSWR below 1.6:1 (this would give me a reflected power of 5.3%).

The cause of this problem was the close proximity of my mast, extending the dipole 300mm past this structure solved the problem.

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The dipole is horizontal for an SSB contest at the moment, I have used a stand off sleeve which the dipoles supporting tube slides into, this allows me to retract the dipole for fine tuning, a self tapping screw is used to hold the dipole either horizontally or vertically.

The bracket for the dipole was their before the mast, hence in the horizontal plane, the dipole it is across the mast stopping it from tilting for maintenance, as I have to get up the ladder to pull the mast top securing pin, it’s no big deal as I will move the dipole out of the way at the same time.

The VSWR is 1.0:1 or as near as damn it!

2016-03-29 09.11.03 (Medium)

Radio Mast Automation – Part 1 – PLC or Relay Control

My mast has an winch to raise and lower the inner section of the mast.

This project is to fully automate the process and add a level of intelligence into the mix, my requirements list is:-

  • Automatically stop the motor at the top or bottom
  • Run-On when mast lowered to release tension from cable
  • If bottom mast inner securing pin is in – Stop mast from raising or lowering
  • Disallow inputs whilst the motor is either lifting or lowering
  • Safety timer on the motor operation should a limit switch fail
  • Means to stop holding an input button increasing the motor run time
  • Don’t lower the mast if the luffing pin is removed
  • Override to allow either a pulsed automatic operation or manual hold for up & down ignoring limit switches
  • Emergency stop
  • All timing sequences reset on restoring emergency stop or override to prevent motor operation
  • Interface with WX Station to automatically lower
  • Visual display of status – what is doing what
  • Automatic battery charging after a number of counted operations or weekly – whichever comes first
  • Battery charging does not interfere with solar panel charging

I was going to use relays, and made a start on the construction, but the more I thought about interlocking and timers the more unrealistic this option became.

SAM_5618 (Small)

The relay unit currently in use which works fine is shown below, two of the relays are for the raise and lower switches, the other two are for overrides.

SAM_5472 (Small)

My plan is to use a Programmable Logic Controller (PLC) which needed to have 12 inputs and 4 relay outputs.

I found a company on the internet called, the model chosen was ELC-18DCD-R-U at £69 ex VAT and I also bought a RS232 programming lead for just under £20 ex VAT, the PLC has a voltage range from 12 to 24v DC is very compact and will do everything I need and more.

A major plus was the programming software is free and very easy to use.


Link to PLC Software Link

Link to PLC Manual

The drawing shows the sensor positions, currently the mast only has up and down limit switches fitted, the upper and lower securing pin detection will be fitted when the parts arrive from the other side of the world.

Mast Contro2l

The way of working will be:

Normal Up & Down

Momentary pressing of the down button on the remote hand held winch unit, will fully lower the mast, pressing the up button will do the reverse.

Luffing the Mast

Luffing (Tilting down) of the mast for maintenance will involve setting the PLC input switch to Luff, this will only lower the mast if the mast is lowered, the lower securing pin is in and the upper securing pin is out.

The logic plan shown below has been imported from the software program into Visio and I’ve added some idents to make it easier for me to fault find at a later date.

Descriptors for the idents is below.

The next stage of the project is to mount the PLC in an enclosure and fit the securing pin sensors, so watch this space.

Dummy Load Refurbishment

At a recent surplus sale at my local radio club (Cambridge & District Amateur Radio Club) I bought a dummy load for £5, getting it on the bench the resistance at the PL259 socket measured 88 ohms.


I also knew that the internal cooling fan was  U/S, so I stripped everything out of the case, ready for cleaning and reassembly.

The tubular resistors have an copper shim inside the aluminium clamping brackets, all parts were cleaned and degreased and put back together, on the rear heat sink I used heat transfer paste, and after replacing the internal fan, installed a cheap thermostatically controlled switch which I got from ebay, the temperature sensor is bonded to the rear resistor clamp .


The temperature selection is set by dip switches on the PCB, I set the fan to operate when the temperature is greater than 35c, power to the PCB is via a fused 2.5mm DC socket.


After reassembly the resistance dropped the 46 ohms and the fan kicks in when tested.

My homemade paint tin dummy load works great but the mineral oil is ‘wicking’ up the cables and finding its way to freedom, this one will mean the paint tin being relegated to the shed.

CCTV Pan & Tilt Head Interfaced to Orbitron and Ham Radio Deluxe

I have blogged  previously  about using a CCTV head as a platform for ham radio antennas and have made a manual controller to do this.

I already have an Easy Rotor Control for my rotator but thought I would experiment with a dual control ERC-M unit in linking it to a Pan & Tilt head I was given.

I bought the ERC-M, two Rotorcards and enclosure with matrix positioning display and front controls for this project. The parts came as a kit and took a few hours to put together, a with a previous kit from ERC, the instructions were excellent and the unit operated first time on power up.

The Pan & Tilt head I have is 24vDC, but will work on 12vDC, once the connections were made to the Rotorcard relays, the next step was to calibrate to positional potentiometers which are part of the head and allow presets to be selected. (Note – the positional pots need a 5v to 15v supply across them, this can be taken from the Rotorcard but as no take off terminals are fitted this board, I fed the pots directly from the power supply)

The kit comes with a CD containing all drivers, manuals and instructions plus a calibration program and operating program, I opted for a USB version of the ERC-M, I needed to point to the USB driver location on the CD during the installation of the ERC-M, after installation, checking in device manager confirmed the controller was using Com Port 6.

Setting the calibration program to the correct com port number allowed me to first calibrate the Pan or Azimuth, once this was done after following the on screen instruction I calibrate the Tilt or Elevation, this needs a bearing to be entered when the platform is at the top position or 90 degrees to ground, once this is done, calibration is as the Azimuth by following the on screen instructions.

The calibration software can be closed and the operational software opened to test functionality of the head, clicking on the compass rose will take the head to that position.

I use Ham Radio Deluxe but the garage PC where I do my building has no radio related software, so I downloaded Orbitron satellite tracking software.

As the Orbitron does not have a physical connection to the ERC-M, the program Pstrotator was also downloaded as the interface as this will connect to Com Port 6 and drive the controller, the internal data exchange between Orbitron and Pstrotator is via DDE, this additional file needs to be downloaded from the Orbitron site.

Pstrotator was only used to test concept and I used the demo version which is time limited.


I entered positional settings in Orbitron and clicked on DDE connect (a pop up will say if you need to download this if you haven’t already), if all I well, the positional data details of the satellite you selected will show in a small splash screen.

Opening Pstrotator, enter setting for the Com Port, type of head (Az & EL) and controller (ERC-D), close and then reopen the program, click on ‘track’ and the head will follow the trajectory of the satellite when in range.

A really cool feature of Pstrotator is the ability to take a feed from  a local WeatherUnderground feeding weather station (Chatteris Weather), when high winds are detected, the antenna will automatically turn to the wind reducing mast windage loading.

This use of a CCTV head to position tracking antennas is certainly a lot cheaper than buying a bespoke unit,  CCTV heads are made for external use and have decent torque, jut check if you get one that they are 24vDC and have the pots for presets, these come up all the time on Ebay for about £50, so all in you can have a quality tracking system for about £200.

I will mount the Rotorcards in a small enclosure and move everything next to the rig and interface with Ham Radio Deluxe, I have tested the tracking element with my existing Azimuth rotator, so I don’t envisage any issues with the ERC-M, the next job is to save up for some 8 core cable from the Rotorcards to the head!

Weather Station – Relay Outputs

My weather station software is Weather Display which is unbelievable in what it can do, the author of the software is very receptive to ideas and modifications and has introduced a feature which I and others have asked for, that is the ability for a physical relay to change state when a condition has been met.

Weather Display used to have the feature to operate a 1-wire single relay, but this has been superseded by an 8 Relay module which was not coded to work with the program.

I bought a board and sent it to Brian Hamilton of Weather Display, and within one afternoon had it working  (it did take a few days to get there as Brian lives in New Zealand)!

The feature Weather Display offers is not only control of relays via Weather Display, but using a Phone or Tablet app.


The relays can be assigned to Temperature, Wind Speed, Rain, Lightning (depending on sensors) or a timed schedule, these parameters are set and adjusted from a tab within the program.

SAM_5542 (Medium)

The relay board is powered by an external 12v supply with a 1-wire data lead going through a USB interface to the PC, activated relays are indicated by the LED.

SAM_5537 (Medium)

The app allows full control of the relays if configured, or for relays that have been set to ‘monitor’, the state of the relay is reflected on the app.

This addition has brought a new dimension to the weather station, and I will be connecting the ham radio mast motor to the relays, so that on detection of high wind or lightning, the mast will automatically retract (and maybe ground all the antennas so the transceivers wont get damaged).

A further benefit not related to weather is that a relay could be remotely switched to operate the heating or lighting etc, I’m using one to turn on a power supply unit so I can remotely operate power to my transceivers.

Note:   The HobbyBoard relays are not rated for high currents, I will be using these relays to operate higher switching capacity relays.

8 Channel Input/Output Manual shows the versatility of this module.

ON8JL D’Star BabyStar Node

Recently bought a Icom 7100 for the additional features this radio offers, one being DStar enabled, unfortunately I’m unable to access a  remote repeater, hence the BabyStar nodebabystar

This is a small unit with only two physical connections required, these being power (7 Vdc to 15Vdc) and an hardwired internet connection.

When the BabyStar is first powered up it will use an available ip, and this is displayed for a few moments on the screen, typing this ip into your browser opens the BabyStar configuration and status pages.

I have setup in the Icom 7100 a repeater called BabyStar Node, I then lower the RF power of the rig to 0% and simply transmit to the BabyStar and via this, using the internet, to repeaters and reflectors worldwide with FM quality audio both ways.

The version of Firmware on the unit I bought was v1.02, shortly after v1.03 came out, you will need Hyperterminal and a programming lead to complete the update, the process quite easy as the instructions within the User Guide are really good, I found the drivers for the USB to Serial lead here.

Hyperterminal is found on older versions of Windows, such as XP, so make sure you have an old PC about!

22 May 2016 – Updated Firmware to 1.04


Removing Mains Hum From Kenwood TS-2000

Since getting headphones, the mains hum on my Kenwood TS-2000 needed to get sorted as it was really distracting.

To confirm the source I powered the rig on a battery and the hum was still their, unplugging the antennas made no difference until I unplugged the RS232 serial lead to the PC, at that point the hum stopped, I then powered the rig from the Power Supply Unit and the hum only reappears when the serial lead is plugged in.

The issue stems from the fact that the PC running Ham Radio Deluxe (HRD) radio program is fed from an Uninterruptable Supply and this has caused a Ground Loop to be created.

I bought off eBay an RS232 opto isolator thinking this would cure it, unfortunately this stopped HRD communicating with the radio so I was stuck! posting the problem on the Yahoo Group forum came up with the answer.

The simple answer from Dave (G4UGM) was not to connect the Serial  pin 5 Ground wire making sure the outer shells of the D9 Socket & Plug were connected, and this did the trick.

(Scroll down for update)

The Serial connections on the Kenwood TS2000 are:

1- Not connected

2- RXD

3- TXD

4- Not connected

5- GND (did not use)

6- Not connected

7- RTS

8- CTS

9- Not connected

The finished unit with pin 5 disconnected goes in the back of the radio, the male and female connectors were soldered back to back, pin for pin except the break of Pin 5  –SAM_5535 (Medium)

29 September 2015     ***UPDATE***

Not sure what changed, but the mains hum came back!!, knowing that a 3 wire opto-isolator didn’t work, I bought an 8 wire opto-isolator from Tronicore, this comes complete with serial leads and a 12vDC PSU (American Power Plug).

I powered the unit from my rig supply, so didn’t use the PSU which came with it, the only other thing I needed was a 9 pin gender changer (Female to Male) to connect to the serial port on my PC.

The interface only works one way round so watch for that, mains hum has gone 🙂