Category: Radio

Single Board Computers and Amateur Radio

Single Board Computers and Amateur Radio

Since the advent of the home computer there have been radio amateurs who have explored the possibilities of using computers in their shacks and as computer technology and software have developed it has allowed more amateurs to be able to use a computer in their shack even if it is just for logging and looking up call signs on QRZ.Com.

In recent years there has been a new kid on the block, the Single Board Computer or SBC which as the name suggests has all the necessary components required mounted on a single board whereas on a desk top computer the various components are attached to a central circuit board via cables.

There are a number of SBC’s available but the one that kicked off this change is the Raspberry Pi SBC, there is a lot of support out there for this SBC and over the past few years they have been featured more and more in articles in Amateur Radio magazines here in the UK and abroad where radio amateurs have used them in their radio related projects.

So what is the Raspberry Pi ?

First and foremost, the Raspberry Pi was a product that was produced to be a fairly cheap way for children to get involved in computing and programming either through education in schools or for use at home and in order to facilitate this further the cost of a Raspberry Pi has always tried to be around the £30 mark. Despite being made to what you might consider to be a tight budget the Raspberry Pi uses the best components available at that time.

Over the years there have been various models of the Raspberry Pi and currently the main model (most powerful) of the Pi is the Raspberry Pi model 3 B+ which can be purchased for around £32 to £34 depending upon where you buy it.

Since its release in 2012 the Raspberry Pi is one of the best-selling computers of all time (number 3 in the rankings according to a recent report that I read). Makers and hackers have since taken up its use in a big way and use it in all manner of smart tech projects and so have radio amateurs. Due to its cheap price several of these little computers can be used at once for various radio applications, consider if you ran two or three separate computers/laptops in your shack then the space required let alone the cost involved would be prohibitive for most people.

Specifications for the Raspberry Pi model 3 B+

  • Broadcom BCM2837B0, Cortex-A53 (ARMv8) 64-bit SoC @ 1.4GHz
  • 1GB LPDDR2 SDRAM
  • 4GHz and 5GHz IEEE 802.11.b/g/n/ac wireless LAN, Bluetooth 4.2, BLE
  • Gigabit Ethernet over USB 2.0 (maximum throughput 300 Mbps)
  • Extended 40-pin GPIO header
  • Full-size HDMI
  • 4 USB 2.0 ports
  • CSI camera port for connecting a Raspberry Pi camera
  • DSI display port for connecting a Raspberry Pi touchscreen display
  • 4-pole stereo output and composite video port
  • Micro SD port for loading your operating system and storing data
  • 5V/2.5A DC power input
  • Power-over-Ethernet (PoE) support (requires separate PoE HAT)

In order to use this single board computer (as with most SBC’s), you will need to connect it to a monitor via the HDMI connector, you will also need a keyboard and mouse, power is provided by the use of an old phone charger with a micro USB connector or an official Raspberry Pi power supply.

The Raspberry Pi does not come with an operating system loaded onto the board so in order to use it you have to load an operating system onto a micro SD card which then plugs into the appropriate Micro SD slot on the Pi. The Raspberry Pi website has various operating systems that are available to download and when it comes to using the computer for amateur radio purposes then fortunately there are amateurs out there who have written software for us to use.

Amateur Radio Uses for SBC’s

About three years ago I bought myself an SDRplay software defined radio. There are various software downloads available for the SDRplay which are supported by Windows, Mac, Linux etc. and one of the computers listed that is supported with compatible software is the Raspberry Pi. I initially used the SDRplay with a windows laptop, I had heard of the Raspberry Pi but at that time I didn’t know anything about them or what they were.

On club night in the spring of 2016 I was sitting next to a couple of members who were discussing creating a D-Star hotspot using a Raspberry Pi, I mentioned that my SDR radio could be operated using a Raspberry Pi, but I didn’t know anything about them. The upshot was that I was lent a Raspberry Pi 2 model B which I had a play around with at home, the only down side for me was that the connection to the internet was via an Ethernet cable and considering my shack is in the front upstairs bedroom and my internet router is downstairs this created a bit of a problem, I didn’t have an Ethernet cable that long and I didn’t really want to go down that path every time that I wanted to connect this computer to the internet.

Doing some research on the internet about the Raspberry Pi I saw that about a month or so earlier a raspberry Pi 3 model B had been released with an increased performance over the Pi 2 and it also had Bluetooth and Wi-Fi connectivity as standard. I decided to buy one but due to the improved connectivity of the new version of Pi it was selling out fast, so I had to trawl through a lot of sites before I found a trader who still had some in stock.

So now I had my own Raspberry Pi and I connected it to my mouse, keyboard and monitor. I found that it was just a computer but in a different form factor (Linux based) and there is quite a lot of software already loaded onto the board. There is software relating to programming and coding and a Libre Office package which (I think) is very similar to Microsoft Office and I now also use it on my Windows laptop.

I downloaded the software for the raspberry pi off the SDRplay website and loaded it onto a micro SD card, connected everything up and I was up and running without any problems at all.

Another SBC that I use is the Latte Panda which does utilise Windows 10 as its operating system and it is downloaded onto the board so basically any software that you would use on a laptop or base home computer can be downloaded onto this SBC.

Since my initial foray into connecting my SDRplay to a Raspberry Pi, I have set up another Pi as an ADSB receiver with a connected dongle which I have running 24/7.

I have also played around using the Raspberry Pi for decoding data modes, namely FT8.

I am continually looking at other amateur radio uses for the  SBC’s that I own and apart from the projects I have outlined they can be used in the following ways; As your main shack computer, for logging, as a WSPR transmitter, for tracking satellites, as a DV Hotspot, as an APRS gate, as a rotator controller or for decoding CW to name just a few applications.

For their cost and size these little computers are great fun to use and are a very cost-effective way of using a computer in the shack and going back to comments made at the beginning of this post I can potentially use four of these little computers at the same time for ham radio.

 

73’s Graham M0GAE

Sending Sounds into Space

Sending Sounds into Space

Early in 2018 the club was contacted by artist Sian Hutchings who was in her first year of a masters degree in fine arts at Northumbria University, Newcastle and she wanted some help with a project that was going to come to a head with an event at the Baltic Centre for Contemporary Art in Gateshead on the 15th March.

The club is no stranger to working with artists having previously been involved with the Waygood group and an event called Scatter in the AV08 Festival involving artist Marco Pelijhan again at the Baltic Centre for Contemporary Art in 2008.

Anyway Sian’s project centered around the ‘Voyager Golden Record’ which were two phonograph records that were included aboard both Voyager spacecraft launched in 1977. The records contain sounds and images selected to portray the diversity of life and culture on Earth, and are intended for any intelligent extraterrestrial life form, or for future humans, who may find them. The records are considered as a sort of a time capsule.

Sian wanted to update the recordings stating that she considered the recordings didn’t reflect the way we live in the 21st century and weren’t a true reflection of modern society.

Sian planned to record an updated version of the golden record and transmit the recording herself so she contacted the RSGB to find out how she could do this. Sian was informed that she would have to complete the Foundation licence course in order to do this and due to her timescale it wasn’t a feasible thing to do. The RSGB did suggest that she contact a local amateur radio club to see if they could help and gave her our contact details, in due course Sian did contact us which resulted in Glen and I going into Newcastle to have a meeting with her at her studio.

At the meeting Sian outlined her idea to update the golden record and Glen and I told her how we could help which basically meant that we would be able to transmit her recordings, also we would be able to let her see the transmission via an SDR radio receiver but this would all be dependant on whereabouts in the Baltic we would be based in relation to siting antennas. A follow up meeting at the Baltic was arranged and I took a dual band 2m/70cm antenna to show Sian what we might use as Glen thought that 70cm might be a better frequency to use as trying to find another amateur on the band was as likely as finding teeth in a hen and it therefore hopefully wouldn’t cause any disruption to what Sian wanted to do, also it is a frequency that is suited to satellite (space) communication. We also took along a couple of radios to test the suitability of the location.

We were to be sited on the first floor and there weren’t a lot of options for feeding coax to the exterior and then onto the roof to feed antennas, it was decided to set up in the outside lobby area and fire the radio signal out of the glass windows running the full height of the building. This would be an easier option as we were right in the heart of the building and all other options quite frankly would have been a nightmare to sort out. 

Having completed the recce Glen and I had a better idea of what we could offer, Sian arranged workshops to record the sounds and on the allotted day Glen and I arrived at the Baltic in the afternoon and set up our station which consisted of my 70cm yagi antenna that was mounted on a microphone stand angled at about 45 degrees to the horizon, Glen’s Yaesu FT 817nd provided the transmit option along with a laptop which used a USB drive with the recordings provided by Sian from her workshops. I took along my SDRPlay RSP1 software defined radio to receive the transmitted signal and projected it onto the large screen in the cinema for a visual effect.

Sian was given a handheld transceiver to start each transmission using with the callsign that had been applied for GB8NOE, this related to our 2008 involvement at the Baltic and there is an 8 in 2018 (very tenuous I know). The letters related to the name of the group of artists also involved with Sian called the Noematic Collective.  

Sian transmitted four three minute recordings of sounds from her workshops and the people at the event were able to move between the theatre where I was projecting the image of the received signal from my SDR receiver and the corridor area where Glen was at the transmitting end of things.  There was an additional twist a vinyl recording was made of Sian’s recordings on an original recording machine from around 1930 I believe.

The event seemed to go well and Sian was very happy with the way that things went, the people attending also enjoyed it as well.

Check out our video page to see Sian’s video of the event.

 

 

 

 

73’s Graham M0GAE

 

 

 

 

 

FT8 – The Basics

FT8 – The Basics

FT8.
It has been around for a while now and the protocol itself has undergone some radical changes recently so what’s all the fuss about, and is it actually worth bothering with?

Ham Radio digital modes are a bit like Marmite, you either love them or you hate them and FT8 is no exception to this rule, well that’s not strictly true because FT8 has come in for it’s fair share of stick over recent times due to it’s quick and dirty QSO method. Basically FT8 has a very stripped back QSO exchange that only actually comprises of CQ Call, a signal strength exchange and a confirmation.

FT8 was developed by Joe Taylor K1JT and amateurs typically use it as part of the WSJTX software package which can be downloaded from here

Here is a typical conversation over FT8:

“CQ G0SBN IO95”  CQ call from G0SBN
G0SBN 2E0EFP IO95” 2E0EFP replies with their location
2E0EFP G
0SBN +06” G0SBN responds with a signal report
G0SBN 2E0EFP R-02”
2E0EFP confirms signal report & replies with his own report
2E0EFP G0SBN RR73” G0SBN
 says Reception Report Received, Goodbye
G0SBN 2E0EFP 73” 
2E0EFP says Best regards

Each message of up to 13 characters takes 13 seconds to send. There are 4 slots per minute, and your transmission  block lasts for 15 seconds, then the software listens for any replies for 15 seconds, and so on. A typical exchange above takes around 90 seconds to complete. Great ! You’re thinking I can get loads of DX in a short window, and that is indeed a fact but it’s quite devoid of any user interaction. This is where some amateurs seem to have an issue because it’s basically M2M (Machine to Machine) transactions and can actually be automated so the operator needn’t even be in front of his radio / shack PC to stack up a load of QSO’s

Is that cheating ? You decide !

So I am guessing by now the burning question is how do I get into this brave new world and make some QSO’s ?

Now this isn’t going to be a full on guide on how to setup your radio for FT8 but I will share some details on some tips I have found during my setup etc. As a minimum you will need the following:

A shack PC, (WSJTX Can be ran on Windows, MAC OSX, Linux)
An audio interface from your shack PC to you radio
Optional CAT Control of radio from shack PC

As well the above you should check the following settings on the radio, AGC is off, Data mode is ON and the SSB mode is USB. Most FT8 or digital modes in general users normally say the ALC should not be invoked by the radio when transmitting.

Now there is a little bit of PC jiggery pokery required here to ensure your shack PC can hear the signals coming from your radio (via the mic input) and can also send the data signals to the radio via the speakers output. Withregards to the ALC invocation, I would normally set the sound card input level on the radio to a fairly low setting and then set the shack PC speaker volume manually when transmitting to make sure the ALC is not being triggered.

Similarly with the reception of signals, you don’t want the RF from the radio overloading and clipping the audio into the PC, so again check your Mic level on your sound card and monitor the received signal on WSJTX to ensure that the reception signal is around -60dbm.

Have a look at the bottom left on the image to see the received signal strength.

 

 

 

 

As well as the operating system tweaks for the audio output and recording levels there are some settings in WSJTX that need to be completed to tell the software which audio interfaces on the shack PC to use.

WSJT-X Settings screen (audio)
WSJT-X Settings screen (audio)
  • RIG – Radio interface settings – most common models of radio already have their comms settings built-in to WSJT-X, so simply select your radio.
  • CAT CONTROL – Connecting to the radio’s CAT/DATA port for controlling the radio. Typically the interface will appear as a serial COM port.
  • PTT – So that the PC can put the radio into transmit, the software needs to know how to trigger Transmit. Often this will be a separate COM port that needs setting up in the software
WSJT-X Settings screen (radio / PTT)
WSJT-X Settings screen (audio)

As well as the audio settings, Your computer’s clock does have to be very accurate with FT8. I use the Dimension 4 for keeping my clock accurate. This runs in the background and uses NTP to keep your clock in-sync to one of the online atomic clock servers periodically.

Anyway give it a shot, even if you are a foundation licence holder you can make some great contacts using 10w and a modest antenna!

Enjoy your radio !

2E0EFP

LiFePO4 Portable Power Kit

LiFePO4 Portable Power Kit

Recently I was researching an alternative to Sealed Lead Acid Batteries (SLAB), the cause of this research…back pain. While SLAB’s have performed ok for my car portable use, I was reminded just how heavy a 50AH SLAB is after straining my back putting it back on the shelf. So having seen a number of posts and videos on the Internet about the weight advantage I needed to give alternatives some serious thought.

I suspect like me, many of you will have heard of Lithium batteries but what I hadn’t realised is that there are different types and specifications. I was looking for three things in a new battery; appropriate voltage for amateur radio use (13 to 14 volts), low voltage sag (little voltage drop when under load), and a high number of recharge cycles (reduced cost of ownership).

Lithium ChemistryNominal Voltage
(4 cells in series)
Recharge Cycles
Lithium Titanate9.6v3000-7000
Lithium Nickel Cobalt Aluminium Oxide 14.4v500
Lithium Cobalt Oxide14.4v500-1000
Lithium Manganese Oxide14.8v300-700
Lithium Nickel Manganese Cobalt Oxide14.8v1000-2000
Lithium Iron Phosphate (LiFePO4)13.2v1000-2000

 

I hope you agree that Lithium Iron Phosphate (LiFePO4) came out as the most suitable. I was also fortunate that while away on a DX’pedition to the Isle of Barra with Bob (M0KLO) he kindly lent me his KX3 and a small radio model style 13v LiFePO4 4.2AH battery pack to try. It was certainly compact in size, light weight, and an ability to maintain voltage during transmit but the total capacity of 4.2AH I felt was a bit small for what I had in mind. 

A battery of about 15AH seemed to be about the size suitable for my needs based on my initial transmit tests with a Yaesu FT-891 “field” radio which suggested about 8 amps on transmit was a good target if I wanted 3 hours of operating time on a single charge. Remember that this is not an exact science as less current is drawn when listening as to transmitting and whether you use CW, Data, or SSB.

A search on the Internet provided a range of options from which I produced a shortlist:

  1. “radio control” style soft battery packs to make up a battery of 17AH. Various comments on the Internet suggested quality control of these packs is variable. Costs today (Mar’2018) for a 8.4AH pack is £ 52.83 + p/p. Due to the manufacturing process if one of the internal cells develops a fault the whole battery is a right off. Requires a balance charger to maintain cells. https://hobbyking.com/en_us/zippy-flightmax-8400mah-4s2p-30c-lifepo4-pack-xt90.html

 

  1. Electric Golf Cart suppliers have a good selection of LiFePO4 batteries in capacities from 15-40AH available with chargers and 3-5 year guarantees. Mainly sealed units with an internal Battery Management System (BMS), while this is perhaps convenient it has the drawback that if a cell or the BMS develops a fault the battery may be a right off. Generally supplied with a simple charger. Costs depending on capacity and warranty term but are generally £150  to £300 per unit. NB: Always double check golf cart batteries, are they definitely LiFePO4?www.topcaddy.co.uk/category/batteries/lithium-batteries/

 

  1. Electric Bikes commonly use LiFePO4 packs of various sizes (8,10,12,15AH), individual cells can be purchased and made into a pack. All of the required components can be purchased online or from an electric bike components supplier. Costs increase as cells capacity increases. For 4x15AH cells + cable bits to make 13.2 battery (Mar’2018) approximately £100. Simple chargers are available similar to the ones provided by the Golf Cart suppliers, but would recommend radio model style balance chargers suitable for LiFePO4 batteries.
    LiFePO4 (UK) Battery supplier
    http://eclipsebikes.com/index.php?cPath=25_10
    ISDT T6 LiFePO4 charger
     https://hobbyking.com/en_us/isdt-t6-lite-600w-charger.html?___store=en_us
    ISDT Battery Checker
    https://hobbyking.com/en_us/bg-8s-smart-battery-checker.html

 

I decided on option 3, if there was a problem with an individual cell I could replace it at minimum cost and it allowed me to take control of the management of the battery pack and individual cells. As a self-build I could also choose on different form-factors depending on requirements and components. It is also a simple task to increase the capacity of the pack by putting another one in parallel if needed at a later date. I also purchased a radio control style charger (ISDT T6).  This charger provides greater control of charging and also includes storage charge and discharge options and very importantly it allows charging of cells without a balance lead connected as I would be Bottom Balancing. Note that some LiFePO4 chargers will refuse to work without a balance lead connected. I also purchased the ISDT Battery Checker for more precise measurement of individual cell voltages on charge, storage, and discharge.

The rationale for bottom balancing is that I want the cells to converge to the same state of charge when discharged, before use and I charge the whole battery as one, rather than have the charger bulk charging the cells and top balancing them when using balance leads. I’ve included the following YouTube links for the background to bottom balance and not using a BMS. 

Bottom or Top Balancing
https://youtu.be/0KSFitqvap0

One example of how to Bottom Balance a battery pack
https://youtu.be/J2WvQre8sAQ

To achieve bottom balance I discharged the individual cells to 2.7 volts each and measured the voltage variation (after a settling period of 24hr) between the cells using the ISDT Battery Checker via the balance leads to achieve a variation between cells of a couple of mV. I then charged the cells to 3.4 volts per cell using the chargers (ISDT T6) upper storage charge setting of 3.4v and a charge current of 1/10th the pack capacity i.e 15AH divided by 10 = 1.5 Amps. The cell voltage variation at 3.4v across the pack was 8mV. I’ve found that if the individual cell charge voltage is increased to 3.6v, the cell voltage difference will also increase to 100+ mV. Also if the charge current is increased for example to 5A then the cell voltage variation will increase at top of charge. This in itself is not a problem and is predicted however monitor the voltage to make sure no individual cell goes beyond the 3.6v manufacturers specification.

My final choice was for 2×2 rather than the 4×1 cell pack, mainly because it fits neatly into a box that I subsequently purchased and it also fits better the compartment underneath the boot-floor of my car. The red/black leads with PowerPoles fitted are for the high current connection to the radio, and are also used when charging and discharging, the white leads are the low current balance leads that are used for voltage monitoring. If the ISDT T6 Lite is used to perform a discharge the balance leads are connected and the T6 will not let a cell go below 2.8v. While using the battery pack with my radio a small voltmeter is connected to the balance leads which cycles continually indicating pack and individual cell voltages during use. The audible alarm is set to 2.7v, if any cell reaches this lower limit an alarm sounds and I stop transmitting and disconnect the battery to prevent further discharge. After use the pack gets a storage charge and stored in a dry and cool place in the garage. 

Enjoy your radio
Glen G0SBN/P

Amateur Radio with a Clansman PRC351 / PRC352

Amateur Radio with a Clansman PRC351 / PRC352

This particular radio consists of a transceiver, a 24 volt battery, an antenna tuning unit, a 20 watt amplifier, a telephone style handset and a combat whip antenna.

Why does this Clansman have the number 351 and 352? Well it all depends on whether the amplifier is attached. The 20 watt amplifier on the right of the picture above, the one with the heat dissipation fins, is what turns the PRC351 into a PRC352. Note that when connecting the amplifier the whip antenna can no longer be used, it requires a ground spike, and a resonant antenna such as a dipole or the Land Rover FFR Antenna Tuning Module and Whip. Also remember that the output with amplifier is 20 watts so it exceeds the maximum permitted power limit of a UK Foundation Licence.

The transceiver unit of the PRC351 provides an RF output of 4 watts on transmit, with a frequency range of 30 MHz up to 75.975 MHz NFM. So for Amateur Radio I plan to use the PRC351 on the 4m and 6m bands NFM segments of the UK band plan.

But before I start I need to assemble the separate components that make up the radio and make sure it works. Having completed the PRC351 assembly I planned to confirm the operating frequencies of the PRC351 on 4m and 6m with a SDR receiver. I tuned the SDR to 52.000mhz (6m) and tuned the PRC351 using the frequency control knobs. I then set the “ON” knob to the “*” position to remove any squelch, and selected the “L” setting for local. The next step is to match the antenna with the radio’s ATU, the ATU is designed to provide tuning to the whip when fitted. On completion I pressed the PTT button on the telephone handset. Unfortunately I noticed that there was a noticeable buzzing sound and no transmitted audio.

On close inspection of the telephone handset the probable cause was clear to see, the microphone mouth piece slots were full of mud. I stripped the handset and cleaned away any debris and gave the speaker and microphone a check over using the multi meter. Now that the handset was reassembled, another test, and I had audio, however there was still an annoying buzz. I did a bit of research on the Internet and it turns out that the PRC351 radio has tone squelch of 150khz. I haven’t found any information so far on how to disable the feature, so I plan to use the PRC351 with the squelch OFF as the background noise isn’t too offensive through the handset, and inhibit the tone as much as possible during transmit.

 To do this the unit needs to be opened which is simply undoing 8 Allen bolts, being very careful not to damage the internal brown ribbon cable while removing the end panel and unplugging it. Once apart disabling the 150khz tone is quite simple, locate the module “13” and gently turn pot “R9” fully ant-clockwise. Now that the PRC351 is re-assembled I conducted another transmission test, The SDR demonstrated it was on frequency and with clear modulation, and no annoying 150khz tone.

    

If you’re like me now’s the opportunity to tidy up the radio with a quick clean and paint job, gently removing the labels to be re-applied later.

Power to the PRC351 is from a Nickel Cadmium rechargeable battery pack which includes a “state of charge” indicator. The label on the battery provides some relevant battery information and a date of manufacture of 2005, so I’ll probably replace the cells in the pack with new lithium equivalents and include a charging circuit.

  

Hope to hear you on the 4m or 6m bands using my refurbished PRC351…

Ray M6OZA

A Tank For An Antenna

A Tank For An Antenna

ORIGIN

At one of the meetings of the Tynemouth Amateur Radio Club in the spring of 2006 somebody brought along some a few bits and bobs to pass on if any body could make use of them and at the end of the evening there was a green rod left.

I picked it up and was examining it when one of the members told me that it was a section of a Tank Antenna and I needed 4 sections to make an antenna for use on the Amateur bands. He told me to take it and to hold onto it as I would only need three more sections to be up and running.

A short while late I received a call from the same club member to say that he had a complete Tank Antenna and if I was interested in it I could have it for a donation to club funds.

I hot footed it around to his house and made a donation in exchange for it, the Tank antenna as previously outlined consisted of four rod sections, a top, middle and two bottom sections which measured about 4.9 metres when fitted together. The sections are constructed out of sprung steel (so I’m told), given a copper coating and painted green. They have a short broad thread on them and are pushed together and given a quick twist to join together.

MOUNTING

Having bought my Tank Antenna, I now had to figure out how I was going to mount it.

Another club member had a spare mount which he gave me. This consisted of a short metal tube that the Antenna fits into, a metal collett that tightens to secure the Antenna, and all this is mounted onto an insulator which is about three quarters of an inch in diameter and a couple of inches long.

For several weeks I pondered on how I was going to mount the Antenna with or without the mount that I’d been given. While looking at mounting options in my garden one thing that really struck me was that it has a low impact visually.

I now had to decide how I was going to mount it. Looking on the internet you will see vertical antennas on the market that are mounted close to ground level so that was an option. There is a lot said about Stealth Antennas and I thought that it might be a good antenna to mount at the top of the fence and couple it to an auto ATU.

In June 2006 a couple of us from the radio club decided to go out for the day and play radio, it was planned to go to a farm that we have been lucky to gain permission to use for our various field days.

With this planned it made me work a bit quicker to sort out a way of mounting the Antenna.

Looking at the insulator there is a hole underneath and I wondered if it would sit on top of a section of fishing Pole. It would but there would be too much flex and it would probably fall to the ground. The insulator would fit inside a Swaged pole and also inside a section of fishing pole.

I had a couple of spare sections off a fishing pole that was broken as a result of my son using the pole to retrieve his Frisbee out of a tree, he took it apart and put it back together again the wrong way around and trying to sort it out damaged a few sections of the pole, so I now had two spare sections.

I decided to mount the antenna at ground level and cut one of the poles down and fitted the mount inside. I had a Ground Spike from another manufactured Portable Antenna, so I decided to use that, and the Pole fits nicely inside the tube attached to the ground spike.

The Antenna was now mounted and supported.

RADIALS

The next thing that the Antenna needed was Radials.

The Antenna is about 4.9 metres long, so you don’t have to think too hard to work out that it was around a quarter of 20 Metres. Thinking back to a talk given by the Chairman of the club at the time on ground planes and radials I remembered various points discussed and using these principles I made up 12 radials. In the talk given to the club it was mentioned that a good number of radials to use was 120. I couldn’t manage 120 so I decided on 12.

I mounted the radials on a bolt that was connected to a short earthing strap and that would then be attached to the Spike or Pole. I have a SOTA beam which comes with a length of coax with a BNC connector on one end and lengths of wire soldered to the centre core and outer braid of the coax cable with crocodile clips attached to clip onto the antenna. I had made up another similar length of coax with a PL 259 plug on the end, so I used this and connected the centre core of the coax to the metal collet on the antenna mount and the outer braid to the earthing strap which was connected to the radials.

I made the radials slightly longer than the antenna with the intention of folding them back until I got the SWR right and I would then cut them to length. I attached automotive connectors onto the radials in order to thread them onto the bolt.

      

OPERATION

On the 8th June2006 along with the other two members of the club Tony and Glen we went to the Farm to play with our Radios and Antennas.

The three of us have Yaesu FT 817’s and we were going to have a QRP day.

I took along the Antenna, my 817, an SWR meter, an ATU and a small amplifier because on my previous attempt at portable QRP operating I didn’t have any success with SSB with the antenna that I used on that day and I had people who were using higher power bleeding over the top of me (Glen).

To power this entire set up I also took along a Leisure Battery, over the top I know but I wasn’t going to take any chances and if I wasn’t successful with the QRP I was going to use the amplifier, so the extra power would be handy.

I set the Antenna up, connected it to the radio and switched on. Immediately I was receiving good clear strong signals.

I hooked up my SWR meter and checked the SWR and it appeared to be spot on, the needle only moved a fraction on the meter.

I called Tony and Glen over and checked the SWR again to show them how good it was (I expected to be fiddling on with the radials for some time to get the SWR right).

When the needle hardly moved Glen said,

It’s broken”.

I kept the SWR meter connected to the radio, but I could have actually removed it.

I made only made 12 contacts but at a fairly leisurely pace, it was also a social event with plenty of chat.

My first contact came after a couple of CQ calls and was with Ian G3PHD in Tilbury, Essex who gave me a 5 & 7. I had one 59 report, a couple of 57 and a lot of 55 reports which when you actually take time to understand the RST system of reporting 5 by 5 reports are perfectly satisfactory. On this first outing I contacted a German station DQ2006S who gave me a 55 report and he obviously found it hard to believe I was running only 5 watts, he kept asking me to confirm I was QRP I confirmed it and he came back to tell me that he was running 500 watts.

As a fun club event on the 15th of July that year a few of us organised a QRP Barbecue come QRP competition. The basic idea was that we would have a day out at the farm, do some operating and have a barbecue. The competition side of events was that Glen erected a wire dipole for 40 metres and I took along the Tank antenna for 20 metres and we both took our 817’s. Competitors would have a 15-minute slot on each antenna and the person with the most contacts was the winner. There was an adjudicator sitting with each competitor to verify the number of contacts.

It was a great day out with fantastic weather, good food (if I do say so myself), good company and overall it was good fun.

DEVELOPMENT

Since that first outing and success with my antenna I have made another coax lead with automotive connectors on to tidy up the connection between the coax and the antenna, I have also tidied up the connection with the radials. I have also shortened the section of fishing pole which sits inside the ground spike, it was initially too long and one windy day with it moving about it split the fibreglass tube and fell over. Lowering it takes away that strain on the tubing.

During another day out on the farm in mid-February 2007, my first contact of the day was with PT7CB in Brazil! Wow I was over the moon; this was using the internal batteries on the 817. I also had a contact with CN8PA in Casablanca which was a first for me, so I was also very pleased with that.

Initially the Antenna was not intended to be used solely for QRP and it could certainly be used with more power or as a home base antenna, but I get such a buzz from making a contact using it on QRP that I am now totally hooked, and I would always keep sure that I have a Tank antenna for portable work.

Coming up to date in August 2018 twelve years on from when I first used the antenna.

I still have the antenna; the connections and radials are still working perfectly, and it has been used on many occasions at various power levels. The only further development that I have made with it is a tripod mount for use when I’m on a hard surface and cannot hammer the ground spike into the ground. It is a camera tripod that I was given with the tilt/mounting head on a central pillar that can be raised or lowered in the tripod. I simply took the tilt head off and the section of fishing pole with the antenna mount attached slides over the top of the pillar.

If you have a moment come and ask me about my Tank antenna, I’ll be only too pleased to tell you about it.

Enjoy your radio… 

 

 

 

 

 

 

Graham M0GAE

 

 

M6OZA on ADSB Flight Tracking

M6OZA on ADSB Flight Tracking

So if you’re like me, a bit of a geek or maybe handy with technology, you’ve probably got drawers and shelves at home full of bits and bobs that “may come in useful one day”. This article is about how I made some of my “bits and bobs” into something quite useful…

I’ve always had an interest in radio, technology, and programming so when I was given a Raspberry Pi and a RTLSDR dongle for Christmas a few years ago I wanted to combine them into a radio project.

Up to this point the Raspberry Pi had spent a few short weeks being a Kodi box, and then a WiFi repeater, before being destined to the bottom drawer. My first experience of Software Defined Radio (SDR) was with the RTLSDR dongle, an entry level model, but it had done the trick of luring me back into radio monitoring and listening to shortwave. After a while I upgraded to a better model but having explorered everything I thought I could, it also ended up in the bottom drawer.

I’d started to acquire a small collection of old 1980’s – 1990’s Realistic scanners, these analogue scanners had served me well. Military air scanning had become “my thing” and I found myself scanning the frequencies after work listening to transmissions from practice flights off the North East coast. These flights were mainly controlled out of RAF Boulmer, not far from my location at the time. However, after a while I guess listening wasn’t enough and I was on the hunt to improve my setup when I came cross ADSB and MLAT aircraft tracking. I read up on the subject and eventually found an article that described how it was possible to use a Rasberry Pi and a RTLSDR dongle to make a suitable receiving station. I’ve included a link to the original article here.

I suggest you simply follow the instructions on the website to upload the software onto an sdcard and install it in your Rasberry Pi. All you then need to do is plug in your usb RTLSDR dongle and you’re ready to go.

So what type of antenna do I use, as the ADSB aircraft signals are on 1090MHz? As with a lot of things today the antenna can be purchased online, but why not make your own. You’ll need an empty beer can, if you don’t like beer a lager one will work just as well 🙂

The picture below is one I made. The beer can acts as a ground plane and the short vertical wire (1/4 wavelength long on 1090MHz) is connected to a sma connector.

The paint was just for practical reasons, to stop rain water shorting out the antenna to the can (groundplane). I happened to have Citroen saxo blue in the cupboard, but any colour will do. A blob of silicone around the connector would serve just as well. The measurements should you require them are: Antenna length 69mm, Can length 69mm.

For maximum receive range mount the antenna on a non-conductive mast, mine is on the chimney stack as a temporary measure. At this height I’m seeing a range of 100-150 miles from 200-350 tracked flights a day. It will work at ground level but range will be much shorter and the number of heard aircraft will be less.

Now I don’t only hear them I can see them as well…brilliant !

A year or  so down the line, I have now upgraded my system to include a flight-aware dongle to replace the RTLSDR, a 1090mhz pre amplifier, and I have upgraded the antenna to a high gain 8 section co-linear. Although not needed to get started, these upgrades have improved my receive capability significantly.

 

So don’t throw away your “bits and bobs” as they may come in useful one day. Have fun building your own ADSB receiver. If you liked this article please give it a thumbs up.

73 Ray M6OZA

ILLW 2018 Event

ILLW 2018 Event

The International Lighthouse & Lightship Weekend is upon us !

So as a club (Tynemouth Amateur Radio Club) once again had the change to operate from the Lightship LV50which is the home of The Royal Northumberland Yacht Club and is berthed in the Marina of Blyth Harbour on the North East coast of the UK.

Now this is no small issue, because this vessel is the last all-wooden light vessel, constructed for Trinity House in 1879.  Her design of 1878 is credited to Bernard Weymouth, Secretary to Lloyds and one of the architects of the “plimsoll line” and H.Y. TYNE III is one of the last remaining wooden lightships afloat.

So all in all a proper privilege to be aboard and also be allowed to string antennas and the such like to the mast, and that’s not all.. It’s got a full operating restaurant and bar inside ! Bacon Sarnies for brekkie anyone !!

We setup in the fore peak of the boat with 2 x Kenwood TS590’s one for CW & Digital and one for SSB operation, we would use WinTest for logging and a number of the guys from the club said they would call in during the day and operate. Initially myself and Glen Thompson were at the helm with me on SSB.

Now this is my first year taking part in this event with a club and also for any length of time operating. so you can imagine my surprise when at first I thought my receiver was a bit deaf !! Argh !! We did some investigation but came up with nothing and I had S5 -7 of noise almost all day ! It dawned on me after lunch that the plethora of masts on the yachts in the Marina wouldn’t exactly be helping our cause. I suspected they were acting as a random set of parasitic elements and bouncing RF all over the place..

This was kind of confirmed when Bob (one of our members) tuned into the event from home and confirmed the bands were indeed fairly active and we confirmed we could hardly hear anything !!!

So its back to the drawing board tomorrow and move a vertical antenna quote away from LV 50 and the Marina whilst still staying onboard to operate, watch this space for an update from day 2 ! That said we still managed 100+ contacts across SSB/CW/Digi for the day so not too bad a haul for a days work.

Stay tuned for tomorrow’s shenanigans.. I’ll hopefully be there for a few hours to take pics and generally make a nuisance of myself ! LOL

Here’s the SSB List from today.

14220.0 SSB I1JHS 
14220.0 SSB IV3LBP 
14220.0 SSB DA2018LH 
14220.0 SSB DL4EAM 
14220.0 SSB ON6OO 
14220.0 SSB DD0PM 
14220.0 SSB DL8GA 
14220.0 SSB DK4IM 
14215.0 SSB F8GGV 
14215.0 SSB PB8DX 
14215.0 SSB PD0TV 
14215.0 SSB SV9RGI 
14215.0 SSB RX3DPK 
14215.0 SSB F5IDJ 
28470.0 SSB DH2DAM 
28483.0 SSB DH1AD 
28483.0 SSB PA3AJI 
28491.0 SSB PA3EFR 
14218.3 SSB GB1DLH 
14220.0 SSB OV1LH 
14260.0 SSB DL0PJ 
14260.0 SSB DJ9IN 
14175.7 SSB S59DXX 
7107.1 SSB PA6FXU 
7103.0 SSB GB4EUL 
7197.0 SSB DA2018LH 
7166.0 SSB GB2SJ 
7155.0 SSB EI0DXG 
21127.7 SSB S51LGT 
21127.7 SSB F4FET

Field Day – July 2018

Field Day – July 2018

Sat 21st July, A day that will be long remembered, by me at least… !

It was the summer Tynemouth Amateur Radio Club Field Day, one of a few we have planned over the summer, which in fact so far is proving to a proper corker of an English summer

There were 6 vehicles and 7 members present in total and an amazing array of kit and antennas ! Everything from an 80m Doublet to a 2m Beam was present and almost everything in between.

I was operating with my friend Carl Gorse (2E0HPI) using the DXCommander vertical antenna which I find is an excellent all round vertical that covers multiple bands. Initially we set out to use my TS590SG which turned out to be a no go at anything over 10 watts as the car 12v system just could not provide the current and the radio simply shut down each time TX over 10 watts was used.. Luckily ! I had my trusty KX 3 and LifePO battery box at hand which I normally take on portable ops with Carl so we reverted to that and blasted out our mighty 15 watts LOL !!

We did well with a total of around 18 in the log, mainly from Europe but we had some great craic in the sun, eating sandwiches and talking radio with the other members, I took along my restored WWI Lancaster bomber radio, a marconi R115A receiver so we could listen to AM broadcast radio just for some entertainment !

The log for the day read like this :

40 Meters

(7.160 Mhz)
G4SQA
M3FEH
(7.096 Mhz)
F4FMU
ON7RN
F2YT
ON3EA
2E0WDX /M
(7.144 Mhz)
F4HXC /P
(7.180 Mhz)
ON6OO
G7VQE
F4HZR
MM0JEL
G0FVH
DK0WK /P
DL4ABN

Echolink (2 Meters)
M1PVF /M

17 Meters

(18.144 Mhz)
DG4FCN