QRP Portable Operation

A Portable QRP Solution – Or having fun with Ham Radio when Travelling

Before you stop reading and dismiss this a another one of those articles that needs a suitcase full of equipment that then uses a wire antenna hanging from the balcony of the hotel or looped over a nearby tree- hear me out!

Working The World on 5Watts

This article has been written to tell you of some of the fun I have had with a QRP HF Station while traveling around the world. Normally I wouldn’t bother writing an article about what I have been doing however a number of my friends have been urging me to tell the story – so here goes!

If you have read this far then I am sure you have or want to take Ham-radio Portable. If you are like me and don’t want to reinvent the wheel you will have gone on to the internet and searched for possible ways to achieve this magical state of QRP Portable and found that most of the articles just don’t meet your needs?

Well that is exactly what happened to me and after quite a period of searching with little reward I began thinking “How hard can it be”?
What was so special about what I wanted to do? Was it so different from all those that had gone before me? Could it just be that I was not able to grasp the merits of the solutions that I was reading about?

In most of the solutions presented much of the discussions centered on the assembly of equipment and how to power the QRP station and then as almost like an afterthought the antenna solution became a loaded whip requiring a counterpoise or a long wire thrown over a balcony or a near by tree (assuming one existed).

What I wanted to do was to have a QRP Station that would be able to be carried onto an Aircraft without the need to have a separate suitcase full of equipment. I wanted to have an antenna that was efficient and not requiring a tree or a balcony and lastly I didn’t want a large battery to have to be carried around. On the surface that all seems rather reasonable to me and so the project began!

Initially I was drawn into the age old debate why not use a computer based solution such as “Echo Link” then all I would need is a computer? But this solution assumes that there will always be an internet connection where ever I was traveling and of cause this is far from the case. Secondly this solution while a great innovation that provides the ability to talk other Ham Radio operators around the world still does not give you the facility to use HF as most of the stations are using keyboard to keyboard or via a 2m or 70cm repeater contacts.

I have in the past taken a Dual Band Hand Held Transceiver which certainly works for calling into one of the local repeaters on 2m or 70cm if there is one but in 9 out of 10 locations there is no activity if there is a repeater and in many cases there has not been one in the location I was visiting.

FT817ND and Auto-Tuner

What then is the solution? It turned out to be staring me in the face. I have been using YAESU FT817 Transceivers for my Microwave Transverters with great success and have found these little units to perform very well. In addition they fit the QRP requirements very well with a maximum of 5watts output and in addition they are Multi-Mode and have an internal battery. In addition these units cover all of the HF Bands as well as 6m 2m and 70cm so if I did want to try one of the local repeaters then I would be able to!

In addition to the features outlined they have the ability to be interfaced to a laptop running software like Ham Radio Delux making it easy to keep a computer log of all my contacts.

The first part of the solution was at hand and now what was going to be the antenna? I am sure many of you have read at some time articles in Amateur Radio magazines discussing “Magnetic Loops” an how effective and efficient they can be for Ham Radio applications. In the 1980′s and 1990′s a number of manufactures produced a range of these antennas and while popular in some areas of the world at the time there seems to be little interest shown in this decade.

Searching the internet produced a number of designs all of which seemed to need a lot of setting up and critical placement of the feed point. I decided to try and produce a loop that I could take portable that was not critical to set up with robust elements that were almost self supporting. During the test phase I tried all manner of shapes and sizes. While most of them worked, the difficulty of support always seemed to be an issue along with how to make it small enough to take on board an Aircraft.

Squid Pole Mount

Finally I settled on a loop that was easy to assemble and dismantle, there were no critical components and it could be scaled to cover 40m to 6m and it has now been with me on a number of trips without any disasters.

The Loop Tuner

The accompanying photographs show the final solution. The antenna is made from 12 x 30cm lengths of aluminum 10mm wide by 2mm thick with a 3/16″ hole in each end. The pieces are held together with zinc plated 3/16″ bolts, spring washers, star washers and wing nuts. When assembling the antenna a star washers is placed between the aluminum bars to allow it to hold its shape with the spring washer ensuring when the wing nut is tightened the assembly remains secure. The loop is tuned using a 2 gang double spaced tuning capacitor (third gang obvious in the photographs was not used) mounted in a rectangular plastic electrical junction box with a switch to add or subtract the second gang depending on the tuning range required. A knob is fitted to the Tuning Capacitor to indicate tuning position and also to prevent RF burns (yes even at 5watts it will burn you).

Tuner and Couplers

The antenna is fed at the opposite side of the loop to the tuning box. The coupling is effected by the use of a toroid with 5 turns of hookup wire connected to a BNC socket one end of the loop has 0.1ufd capacitor in series to earth. As seen in the photographs the loop element passes through the Toroid forming an RF transformer connection to the antenna. As shown the Toroid assembly is placed an an electrical junction box to prevent damage. I have used 2 of these pickup units, one with 5turns (80, 40,30&20m) and one with 3turns to cover the remaining bands.

The Antenna is connected to the YAESU FT817 using a length of RG58 cu with BNC connectors on each end.

The Coupling Transformers

By now some of you will be saying but what do you hang the antenna on? My answer a “Squid Pole” as shown in the accompanying pictures. When collapsed it is permitted as cabin luggage. I have also supported the antenna from a curtain rod in a hotel room with good success.

The tune up process is simple: assemble the antenna, Attach to whatever support you decide to use however if you use the squid pole outside as is shown in the pictures it is best located with the bottom of the loop a maximum of 300mm above the ground. In the case of using it in a hotel room its shape can be changed to suit the window size available.
Once built turn on the transceiver, select the frequency to be used and tune the antenna for maximum received signal.

Packed Up and Ready to Travel

Call CQ and have fun – I certainly have !

Post script:
I invested in a LDG Z-817 battery powered tuner on one of my trips – best thing I could have done. The beauty of this device is that once the Antenna is initially tuned on a particular band the tuner allows frequency changing within any given band without the need to retune the Antenna and because it is battery powered from its own dry cells is fully automatic without draining the Transceiver battery. Push the “Black” button and it tunes!

Amateur Radio in the Field

The Transceiver Console

Amateur Radio Field Days have the ability to conjure up many and varied images depending on the experiences of those involved while portable. For many they are a fantastic experience to allow those participating the opportunity to test their operating skills, equipment reliability and their ability to establish a fully operational station in some remote location. On the other hand for others, field days / portable events are or have been nothing short of a full blown disaster, resulting in the operator vowing never to undertake the experience again!

Operating in the VHF/UHF 2011 Winter Field Day

From my point of view, field days are a challenge and though I can say I have had the odd bad experience for the most part the experience has been extremely rewarding. My experience spans the last 50 plus years beginning the late 1950’s on frequencies from 160m to 3cm with equipment that has been predominately “home brew”. In the early days every thing was Xtal locked Transmitters and a variety of second world war radio equipment with AM reigning supreme, then Phasing and Filter SSB and FM (transmitters, receivers and transceivers both valve and solid state) all of which provided substantial rewards with a few disasters thrown in for good measure.

The 2011 Winter VHF / UHF Field Day has come and gone and for the most part all who participated had a good time proving once again, that these events can be fun provided suitable planning is adopted to ensure, as far as possible, all the variable are under control

The following is an account of my efforts to participate in the 2011 Winter VHF / UHF field day activities using an entirely new configuration from previous years. The catalyst for this new configuration was defined by a major portable disaster that was inflicted on me earlier in the year. The disaster occurred due to a freak wind gust that virtually saw all of my microwave equipment and its respective antennas blown over and slammed into the adjacent roadway. Determined that this was never going to happen again, I set about designing a solution that would allow my field day / portable operation to occur at any location that a 4×4 and trailer could drive to!

With this in mind I settled on a design that relied heavily on the use of a standard box trailer. I was however, determined to produce a system for mounting antennas that was easy to set up for field days / portable operation, but flexible enough to allow the trailer to be used as a trailer at other times.

From past experience the design for such an antenna system also had to accommodate the ability for any mast to slowly rotate while supporting antennas for at least eight bands VHF / UHF and Microwave (6m, 2m, 70cm, 23cm, 13cm, 9cm, 6cm and 3cm). Because I also wanted to operate portable on the HF bands the design needed to allow for a HF Mosley TA33jr tri-band Yagi to be installed in the place of the VHF / UHF and Microwave antenna.

The design had to allow for all of the antenna and mast components to fit into the box trailer. The thought of having antenna components draped all over my vehicle was not an option even for transporting pipe sections and antennas.

For those of you familiar with going “off the beaten track” the last thing you need is to have low lying branches getting tangled up with your carefully designed and crafted VHF / UHF antennas. The antennas will always come off second best resulting in a disaster and spoiling what could have been a great portable experience.

With these thoughts clearly in focus, the build requirements began to take shape.

If the design was to be robust and reliable a number of major factors had to be addressed.

Putting the Mast Together

Firstly the mast needed to have a solid base with a means of rotating but be devoid of any support “guy” wires. In addition, with so many antennas (which includes a number of off-set and prime focused dishes) on the mast, the design must incorporate an easy solution to raising and lowering the mast in windy conditions.

In addition to those items identified there was a need to ensure that the total system could be assembled and raised & lowered by one person!

The following images show the system on its maiden field day outing during the Winter VHF / UHF and Microwave Field Day 2011. The systems performed flawlessly with a set-up / dismantle time of about 45minutes.

Packed Up and Ready to Go!

The base for the system is manufactured from 50mm angle iron that was formed into a frame that sits in the base of the trailer. To this is added cross braces, made from the same material and positioned in the centre of the frame to hold the base solidly in the trailer while providing an anchor point for the tilt over pivot. The base frame has a vertical mast section attached that is supported by 25mm angle iron diagonal struts. This mast section acts as a “gin” pole for raising the main antenna mast. A standard boat winch is fitted to the back stay with the cable passing through an enclosed pulley at the top and then connecting to the mast section. The winch is stabilised by a diagonal strut that prevents the winch from twisting. The base pivot is a 200mm stub of 40mm galvanised water pipe on which is mounted a Yaesu G-800DXA variable speed Rotator. This rotator is pinned through the stub to ensure it always has a fixed location.

Getting Ready to add the Transverters

The mast section is 50mm x 3m aluminium scaffold tubing which is further reinforced with an additional 45mm aluminium pipe in the centre that then protrudes 300mm out of the top of the main mast to facilitate a support for a further 40mm x 2m aluminium mast to accommodate the VHF / UHF Antenna.
Note: This upper section can be replaced by a 50mm x 3m aluminium mast section on which the Mosley TA33jr is mounted for HF operation.

The top section for the mast, when used for VHF / UHF, supports “Loop” antennas for 6meters and 2meters, a GPSDO (GPS Disciplined Oscillator for locking the Microwave Transverters) antenna and an 14 element Yagi for 70cm. The 2 meter “Loop” can be replaced by an 8 element Yagi if greater gain and directivity is required. In addition there is a tri-band Vertical for 2m, 70cm and 23cm located at the top of the mast.

The Top Section with GPSDO Antenna Clearly Shown

On the 50mm section of the mast there are two cross arms. The top cross arm supports the 23cm Yagi plus Transverter, the 13cm (Square Patch) Antenna plus transverter and the 3cm – 300mm Prime Focus Dish plus transverter.

Assembling the Antennas

On the lower cross arm there are two stub masts to support the 9cm and 6cm off-set dishes. These stub masts are pinned to the cross arm so as ensure they are angled forward by 22degrees to the vertical. In addition this cross arm is pinned to the centre mounting plate to ensure that this angle is always maintained.
Note: With off-set Dish Antenna the plane of the dish needs to be set at 68 degrees with respect to the horizontal to ensure that the focal point of the dish points to the horizon. Since every off-set dish is slightly different the exact angle needs to be derived experimentally. The mounting plate for these types of dishes has an adjustment protractor so it is a simple matter to change the actual position within a few degrees.

The bottom section of the 50mm mast has a bearing fitted with a suitable plate that attaches to an angle plate on the centre tripod to ensure the entire assembly is stable and aligned for rotation when vertical.

To ensure total stability of the box trailer 50mm stabilising legs were added that are adjustable to cater for undulating ground. The wheels of the trailer were also “chocked” using caravan wheel wedges to complete the stabilisation process.

The cable assemblies for all the antennas, DC feeds for the transverters and IF & PTT cables are bundled into three looms that are supported by attachment tabs that bolt to the mast to ensure no load is placed on the equipment and antennas. Short sections of PVC tubing are affixed to the cross arms to route the cables to the respective transverters again removing loading on the connectors.

The 12volt DC feeds to the transverters are terminated in a distribution box that is attached to the base tripod with a single feed going directly to the main DC distribution centre that monitors voltage and current to the transverters. This distribution centre also provides polarity and overload protection for all the devices connected which includes the GPSDO.

Note: The 12 volt DC feed to each transverter uses standardised polarised plug to ensure compatibility of all of the transverters. This also applies to the IF / PTT cables that are all terminated in BNC connectors.

Every cable (Antenna feed-lines, DC supply cables and IF/PTT cables) has identifying labels at each end that have clear heat shrink tubing over them to protect the label from damage. This ensures that there are no “slip-up’s” when assembling the system.

Each transverter has its own metering system that monitors Voltage, PA Drive and Power Output. These meters are easily visible from the operating position and ensure that the systems are working effectively.

As shown in the following image all of the equipment is carried in the SUV in a dedicated frame made specifically to ensure that all of the equipment travels safely. Aluminium carry cases are used to house many of the items to ensure nothing is forgotten and provide protection for individual components.

A Place for Everything and Everything in its Place

There are five major cases that house essential equipment required for successful Field Day operation.
• The first of these is a battery box with built-in protection that contains the 150 ah AGM Battery and 600 watt Sine Wave DC to AC inverter to provide 240v AC for the YAESU Rotator and any other AC system that may be required. (A second 150 ah AGM Battery is also carried to support the main Battery)
• The second is a “roady 19” rack case” that has been setup to hold all the Transceivers required for the VHF / UHF & Microwave operation. These include ICOM IC7000, ICOM AT180 Tuner, ICOM IC1200 FM, YAESU FT-817ND Tuneable IF, and a YAESU FT-8800R.
A second version of this case has been developed for HF that houses a ICOM IC-7000, ICOM AH-4 Tuner and IC 208H dual band FM transceiver.

The Operating Position

• The third case is the Stanley “FATmax” Toolbox that is central to all the portable operation. This unit has three large draws that allows storage of all the cables, the YAESU Rotator control head & rotator cable and DC control Centre. The three draws open out to form a natural console for operating with the “roady” case placed on top of the toolbox with the lid acting as a table top. To achieve a flat surface an insert of 3ply was shaped to fit into the lid. The lid needed to be supported as the hinges would not be able to hold the weight of a laptop and so a support was produced using two pieces of aluminium tube. One as a cross brace and the other as a strut from the axle of the toolbox.

• The forth case houses the laptop computer, and transceiver interfaces that allow interconnect with the ICOM and YAESU transceivers. The Laptop provides for logging of contacts by reading the Frequency and Mode directly from the transceivers. There is also an added advantage in making this interconnection with the transceiver because the Laptop also displays the Frequency in large figures that are easy to read in direct sunlight. This fact alone overcomes the deficiency of many transceivers being impossible to read their LCD displays in sunlight.
• The last case houses the 160watt Solar Panels that provide a trickle charge for the AGM Battery throughout the daylight hours without having to resort to use fuel based charging systems.

When operating HF portable the system is supported by a 2 KVA four stroke Honda Generator that produces little noise and allows prolonged operation during the evenings.

It's Great when a Plan Comes Together

Lastly my thanks go to all those operators who provided the contacts with me throughout the 2011 VHF / UHF & Microwave Winter Field Day. I was fortunate to make numerous contacts on all of the 8 bands that this portable system supports. The contribution made by all of the operators has contributed, in a very positive way, to the success of the project that yielded a very rewarding and satisfying experience for me!

Microwave Transverter Additions

The following shows some additional images of my Microwave transverters. As mentioned previously the transverters were designed to allow power amplifiers to be added. This is accomplished by adding a second die-cast enclosure on the base of the transverter. The following shows the 10Ghz transverter Power amplifier, pre-amplifier and sequence switcher.

10Ghz Power Amplifier, Pre-amplifier and Sequencer

You will also note that the 10Ghz Transverter shown in the next image has a panel meter mounted on the rear of the main transverter enclosure. Metering plays an important role in portable operation and in this case the DC supply voltage can be monitored as can the Power amplifier drive, and Power Output. In this case I have rescaled a 50uA meter to show DC volts in Black and RF levels in Red. The scales were produced using Microsoft XL with aid of the drawing tools available in the software. This image was then scaled down to fit the meter. The normal meter face was removed (2 screws) and used as a template for the new meter face. I printed the new meter faces on “Matt Photographic Paper” on a laser Colour printer.
The meter scales are selected by the toggle switches on the side of the transverter.

10Ghz Transverter showing metering

In the next image there is a view of the side of the transverter showing the Power Connector, Main DC Fuse, Toggle Switches for Power On/Off, DC/RF, Power Output/Drive Level and finally the IF connection.

10Ghz Transverter Side View

3.4Ghz Transverter showing Connections

As shown in the above image of the 3.4Ghz transverter, while no power amplifier has been added to the basic unit, the connections are essentially the same with one exception, the Drive/Power Output switch has not neen added. If however a power Amplifier Unit is added, there is room to add the switch. It will also be noted that the format of the 3.4Ghz transverter is the mirror image of the 10Ghz transverter shown previously.

VK4ZQ Microwave Transverters

I thought it was about time to show some of my workshop activities over the last six months. However before doing so, I think it would be appropriate to discuss why I have developed the equipment in the form I have! While I have “done it my way”, I am sure you are aware there are many ways to become active on the Amateur Radio Microwave Bands.

Initially I was going to develop my microwave activity from my home QTH however I decided that, while this would be a relatively easy task, it would not assist in any way to promote the microwave bands, within the wider Amateur Radio Community within Brisbane, which is located in the southeast corner of Queensland, Australia. My home station allows me to be QRV from 160m to 13cm and while this has been a good spread of frequencies in which to enjoy our hobby I wanted to take up the portable gauntlet and actively pursue the microwave bands from a range of portable locations. It was this decision that has tempered the development of my equipment.

Setting the Specifications

To begin with I want to develop a series of Transverters that all shared a common format. This would ensure that all of the basic components used would be able to be purchased in bulk meaning that it would force me NOT to use some obscure and not readily available object from the junk box such as connectors, meters, switches and power connectors from older equipment and or obsolete projects. I further decided to arrange the layout of external controls and connectors in a common format or a mirror thereof. In addition I decided to use common type of connectors for the power to each of the Transverters. I also standardized on the drive level for each transverter thereby over coming a potential problem by overdriving the transverter. The final decision was to feed the PTT voltage for the transverter to the centre conductor of the common IF coax to the transverter. This ensures that every time the transverter is used the IF coax is validated and of cause there is one less control cable to be provided.

With these requirements clearly set, there were four (4) other specifications that had to be established. The first requirement that was clearly etched in my mind as a direct result of operating porable over many years, was the need for the supply voltage for all of the transverters to be the same! Why, well any of you who have worked portable will know just how difficult it becomes to generate higher voltages easily and to maintain this higher voltage for long periods of time while working in some out of the way portable location. The second was the drive level for the transverters which I was determined to have set at 5 watts; Why? Because my IF Transceivers are Yaesu FT817′s with a maximum of 5 watts output thereby overcoming the fear of overdriving and destroying the transverter. Requirement number three clearly focused on the antenna and feed line and how they would be combined to each transverter. In reality the solution was obvious and was based on how would the equipment be moved and setup quickly! Since my method of transportation for all the equipment is an SUV, ther was a need for every thing to fit in or on the vehicle! The choice, tripods would be used to support the antennas with the transverter attached to the antennas.

The fifth issue was to look at how to increase the power output of any or all of the transverters should the need arise!

The following images show the finished transverters covering 1.3, 2.4, 3.4, 5.7 and 10Ghz.

In future postings I will describe what components were used.

3.4 and 5.7 Ghz Transverters

5.7 and 3.4 Ghz Antennas with Transverters and Feed Horns

10Ghz, 1.3Ghz and 2.4Ghz Transverter Top View

2.4Ghz, 1.3Ghz and 2.4Ghz Transverters and Antennas

GPSDO

The Project
The following outlines how I established a portable GPS Disciplined Oscillator for use with my microwave Transverters. The unit is based on the Trimble Thunderbolt and the object of the Project was to allow the “Thunderbolt” to be used in the field as well as in the radio shack.
Prior to commencing the project I reviewed as many articles as I could find on the internet as I was not looking to reinvent the wheel. While there are many excellent ideas appearing in the articles I could not find an article that satisfied my requirements. My needs were quite simple I thought and really centered on a high percentage of usage away from the home QTH.
For portable work there was a need to allow the unit to be operated on 12 volts DC making it compatible with all of the microwave transverters and other portable equipment used by me for field days and portable style operation. In addition there was a need to make the change over process from AC to DC as simple one and ensuring that the unit would also be polarity protected.
“Those of you who have operated portable will know how easy it is, even for the most experienced operator, to make a mistake, in the haste of the moment, when setting up a portable station, to reverse the supply polarity and without polarity protection the ultimate failure occurs! The result equipment destroyed.” The challenge, in fulfilling these requirements, was to make sure that the solution adopted was cost effective. By the way the total cost of my project was under $200 and has resulted in a very functional and flexible piece of equipment.
In developing this project I was determined to use readily available components and to make the unit as light as possible while allowing it to be robust to allow it to survive Field Day activities.

Front panel

Back panel

This image shows the inside of the unit.

An explanation of the Project will follow shortly.

Welcome

Welcome to my Blog. This site will focus on Mobile, Portable and Home Station projects associated with Amateur Radio with and emphasis on the Microwave Band from 23cm to 3cm.

I will also be describing a number of projects in the microwave area that I am currently working on or have completed in the past.