Becoming A Great Elmer


Teaching Amateur Radio License Classes

Teaching Amateur Radio License Classes

There is much being said and written these days about the importance of bringing new people, especially young people, into our Hobby. There are many obvious reasons for this. As we all get older or get busy with other aspects of our lives, some will leave the hobby. Also, we have the use of many commercially valuable portions of the RF spectrum and there is always pressure to reallocate bands or segments of bands which are not fully utilized. In my mind, the most important reason to bring new HAMs into our hobby has to do with the energy and new ideas that these folks bring to Amateur Radio. Amateur Radio has always been a learning hobby and new folks help us to keep this important part of what makes our hobby so much fun vibrant.

Anita (AB1QB) and I putting a lot of time and energy into getting folks started in Amateur Radio and helping them to build their skills and progress. Our Amateur Radio License Classes and the youth outreach work that we’ve been doing are two good examples of this. To make these efforts as successful as they can be, it’s also very important to provide good opportunities for folks who are new to various aspects of Amateur Radio to learn and gain experience. This means becoming an “Elmer” or a HAM Radio mentor to people who are less experienced in some part of the hobby than you are.

Perhaps the most challenging part of Amateur Radio for many new HAMs is making the transition from getting their initial license or a license upgrade, to getting on the air with their new privileges. I think that this is equally true for newly licensed folks and for folks who have upgraded to a higher license class and are looking to get onto the HF bands. It’s impossible to teach everything that one needs to get the most from their Amateur License in classes alone.

Help A Young Person Learn To Operate From Your Shack

Help A Young Person Learn To Operate From Your Shack

So what does effective Elmer’ing look like? I think that the answer is different for every HAM. For a new Tech, it may be as simple as helping the person to pick their first radio and antenna along with some help getting it programmed for the local repeaters. For a person upgrading their license to gain HF privileges, it is often about helping to get a first HF antenna up along with helping them to select equipment for and assemble a first HF station. All of these folks will also benefit from help getting on the air and learning to operate. Most of all, a great Elmer is someone who is willing to give their time to help a person who is new to an aspect of Amateur Radio learn and get started doing what they want to do.

I have personally found that being an Elmer to be one of the most rewarding and enjoyable aspects of Amateur Radio. Every time that I help someone get on the air for the first time or help someone to build their first HF antenna or station, I get the same enjoyment as when I did these things for the first time in my Amateur Radio experience.

Elmer’ing is also a great opportunity for the “Elmer” to learn new things. Newer or less experienced folks will have different things that they want to try or learn about than those things that we “Elmers” consider our “tried and true” Amateur Radio activities. A great Elmer will help the less experienced HAM take on these projects and learn along with them. This gives the less experienced person the confidence and support that they need to try more difficult projects with confidence. The learning experience associated with being an Elmer has often been the best part of the experience for me.

So how does one get started with Elmer’ing? You could open your station to newer HAMs and offer them a chance to get on the air and learn to operate. There is always someone looking to put up a new antenna or to repair an existing one. These are all great opportunities for Elmer’ing. Also, you could consider creating a presentation that you can deliver at your local radio club meetings as a way to share specialized knowledge or experience that you may have. If you are new licensed, perhaps you could help someone who is studying for their license exam with some of the areas that they are finding difficult. Also, new folks tend to have experience with computers and the Internet that many of the folks who have been in the hobby for a while can benefit from. This can be a 2-way Elmer’ing opportunity.

I hope that all of our readers will consider becoming an Elmer in some way. Your efforts to help someone new or less experienced can provide you with the satisfaction that you helped to make Amateur Radio a better hobby for everyone.

– Fred (AB1OC)

A New Project – Digital Fast Scan Amateur Television


Digital ATV CQ Call

Digital ATV CQ Call

Skip, K1NKR a local friend and VHF/UHF expert and I began talking about the idea of building a Fast Scan Amateur Television (ATV) System some time ago. Our early research and the antenna equipment which we had in place at our stations led us to plan our ATV project around the 70 cm band. The 70 cm band plan in the United States has allocations for Fast Scan ATV transmissions with a bandwidth of up to 6 MHz. Our research led us to Jim Andrews, KH6HTV’s excellent website where we discovered that it was possible to build a Digital ATV station using reasonably priced commercially available DVB-T format Modulators and Demodulators. Jim’s site has a wealth of great Applications Notes on Digital ATV and its a great place to start to learn about this technology. A combination of a DVB-T Modulator and Demodulator from Hi-Des was chosen as the heart of our Digital ATV System. We also worked with Jim to secure the needed Wideband Linear Power Amplifiers for the 70 cm band. We began receiving the equipment to build our Digital ATV Stations late last year. We’ve done quite a bit of testing on the air and some custom development work which has resulted in a pair of excellent performing Digital ATV stations. The picture above shows a Digital ATV “CQ” that I sent to initiate one of our early QSOs.

Digital ATV Transceiver

Digital ATV Transceiver

Here’s a picture of Skip receiving my “CQ” at his end. The picture quality produced by the equipment that we’re using and the DVB-T format is phenomenal. The Hi-Des Modulators which we are using have a large number of parameters which can be set to determine the format and bandwidth of the signals we generate. After some experimentation, we have settled on using QPSK modulation and a 6 MHz signal bandwidth. This combination delivers excellent picture quality with more that adequate motion performance. We see very few if any picture artifacts using our current format. We’ve also done some experimentation with QPSK and a 4 MHz signal bandwidth. I plan to share more on signal formats in a future article on our blog.

Digital ATV System User Interface

Digital ATV System User Interface

We are both using HD Digital Camcorders as our primary video signal sources and 1080p monitors to display our received signals. I opted to include an HDMI Video Switch from Gefen in my setup which also allows me to send video and graphics from a variety of different sources including my PC over the air. The monitor in the picture above on the right is a touch screen display which I use to control my ATV Transceiver system.

AB1OC Digital ATV Transceiver

AB1OC Digital ATV Transceiver

Early on, I decided to build a Transceiver like setup. I wanted to create a unit which was simple to use just like the HF Transceivers that are available today. Some of the key capabilities that I wanted to create included:

  • Real-time selection and switching between multiple HD video sources
  • Transmission of PC sourced Video and Graphics over the air
  • Preview and cueing of the next video transmission while receiving
  • Simultaneous display of both receive and pending transmit video
  • Built-in Transmit/Receive (T/R) switching with termination and protection of the Tx power stage
  • Sequencing of T/R stages including my tower mounted pre-amplifier system
  • Power and SWR monitoring with automatic trip on high SWR
  • An internal low-noise RF preamplifier to provide additional receive signal gain if needed
  • Touch screen graphical interface for configuration and operating the system
  • Recording of both sides of on-air video QSOs to an attached PC

To achieve these goals, I decided to build a Raspberry Pi 2 based Linux controller of my ATV Transceiver and to package all of the ATV components and video switching/conversion gear needed in a small rack mount enclosure. Many of the components in the system communicate with each other over an ethernet LAN and the transceiver is networked to computers and other devices via an external ethernet connection. More on the details of the Transceiver design to come in a future article.

Skip and I recently produced a short video to demonstrate how Fast Scan Digital ATV works and to show the quality that these systems are capable of producing. Our project is still a work in progress and I expect that we will continue to learn as we perform more tests and continue development of our systems. I plan to post additional articles here to share the details of our designs and learning from our on-air testing as we proceed.

– Fred (AB1OC)

Software Defined Radios – The Future of Amateur Radio?


Modern SDR Example - FlexRadio 6000 Series

Modern SDR Example – FlexRadio 6000 Series

Computers and Digital Signal Processing already play a big role in recent Amateur Radio transceivers. Many HAMs have a good understanding of these features and regularly use them for all manner of filtering, noise reduction and signal processing tasks while on the air. We’ve also seen more and more radios with Spectrum Scopes which make it easier to visualize what is on a given band in real time. Thanks to increasing volumes in color displays, Digital Signal Processor (DSP) applications and low-cost processors, these capabilities are now common – even on entry-level HF transceivers.

Software Defined Radios (SDRs) are the next logical step in this evolution. SDRs are not new, they have been around for some time now. SDR technology has continued to improve as the cost and performance of Analog to Digital Converters, Programmable Logic Devices and other processors that make up the hardware side of SDRs have improved. We are now to the point where it is possible to build an SDR for Amateur Radio applications which can directly sample RF at frequencies as high as 150 MHz.

Direct Sampling SDR receiver designs have some important advantages over more conventional single conversion and super-heterodyne receiver (i.e. multiple conversion) designs. These include:

  • Higher dynamic range
  • Low phase noise
  • Ability to cover multiple bands simultaneously with multiple receivers
  • Very high-quality spectrum displays
  • Flexible, high-performance filters
  • The ability to add new modulation schemes and other features via software updates

The first two items above (dynamic range and phase noise) are particularly important as they result in receiver performance which is significantly better than that which can be achieved with the best direct and superhet designs. Take for example a busy contest environment when a band is very crowded (ex. 40m at night in a worldwide DX phone contest). There are many strong signals crowded closely together on the band. Even the best conventional design receivers will have trouble hearing moderate and weak signals in this environment. The problem is that the strong signals tend to overload the analog circuitry in the conversion stages of conventional radios which produces a great deal of Intermodulation Distortion Design products. Phase noise also compounds this problem.

A direct sampling SDR converts the incoming RF signals with high dynamic range Analog to Digital conversion and then performs all of the filtering and demodulation of the incoming signals in software. This approach limits the potential for Intermodulation Distortion with an end result that all of the signals on the band (including the weaker ones) are much clearer. This approach also allows very high order filtering to be applied in the RF domain which results in greatly improved selectivity and rejection of closely spaced adjacent signals with minimal distortion.

By now some may be think that this all sounds great but I don’t want to have to use my computer to make QSOs. There is good news on this front as well. We are beginning to see the major transceiver manufacturers introduce direct sampling SDR technology in radios with conventional “buttons and knobs” interfaces.

Icom IC-7300

Icom IC-7300 (Pending US Release)

New designs like the Icom IC-7300 can provide a way to gain the performance and feature advantages of an SDR in a radio which has a more conventional interface. The entry of the major manufacturers into the direct sampling space and the resulting competition should help to lower prices for all types of SDRs.

RTL-SDR Dongle

RTL-SDR Dongle

Want to give SDR technology a try without spending a lot of $? There are several very good SDR Dongles available along with SDR software at a minimal cost. Dongles are typically receive-only but some can also transmit as very lower power. The use of this technology in digital TV receivers and set-top boxes has made the cost of SDR Dongles very low and there is some very good SDR software available for free on the web. Dongles are generally broad coverage receivers and they can also be used to listen to signal outside the Amateur Bands.

It is interesting to follow the rapid evolution of SDR technology. We recently integrated a FlexRadio-6700 SDR into our station to enable us to operate remotely via the internet. You can read more about this project on our blog.

– Fred (AB1OC)

Software Defined Radio/Remote Operating Gateway Part 3 – On The Air Remote!


Remote Operating Setup In Our Home Office

Remote Operating Setup In Our Home Office

In the previous articles is this series, we explained how we integrated a FlexRadio-6700 Software Defined Radio (SDR) into our station and how we used it as a platform to build the Remote Operating Gateway for our station. The project has turned out to be somewhat involved so we will be providing a series of articles to explain what we did:

With all of the hardware and software installed and the integration steps complete, we will  show some examples of using our remote operating setup on the air in this article. The first set of operating examples were made using the Remote Operating Client PC in our Home Office. This system is shown in the picture above.

Working The VK9WA DXpedition - Left Monitor

Working The VK9WA DXpedition – Left Monitor

We were able to make several contacts with the VK9WA DXpedition to Willis Island using our remote operating setup. The picture above provides a closer look at how we setup our Remote Client PC to work VK9WA (you can click on the pictures here to see a larger view). We just completed a CW contact with the VK9WA DXpedition on 40m and you can see that we have the QSO logged in DXLab’s DXKeeper. We used CW Skimmer to help determine where the operator was listening (more on this in a bit). We also used our Elecraft KPA500 Amplifier to make it a little easier to break through the pileup.

Working The VK9WA DXpedition - Right Monitor

Working The VK9WA DXpedition – Right Monitor

The picture above shows a better view of the second monitor on our Remote Client PC. SmartSDR is running to control our FlexRadio-6700 SDR and it is set up for split operation in CW mode on the 40m band. We also have DXLab’s DXView running and we used it to point our antennas to the short path heading for the VK9WA DXpedition. Finally, we used DXLab’s WinWarbler to remotely key the Winkeyer connected to our SDR in the shack to make the actual contact.

VK9WA DXpedition 30m Pileup Viewed From CW Skimmer

The video above shows the VK9WA DXpedition operating split in CW mode on the 30m band. Note how CW Skimmer allows us to see exactly where  the operator is listening (the VK9WA operator’s signal is the green bar at the bottom and the stations being worked can be seen sending a “599” near the top). You can see many of the folks trying to work the VK9WA DXpedition move near the last station that is worked in the pileup video.

VK9WA DXpedition 30m Pileup  Viewed From SmartSDR

The next video shows the VK9WA pileup in the SmartSDR application which controls the radio. This video provides a closer look at how SmartSDR is set up for split operation. Can you find the station that the VK9WA operator worked?  It is not quite in Slice Receiver B’s passband.

Laptop Remote Operating Client

Laptop Remote Operating Client

We also configured our Laptop PC to be a Remote Operating Client for our station. Our Bose SoundLink Bluetooth Headset is used to as both a wireless microphone and headphones with this system. Our Laptop Client PC can be used from any location on our property via the WiFi Wireless extension of our Home Network.

Window Arrangement For remote Operating From Laptop

Window Arrangement For remote Operating From Laptop

Since our Laptop PC has limited screen space, we created a configuration of overlapping windows to provide access to SmartSDR, key elements of the DXLab Suite and the applications which control/monitor our KPA500 Amplifier and Antennas. Each window is arranged so that a portion of it is always visible so that we can click on any required window to bring it forward when we need to use it.

Operating From Our Remote Laptop Client – A 20m SSB QSO

The video above shows a QSO that we made with AD0PY, David and his friend Daniel in Missouri, USA. We used the FlexRadio-6700 SDR/SmartSDR combination in VOX mode to make transmit keying simpler. At the beginning of the QSO, we  turned out antennas to point to AD0PY. Also note the operation of the KPA500 Amplifier when we transmit in the video. The QSO is logged in DXLab’s DXKeeper at the end of the contact in the usual way. Its fun to make casual contacts this way!

As you can see from this post, there is very little difference when we operate our station remotely or from our shack. This was an important goal that shaped the design of our Remote Operating Gateway and Client PC setup. Our next post will provide some details on how we setup the CW Skimmer and Digital Mode (RTTY, PSK and JT65/JT9) software to work on our Remote PC Clients.

– Fred (AB1OC)

Software Defined Radio/Remote Operating Gateway Part 2 – Client/Server Setup And Software


 

Remote Operating Gateway Client/Server Architecture

Remote Operating Gateway Client/Server Architecture

The next step in our Software Defined Radio/Remote Operating Project was to build a Remote Operating Gateway System in our shack and setup Client PCs to operate our station remotely. In a previous article, we explained how we integrated a FlexRadio 6700 Software Defined Radio (SDR) into our station to create a platform to build our remote operating project around. The project has turned out to be somewhat involved so we will be providing a series of articles to explain what we did:

In this article, we will explain the additional hardware and software that we used to enable remote operating as well as some additional equipment we added to our Client PCs that we use to operate our station remotely. The reader may want to refer to the picture above as you browse this article to better understand how the parts in our remote operating setup fit together. You can click on any of the pictures here on our blog to see a larger, easier to read version of them.

SmartSDR Software

SmartSDR Software Operating With A FlexRadio 6700 SDR

FlexRadio’s SmartSDR Software handles operating the SDR remotely. At the present state of maturity, SmartSDR can operate over a wired or wireless Ethernet LAN connection. At present, both SmartSDR and the FlexRadio-6xxx hardware must be on the same sub-network to function properly. FlexRadio has indicated that they plan to enable SmartSDR operation over wide-area broadband internet connections in the future. The design that we chose for our Remote Operating Gateway and Client PCs will allow operation of our entire station over the internet when SmartSDR is capable of fully supporting this. SmartSDR handles remoting of audio (microphone and speakers/headphones) as well as CW keying over our Home Network (more on this later) as well as control of the radio. With these key functions taken care of, we need to also remote the following functions of our station to fully support remote operation:

Remote control of equipment power is particularly important to provide a means to reset/restart equipment remotely as well as a means to shut down the Transmitter remotely.

Remote GW Control Stack - Antenna, Power and Monitoring

Remote Gateway Control Stack – Antenna, Power and Monitoring

Remote control of power for the components in our Remote Operating Setup is handled by a RIGRunner 4005i power control device. This unit provides remote power control over a network for up to 5 separate groups of devices. It also provides voltage/current monitoring and solid state over-current protection as well.

RIGRunner Remote Power Control Setup

RIGRunner Remote Power Control Setup

The figure above shows how we setup our RIGRunner 4005i. The device is controlled over our Home Network via a standard Web Browser. As you can see from the picture above, this devices lets us remotely control power to all of the devices in our Remote Operating Setup.

Remote Control Relay Unit

Remote Control Relay Unit

The FlexRadio-6700 SDR requires some additional power control handling. Simply removing and applying power to the FlexRadio-6700 SDR will reset the radio and leave it in a power off state. The FlexRadio-6700 SDR does have a remote power control input which can be controlled via a relay closure. We used a microbit Webswitch 1216H device to provide a remotely controlled relay closure to control the power off/on for the FlexRadio-6700 SDR.

Flex-6700 On/Off Control Via microbit Webswitch

Flex-6700 On/Off Control Via microbit Webswitch

The microbit Webswitch 1216H relay unit is also controlled over our Home Network via a standard Web Browser.

SmartSDR Setup - Tx Keying, Tx Interlock and Remote Power Control

SmartSDR Setup – Remote On/Off Control

The FlexRadio-6700 SDR is configured for remote on/off operation via the Radio Setup dialog in SmartSDR as shown above. A cable is run between the remote power on/off port on the FlexRadio-6700 SDR and the microbit Webswitch 1216H relay unit to complete this part of our Remote Control System.

Beams On Our Tower

Beams On Our Tower

It is also important to have full remote control of our Antennas and Rotators to effectively use our station from outside our shack. Control of our Rotators is accomplished by software which remotes serial COM ports over our Home Network.

Network Serial Port Kit

Network Serial Port Kit

We used the Fabulatech’s Network Serial Port Kit package to remote the serial COM ports used to control the microHAM Station Master Deluxe Antenna Controller, the associated antenna Rotators and the WinKeyer associated with our FlexRadio-6700 SDR. This software runs on both the local Server computer in our shack which hosts the Remote Operating Setup and any Client PCs which are used to operate our station remotely.

microHAM Station Master Deluxe Antenna Control via Teamviewer and Development App

microHAM Station Master Deluxe Development Application Via TeamViewer

There is not currently a production software tool to enable remote control of the microHAM Station Master Deluxe Antenna Controllers which we use in our shack. I am planning to develop our own application to do this in the future. The folks at microHAM have been so kind to provide me with the interface specifications needed to control the Station Master Deluxe Antenna Controller remotely along with a Developer Only test application (shown above) which can be used to understand the microHAM Device Protocol. In the interim, I have been using the microHAM Developer Only application along with the TeamViewer Remote Control Software to control antenna selection remotely and to monitor the position of the current selected rotators.

Shack Remote Operating Gateway Server PC Applications

Shack Remote Operating Gateway Server PC Applications

The remaining software required for remote control of our station is provided by the Elecraft applications which control the KPA500 Amplifier, KAT500 Auto-Tuner, and W2 Wattmeter which are used in our Remote Operating Gateway setup. All of these applications along with the microHAM Developer Only Application for Station Master Deluxe control and the DDUtil Program which interworks the FlexRadio-6700 SDR CAT interface with the Station Master Deluxe (see the previous article in this series) are shown above running on our Shack Server PC. This PC is on at all times and is protected by a Uninterruptible Power System (UPS) to ensure that it runs trouble-free.

Remote Operating PC Client Software Applications

Remote Operating PC Client Software Applications

In addition to FlexRadio SmartSDR, each of the Server Side PC applications has a corresponding Client Side application which is used on the Remote Operating Client PC. Shown above are the three Elecraft Client applications for Amplifier, Auto-Tuner and Wattmeter control and monitoring. The client side Network Serial Port Kit application which replicates the WinKeyer, microHAM Station Master Deluxe and Rotator Control COM ports is also shown.

Heil Microphone And USBQ Adapter

Heil Microphone And USBQ Adapter

The PC in our home office will be a primary remote operating location for our station. Audio quality is important to us and we wanted to ensure that the quality of our audio was just as good operating remotely as it is when we operate from our Shack. To accomplish this, we installed a Heil PR781 Microphone, PL2T Boom and USBQ Adapter/Pre-Amp on our home office PC. The Heil USBQ is a USB sound card and microphone pre-amplifier which connects directly to the PR781 microphone to create a high-quality phone audio source which can be used with the FlexRadio-6700 SDR when operating remotely.

Bose SoundLink BluTooth Headset

Bose SoundLink Bluetooth Headset

The speakers our my home office PC are quite good but there are often times when a set of headphones are needed to hear weak signals. We choose a quality Bluetooth Headset from Bose for this purpose. The Bose SoundLink Headset is light weight, is wireless, has excellent fidelity and includes a very good microphone which can be used as an alternative to the Heil PR781. This headset is also very useful when operating from our Laptop Client PC from noisy locations outside our home (more on this in a future article).

SmartSDR DAX Control Panel

SmartSDR DAX Control Panel

The last pieces of the remote operating system are provided two applications which are part of the SmartSDR software package. The SmartSDR’s DAX Control panel provides remote audio connections for Digital Mode Software and the CW Skimmer decoder. Audio is provided by software “audio cables” for each of the FlexRadio SDR’s Slice Receivers and the active Tx Slice. SmartSDR DAX Audio IQ interfaces are also provided for each of the SDR’s Panadapters which permits software like CW Skimmer to monitor and decode a wide range of frequencies simultaneously.

SmartSDR CAT

SmartSDR CAT

The SmartSDR CAT application provides CAT interfaces on both our Client and Server PCs for applications which need to control or monitor what the FlexRadio-6700 SDR is doing. Many loggers and other applications are beginning to implement direct IP interfaces to the CAT channel of the FlexRadio 6xxx Series SDRs. This approach simplifies interworking between the software and the radio and appears to be more reliable than virtual COM-based CAT interfaces.

Client PC Running SmartSDR And The DXLab Suite

Client PC Running SmartSDR And The DXLab Suite (Home Office)

With all of the above elements in place, any client PC that can access our Home Network can be used to operate our station. The picture above shows SmartSDR and the DXLab Suite running on our Home Office PC. The remote emulations of the Rotator, CAT and Winkeyer interfaces are such that DXLab’s applications can fully operate our station as if they we running in our shack.

Client PC Running SmartSDR And The DXLab Suite - Right Monitor

Client PC Running SmartSDR And The DXLab Suite – Right Monitor

The picture above shows a closer view of my Home Office PC’s Right monitor (click on the picture to enlarge it). SmartSDR is running the upper left corner and I am listening to folks operate in the 2015 CQ WW DX CW Contest. The SDR is set on the 20m band and I have the CW Keyer which is built into SmartSDR running. The DAX Control Panel is running on the lower right corner of the screen and its setup for use with the CW Skimmer decoder. DXLab’s WinWarbler is running (top-center) which enables me to use the WinKeyer in the shack to send CW as well via the remote COM port associated with the WinKeyer. Below WinWarbler is the microHAM Developer Only application (accessed remotely via a TeamViewer connection to the Shack Server PC) which shows that I have both of our SteppIR DB36 Yagis are selected as a stack and pointed towards Europe. DXLab’s DXView Rotator Control application is running in the center-bottom of the screen so that we can turn our Yagis towards other parts of the world (rotators are controlled via another remote COM port). Finally, the client KPA500 Amplifier control application is running in the lower left corner to control the amplifier and to monitor the power out and SWR seen by the amplifier being used to operate remotely.

Client PC Running SmartSDR And The DXLab Suite - Left Monitor

Client PC Running SmartSDR And The DXLab Suite – Left Monitor

The picture above shows a closer view of the left monitor. DXLab’s logger, DXKeeper is running at the top/center of the screen. Below it is DXLab’s SpotCollector application which is monitoring spots of the many CW stations around the world that are operating in the contest. DXLab’s Commander applications is running in the lower-right corner of the screen and is monitoring the FlexRadio-6700 SDR’s slice Tx/Rx frequency as well as providing a control interface of the SDR to the rest of the DXLab Suite (via SmartSDR CAT). The Elecraft W2 Wattmeter client control application is just above commander. The W2 Wattmeter client application provides higher resolution power out and SWR monitoring for the remote setup. Bottom-center is DXLab’s Launcher application and just to the left of that is the KAT500 Auto-Tuner Client Control application. Finally, CW Skimmer is running on the left side of the screen.

CW Skimmer Operating Remotely

CW Skimmer Operating Remotely

As you can see, CW Skimmer is decoding a wide range of frequencies in the 20m CW sub-band. It is receiving its audio in IQ format via the SmartSDR DAX application. It is great fun to operate CW this way and I am finding myself making a lot more CW contacts now that I have the remote operating setup in my office.

The next post will provide some samples of remote operation in the form of videos. I will also share some information on setting up a Remote Operating Client on a laptop where screen space is more limited. We plan to take a trip outside our house to operate our station over the Internet and we plan to share information on how that is done. We will also provide future articles on how to setup CW Skimmer and Digital Modes (RTTY, PSK and JT65/JT9) on the HF Bands and use them remotely.

For now, we are really enjoying the freedom to operate our station remotely!

– Fred (AB1OC)

Software Defined Radio/Remote Operating Gateway Part 1 – System Design And Hardware Installation


Flex-6700 Software Defined Radio Stack

Flex-6700 Software Defined Radio And Remote Operating Gateway

We’ve been planning to add a remote operating capability to our station for some time now. We also did some previous work with a FlexRadio Software Defined Radio (SDR) in our station and we felt that an SDR would be a good platform to build a remote operating project around. We decided to combine our remote operating goals with a next generation SDR upgrade (a FlexRadio-6700) for our station. This project has turned out to be somewhat involved so we will be providing a series of articles to explain what we did:

We will be tackling our goals of building a Remote Operating Gateway (GW) in two stages. Stage 1 will focus on operating our station from other rooms in our house (our Home Offices are prime locations for this). Stage 2 will involve operating our station “On The Go” from anywhere in the world that has sufficient Internet Access is available. We also want to enable full control of our station when operating remotely including:

  • Use of our Amplifier
  • Antenna Selection
  • Rotator Control
  • Equipment Power Monitoring and Management

We also use a microHAM station control system and contesting equipment and we want to fully integrate our new Flex-6700 SDR with this gear. Our Flex-6700 uses a dedicated Microphone to avoid some audio integration issues that we encountered between the Flex-6700 and the microHAM MK2R+ that we use in our station.

SDR/Remote Operating Gateway Architecture

Flex-6700 SDR/Remote Operating Gateway Architecture

The first step in this project was to develop a system design (pictured above). We opted for an architecture which uses the Flex SDR as a third radio in Anita’s Operating Position. Her position is now an SO2R setup with a Yaesu FTdx5000 as the primary radio and a choice of either an Icom IC-7600 or the Flex-6700 SDR as the second active radio.

Elecraft KPA500 Amplifier and KAT500 Auto Tuner

Elecraft KPA500 Amplifier and KAT500 Auto Tuner

Elecraft W2 Watt Meter

Elecraft W2 Watt Meter

FilterMax IV Automated Band Pass Filter

FilterMax IV Automated Band Pass Filter

The Flex-6700 SDR has an associated Elecraft KPA-500W Amplifier/KAT500 Auto Tuner combination, an Elecraft W2 Wattmeter, an automated band pass filtering via an Array Solutions FilterMax IV and a dedicated microHAM Station Master Deluxe (SMD) Antenna Controller. The Elecraft components are good choices for our remote operating project because they all have applications which enable them to be controlled and monitored over a network (more on this later in this series of articles).

Station Antenna System

Out Station’s Antenna System

The additional microHAM SMD allows the Flex-6700 SDR to have full access to and control over our entire antenna system and associated rotators.

K1EL WinKeyer

K1EL WinKeyer

Our setup also includes a K1EL WinKeyer to enable computer controlled CW keying of the Flex-6700 SDR. This device is relatively inexpensive in kit form and was fun to put together. We have a Bencher Iambic Paddle connected to the WinKeyer for in-shack CW operation.

SDR microHAM Integration

SDR microHAM Integration

The diagram above shows the details of the device interconnections which make up the SDR Radio System. The microHAM SMD Antenna Controller requires a serial CAT interface to its host Flex-6700 SDR to determine what band and frequency the SDR is on. The Flex-6700 SDR does not provide such an interface directly but it does create CAT control virtual ports on a host Personal Computer (PC).

DDUtil Setup - SDR Virtual CAT Access

DDUtil Setup – SDR Virtual CAT Access

DDUtil Setup - Bridging Physical Serial Port To SMD

DDUtil Setup – Bridging Physical Serial Port To SMD

To solve this problem, we used an application called DDUtil to bridge the derived CAT port associated with the SDR to a physical serial port on the PC. The PC’s physical port is then connected to the microHAM SMD associated with the Flex-6700 SDR. The pictures above show how DDUtil is set up to do this.

Station COM Port Configuration

Station COM Port Configuration

The microHAM gear, WinKeyer, Rotators, Radio CAT Interfaces, Amplifier/Auto Tuner Interfaces, etc. all use serial or COM ports on a host PC for control. It’s also true that many loggers have trouble with accessing serial ports above COM16. All of this requires a carefully developed COM port allocation plan for a complex station like ours. The figure above shows this part of our design.

A-B Switching Design For Radio Port 4

A-B Switching Design For Radio Port 4

microHAM Bus Expansion And Antenna Switching Gear

microHAM Bus Expansion And Antenna Switching Gear

The last part of the hardware puzzle required to integrate the SDR into our station was the installation of a second microHAM uLink Bus Hub, microHAM Relay 10 Control Box and an A/B antenna switch which is controlled by the microHAM SMDs. This allows the 4th radio port on our antenna switching matrix to be shared between the Icom IC-7600 and the Flex-6700 SDR.

microHAM Configuration For SDR Station Master Deluxe

microHAM Configuration For SDR Station Master Deluxe

The last step in the integration of the Flex-6700 SDR was to configure the microHAM system for the new equipment. This involves adding SMD #5 to the microHAM system and configuring it (and the rest of the system) to know about the Flex-6700 SDR, associated amplifier and its interconnections to the rest of the system.

SmartSDR Software

SmartSDR Software

The Flex-6700 SDR Hardware is controlled and operated via FlexRadio’s SmartSDR Application over a network. We have 1 Gbps wired and an 802.11 b/g/n Wireless Ethernet systems in our how and the SmartSDR/Flex-6700 SDR combination works well over either network. The software based approach used with most SDR allows new features to be added to the radio via software upgrades.

SmartSDR Setup - Tx Keying And Interlock

SmartSDR Setup – Tx Keying And Interlock

It is very important to prevent the Flex-6700 SDR and the associated Amplifier from keying up when the antennas in our station are being switched or are being tuned. The screenshot above shows the configuration of SmartSDR to enable the keying and interlock interfaces between the Flex-6700 SDR and its associated microHAM Station Master Deluxe Antenna Controller to implement these functions. This setup enables the Tx Keying and Tx Inhibit interfaces between the Flex-6700 SDR and the microHAM Station Master Deluxe to work properly to key all of the equipment in the setup (SDR, Amplifier, active Rx antennas, etc.) and to lock out keying when antennas are being switched or when one of our SteppIR antennas are tuning.

Flex-6700 SDR With CW Skimmer

We will cover some additional software and integration steps to realize our Remote Operating goals. For now, check out the above video to see how the system performs. This video was recorded using our Flex-6700 SDR and CW Skimmer during the 2015 ARRL CW Sweepstakes Contest. We are really enjoying operating in CW mode with the new SDR setup!

– Fred (AB1OC)