As explained in a previous article, we have been working on enhancing our Remote Control Ham Station system. The upgrades include additional remote client options, better remote networking via the Internet, and better integration with our microHAM system.
Hamming with a multi-band vertical on a small lot means having to compromise on what to do when it comes to being heard. The current down-slide in the sunspot cycle doesn’t help either. The emergence of weak-signal digital modes such as JT65 and JT9 a few years ago from Joe Taylor, K1JT has been a welcome addition to my operating tools. If you are familiar with Joe’s work, JT65 and JT9 are Taylor-made (sorry Joe) for modest stations and simple antennas. The modes sport S/N levels of -20 dB or lower for Q5 copy, far better than an S1 CW signal. I have been happily working DX over the past several months using the WSJT-X program that integrates with its companion JTAlert logging application to link to DXLab Suites.
Anyone who has used these digital modes knows there is a downside to them. They are SLOOOW. A typical QSO takes 6 minutes to complete with nothing more than a report, acknowledgment, and goodbye. It is like watching paint chip and peel. To keep from falling asleep between exchanges, Steve Franke, K9AN has collaborated with Joe to rev up the process.
Say hello to the new FT8 mode which is the designation of the Franke-Taylor 8-FSK digital mode that Steve developed to integrate with the existing modes supported by WSJT-X. It is sort of like JT65 with a turbocharger. An FT8 receive and transmit cycle each takes 15 seconds to complete compared to 60 seconds for JT65. A transmit cycle switches to the receive mode after 13.5 seconds. When compared to JT65 that allows 12 seconds between cycles for the operator to select a station or a macro, 1.5 seconds doesn’t leave much time to do anything. Fortunately, the mode supports an auto-sequence QSO mode wherein the next macro is automatically selected during a QSO. The result: a QSO can be completed in 90 to 120 seconds.
I first started using FT8 in late July after seeing a number of spots for stations running the mode. I had to update my version of WSJT-X to the current release. Fortunately, JTAlert also has been updated to capture FT8 for logging. I jumped in to work stations on the new mode and promptly screwed up. I tried in vain to manually select a macro when working a station only to find the previous macro being repeated. After a few busted QSOs, I discovered the program automatically switched to the correct macro in the QSO sequence. This is definitely a cool feature to have.
It did not take me long to realize that I could call a DX station off-frequency to avoid competing with stronger stations calling. If he/she answered me, the program would automatically QSY me to the DX station’s frequency. Slick!
The mode is also tolerant of poor band conditions where signal strengths can change as much as 10 dB between transmit cycles. There have been a number of times where I have repeated a macro several times before getting a response and moving on to the next macro. Under such circumstances a QSO may take three minutes to complete, still better than JT65.
To date, I have worked some 200 stations on FT8, including 49 states, most of Europe and a handful of Far East DX stations. I run 40 watts to a 6BTV multi-band vertical and a 17-meter Moxon in the attic of my garage. QRP purists may be aghast as such a QRO level. However, remember that signal strength is about ERP. A monoband beam with 5 watts beats a quarter-wave vertical at the same power level every time. Remember that a vertical with 200 radials situated on rich Iowa loam (Ok, a salt marsh is better) has a gain several dB below a simple dipole and well below a monoband beam.
As a related note, the club here in The Villages kicked off a friendly competition the first of August to see who could work all 50 states. While most folks have parked themselves on 20 SSB, I decided to go after the states using FT8. The JTAlert logging application maintains a running list of stations heard that includes their states so I don’t have to blindly call hoping I have worked a new one. Like shooting fish in a barrel. It is only a matter of time before my elusive Montana station pops up.
To encourage you to try FT8, why not initiate a club competition to work all 50 states? The modest station requirements and free software make it easy for anyone to give it a try. Finally, if you use Logbook of the World, the ARRL has added FT8 as a recognized digital mode so you can get another neat endorsement.
The heart of any Go Kit is the Transceiver. We’ve been using Kenwood equipment for our APRS iGate for some time now and we have had good results with it. Kenwood’s latest 50W transceiver with APRS is the TM-D710GA. This unit provides full support for APRS tactical applications and now includes a built-in GPS receiver making it ideal for our Go Kit application.
We had a chance to look at the iPortable enclosure at Dayton and decided that their Pro 2 4U deep unit would be a good choice for our Go Kit application. The iPortable enclosures are based on a portable rack mount case and include a DC power system, speaker and headphone hookups, a light, and provisions for a cooling fan.
EMCOM Go Kit Construction
With all the components in hand, we began the construction of our Go Kit. Reliability is important in any portable system like this so we put some time into securely mounting all of the equipment and neatly arranging the cabling. First came the shelf which holds the Kenwood transceiver and a SignaLink USB sound card. A combination of drilling the shelf to secure gear with large cable ties and #8 stainless hardware was used here.
Our iPortable case was equipped with both SO-239 and N-connectors on the front panel to allow for antennas and feed lines equipped for either connector type. To make the change over between the connector types easy, we installed separate PL-259 jumper cables for each connector. One simply connects the appropriate jumper to the radio.
The power and AvMap display shelf were next. The AvMap display mount was dissembled and modified to accept a custom mounting bracket.
The iPortable enclosure was drilled to mount a West Mountain Radio PWRgate to handle backup battery charging and management. The PWRgate supports instantaneous switching between an AC power supply and a backup battery and can accommodate a wide range of battery types and sizes.
The last piece of the setup was the antenna. We wanted something that was portable, easy to set up and would provide good performance. We choose a Diamond X-30A 2m/70cm ground plane antenna and mounted it on a 12′ fiberglass push up mast. The feed line is made from 25′ of LMR-400UF coax. Several bungee cords are used to attach the mast to a fence post or other vertical structure.
The picture above shows the completed Go Kit in operation. We typically set one side of the Kenwood TM-D710GA to operate as an APRS transceiver and Digipeater and the other side to operate on a local repeater or simplex FM. The SignaLink sound card is used with a laptop computer running Fldigi and NBEMS for messaging applications. The iPortable case has a 13.8V lighter socket which connects to a power brick to power our laptop PC.
The Go Kit is quite portable when closed. All of the equipment and cable connections are enclosed and protected by the case’s removable end caps. We’ve tested our Go Kit during our club’s weekly repeater net and it worked great. The first real use of our new Go Kit will be at Field Day this year. It will be located in our public information tent and will be used as a “talk-in” system.
Dave Merchant K1DLM, our Field Day chairman, is bringing some 21st Century radio and computer technology to our Field Day setup this year. There are several aspects to this new component of our Field Day plans and the associated IT Test including –
An on-site WiFi Network to enable using the N1MM+ Logger in network mode for sharing of log information, station activity, real-time scores, and messages
A central Score Board and Club Information Computer in our public information tent
We will again be holding our 2017 Field Day operation at the Hollis-Brookline High School in Hollis, NH. We are planning on using the upper baseball field area as our main operating location. We have decided to add a third tower this year and locate it on a soccer practice field which is situated several hundred feet away from our main operating area. All of our antennas and equipment will lie within the required 1000′ circle but the third tower would situate those operating at that location away from the rest of our group. Dave’s solution to this problem was to set up a network and operate two Software Defined Radios (SDRs) at the lower site remotely from our location on the upper field.
Dave has enlisted club member Piece Fortin, K1FOP to be our IT Chairman for Field Day this year. Pierce has been instrumental, along with Dave, in the planning and testing of all of this new technology. Pierce and Dave have a great deal of networking and IT experience and knowledge and we could not have put together what is described here without them.
Dave K1DLM, Pierce, Hamilton K1HMS, Mike Ryan K1WVO, Anita AB1QB, and I have gotten together multiple times to set up and test all of this new technology. I wanted to share some more about the equipment and the associated testing (which has been staged in the kitchen at our QTH – thank you, Anita!).
We began the testing process by setting up our 20m CW station.
Next came our 40m SSB station. This setup uses an Icom IC-7300 Transceiver and allowed us to set up and test N1MM+ on the fly audio macro recording and playback. All three of our SSB stations will have on the flyrecording and playback capability which will allow each of our SSB operators to record and use a custom set of audio macros.
Next came our Digital Station. This station uses one of the two remote Flex-6700 SDRs.
Dave, K1DLM put together a really nice package for the two Flex-6700 SDRs and associated equipment which will be located on the lower field. He used a rack system to mount the two SDRs, power supplies, a three-band Tri-plexor, a set of bandpass filters for 80m, 40m, 20m, 15m, and 10m and a 403A 8×2 networked antenna switch. This setup allows either of the two SDRs to share the tri-band yagi or the 40m and 80m Inverted-V antennas on the tower on the lower field and operate on any of the 5 available HF bands. Antenna and filter switching automatically track the frequencies of the two SDRs making the setup simple to use.
The Digital Station’s remote SDR will be operated using a SmartSDR client running on the Digital Station laptop PC. This station will have a second monitor to better accommodate all of the windows associated with it.
The main display associated with the Digital Station will run decoders for all PSK and RTTY modes. The ability to decode multiple PSK signals simultaneously and multiple RTTY decoders are available. The Digital station also acts as the N1MM+ master station in our Field Day setup for all of the other stations which use N1MM+.
Our Satellite Station 2.0 was also added to the test setup. It uses a MacBook Air laptop running MacDoppler to control the antenna rotators and the Icom IC-9100 Transceiver which are part of our Satellite Station. A Windows 10 Surface Pro computer is included which runs N1MM+ and provides logging and other network functionality for our Satellite Station.
We also tested our GOTA station which uses the second Flex-6700 SDR and a FlexRadio Maestro to provide a more conventional “buttons and knobs” interface for our GOTA operators to use. This station will also have a laptop PC running N1MM+ for logging.
We also build and tested a Scoreboard PC. This computer will be located in the Public Information tent at Field Day and will be connected to a large display. It will show our real-time score, QSOs being logged as they are made and other useful information about our Field Day operations. This computer will also continuously play videos from our Club Video Collection and will provide access to IP video cameras which monitor the tower and equipment on the lower field.
Our networked N1MM+ test bed contained at least one station of each type (CW, SSB, Digital, Satellite, and GOTA) that will be part of our Field Day setup this year. The Station Masters for the additional CW and SSB stations came by to test their setups using the test bed.
The networking system which Dave and Pierce built is central to all of the technology described here. All of the gear is mounted in a single rack which will be located on the upper field during Field Day. The setup includes a Firewall/DHCP server, a commercial grade outdoor WiFi access point, a 4G LTE modem for Internet access, an Ethernet Switch, and a UPS power supply.
The upper and lower fields at our Field Day site are separated by several hundred feet. A thick line of trees between the two locations raised concerns about connecting the upper and lower sites using WiFi. Pierce came up with a great solution to this problem – we will be using MoCA Data Modems and RG6 Quad Shield 75 ohm Coax Cable to provide a 10 Mbps data link between the two sites. We tested the MoCA link using a much longer run of coax cable then we will need to use at Field Day and confirmed full 10 Mbps throughput.
Our networked N1MM+ setup will allow any station in our setup to send messages to everyone who is operating at Field Day. We can use this capability for important communications like “lunch is ready!” or “I need help from Pierce (our IT chairman) on the 40m SSB station”, or “The 6m band is wide open!”.
Our GOTA and Digital stations will be located together in the same tent and will provide our Field Day 2017 visitors to see and use 21st-century Amateur Radio technology to make contacts. We are expecting young people who participated in our club’s High-Altitude Balloon project and from other local schools where we have done Amateur Radio activities to attend. In additional to being a learning opportunity for all of us in the Nashua Area Radio Club, we hope that the state of the art technology that we are using will generate interest among our visitors.