HAB-4 to Launch on Sunday from Hollis-Brookline High School

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Students and Teacher Ready To Launch Their High-Altitude Balloon

Students and Teacher Ready To Launch Their High-Altitude Balloon

We are planning the fourth launch of our High-Altitude Balloon (HAB-4) this Sunday, June 9th between 10:30 am and 11:30 am ET. We will be launching locally from the Hollis-Brookline HS here in Hollis, NH. Read on to learn more about our HAB projects and how to track our HAB while it is in flight.

Source: HAB-4 to Launch on Sunday from Hollis-Brookline High School

HAB-4 Flight Path Prediction

HAB-4 Flight Path Prediction

It’s to easy to track our HAB! All you need is a web browser and Internet access follow our HAB to the edge of space and back. Check out the article (link above) for more information about our HAB and how to track it.

Fred, AB1OC

Satellite Station 4.0 Part 7 – Flex SDR Satellite Transceiver

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Flex-6700 SmartSDR in Satellite Mode

A major part of our plans for Satellite Station 4.0 includes the ability to operate our home satellite station remotely over the Internet. We’ve been using our Flex-6700 Software Defined Radio (SDR) as a Remote Operating Gateway (GW) on the HF Bands and 6m for some time now. Our latest project is to upgrade our Remote Operating GW to support satellite operations on the 2m, 70cm, and 23cm bands.

Remote Gateway Rack with Satellite Additions

Adding the additional bands for satellite operations involves adding a 2m Amplifier, a 70cm Transverter, and a 23cm Upconverter to our SDR-based Remote GW. We decided to repackage our Remote GW set up in a rack mount cabinet on casters. This allows all of the required gear to be placed under the desk in our station in a way that is neat and reliable.

We also added an Ethernet Switch, a pair of USB hubs, and upgraded power and remote controls to improve our ability to manage our station remotely and to simplify the interconnections between our Remote GW and the rest of our station. The final assembly mounts all of the components in the rack on 5 levels as follows:

These purpose of these components is explained in more detail below.

All of these devices are powered from 13.8 Vdc station power to avoid the potential for noise from wall wart transformers inside the rack. Also, attention was paid to the isolation of the digital and RF components on separate levels to minimize the chance that noise from digital signals would leak into the RF chains.

Remote Satellite SDR System Design

The diagram above shows how the added components for the satellite bands interconnect with the Flex-6700. The new components include:

The Flex-6700 can generate and receive signals on the 2m band but it does this at IF power levels. The 2m LPDA brings the IF power level up to a maximum of 75 watts. The DIPs device enables the Flex-6700 to operate in U/v, V/u, and L/v modes.

The 28 MHz splitter allows a total of 4 transverters/upconverters to be connected to the radio. This will enable us to add 5 GHz and 10 GHz bands to our satellite station in the future.

Our Flex-6700 includes a GPS Disciplined Oscillator (GPSDO) which provides an accurate and stable 10 MHz reference output to lock the 70cm and 23cm units frequencies. The 10 MHz Reference Distribution Amplifier expands the single 10 MHz on the Flex-6700 to drive up to 4 transverters or upconverters.

The two USB cables allow the Flex-6700 and SmartSDR to control the LPDA and PTT for the 70cm and 23 cm bands.

2m/70cm Shelf

The rackmount arrangement uses shelves which provide ventilation for the components and enable us to use zip ties to tie down all of the components. The photo above shows the layout of the shelf which contains the 2m LPDA, the 70cm Transverter and many of the RF interconnections. Velcro tape is used to secure the smaller components to the shelf.

2m/70cm Shelf RF Interconnection Details

The photo above shows the RF interconnections. The 70cm Transverter is on the upper left and the 2m LPDA is on the upper right. The rectangular boxes coming from these devices are the sensors for the WaveNode WN-2 Power and SWR Meter that we are using. They are terminated in 50-ohm dummy loads for initial testing. The DIPS device is center bottom and the 4-port device above it is the 28 MHz splitter. All of the interconnections are handled using 50-ohm BNC cables and the unused ports on the 28 MHz splitter are terminated with 50-ohm BNC terminators.

Rear View of Remote Gateway Rack

The photo above shows the rear of the unit. The 10 MHz Reference Distribution Amplifier (bottom center) and the two Industrial 12V powered USB hubs are visible at the bottom of the unit. The DC power distribution components are at the upper left and a set of Internet-controlled relays are at the upper right.

USB Connections via Hubs

One of the USB hubs fans out a single USB connection from the host PC to the USB controlled devices in the Remote GW rack. The other USB hub expands the USB outputs of the Flex-6700 to accommodate the control cables for the devices in the rack and the CAT cable which provides frequency data to the microHam SMD Antenna Controller.

Power Control and Distribution Design

Remote control and distribution of DC power to all of the devices in our Remote GW is an important design consideration. In addition to proper fusing, one must be able to remotely turn individual and groups of devices on and off remotely. The diagram above shows the power distribution and control architecture that we are using.

13.8 Vdc Power Distribution

RigRunner power distribution blocks are used to fuse and distribute power to all of the accessory devices in the rack.

Remote Gateway Power Controls

The RigRunner 4005i provides remote power control via the Internet for all of the major units and accessories in the rack. In addition to controlling power on/off states and providing electronic fusing, the RigRunner 4005i monitors voltage and current to the equipment in the Remote GW. These controls are accessed via a web browser and a network connection. Login/password security is also provided.

Remote Control Relay Unit

A microBit Webswitch device provides Internet controlled relays to manage various station functions including:

After some configuration of the Transverters and PTT controls in SmartSDR, the satellite portion of our Remote GW is up and running. There is quite a bit of software installation and configuration left to do and we’ll cover that in a future post.

You can find other articles about our Satellite Station 4.0 project here:

Fred, AB1OC

Satellite Station 4.0 Part 6 – Tower Finishing Touches

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New Shack Entry and Ground Block

We recently completed the finishing touches on our new VHF/Satellite Tower. The first step was to install a second set of entry conduits into our shack and a new ground block for our satellite antennas. This involved installing 4″ PVC conduits into our shack. The new entries are very close to the base of our tower and this will allow us to keep our feedlines as short as possible.

Hardline Coax Cables Up The Tower

We also replaced the section of our feedlines which run down the tower with 7/8″ hardline coax. We installed a total of four runs for 6m, 2m, 70cm, and 23cm. The use of hardline coax will help reduce our feedline losses – especially on 70cm and 23cm.

Hardlines at Base of Tower

The new hardlines are connected one of the two entries into our shack. The 6m hardline enters on the side closes to our antenna switching matrix and the 2m, 70cm, and 23 cm hardlines will enter the shack via the newly created entry which will be close to our satellite transceiver.

The next step in our project will be to upgrade our Flex-6700 SDR based Remote Gateway for operation on the satellite bands. You can find other articles about our Satellite Station 4.0 project here:

Fred, AB1OC

The Nashua Area Radio Society Story

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Nashua Area Radio Members

Quite a few Nashua Area Radio Society members are headed for the Dayton Hamvention® this week. The theme of Hamvention 2019 is “Mentoring the Next Generation”.  The Nashua Area Radio Society will be receiving some important recognition for our work to bring new Hams into the Amateur Radio service, for our Amateur Radio related STEM learning programs in local schools, and for our many Ham Mentoring projects. We will be recognized as the Dayton Hamvention 2019 Club of the Year.  We will also be sharing The Nashua Area Radio Society Story as a forum presentation at Dayton. You can see our planned presentation at the link below.

Source: The Nashua Area Radio Society Story

We are also being recognized by the ARRL as a Spotlight Club for our Mentoring work. The ARRL has dedicated their “ARRL Spotlight on Radio Clubs and Mentoring” forum on Friday, May 17th at 11:50 am in Forum Room 3 to us so that we can share The Nashua Area Radio Society Story including ideas and programs that have worked well for us.

We hope that our readers who will be attending the Dayton Hamvention this year will join us for our Forum Presentation on Friday and will also stop by and see our display in the ARRL Booth at Dayton.

Fred, AB1OC

Satellite Station 4.0 Part 5 – New IC-9700 Transceiver

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Portable Satellite Station 4.0

Portable Satellite Station 4.0

The new Icom IC-9700 transceiver has begun shipping and we’ve recently added one to our Portable Station. The addition of the IC-9700 completes a key part of our Satellite Station 4.0 upgrade plans.

New IC-9700 In Satellite Mode

New IC-9700 In Satellite Mode

The IC-9700 is based upon Icom’s direct sampling SDR platform. It supports all modes of operation on the 2m, 70cm, and 23 cm bands. The radio also supports satellite modes and D-STAR.

MacDoppler Controlling the IC-9700

MacDoppler Controlling the IC-9700

The new IC-9700 replaced the IC-9100 in our Portable Satellite Station. An updated version of MacDoppler is available which supports the IC-9700 and we tested MacDoppler using both the USB and CI-V interfaces. In both cases, MacDoppler handled the new radio including band and mode selection, doppler correction, and access tone setting properly. Our setup uses an iMac running MacDoppler and MacLoggerDX for radio control, antenna control, and logging and a windows laptop running UISS and MMSSTV for APRS and SSTV. Our setup was easily accomplished by connecting the IC-9700’s CI-V interface to the iMac and the USB interface (for audio and PTT) to our windows laptop.

IC-9700 Display and Waterfall - Working FO-29

IC-9700 Display and Waterfall – Working FO-29

We’ve made about 50 contacts with the IC-9700 so far. The radio is a pleasure to use. The touch screen layout and functions are very similar to the IC-7300 and one does not need to spend much time with the manual to become comfortable using the radio. The Spectrum Scope and associated waterfall are really nice for operating with linear transponder satellites. The screenshot above shows the IC-9700 display while working contacts using FO-29. As you can see, it is very easy to see where stations are operating in the passband of a linear transponder. The Spectrum Scope also makes it very easy to locate your signal in the satellite’s downlink and then adjust the uplink/downlink offset for proper tone.

We’ve also done a bit of APRS operation through the ISS using the IC-9700 and the UISS software. The direct USB interface was used to a windows laptop for APRS. Setting up PTT and the proper audio levels were straightforward and the combination of MacDoppler controlling the VFO in the radio and the PC doing the APRS packet processing worked well.

The IC-9700 can power and sequence our external ARR preamplifiers and we plan to use this capability to eliminate the outboard sequencers that we are currently using with our preamps. We’ll need to climb our tower to change the preamps over to be powered through the coax before we can complete the preamp control changeover.

All in all, we are very happy with the new IC-9700 for Satellite operations. We’ve also noticed that quite a few satellite operators also have the new IC-9700 on the air.

You can find other articles about our Satellite Station 4.0 project here:

Fred, AB1OC

DX’ing and Operating Award Tips

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AB1OC 8 Band DXCC

AB1OC 8-Band DXCC

We’ve been pretty active in Operating Award programs since we built our station a few years back. Operating Awards provide incentives to get on the air and chase all kinds of contacts and they also help us to understand our station’s and our personal operating strengths and weakness. They also provide motivation to improve the latter.

Yesterday was a banner day for me in terms of completing Operating Award goals. I was able to make the needed contacts to complete two that I’ve been working on for quite some time:

  • Worked All Japan – Requires working and confirming all 47 Prefectures (similar to US states) in Japan
  • Top Band DXCC – Working and confirming 100 DXCC Entities (basically countries) on 160m

Both of these goals were completed using the FT8 digital mode for the remaining handful of contacts. I wanted to take a little time and share some of the techniques that have worked for me in hopes that it might help our readers have more fun and meet their operating goals on the air.

DX’ing Basics and Tips

Here are some general techniques and tips for working DX (in no particular order):

  1. Use spotting clusters such as DX Summit to find the DX
  2. Use propagation prediction tools such as those available on DX Summit to assess the best times and bands to use to try to work DX
  3. Subscribe to DX Notifications such as DailyDX to learn about planned operations in rare places
  4. Make time to operate in and BEFORE major DX contests
  5. Vary the times of day, days of the week, and bands on which you operate
  6. Vary the times of the year when you operate
  7. Learn about propagation and how to take advantage of short enhancement effects such as grey line enhancements
  8. Learn how to identify days when the bands are particularly good (and bad) for working DX. Good conditions include very low noise levels, undisturbed ionosphere conditions, and favorable sunspot conditions.
  9. Learn how to use Reverse Beacon Network Tools such as PSKreporter to assess propagation conditions and the real-time performance of your station. Pay attention to how these measurements change relative to the days, times and band that you operate on and related conditions such as solar weather, grey line location, etc.
  10. Equip your station for CW, Digital (FT8 and RTTY), and SSB phone modes and develop your operating skills using all three of these modes.
  11. Learn to use the filtering and other capabilities of your radio and your digital mode software to hear and work very weak signals
  12. Successful DX’ing requires BIC (Butt In Chair); sometimes at challenging hours during the day and at night

You can learn more about items 1 – 3 via the links above and by spending some time on the associated websites.

Item 4 is a big one when you are starting out. There are more “big” DX stations on during major DX contests such as CQ WW DX, CQ WPX, etc. than at any other time. We routinely work a DXCC here in less than 24 hours during these contests. An additional tip here is to set plenty of operating time aside the week BEFORE the contest begins. Many folks travel to interesting DX locations to operate in contests and spend lots of time on the air before the contest checking their stations and assessing propagation from their location. These are excellent times to work the DX as they are not as busy and can often take more time to help you make a contact.

Items 5 – 6 are often overlooked by operators who are just beginning to focus on DX. Many of us have busy daily schedules and we sometimes tend to set somewhat regular times aside to operate our stations. Propagation to different parts of the world varies wildly depending upon the time of day and frequency bands available to the operator. Switching both up will usually add significant numbers of new DX contacts to your log.

In my view, items 7 – 9 are key skills that begin to distinguish the serious DX’er from the pack. A good working knowledge of propagation effects, band openings, and how to measure conditions in real-time are essential skills and are not difficult to learn. I’ll reference a very good book in a bit which has some great basic information on propagation and how it relates to effective DX’ing. I’d also encourage you to set up your station for FT8/WSJT-X and learn to use PSKreporter to measure propagation and your station’s performance as well. If you pay attention to how the band conditions that are shown by PSKreporter change during different times/days and solar conditions, you can learn a great deal about how propagation actually effects your ability to make DX contacts and when the interesting (and sometimes brief) band openings occur to distant parts of the world. You can learn more about how to set up and use WSJT-X, FT8, and PSKreporter here.

Items 10 and 11 relate to both your basic operating skills and your station. Many DX’ers will focus on SSB phone when they first start out. This is a great way to gain operating experience and have fun on-the-air. I strongly encourage the addition of the FT8 Digital Mode (and RTTY) to one’s station early on for two reasons:

  • FT8 coupled with PSKreporter provides important tools for understanding and assessing propagation and your station’s performance
  • You will likely find a great deal more DX that is workable with a modest station using the FT8 mode that can be had with either SSB Phone or CW

You will also want to add basic CW skills to your toolkit as soon as you can as there will be some important rare and semi-rare DX that you can only work using DX. Developing your CW skills to the level required to work a DX contact is pretty easy and is a good stepping stone to developing contesting and conversational DX’ing skills. Learning to use the features of your radio and your digital SW is a topic unto itself. The book which follows has some great information on using your rig and other capabilities of your station to work DX. FT8 software tools such as JTDX and JTAlert also bring some important capabilities that the DX’er can take advantage of (read more via the preceding links).

Item 12 probably does not require any explanation…

One DX’ing Book To Read…

AC6V's DX101s HF + Six Meters DXing Reference Guide

AC6V’s DX101x HF + Six Meters DXing Reference Guide

Before I share my recent experiences and how the items above fit in, I’d like to share one more resource. While there is no substitute for getting on the air and operating, I would recommend AC6V’s DX101x Book as a comprehensive beginners guide to DX’ing. I read this book cover to cover several times when I was starting out and found it to contain a wealth of great information on all of the above topics and more.

Back To Yesterday’s DX…

Now I’ll share how I used these ideas yesterday to complete WAJA and Top Band DXCC. I began the day with a focus on completing my Worked All Japan (WAJA) award. Prior to this time, I had completed over 800 contacts with stations in Japan, working and confirming over 250 cities there. I had also managed to work and confirm 46 of the 47 prefectures in Japan. These left needing just 1 contact with someone in the Miyazaki Prefecture for my WAJA. This prefecture seems to be a beautiful place with 12% of its land being designated as Natural Parks. Hams in Miyazaki have area 6 callsigns.

The Search for Noda San, JA6FUV

My initial approach to securing my contact with someone in Miyazaki was to work as many JA6’s as I could find on 40m, 30m, and 20m (the most open bands from New Hampshire to Japan over the last year). After months of trying without success, I decided that I needed a better approach.

40m FT8 Opening to Japan

40m FT8 Opening to Japan

I decided to use PSKreporter to see if I could identify a station in Miyazaki that I could contact. The data in PSKreporter is time sensitive so its important to do this analysis at the times of day that you expect band openings to your target location (in my case Japan early in the day). For my conditions here in New Hampshire, the best time to work Japan is in the morning between about 9:30z and 11:15z. My analysis of the PSKreporter data identified one, and only one station, JA6FUV owned by Katsuyuki Noda. I next contacted Noda San to learn about his station and see if he might help me with a contact. He was happy to try but cautioned me that he had a 100W rig and a dipole antenna for 40m and warned that making a contact with the USA would be difficult. He also indicated that he was on most days at around 11:00z (7 am local time at my location).

Solar and Band Conditions

Solar Conditions

The next several days were marked by poor solar weather and associated band conditions. The K was 3-4 and the A rose to 20. Noda San heard me only one time during this period and I did not hear him at all. As of early this past week, we had both given up. Here’s where the BIC aspect and propagation assessment skills came in. I was up every day at 9:00z (5 am local time) and on the 40m band trying to work Japan. Some days I made only a few contacts, others were a little better but no sign of JA6FUV. What I learned from this was the very best time for propagation was to Japan on 40m is a 30 minute period from 11:30z – 12:00z and I shared this information with Noda San.

Two days ago, I found the K to be 0 and the A to be 3 with the resulting band conditions to Japan on 40m as quiet as I had seen them in a while. I alerted Noda San and the following morning I found the band wide open to Japan at 9:30z. I worked maybe 15 JA’s before JA6FUV appeared on PSKreporter. JA6FUV is the station at the very bottom center of the PSKreporter image above. I began a series of directed FT8 calls to JA6FUV. After a few minutes, Noda San answered and my Miyazaki Prefecture contact was finally completed! The signal report on my end was only -19 which is right on the edge of what I can hear. Noda San reported my signal as -15 which was solid but not particularly strong. All of this shows how the various tools and tips can come into play to make an important but difficult DX contact happen.

The Path To Top Band DXCC

My other goal for this past winter season was to complete my Top Band DXCC (100 countries on 160m). We have an Inverted-L transmit antenna and some good low-band receive equipment here at our station so I felt that this was a reasonable goal. Given we are at the bottom of the solar cycle, it’s also a good time to work DX on 160m and 80m. Things got busy and I did not get the time to operate that I would have wanted nearly the end of winter. Still, I got my first 90 and then 95 confirmed DXCCs on 160m.

Upon seeing the expected solar conditions and the very quiet band conditions while working JA6FUV, I decided to take another run at DXCC 160m. While operating sporadically on 160m since the beginning of the year, I learned that there are two primary DX openings each day on 160m from here in New Hampshire. The first occurs early the morning at about 9:00z (5 am local time) and lasts until just before the grey line turns to daylight. This is a good time to work Australia, New Zealand, and the Pacific on 160m. Contacts during this time helped to get me to 95 on Top Band.

The most productive opening occurs just as it begins to get dark here (grey line enhancement again) at about 22:00z and lasts through the night until the grey line passes over Europe at about 06:30z (2:30 am local time). There are many more DXCCs that I can work in Europe so I decided to try this second opening last evening to complete my Top Band DXCC.

160m FT8 Opening to Europe

160m FT8 Opening to Europe

Again, the combination of propagation, band opening, and solar weather experience paid off. As you can see from the PSKreporter view above, I caught a very good opening into Europe and South America on 160m last night. I was able to work over 70 stations on Top Band – including CN2FA (Morocco), LX1JX (Luxembourg), IS0CDS (Sardinia),  HR5/F2JD (Honduras), and ES4IN (Estonia) – the last 5 DXCC’s needed to for 100 on 160m.

BTW, I have had a great experience with confirmations on Top band and have managed to confirm all 95 DXCC’s that I had worked prior to last evening. Hopefully, these last 5 will all confirm as well.

A Final Through – It Really Takes BIC…

Again, there is no substitute for BIC when trying to meet DX’ing goals. It took me exactly 850 contacts to work the required 47 prefectures for my WAJA. It took 1,252 contacts on Top Band to work (and hopefully confirm) the required 100 DXCC’s there. Both awards involved many contacts using SSB, CW, and Digital modes to get there. I certainly had a lot of fun meeting these two goals and I learned a great deal about the associated bands and propagation in the process.

AB1OC Operating Awards In Our Shack

AB1OC Operating Awards In Our Shack

I hope that this will help our readers to have fun DX’ing and to become accomplished DX’ers. What this is really all about is building your operating skills, experience, and station. The paper awards are like earing an educational diploma – the award is a reminder of the path you’ve walked and the knowledge that you’ve gained along the way.

Fred, AB1OC

JTDX – Feature Rich Software for FT8 and Other JT Modes

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JTDX Main Window

JTDX Main Window

We’ve recently begun experimenting with a WSJT-X derivative for FT8 and other JT Modes. Its called JTDX. The JTDX software is created by Igor Chernikov, UA3DJY, and Arvo Järve ES1JA. The stated purpose for JTDX from the JTDX website is:

JTDX supports JT9, JT65, T10 and FT8 © digital modes for HF amateur radio communication, focused on DXing and being shaped by the community of DXers.

The latest release candidate of JTDX supports some interesting additional features beyond WSJT-X including:

  • Additional FT8 and JT65 decoder options which can provide improved sensitivity
  • Advanced automatic sequencing and QSO selection features
  • Decoded messaging filtering features

We’ve been testing JTDX V2.0 release candidates here for about a month now. the JTDX feature additions definitely provide some useful enhancements. The JTDX software is derived from WSJT-X and we’ve been using it here for DX’ing and for weak signal work on 6 meters. It appears to have most of the features of the current version of WSJT-X with the notable exception of support for specific contest exchanges.

JTDX Decoder Options

JTDX Decoder Options

JTDX adds a number of FT8 decoding options that are useful on crowded bands and in situations when signals are very weak. These features can be selectively enabled to match band and signal conditions as well as the user’s available CPU horsepower. With all features enabled, JTDX seems to decode more signals on a crowded band than WSJT-X.

QSO Partner Decoder Filtering

QSO Partner Decoder Filtering

There is also a QSO partner decoding “filter” option which concentrates the FT8 decoder on a narrow bandwidth around a specific weak signal that you are trying to receive and decode. This feature seems to help to decode very weak signals in a crowded band when they are surrounded by other, stronger callers.

PSKReporter on 20m Band, FT8 Mode

PSKReporter on the 20m Band, FT8 Mode

You may have experienced the crowded conditions in the FT8 sub-band on popular bands like 20m.

Typical Stations Decoded on 20m FT8 Sub-band (JTAlert Display)

Typical Stations Decoded Simultaneously on 20m FT8 Sub-band (JTAlert Display)

If you call CQ with Auto Sequence and Call First turned on in WSJT-X, you may find that you don’t have much control over what stations are selected to answer your CQ. It’s also common for the Auto Sequencing in WSJT-X to “get stuck” on a caller that how fails to complete a QSO for whatever reason.

JTDX provides some useful features to prioritize the selection of callers in these situations.

JTDX Auto Sequencing Caller Selection Options

JTDX Auto Sequencing Caller Selection Options

You can see these options on the menu above. Options include choosing a station to answer based upon distance or best Signal To Noise Ratio (SNR), including or excluding stations that you’ve worked before, or including or excluding other stations calling CQ. These features allow JTDX to do a better job selecting a QSO to Auto Respond to when you are calling CQ.

JTDX Auto Sequencing Configuration Options

JTDX Auto Sequencing Configuration Options

What about the problem of “stuck” QSOs? JTDX has some useful features that limit the number of tries that the Auto Sequencing algorithm uses before returning to calling CQ or working the next available caller. These features prevent the Auto Sequence algorithm from getting stuck during a contact when your QSO partner fails to respond or decided to work someone else.

Directed CQ - CQ DX

Directed CQ – CQ DX

JTDX also has the ability to enforce “directed CQ’ing”. Directed CQ’ing is when you call, for example, “CQ DX” and get responses from callers in your country. JTDX Auto Sequencing can be configured to ignore such callers and only work DX stations that answer your CQ. Directed CQ’s can also be applied to specific regions of the world (CQ AS for example) as well.

Decoded Message Filtering Options

Decoded Message Filtering Options

Finally, you may have experienced a flood of decoded messages on a busy band. It is almost impossible to read and process all of the information a large number of decoded messages in the 15 seconds available. JTDX has some good filtering options to selectively hide decoded messages to enable the operator to focus on messages from stations that they are looking for. The image above shows a very simple application of this capability to limit the decoded message display to only CQ messages. More complex rules are possible via configuration in the Filters tab.

There is a learning curve with JTDX and it takes a little time to learn to use all of the new features. There is a basic getting started guide that helps to get JTDX setup and configured at your station and some useful FAQ documents to help you learn about some of the JTDX features. The best source of information on the more advanced features is the JTDX groups.io group.

I don’t think that JTDX is a replacement for WSJT-X. We run both here and they both work well. JTDX has some important advantages in crowded band situations and is my tool of choice for working DX with FT8. I also like the more sensitive decoder in JTDX for weak signal FT8 work on the 6m band. WSJT-X is a better tool for contests as it contains support for specific contest exchanges via FT8 – a feature which JTDX does not yet support. WSJT-X also supports important modes like MSK144 for Meteor Scatter QSOs.

If you are new to FT8, I’d suggest you begin with WSJT-X and use it to learn the basics of the FT8 protocol and how to operate using FT8. You can find a Video Introduction to WSJT-X and FT8 here on our blog to help you get started and get on the air with FT8 using WSJT-X.

Fred, AB1OC

Satellite Station 4.0 Part 4 – Tower Camera and J Mode Desensitization Filter

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IP Camera View of New Tower

IP Camera View of New Tower

It is winter here in New England and it is not the best time of year to work outdoors. I have been able to complete a few finishing touches on our new Satellite and 6m Tower.

Installed IP Camera

Installed IP Camera

The first enhancement is the addition of an SV3C IP Camera. The camera allows us to see what is going on with our antennas. The camera has IR illumination so we can see our antennas when operating at night as well. The camera will also be useful for demonstrations when we operate our satellite station remotely in the future. This camera can use Power Over Ethernet (PoE) for power and is compatible with most popular security and webcasting software.

The video above is from our IP Camera while our antennas are tracking AO-7 during a high-elevation pass.

The second enhancement relates to VU Mode (or J Mode) satellites such as SO-50 and FO-29 which use a 2 m uplink and a 70 cm downlink. Satellite ground stations are prone to problems with 70cm downlink receiver desensitization when transmitting on a 2m uplink. The symptom of this problem is difficulty in hearing your own transmissions in your downlink receiver while being able to here other operators in the downlink just fine. Our antennas are separated enough here that we have only minor problems with J Mode desensitization at our station. Fortunately, this is not a difficult problem to take care of.

Comet CF-4160N Duplexer

Comet CF-4160N Duplexer

Installation of a good quality duplexer in the 70 cm path between the antenna and electronics such as our 70 cm preamp provides about 60 dB of additional isolation when operating in J Mode. The Comet CF-4160 Duplexer is a good choice for this application.

J Mode FIlter Installed In Preamp Box

Duplexer J Mode FIlter Installed In Preamp Box

We added one to the preamp box on our tower to create a J Mode desensitization filter. The duplexer is mounted on the left side of the 70 cm preamplifier which is on the right side in the image above. The 70 cm output of the duplexer connects to the feedline from our 70 cm antenna and the common output goes to the input of our 70 cm preamp. We also added a connector cap to the unused 2 m port on the duplexer to protect it from moisture. You can read more about this approach to J Mode desensitization filtering here.

The next stage of our project will be to add hardlines to our new tower and install a second entry to our shack near our new tower to bring our feedlines and control cables permanently into our shack. These projects will have to wait until spring. For now, we are enjoying operating our new antennas from a temporary station set up in our house. We also have a new IC-9700 Transceiver on the way and we should have it installed sometime during the next couple of months.

You can find other articles about our Satellite Station 4.0 project here:

Fred, AB1OC

Raspberry Pi Satellite Tracker Interface How To

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GHTracker Running On A Raspberry Pi 3

Sat Tracker – GH Tracker Running On A Raspberry Pi 3 B+

I have received several requests to share the image and construction details for the Raspberry Pi Satellite Tracker Interface that we use with MacDoppler as part of the Satellite Stations here. You can read more about the motivation for this project and its initial design and testing here.

This article explains how to put a Sat Tracker together.

The information and software described here are provided on an “as is” basis without support, warranty, or any assumption of liability related to assembly or use. You may use information and software image here only at your own risk and doing so releases the author and Green Heron Engineering from any liability for damages either direct or indirect which might occur in connection with using this material. No warranty or liability either explicit or implicit is provided by either AB1OC or Green Heron Engineering.

Now that we have that out-of-the-way, here are the components that you need to build your own Sat Tracker:

The Sat Tracker image includes a display driver for the specific touch display listed above and will most likely NOT WORK with any other touch display. You will also need a Green Heron RT-21 Az/El or a pair of Green Heron RT-21 single rotator controllers from Green Heron Engineering that are properly configured for your rotators.

If you have not worked with the Raspberry Pi before, it’s a good idea to begin by installing NOOBS on your SD card and getting your Raspberry Pi to boot with a USB Keyboard, USB Mouse, and an HDMI display attached. This will give you a chance to get familiar with formatting and loading your SD card with the Raspbian build of the Debian OS for the Raspberry Pi. I’d encourage you to boot up the OS and play with it some to get familiar with the OS environment before building your Sat Tracker.

Etcher Writing Raspberry Pi SD Card Image

Etcher Writing Raspberry Pi SD Card Image

The first step in building your Sat Tracker is to put together the hardware and write the image to your SD Card. Use the enclosed instructions or search the web to find information on how to do each of these steps:

  1. Install the Heat Sinks on the Raspberry Pi 3 B+ Motherboard. Make sure your chipset heat sink will clear the back of the case. If it won’t, it’s fine to just install the CPU Heatsink.
  2. Assemble your case to the point where it is built up to support the touch display
  3. Carefully install your touch display on the Raspberry Pi Motherboard
  4. Install the remaining pieces of your case including the nylon screws and nuts which hold the case parts together
  5. Download the SD Card image from the link below, unzip it, and load the image onto your SD card using Etcher
  6. Install your SD card in the slot on your Raspberry Pi Motherboard
  7. Connect your Raspberry Pi to the outside world as follows:
    • Connect Two USB cables – one end to the Elevation and Azimuth ports on your Green Heron Engineering RT-21 Controller(s) and the other ends to two of the USB connections on the Raspberry Pi
    • Connect a wired Ethernet Cable to your Raspberry Pi via a common Ethernet Hub or Switch with a PC or Mac that has VNC Viewer Installed. You will need a DHCP server running on the same network to supply your Raspberry Pi with an IP address when it boots. Your router most likely provides a DHCP function.
    • Connect your USB power supply to the Raspberry Pi Motherboard and power it up

Your Sat Tracker should boot up to the desktop with GH Tracker V1.24 running. The touch display works fine for using GH Tracker but its a bit small for configuring things. To make the configuration steps easier, the image comes up running VNC Server. I like to use VNC Viewer on my PC to connect to the Sat Tracker using VNC to perform the steps that follow. Note that both the Raspberry Pi and your PC must be on the same sub-network for the VNC connection to work. I’ve also included the following commands in the Sat Tracker image which can be run from the Raspberry Pi terminal window to make the configuration process easier:

$ setdisp hdmi # Disables the TFT display & uses the HDMI interface
$ setdisp tft  # Disables the HDMI interface & uses the TFT display
$ reboot       # Reboots the Raspberry Pi causing
               # the latest display command to take effect

If you select the HDMI interface, you will find that VNC Viewer produces a larger window enabling you to perform the following configuration steps:

  1. First, you need to determine the IP address of your Sat Tracker. This can be done via your DHCP server or by touching the network icon (up and down arrows) at the top of the display on the Sat Tracker.
  2. Use VNC Viewer on your PC or Mac to connect to the IP address of your Raspberry Pi. The default password is “raspberry“.
  3. Once you are connected, open a terminal dialog on the Sat Tracker, set your display to hdmi mode via the command shown above, and reboot your Sat Tracker.
  4. Reconnect VNC Viewer to your Sat Tracker and click on the Raspberry button (Start Menu Button) at the top left of the screen, select Preferences, and run Raspberry Pi Configuration. Select Expand Filesystem from the System Tab. This will expand the filesystem to use all of the available space on your SD Card. You can also change the system name of your Sat Tracker and your login password if you wish. When you are done making these changes, reboot your Sat Tracker.
  5. Reconnect to your Sat Tracker via VNC Viewer and select Setup -> Rotator Configuration from the menu in the GH Tracker App. Select the TTY devices (i.e. COM Ports) associated with the Azimuth and Elevation connections to your RT-21 Controller(s) via the two dropdown boxes. You can also configure the operational parameters for GH Tracker at this time. The ones that I use with our Alfa-Spid Az/El Rotators are shown below.

    GH Tracker Rotator Configuration

    GH Tracker Rotator Configuration

  6. Configure your Green Heron Engineering RT-21 Controllers to work with your rotator(s). The settings below are the ones that we use with the RT-21 Az/El controller and Alfa-Spid Az/El Rotators that we have here.

    GHE RT-21 Az/El Controller Settings for Alfa-Spid Rotator

    SettingAzimuthElevationNotes
    Park Heading0 degrees90 degreesSet via MacDoppler. Minimize wind loading and coupling to antennas below. Also enables water drainage from cross-boom tubes.
    Offset180 degrees0 degreesAzimuth dead spot is South. Elevation headings are from 0 to 180 degrees.
    Delays6 sec6 secMinimize relay operation during computer tracking
    Min Speed23Creates smooth start and stop for large array
    Max Speed1010Makes large movements relatively quick
    CCW Limit180 degrees355 degreesCCW and CW limits ensures predictable Azimuth heading for range around 180 degrees. Elevation limits permit 0 to 180 degree operation. Elevation limits shown can only be set via GHE configuration app.
    CW Limit179 degrees180 degrees
    OptionSPIDSPIDAlfa-Spid Az/El Rotator
    Divide Hi360360Rotator has 1 degree pointing accuracy
    Divide Lo360360
    Knob Time4040Default setting
    ModeNORMALNORMALDefault setting
    Ramp66Creates smooth start and stop for large array
    Bright22Easy to read in shack
  7. Configure the source of tracking data to be MacDoppler (UDP) from the GH Tracker Source Menu. We use UDP Broadcasts with MacDoppler running on the same Mac with VNC Viewer to run our rotator. Finally, press the Press to start tracking button on GH Tracker and run MacDoppler with UDP Broadcast on and Rotators Enabled to start tracking.

    MacDoppler Tracking AO-91

    MacDoppler Tracking AO-91

  8. Once you are satisfied with the operation of your Sat Tracker, use VNC Viewer to access the terminal window on your Sat Tracker one last time, set your display to TFT, and reboot.

The most common problems that you’ll run into are communications between your Sat Tracker and your Green Heron Engineering RT-21 Controller(s). If the Azimuth and Elevation numbers are reversed in GH Tracker, simply switch the TTY devices via the Setup Menu in GH Tracker. Also, note that it’s important to have your RT-21 Controller(s) on and full initialized BEFORE booting up your Sat Tracker.

Most communications problems can be resolved by initializing your tracking system via the following steps in order:

  1. Start with your RT-21 Controller(s) and you Sat Tracker powered down. Also, shutdown MacDoppler on your Mac.
  2. Power up your RT-21 Controller(s) and let the initializations fully complete.
  3. Power up your Sat Tracker and let it fully come up before enabling tracking in GH Tracker.
  4. Finally, startup MacDoppler, make sure it is configured to use UDP Broadcasts for Rotator Control and make sure that Rotators Enabled is checked.

The VNC Server on the Sat Tracker will sometimes fail to initialize on boot. If this happens, just reboot your Sat Tracker and the VNC Server should initialize and enable VNC access.

I hope you have fun building and using your own Sat Tracker.

Fred, AB1OC

First Winter Field Day For The Nashua Area Radio Society

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AB1OC Operating at Winter Field Day

AB1OC Operating at Winter Field Day

Source: Our First Winter Field Day – The Nashua Area Radio Society

The Nashua Area Radio Society participated in Winter Field Day for the first time this past weekend. We put up a 40 ft tower and we were QRV on all allowed bands from 160m through 2m and 70cm. Our station was a four transmitter one and we produced a great score during the 24-hour operating period. Winter Field Day presents some unique challenges that we did not encounter during Summer Field Day.

We put together a station for 160m for the first time as well as some other new things. You can read all about our approach to a station and operating for Winter Field Day via the link above.

Fred, AB1OC