Category Archives: Satellites

Articels about Amatuer Radio Satellite ground station design, construction, and operation.

Remote Operating Enhancements

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Updated Remote Operating Setup

Updated Remote Operating Setup

As explained in a previous article, we have been working on enhancing our FlexRadio 6700-based Remote Operating Setup to include additional remote control client options, better remote networking via the Internet, and better integration with our microHAM system.

Remote Operating Enhancements

Remote Operating Architecture

Remote Operating Gateway Architecture

This project involved the addition of the following capabilities to our base Remote Operating Setup:

These steps are now complete, and we have some good results to share.

SmartSDR Configuration

SmartSDR V2 Remote Connection

SmartSDR V2 Remote Connection

The first part of the upgrade was to update to SmartSDR V2. This upgrade enables much improved SmartSDR operation over the Internet. Our previous approach, which used a tunneled VPN connection combined with the previous versions of SmartSDR, did not always perform well when used with low-bandwidth or high-latency Internet connections. SmartSDR does much better in this area.

SmartSDR CAT Remote

SmartSDR CAT Remote

DAX Operating Remote

DAX Remote

 

 

 

 

 

 

 

 

 

 

 

 

Both the SmartSDR CAT and the SmartSDR DAX application have been updated to allow software on a PC being used to operate the FlexRadio SDRs over the Internet to gain access to CAT and sound interfaces associated with the radio.

Maestro Operations

FlexRadio Maestro Console

FlexRadio Maestro Console

We also added a Maestro Console to enhance the usability of the SDR radio portion of our Remote Operating Gateway. The Maestro is very easy to use and extends the available controls and display space which was limited when using just a laptop PC. The Maestro supports direct microphone connections for phone operation and also works with connected CW paddles for operation in CW mode. I have been using a single-level paddle along with our Maestro at speeds of 22 WPM with full QSK. Sending CW at these speeds with the Maestro works well.

The Maestro has built-in WiFi and Ethernet connections and full support for SmartSDR V2’s connections over the Internet. The Maestro can operate from AC power or from an internal battery pack. I have a couple of spare rechargeable batteries for our Maestro to support longer operating sessions on the battery.

Remote Operation using TeamViewer

TeamViewer VPN

TeamViewer VPN

We have been using a combination of TeamViewer Remote Control software and a router-based VPN solution to enable control of our antenna controllers and station power/amplifiers. This arrangement works well, but most of our readers probably do not have a router to support VPN connections or the networking knowledge to set up a secure VPN system.

Using TeamViewer’s built-in VPN capability, a much simpler VPN solution can be realized. You simply install TeamViewer on a PC in your shack that can access your station accessories and on your remote-operating laptop or PC. You then enable TeamViewer’s VPN option, and the configuration is complete.

TeamViewer VPN Connection

TeamViewer VPN Connection

We now use TeamViewer to set up both a VPN connection and a remote desktop control connection to a computer in our shack which can control amplifiers, power, and other station accessories associated with our Remote Operating Gateway. We use TeamViewer in this way to control our microHAM Station Master Deluxe antenna controllers, RigRunner remote power controller, a microBit Webswitch device, and an Elecraft KPA500 amplifier which are all part of our station’s Remote Operating Gateway.

DXLab Operating Remote

DXLab Operating Remote

With the addition of the SmartSDR and the updated TeamViewer/VPN setup, we can operate our station remotely over the Internet. We have tested our setup using a Wireless Hotspot modem and Verizon’s LTE service. The combination of our PC running the DXLab Logging Suite and the Maestro work great in this configuration.

Startup Sequence

We have found the need to initialize the networking configuration in a specific order to get everything running correctly. The steps that we use are as follows:

  1. Connect the laptop PC to the Internet
  2. Bring up the TeamViewer VPN connection
  3. Run SmartSDR on the laptop PC and log in to SmartSDR Remote
  4. Bring up the DXLab’s Suite, including Commander (currently, DXLab’s Commander has some issues connecting when the FlexRadio protocol is used. We have found that the KENWOOD protocol works fine.)
  5. Bring up the remote control application for the Elecraft amplifier and access our RigRunner power controller and microBit Webswitch units to turn on accessories as needed.
  6. Initiate a second TeamViewer Remote Control connection and use it to run the microHAM remote antenna controller in a single window
  7. Shut down SmartSDR on the laptop PC and bring up the connection to the radio via the Maestro.

There is obviously still some room for simplification in this initialization procedure. I expect some simplification as all the software involved becomes more mature and is further adapted for remote operation.

Once initialized properly, it’s simple to use the PC and Maestro combination to work SSB Phone or CW contacts. The DXLab Logging Suite will follow the radio and track modes, handle split operation, and allow control of our antenna rotators via DXView. We can click on spots in DXLab’s SpotCollector to automatically set the FlexRadio SDR’s mode, frequency, and split configuration. The Maestro and DXLab will stay in sync during tuning, mode changes, and other radio operations.

Remote Operation with WSJT-X

Remote Digital Operation using WSJT-X and FT8

Remote Digital Operation using WSJT-X and FT8

The final part of this project was to add the latest version of the WSJT-X software to our Remote Operating client laptop PC to enable FT8 operation on the HF bands and MSK144 for Meteor Scatter work on 6m.

SmartSDR and JTAlert Supporting Remote FT8 Mode

SmartSDR and JTAlert Supporting Remote FT8 Mode

We do not use the Maestro for digital operations. Instead, SmartSDR running on our remote laptop PC is used. We also use the JTAlert application to create an automated bridge between WXJT-X and the DXLab Logging Suite.

The combination of SmartSDR V2 and WSJT-X works great remotely. We have used this combination to make quite a few FT8 contacts on the HF bands and several Meteor Scatter contacts on 6m using MSK144 mode.

These enhancements to our Remote Operating Gateway have helped Anita and me operate more. I have our Maestro in my home office or on a table in our kitchen, where we can listen to the bands and work DX when the opportunities come up. Remote Operating, even if it’s just from another room at your QTH, is great fun!

Additional Planned Enhancements

In the near future, we should be able to begin the next step in our station upgrade plans – the addition of an Elecraft KPA1500 shared amplifier. The new amplifier will enable our Remote Operating Gateway to operate at 1500w on the HF bands and 6m.

This project has turned out to be somewhat involved, so we will be providing a series of articles to explain what we did:

Fred, AB1OC

Icom IC-9700 VHF/UHF/1.2GHz Prototype Transceiver

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Source: Icom IC-9700 VHF/UHF/1.2GHz Prototype Transceiver

Another new radio from Icom is based on their SDR platform. This looks like a great radio for Satellite and EME use. We will put in a pre-order for this radio and plan to include it in our Portable Satellite Station. I’ll post more here as details become available.

Fred, AB1OC

Portable Satellite Station Design and Operation

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Building and Operating a Portable Satellite Station Presentation

Portable Satellite Station Design and Operation Presentation

Anita and I attended the New England Regional Hamvention this past weekend. We gave a presentation on Portable Satellite Station Design & Operation there. You can view a copy of our presentation here.

Satellite Station Portable - Radio and Supporting Equipment

Portable Satellite Station 2.0 at a Recent License Training Class

The Videos from our presentation are below –



We did two additional talks about the Nashua Area Radio Club’s activities, including one on our High-Altitude Balloon Project. You can view those presentations here.

Also, we are planning to have our 2.0 Portable Satellite Station setup at the Nashua Area Radio Club’s upcoming Technician License Class on Sept. 30 – Oct. 1. If you are in the area and would like to see the station in operation, please contact us at activities@n1fd.org to arrange for a visit. You can do that here if you’d like to register for one of our license classes.

Fred, AB1OC

LEO Satellite Contacts via Easy Sat and Linear Transponder Satellites

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Satellite Antenna Details

LEO Satellite Station 2.0 Antennas

We recently did a Tech Night at our club on Building and Operating an LEO Satellite Ground Station. As part of my portion of our Tech Night presentation, I recorded several LEO satellite contacts. I made videos showing the operation of the computer controlling our Satellite Station 2.0 during these contacts. These videos give an idea of what it’s like to operate through LEO satellites.

The video above records several contacts through SO-50 – an FM “Easy Sat.”

In the next video, several contacts were made through FO-29, a linear transponder satellite.

The distortion you hear in my voice results from my voice coming back delayed through the satellites.

We will have our Satellite Station 2.0 setup at Field Day this year. If you are local to Nashua, NH, you are welcome to visit us during Field Day and see our Satellite Station in operation.

You can read more about the station used to make these contacts here on our Blog.

Fred, AB1OC

A Portable Satellite Station Part 4 – 2.0 Station First Contacts!

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Station Packed and Ready for Transport

Station Packed and Ready for Transport

With our new 2.0 Satellite station built, tested, and packed; we were ready to try it in a portable environment. Fortunately, the Nashua Area Radio Club had a Technician License class coming up and we thought that the new station test would be a great way for our students to learn about Amateur Radio Satellites.

Satellite Status from AMSAT Website

Satellite Status from AMSAT Website

Final preparations included checking the operational status of potential satellites on the AMSAT website. The page shown above is like a spotting cluster for LEO Satellites – it shows satellite activity reported by HAM satellite operators. Using this information, we configured MacDoppler to track the active satellites.

Satellite Pass Predictions

Satellite Pass Predictions

Next, we used MacDoppler to generate pass predictions for the weekend of our Technical Class. We assembled this data for all of the potential satellites and color-coded the available passes to identify those which had the best chance of producing contacts.

With this done, we loaded our portable tower, antennas, and all of the rest of the gear into our pickup truck and transported it to the class site.

Sateliite Antennas Setup Portable

Satellite Antennas Setup Portable

The first step at the class site was to unload all of our gear and move the portable tower to a suitable location. We used a compass to orient the tower to true north and leveled it. We used the weight bags that we made up to anchor the tower securely and then installed the antennas, rotator loops, and control cables. The antenna system worked out very well in the portable environment and was easy to set up.

Satellite Antenna Details

Satellite Antenna Details

Here’s a closer look at the LMR-400 UF coax cables which connect the antennas to the rest of the system. The loops just behind the antennas are necessary to keep the coax from affecting the pattern of the antennas. The coax cables shown were made long enough to allow the antennas to be rotated through their full travel in the azimuth and elevation directions without binding.

Satellite Station Portable - Radio and Supporting Equipment

Satellite Station Portable – Radio and Supporting Equipment

The final step in the portable setup was to put the IC-9100 Transceiver and Supporting Equipment together in the building and check everything out. We heard an ON4 station through FO-29 near the end of a low-angle pass as soon as we got everything hooked up and working. A very good sign!

We took some time to fine-tune the calibration of our rotators and to check the operation of the computer controls – everything checked out fine. The video above shows MacDoppler controlling the Azimuth/Elevation rotator and the IC-9100 Transceiver during the testing.

First Contact using New 2.0 Station (AO-85)

First Contact using New 2.0 Station (via AO-85)

With all the setup done, it was time to try to make our first contact. Fortunately, we did not have long to wait. We caught a medium-angle pass of AO-85, a U/V Mode FM Easy Sat. With MacDoppler setup and tacking, we immediately heard contacts being made through AO-85. I gave a whistle and adjusted my uplink VFO until I heard my signal coming back through AO-85. I gave a quick CQ call and immediately got a response from Jonathan, NS4L in Virginia, USA! It took a few seconds to exchange call signs and grid squares, and our first contract with our new station was in the log.

Explaining Satellite System to License Class

Explaining Satellite System to License Class

Our Technician License Class students were very interested in the station. We spent some time explaining the setup and demonstrating how it worked. We made more contacts between our class sessions using AO-85 and FO-29 (a V/U Mode Linear Transponder Satellite). Our most interesting contact was with Burt, FG8OJ, in Guadeloupe through FO-29. Working DX using the new station the first time we used it was great.

We learned several things during our first use of the new station. First, while the 35 ft. maximum separation allowed between the antenna system and the rest of the station is adequate in many applications, the antenna system’s close proximity to the building we were in blocked passes to the west of us with this separation. We have subsequently made up an additional set of feed lines using a pair of 100 ft. long 7/8″ hardline coax cables to allow for a greater separation in portable deployments such as this one.

We were glad we had the Heil Pro 7 Headset with us, and we used it for most of our contacts. The separate speaker allowed our students to hear the contacts well, and the boom microphone on the Pro 7 Headset eliminated feedback due to our voice coming back through the satellites. We improvised a mono-to-stereo converter cable to connect the Heil Pro 7 Headset to one of the two speaker outputs on the IC-9100 Transceiver. This allowed the radio to drive the separate speaker and the headphones at the same time.

We were glad to have the low-noise preamps available. These were especially useful during low-angle satellite passes, and our sequencing setup worked well.

All in all, the first test of our new 2.0 Portable Satellite station was a success. Our license classes students enjoyed learning about Amateur Satellites and had fun, along with us making contacts through a few of them. Our next goal will be to get packet modes and APRS working with our setup. We plan to do another article in this series when this part of our project is completed. Other articles in this series include:

We plan to add larger antennas and switchable polarity to our portable satellite station soon. This will enable us to make contacts using Satellites and the ISS in more difficult conditions.

You may also be interested in the satellite station at our home QTH. You can read more about that here.

Fred, AB1OC

A Portable Satellite Station Part 3 – 2.0 Station Radio and Supporting Equipment

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Satellite Station Transceiver and Related Equipment

Portable Satellite Station Transceiver and Related Equipment

With the Antenna System for our 2.0 Portable Satellite Station complete, we turned our attention to assembling the Transceiver and supporting equipment. The equipment used for this part of the project includes:

The Icom IC-9100 provides 100W on 2M and 75W on 70 cm, which is more than enough power for our application. It also has some nice satellite features, such as support for synchronized VFO tracking between the radio’s 2M and 70 cm VFOs. This radio also uses a single USB connection to allow computer control of the radio and the creation of a sound card interface on the host computer. A Heil Pro 7 Headset will be used for operator audio to avoid feedback due to our audio coming back from the satellite. The Icom SP-23 speaker is included to allow observers to hear satellite contacts while they are in progress.

Radio Management via MacDoppler

Radio Management via MacDoppler

The MacDoppler software provides automated control of the IC-9100, including mode selection and automatic correction of both VFOs for the Doppler shift. These features greatly simplify the operation of the radio, especially when satellites with SSB/CW transponders are used.

The video above shows MacDoppler’s management of the IC-9100 Transceiver during a pass of AO-73. The constant adjustments of the VFOs take care of Doppler shift correction and ensure that our signal stays at a fixed position in the transponder passband of linear transponder satellites.

Preamp Sequencers and Output Monitoring

Preamp Sequencers and Output Monitoring

M2 Antenna Systems S3 Sequencers are used to provide control of the Advanced Receiver Research low-noise preamps on our portable tower. One of the nice features of the Icom IC-9100 is that it can be configured to provide separate keying lines for the 2M and 70cm VFOs. This allows a preamp to remain enabled on the receive VFO while the other VFO is in transmit mode with its preamp shutdown by the sequencer. This arrangement is very useful during tuning when one needs to hear your signal coming back from a satellite. A custom-made cable assembly was made to interconnect the S3 Sequencers with the ACC socket on the IC-9100, the Weatherpack connector on the tower preamp control cable, and DC power.

We used the excellent WaveNode WN-2 Wattmeter again in our portable satellite setup. This modular output monitoring system has sensors for VHF/UHF use as well as voltage, signal quality, and other monitoring functions.

DC power for the setup is provided via a Powerwerx SS-30DV Power Supply and a RigRunner 40007U distribution unit. We use this power supply in all of our portable setups. It is lightweight, provides plenty of power for a 100W station and accessories, and is quiet from an RF perspective.

Equipment Packing and Protection

Equipment Packing and Protection

With the transceiver test of the station complete, we turned our attention to transporting the setup. Proper protection of the equipment during transport was provided via a large case from Pelican. We combined this with a roller bag and an inexpensive storage bin for documentation and accessories, which are not very fragile. We also included our RigExpert antenna analyzer in the setup to make testing the station during setup in a portable environment easier.

Station Packed and Ready for Transport

Station Packed and Ready for Transport

With all of the assembly and testing of our 2.0 Portable Satellite Station components complete, we packed up all the components. We used an inexpensive furniture dolly to allow us to roll the tower around to load and unload it.

We are ready to test our new station in a portable application. More on that in the final article in this series. Other articles in the series include:

You may also be interested in the satellite station at our home QTH. You can read more about that here.

Fred, AB1OC

A Portable Satellite Station Part 2 – 2.0 Station Goals and Antenna System

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M2 Antenna Systems LEO Pack On Display at Dayton 2016

M2 Antenna Systems LEO Pack on Display at Dayton 2016

We came upon the M2 Antenna Systems booth while walking around the exhibit halls at Dayton last year. M2 had one of their LEO Pack satellite antenna systems on display there. This got us thinking about building a new, more capable version of our portable satellite station. The LEO Pack is a relatively lightweight circularly polarized antenna system for working satellites using the 2 m and 70 cm bands. It turns out that AMSAT members can purchase the LEO Pack at a discount. Starting with the LEO Pack in mind, I began to lay out some goals for a new 2.0 Portable Satellite Station:

  • Be capable of working all active Amateur LEO Satellites, including those using linear transponders and digital modes
  • Be portable and manageable enough to be set up in an hour or less
  • Be simple enough to operate so that HAMs who are new to satellites can make all types of satellite contacts with a relatively short learning curve
  • Be manageable to transport and store
  • Utilize computer-controlled antenna tracking to aim the antennas
  • Utilize computer control to manage radio VFOs to compensate for Doppler shift
  • Be easy to transport and store
Computer Controlled Satellite Station Via MacDoppler

Computer Controlled Satellite Station via MacDoppler Software

We decided to take a computer-controlled approach for both antenna aiming and Transceiver VFO management to meet our goal of making the station simple to operate for new satellite operators. After some research on the available options, we choose MacDoppler from Dog Park Software Ltd. for this purpose. MacDoppler runs under Mac OS/X and works well on our MacBook Air laptop computer, which is very portable. This program also has broad support for many different rotator and transceiver platforms and is easy to understand and use. Finally, the program features high-quality graphics, making the station more interesting to folks with limited or no experience operating through Amateur Satellites.

With the satellite tracking software chosen, we made selections for the other major components in the 2.0 Portable Satellite Station as follows:

I will explain these choices in more detail as our article series proceeds.

Glen Martin Roof Tower

Glen Martin 4.5′ Roof Tower

Our solution to making the antenna system portable is built around a Glen Martin 4.5′ Roof Tower. This short tower is a high-quality piece made of extruded aluminum parts. The tower is very sturdy when assembled and is light in weight. We added a pair of extended “feet” to the tower, which is fabricated from 36″ x 2″ x 1 /4″ strap steel. This gives the tower a firm base and allows us to use sandbags to weigh it down (more on this later).

Our chosen Yaesu G-500 AZ/EL Rotator is a relatively inexpensive Azimuth/Elevation rotator suitable for lightweight satellite antennas such as those in the LEO Pack. This rotator can be installed as a single unit on the top of a tower or separated using a mast. We choose the latter approach as it is mechanically more robust and helps to keep the center of gravity for our portable antenna system low for improved stability.

Yaesu G-5500 Elevation Rotator

Yaesu G-5500 Elevation Rotator

Separating the Yaesu AZ/EL rotator requires a short mast and a thrust bearing. The mast was made from a 1-3/4″ O.D. piece of EMT tubing from our local hardware store. The thrust bearing is a Yaesu GS-065 unit. Both of these pieces fit nicely in the Glen Martin Tower. The thrust bearing provides support for the LEO Pack and G-500 elevation rotator and greatly reduces stress on the azimuth rotator. We also added a Yaesu GA-3000 Shock Absorber Mount to the azimuth rotator. This part provides shock isolation for and reduces strain on the azimuth rotator during the frequent starts and stops which occur during satellite tracking.

LMR-400 Feed-lines And Antenna Connection Jumpers

LMR-400UF Feed-lines and Antenna Connection Jumpers

We decided to use LMR-400 UltraFlex coax throughout our antenna system. LMR-400UF coax provides a good balance between size, flexibility, and loss for our application. To keep feed-line losses reasonable, we limit the coax’s total length from the transceiver output to the antenna feed point to 50′. This results in a loss of about 1.3 dB on the 70 cm band. Our planned IC-9100 Transceiver, which has a maximum output of 75W on 70 cm, will deliver a little more than 50W maximum at the feed point of the 70 cm yagi. This should be more than enough power to meet our station goals. Allowing a total of 15′ for antenna rotator loops and transceiver connections, we settled upon 35′ for the length of our coax feed lines between the tower and the station control point.

Portable Tower Cable Connections and Base Straps

Portable Tower Cable Connections and Base Straps

We added custom fabricated plates to the tower to act as a bulkhead for the feed line and control cable connections and to mount our low-noise preamplifiers. The control connections for the rotators and preamps were made using 6-pin Weatherpack connectors and rotator control cable from DXEngineering. The control cables are also 35′ long to match the length of our coax feed lines. This length should allow the tower and the control point to be separated by a reasonable distance in portable setups.

Low-Noise Preamplifiers From Advanced Receiver Research

Low-Noise Preamplifiers from Advanced Receiver Research

We added tower-mounted Low-Noise Preamplifiers from Advanced Receiver Research to improve our satellite antenna system’s receive sensitivity and noise figure. Two preamps are used – one for the 2 m and one for the 70 cm antennas. While these units can be RF-switched, we decided to include the preamp control lead in our control cable to allow for control of the preamp switching via sequencers. This was done to provide an extra measure of protection for the preamps.

Levels And Compass For Tower Setup

Levels and Compass for Tower Setup

We added a compass and a pair of bubble levels to the tower assembly to make it easier to orient and level it during setup. The picture above also shows the Yaesu shock-absorbing mount for the azimuth rotator.

Weight Bags To Anchor Portable Tower

Weight Bags to Anchor Portable Tower

Finally, we added a set of weight bags to securely anchor the tower when it is set up in a portable environment. These bags are filled with crushed stone and fastened to the legs of the Glen Martin tower with velcro straps.

LEO Pack Antenna Parts

LEO Pack Antenna Parts

With the tower and rotator elements complete, we turned our attention to the assembly of the M2 LEO Pack. The LEO pack consists of two circularly polarized yagis for the 2m and 70 cm bands. The 2m Yagi is an M2 Systems 2MCP8A which has 8 elements (4 horizontal and 4 vertical) and provides 9.2 dBic of forward gain. The 70 cm Yagi is an M2 Systems 436CP16 with 16 elements (8 horizontal and 8 vertical) and provides 13.3 dBic of forward gain. The Yagi’s are meant to be rear-mounted on an 8.5′ aluminum cross boom included in the LEO Pack. The picture above shows the parts for the two antennas before assembly. It took us about a 1/2 day to assemble and test the antennas, and both produced the specified SWR performance when assembled and tested in clear surroundings.

Assembled LEO Pack On Portable Tower

Assembled LEO Pack on Portable Tower

The picture above shows the assembled LEO pack on the portable tower. We attached a short 28″ piece of mast material to the cross boom as a counterweight to provide better overall balance and minimize strain on the elevation rotator. The antennas and the two outer sections of the mast can be easily removed to transport the antenna system.

2m Circularly Polarized Yagi Feed Point

2m Circularly Polarized Yagi Feed Point

The LEO Pack yagis achieve circular polarization via a matching network that drives the vertical and horizontal sections of the antennas with a 90-degree phase shift. The phase shift (and a final 50-ohm match) is achieved using 1/4 wave delay lines made of coax cables. We configured our antennas for right-hand circular polarization. The choice between right and left-hand circular polarization is not critical in our LEO satellite application as most LEO satellites are not circularly polarized. The advantage of circular polarization in our application is the minimization of spin-fading effects.

Green Heron RT-21 Az/El Rotator Controller

Green Heron RT-21 AZ/EL Rotator Controller

The final step in the construction of our antenna system was to add the rotator controller and test the computer aiming system. We have had very good results using Green Heron Engineering rotator controllers in our home station, so we selected their RT-21 AZ/EL rotator controller for this application. The RT-21 AZ/EL rotator controller is two rotator controllers in a single box. The rotator control parameters, such as minimum and maximum rotator speed, ramp, offset, over travel, and others, can be independently set for each rotator.

Rotator Test Using MacDoppler

Rotator Test Using MacDoppler

The RT-21 AZ/EL Rotator Controller connects to our computer via USB cables. We run Green Heron’s GH Tracker software on our MacBook Air laptop to manage the computer side of the rotator controller and to provide a UDP protocol interface to the MacDoppler tracking software. The picture above shows the test setup used to verify the computer-controlled antenna pointing system.

Mixed OS/X and Windows Software Environment

Mixed OS/X and Windows Software Environment

One challenge associated with selecting a Mac OS/X platform for computer control is what to do about the inevitable need to run Windows software as part of the system. In addition to the GH Tracker software, the WaveNode WN-2 Wattmeter and digital modem software for satellite/ISS APRS and other applications require a Windows run-time environment. To solve this problem, we use a virtual machine environment implemented using VMware Fusion and Windows 10 64-bit on our MacBook Air Laptop along with Mac OS/X. The Unity feature of VMware Fusion allows us to run Windows apps such as GH Tracker as native Mac OS/X apps. The picture above shows an example of this.

Rotator Controller and Software Configuration

Rotator Controller and Software Configuration

With the antennas removed from the cross boom, we tested the operation of the computer-controlled tracking system. The Yaesu G-5500 AZ/EL Rotator has some limits as to its pointing accuracy and backlash performance.  Experimentation with the combination of the RT-21 AZ/EL rotator controller, GH Tracker, and MacDoppler setups was required to achieve smooth overall operation. We finally settled on a strategy of “lead the duck” tracking. The idea here is to set up the rotators so that they over-travel by a degree or so when the computer adjusts them and couple this with a relatively wide 2-3 degree tracking resolution. This maximizes the overall accuracy of the pointing system and minimizes the tendency towards the constant start-stop operation of the rotators during satellite tracking. Our current configuration for all elements involved in the tracking system is shown above.

With the antenna system complete and tested, we can move on to the next step in our project – the construction of a computer-controlled transceiver system. We will cover this element in the next part of this series. Other articles in the series include:

You may also be interested in the current satellite ground station at our home QTH. You can read more about that here. Our first permanent satellite station at our home QTH used Eggbeater antennas. You can read more about that system here.

Fred, AB1OC

A Portable Satellite Station Part 1 – A Simple Station for AO-85

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Portable Satellite Station Contact

Portable Satellite Station Contact

Our club, the Nashua Area Radio Club, has quite a few members who are interested in space communications. We built a simple portable satellite station last year for our 2016 Field Day operation to learn about satellite communications and create something new for folks to work with during 2016 Field Day.

Simple Portable Satellite Station

Simple Portable Satellite Station

Our 1.0 Portable Satellite Station was a relatively simple setup built around an HT, an Elk 2m/70cm satellite antenna, and some gear to improve the receive performance and transmit power output of the HT. All of the gear was mounted on a board to make it easy to transport and it is powered by a LIPO rechargeable battery. The gear in our 1.0 station is made up of the following:

Improved Satellite Antenna Mount

Improved Satellite Antenna Support

Our first contacts with our 1.0 station were made using the Elk Antenna hand-held. Later, we created a “plumber’s special” setup with a camera tripod to make pointing the antenna easier. Note the angle meter from a local hardware store which measures the elevation angle of the antenna.

AO-85 (Fox-1A) U/V Mode FM Cube Sat

AO-85 (Fox-1A) U/V Mode FM Cube Satellite

This setup worked great for making FM contacts through AO-85 (Fox-1A), a  U/V mode FM EasySat. We used the 1.0 station on multiple occasions including Field Day 2016 and several of our club members used it to make their first satellite contacts. The Full-Duplex HT allowed us to hear our own signal coming back from the satellite which was an important tool to help with aiming the antenna properly. The ELK Dual-Band antenna is also a good choice because it uses a single feed point and a single polarization for both the 2m and 70cm bands.

1.0 Station Team Operating Approach

1.0 Station Team Operating Approach

We used the team operating approach outlined above. This worked especially well for new folks who had not made a satellite contact before as it enabled each of the three team members involved in making the contact to focus on a specific part of the contact. We used orange plastic tent stakes to make AOS, Time of Closest Approach, and EOS to mark headings for each satellite pass. Small flashlights used at the stakes made them glow for night-time passes.

We certainly had a lot of fun with our 1.0 Satellite Station and I expect that we’ll continue to use it. As we gained a little experience with AO-85, we decided that we wanted to build a more capable Portable Satellite Station that we could use to operate with linear transponder satellites and which included a tracking system and better antennas. I know from experience with our home satellite station that DX contacts are possible using higher altitude linear transponder satellites like FO-29.

We would also like to be able to use APRS and other digital modes through satellites as well as receive SSTV pictures from space.

These goals have become the basis for building our Portable Satellite Station 2.0. More on the new station in Part 2 of this series. Other articles in the series include:

You may also be interested in the satellite station at our home QTH. You can read more about that here.

73,

Fred, AB1OC

LEO Satellite System Part 3 – Final Installation And First Contacts

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Eggbeater Antennas And Preamps SystemsOn Tower

Eggbeater Satellite Antennas And Preamp System On Tower

With some help from Matt Strelow, KC1XX  of XX Towers, we’ve gotten our LEO Satellite Antennas and Preamp System installed on our tower. We installed the antennas on a sidearm at about 80 ft and installed the preamp system (the upper left gray box) next to the antennas on the tower. The design and construction of our LEO Satellite System was covered in the Part 1 and Part 2 articles here on our blog.

Hardlines At The Tower

Hardlines At The Tower Base

I choose a 7/8″ Heliax Hardline Coax (Andrews AVA5-50) for the feedlines between the antennas on the tower and the shack. I choose this type of cable to hold our losses end-to-end to about 1.0 dB for the 432 MHz side of the system. Our Icom IC-9100 Transceiver, which we will use for satellite work, provides 75W of output on the 70cm band, resulting in a maximum of about 45W at the antenna – plenty of output power for LEO satellite uplink work. The end-to-end loss on the 144 MHz side is about 0.6 dB resulting in an 85W out the maximum from 100W in. The antennas were connected to the preamps and through to the hardline coax cables using short LMR-400UF coax jumpers, and crimp-on N-type connectors were used throughout the system. The conduits buried under our lawn had plenty of capacity for the two additional hardline cables (the lower pair of large coax cables in the picture above). I also routed the control cables for the preamps through one of our smaller conduits.

Hardline Terminations At Shack

Hardline Terminations At Our Shack

The hard lines (cables with orange and purple tape) were terminated with N-connectors, and the shack entry end through grounded PolyPhaser Lightning Protectors.

VHF - UHF Antenna Switching Console

VHF – UHF Antenna Switching Console

The two sides of the LEO Satellite Antenna and Preamp system were terminated on our VHF – UHF switching console in our shack. The console uses Hofi-Technik Rotary UHF Antenna Switches to allow selection of the LEO Satellite Antennas as well as our M2 Antenna Systems 144 MHz and 432 MHz Yagis and a Diamond X-300NA 2m/70cm ground plane vertical, which we use for repeater work.

Preamp Control Cable Terminatons On Tower

Preamp Control Cable Terminations On Tower

We also terminated the control cable from our Preamp System on Control Line Static Suppressors at the base of our tower.

Preamp Sequencers

Preamp Sequencers

The Preamp Control Cable was routed to a pair of M2 Antenna Systems S3 Sequencers (top units in the picture above) to enable proper Tx/Rx sequencing to protect the tower-mounted Preamps from damage during transmit. These units allow the 144 MHz and 432 MHz Preamps to be turned on/off separately, as well as enabling the noise test function on the 144 MHz preamp. With all of the installation work done, I confirmed that the SWR reading on both antennas was in the specification at the input to the IC-9100 Transceiver and that both Preamps work (via an observed increase in noise level) when turned on.

Nova For Windows (FO-29 Satellite Pass)

Nova For Windows (FO-29 Satellite Pass)

The final step was to install the Nova For Windows program and download the latest Keplerian Elements for the HAM satellites that are currently operational. Nova For Windows allows me to determine when a given satellite is making a pass that covers both my QTH and the area where I want to try to make contacts. The program can also predict future passes, making planning satellite operating times easier. The picture above shows the footprint of the FO-29 and the ISS during a pass over my location.

Fuji Oscar FO-29 Satellite

Fuji Oscar FO-29 Satellite

On the day and time, I tried to make my first contacts, only satellites with Linear Transponders were making useful passes overhead. I try my first contact through FO-29 (Fuji Oscar 29), a V/U Mode (145 MHz uplink/435 MHz downlink) satellite.

First Satelllite Contact - EA1QS In Spain

First Satellite Contact QSL – Pablo, EA1QS In Spain

With my IC-9100 setup in Satellite/SSB Phone mode to transmit and receive on the proper frequencies and side bands and with the Tx and Rx sides set to track each other (this is one of the useful satellite Features provided by the IC-9100), I began by locating a clear frequency on FO-29’s transponder and transmitting on the uplink while adjusting my Rx offset until I could hear my own transmissions coming back from the bird. Once I found my receive frequency, I began looking for a station to work. As good luck would have it, I found Pablo, EA1QS in Spain, and made my first contact! It took some care to stay on frequency during the brief contact as the Doppler shift associated with the path through FO-29 was changing fairly rapidly.

I also made two contacts with W1AW/9, the ARRL Centennial QSO Party Operation in Illinois, USA. I made these two contacts through two different satellites. The first contact was made through VUSat VO-52, a U/V Mode (435 MHz Uplink/145 MHz Downlink) satellite, and the second one was made using FO-29 again. I was quite fortunate to make the contact through VO-52 as its batteries failed, and the bird went out of service just 12 days after my contact was made.

M2 Antenna Systems 70cm and 2m Yagis On Top Of Our Tower

M2 Antenna Systems 70cm and 2m Yagis On Top Of Our Tower

My early experiences with our new LEO Satellite System have been good. The M2 Antenna Systems Eggbeater Antennas and tower-mounted Preamp System work quite well when the Satellites being worked are 30 degrees or more above the horizon. I can use our weak signal 2m and 70cm yagis (top two antennas shown above) and the associated tower-mounted Preamp Systems (two grey boxes just below the top of the tower) for Satellite passes below 30 degrees. This mode of operation will require computer tracking, which I can do via Nova For Windows or the Ham Radio Deluxe Satellite Software, both of which I already have. I plan to try this combination and provide additional setup and operational results for this configuration sometime in the future.

Its been a very busy summer, and I have not as much time to operate using LEO Satellites as I would like. With WRTC 2014, the ARRL Centennial Convention over, and the 13 Colonies Special Event and W1AW/1 New Hampshire portable operations completed, I hope to have more time to devote to Satellite Operation. It’s a lot of fun to make contacts through satellites, and this mode of operation will give us the chance to learn some new skills.

Other articles in the series include:

You might also be interested in the series on our Portable Satellite Station. You can read about that here.

– Fred (AB1OC)

LEO Satellite System Part 2 – Antenna Assembly And Ground Test

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Assembled Eggbeater Satellite Antenna System

Assembled Eggbeater Satellite Antenna System

We continued our project to add LEO Satellite capability to our station this past weekend (you can read about the design of our LEO Satellite System here). With 370′ of 7/8″ Hardline Coax (LDF5-50A) ordered and with Matt Strelow, KC1XX of XXTowers scheduled to help with the antenna installation on the tower later this week, the only prep work left was to assemble our M2 Eggbeater Antenna System and preamps and test the setup. The first rule of tower work is to assemble and test as much on the ground as possible. To this end, we decided to mock-up the entire antenna system a few feet up from the base of our tower. The first step in the process was to assemble the M2 Eggbeater Antenna System. This step was not difficult.

Ground Pre-assembly And Test

Ground Pre-assembly And Test

We next assembled a Rohn sidearm mount and attached it to our tower about 5 feet from the ground. We then mounted the antennas and cross boom on the sidearm mount and did some SWR sweeps on just the antennas with a RigExpert Antenna Analyzer to ensure that the they were performing to specifications. Both antennas checked out just fine. They both had SWR readings of 1.2 or less across a very wide bandwidth.

Satellite Preamp System Mock Up

Satellite Preamp System Mock-Up

The final step in the pre-assembly process was to mount the preamp system that we had assembled previously to the tower. We also built all of the coax cables needed to connect the system from the planned 7/8″ Hardline Coax Feedlines (LDF5-50A) through the preamps and to the antennas. We used LMR-400UF Coax for these jumpers along with crimp-on N-connectors (we crimp and solder the pins on these connectors to the inner conductor of the coax to improve reliability). We installed heat shrimp tubing to seal the connectors in the crimp ferrule area and then covered all of the exposed connectors with electrical tape and CoaxWrap sealing tape. We also installed a 200′ length of DX Engineering Heavy Duty Control Cable (DXE-CW8-HD) to the preamp system. With these steps done, we again verified that the SWR performance of both antennas checked out within specifications.

I plan to pre-install a run of control cable from the control line surge protectors at the base of our tower to the shack and hook the control cable up to our M2 Antenna Systems S3 Sequencers sometime later this week. With these steps done, we will be ready to put our LEO Satellite System on our tower and perform the final integration and testing steps with the rest of our station.

Other articles in the series include:

You might also be interested in the series on our Portable Satellite Station. You can read about that here.

– Fred (AB1OC)