EME Station 2.0 Part 8 – Elevation Rotator Assembly and Sub-System Test

Elevation Rotator and MAP65 EME Preamp System Test

The next major component in our new EME station is the assembly of the Elevation Rotator. This step also involves pre-assembly and testing of the MAP65 Pre-amp Housing, Antenna Power Dividers, Transmit/Receive Sequencer, and the Rotator Controller. Here are the components involved in this part of our project:

We choose the MT-3000A Elevation Rotator for its heavy-duty construction. This will be important to handle the weight of our EME antenna array as well as the winter conditions that we encounter here in New England.

Elevation Rotator Assembly

MT-3000A Elevation Rotator Parts

MT-3000A Elevation Rotator Parts

The first step was to inventory all of the parts for the MT-3000A Elevation Rotator and carefully read the MT-3000A manual from M2 Antennas.

Assembled MT-3000A Elevation Rotator

Assembled MT-3000A Elevation Rotator

Assembly of the MT-3000A is pretty straight forward. It uses a chain-drive system to produce a very strong, high-torque elevation rotator system. It’s important to fill the gear-box with the supplied gear oil and to lube the chain with the proper lubricant prior to testing and installing the rotator. Spray style chain lubricants for motorcycle chains work well in this application.

Rotator Controller Integration and Testing

Green Heron RT-21 Az-El Rotator Controller

Green Heron RT-21 Az-El Rotator Controller

The next step was to make up a rotator and connect the MT-3000A to our Green Heron RT-21 Az/El Rotator Controller for a test. The RT-21 Az/El is a very flexible controller that is capable of controlling almost any popular antenna rotator. We’ve already tested this unit with the M2 Antennas OR2800G2 Azimuth Rotator that is installed on our EME tower.

RT-21 Configuration of the MT-3000A Elevation Rotator

RT-21 Configuration of the MT-3000A Elevation Rotator

The MT-3000A is a pulse-counter style rotator with 0.1-degree positioning resolution. It required a custom setup in the Green Heron RT-21 Az/El which was easily accomplished with Green Heron Engineering’s setup utility. One must determine the correct Divide Ratio setting by experimentation. When the correct value is found, a rotation of 90 degrees on the controller will result in exactly 90 degrees of actual movement by the MT-3000A. This calibration was much easier to do with the MT-3000A in our shop than it would have been once the unit was installed on our tower. We also set up the RT-21 Az/El Controller to allow for 5 degrees of rotation beyond the 0 and 90-degree points.

After some testing, I decided to use the 42Vdc tap setting in the RT-21 Elevation Controller with our MT-3000A. The specifications for the MT-3000A allow for up to 42 Vdc to be used to run its motor. To be safe, we set the Max Speed setting in the RT-21 Az/El to “8” which resulted in a maximum of 40 Vdc measured with a voltmeter at the output of the controller.

Assembly and Integration of MAP65 Housing and Cross Boom

Elevation Rotator and MAP65 Preamp Housing Assembly

Elevation Rotator and MAP65 Preamp Housing Assembly

The next step was to install the H-frame Main Boom center section and Truss Support Tubes in the MT-3000A. The MAP65 EME Preamp Housing is mounted on the horizontal Truss Support Tube as shown above.

MAP65 EME Preamp System Housing

MAP65 EME Preamp System Housing

A control cable for the MAP65 EME Preamp Housing was made up and connected to the terminal strip on the housing.

EME Sequencer Testing

S2 Sequencer

S2 Sequencer

The S2 EME Sequencer from M2 Antennas is designed to control the MAP65 Housing but its internal jumpers must be properly set to do this. We spent some time with the manual for the S2 Sequencer and for the MAP65 Housing carefully setting the S2 Sequencer’s jumpers and verifying proper voltages at both the output of the S2 Sequencer and the terminal strip in the MAP65 housing with a voltmeter. The manuals for the S2 EME Sequencer and the MAP65 EME Preamp Housing were clear on these steps.

Mounting Power Dividers

Power Divider Mounting Bracket

Power Divider Mounting Bracket

The next step in this part of our project was to mount the M2 Antennas 4-Port Power Dividers that are used to connect the MAP65 Pre-Amp housing to the four 2MXP28 Antennas. Two power dividers are required as each antenna has a separate feed point connection for their horizontal and vertical polarities. We made up some custom mounting brackets for the power dividers from 1-1/4″ aluminum angle material.

MAP65 EME Preamp Housing Connections

MAP65 EME Preamp Housing Connections

The MAP65 Preamp Housing connects to the outputs of the two Power Dividers that feed the H-polarity and V-polarity of the antenna array. The outputs from the MAP65 EME Housing connect to the H-polarity and V-polarity receive coax cables and the Transmit Hardline Coax Cable that runs from the tower to our shack.

Coax Interconnect Cables

Power Divider and Feedline Jumper Coax Cables

Power Divider and Feedline Jumper Coax Cables

The final step was to make up LMR-400 coax cables to connect the MAP65 Preamp Housing to the Power Dividers. We used right-angle male N connectors to make the connections to the 4-Port power drivers to avoid sharp bends in the cables.

We also made up three additional LMR-400uF coax cables to connect the MAP65 Preamp Housing to the coax Tx and Rx feedlines that are installed on our tower. It’s important to keep the H-Pol and V-Pol cables as close to identical in length as possible to minimize and phase differences between the associated receive feedline systems.

Next Steps

The next step in our project will be the final assembly and preparation of the H-frame which will be used to mount our four 2MXP28 Antennas. You can read more about our EME station project via the links that follow:

If you’d like to learn more about How To Get Started in EME, check out the Nashua Area Radio Society Teach Night on this topic. You can find the EME Tech Night here.

Fred – AB1OC

Tech Night – VHF+ Weak Signal Stations Part 1 (Intro and 6 Meters)

Tech Night - VHF+ Weak Signal Stations Part 1 - Overview and 6 Meters

Tech Night – VHF+ Weak Signal Stations Part 1 – Overview and 6 Meters

We recently did a Tech Night on building and operating VHF+ stations as part of the Nashua Area Radio Society’s educational program. I wanted to share the presentation and video from this Tech Night so that our readers might learn a little more about how to get started and build their own VHF+ Weak Signal Station.

There is a lot to this topic so we’re going to cover it with two Tech Night presentations. The first one in the series is included here and it provides an Introduction to the VHF+ topic along with details on building and operating a station for the 6 Meter Band.

July 2020 Tech Night Video – VHF+ Weak Signal Stations Part 1 – Introduction and 6 Meters

You can view this Tech Night session via the video above. Here’s a link to the presentation that goes with the video. You can learn more about the Nashua Area Radio Society’s Tech Night program here.

We have built a number of stations and antennas for the VHF+ Bands (6 Meters and above). Here are some links to articles about those projects and our operations on the VHF+ Bands here on our Blog:

Fred, AB1OC

Tech Night July 14 – Building and Operating a VHF+ Station

Completed Antenna Stack On New Tower

6m Yagi and 2m/70cm/23cm Satellite Antennas On A Tower

We will be hosting a Tech Night about Building and Operating a VHF+ Weak-Signal Station tonight, July 14th at 7 pm Eastern Time. The live, interactive video of our tech Night will be shared via a Zoom conference and all of our readers are welcome to join. I plan to cover the following topics during our session this evening:

  • Why do weak-signal work on 6 meters and above?
  • What can you work and what modes are used on these bands
  • How does propagation work at 50 Mhz and above and how can you measure it?
  • How does one operate using SSB, CW, and digital modes on these bands?
  • What equipment is needed and what are some possible ways that you can put together a VHF+ station?
  • Some demonstration of actual contacts

In addition to an overview of how to get on all of the bands above 50 MHz, we will focus on the 6 Meter (Magic) band. The session will include demonstrations of FT8 and Meteor Scatter contacts on 6 m. I will also briefly describe the 6 m station here at AB1OC-AB1QB and show how we use it to make contacts. A second Tech Night will cover stations and weak-signal operating on 2 m and above.

The Zoom information for our Tech Night Session follows. We suggest that you join early so that you have a chance to make sure that your computer, speakers, microphone, and camera are working.

July 14th, 7 pm Eastern – Nashua Area Radio Society Tech Night. Fred, AB1OC Setting up a VHF+ Station. Here’s an opportunity to learn how to add 6 m and above weak-signal modes to your station. Join Our Zoom Meeting

We hope to see many of our readers this evening!

Fred, AB1OC

Getting Started With Amateur Satellites (and Progressing to Linear Birds)

Get Started with Amateur Satellites

Get Started with Amateur Satellites

We get quite a few requests from folks to explain how to get started with Amateur Radio Satellites. Requests for information on how to build a computer-controlled ground station for Linear Satellites are also pretty common. I recently got such a request from our CWA class so I decided to put together a session on this topic.

We covered a number of topics and demonstrations during the session including:

  • How to put together a simple station and work FM EasySats with HTs and a handheld antenna
  • A recorded demonstration of some contacts using FM EasySats
  • How-to build a computer-controlled station and work Linear Transponder Satellites
  • Fixed and Portable Satellite Station Antenna options
  • A recorded demonstration of some contacts using Linear Satellites
  • How-to work digital (APRS digipeater) contacts
  • How-to receive SSTV Transmissions from the ISS

About 30 folks attended this session and there was some good Q&A throughout.

Getting Started With Amateur Satellites

The presentation was recorded and can be viewed above. Here’s a link to the associated Powerpoint Presentation.

There are lots of articles about building and operating Amateur Satellite Stations here on our blog. The following are links to several articles and series on this topic:

I hope that you find this information useful for your Amateur Satellite projects!

Fred, AB1OC

Tech Night – Getting Started In EME Communications

Tech Night – Getting Started in EME (Click to View The Presentation)

We recently did a Tech Night Program as part of the Nashua Area Radio Society’s Tech Night program.. I wanted to share the presentation and video from this Tech Night so that our readers might learn a little more about how to get started in EME or Moonbounce Communications.

April 2020 Tech Night Video – Getting Started in EME Communications

You can view the Tech Night presentation by clicking on the video above. Here’s a link to the presentation that goes with the video. You can learn more about the Nashua Area Radio Society’s Tech Night program here.

The second Tech Night in the EME Series was about Building and Operating an EME Station. You can view that Tech Night here.

We are in the process of upgrading our EME station to include adaptive polarity. you can read more about that project here.

Fred, AB1OC

EME Station 2.0 Part 6 – Tower Grounding System

Tower Ground System

Tower Ground System

Now that spring is here, we’ve continued work on our EME station project. The most recent project was to build complete the ground system for our new EME tower. The proper way to ground a tower is shown above. Each leg of the tower is connected to an 8′ ground rod via a heavy-gauge ground cable. The cable is attached to the tower leg using stainless steel clamps meant for this purpose. The three ground rods associated with the tower legs are then bonded together using a heavy copper ground cable ring.

Ground Cable CAD Weld

Ground Cable CAD Weld

The ground cables are welded to the top of the ground rods using CAD weld on-shots. This creates a strong connection that will not corrode or fail. It is important that the ground rods be free of dirt, corrosion, oxidation, and burrs before performing the CAD welding. We used a combination of 3-wire and 4-wire one-shot CAD welds to build our ground system and connect it to the bonding system running from out tower to the entry to our shack.

Main Grounding System Bonding

Main Grounding System Bonding

The final step was to connect the bonding run from the tower to the perimeter grounding system around our house. This completed the tower grounding system and enabled us to complete our final permit inspection courtesy of our local building inspector.

Finished Tower Base

Finished Tower Base

With all of this work done and the inspection complete, we added a mulch bed around our new tower to make this area of our lawn easy to maintain.

The next step in our project is to begin building the antennas that will go on our EME tower. You can read more about our EME station project via the links that follow:

If you’d like to learn more about How To Get Started in EME, check out the Nashua Area Radio Society Teach Night on this topic. You can find the EME Tech Night here.

Fred, AB1OC

Satellite Station 4.0 Part 11 – Phone Patch/Telebridge Capability

Council Rock South Students Contact the ISS

Council Rock South Students Contact the ISS

I have joined the ARISS Program as a Mentor to help schools make contacts with astronauts on the International Space Station (ISS). School contacts as part of the ARISS program can take two forms – Direct Contacts and Telebridge Contacts.

ARISS Direct Contacts

Direct contacts involve setting up a space communications ground station at the school making the contact.

ARISS Direct Contact Ground Station Antennas at Council Rock HS

ARISS Direct Contact Ground Station Antennas at Council Rock HS

Direct Contacts involve a great deal of preparation and a local Ham Club which has considerable VHF weak-signal experience and equipment to partner with on a school’s contact. There can also be considerable expense involved in assembling the necessary ground station for a Direct Contact. In addition, some locations are much better than others in terms of access to good, high-angle ISS passes and an environment that is relatively free of nearby obstructions like buildings, hills, etc.

Our radio club, The Nashua Area Radio Society, supported a Direct Contact at Hudson Memorial School in December 2018. It was a fantastic experience. You can read more about what was involved here.

ARISS Telebridge Contacts

students at Maani Ulujuk High School in Rankin Inlet, Nunavut, Canada

Students at Maani Ulujuk High School in Rankin Inlet, Nunavut, Canada

Telebridge contacts involve using an existing ground station in a different location with an audio link to the school making the contact via telephone. This type of contact provides a high-quality experience with an astronaut on the ISS without the need to construct a ground station at the school. It enables the teachers involved in the contact process to focus on the educational aspects of their contact with the ISS.

All of the ARISS Telebridge Ground stations are built and operated to very high standards.

Also, schools in difficult locations or those who don’t have the needed support of a local Ham Radio club with the necessary space ground station equipment can still enjoy making a contact with an astronaut on the ISS. In addition, a Telebridge contact also enables the supporting Amateur Radio Club to focus on providing great Amateur Radio activities and educational support to their partner school.

Adding Telebridge Capability to Our Station

Space Communications Ground Station at AB1OC-AB1QB

Space Communications Ground Station at AB1OC-AB1QB

We’ve used the station here to make many satellite contacts and to listen to ARISS contacts from the ISS. We’ve also used our station to receive images from the ISS during ISS SSTV events. We’ve decided to add a Phone Patch to our station here to enable it to be used as a testbed for schools preparing for Telebridge contacts.

Adding A Telephone Patch

Phone Patch To Enable Telebridges

Phone Patch To Enable Testing and Hosting Telebridge Contacts

A Telephone Patch enables a third party to communicate over an Amateur Radio link using a telephone. A Phone Patch provides a connection between a Transceiver and a telephone line. It also handles creating a proper balance at the 2-wire Hybrid Interface that connects to the telephone line to the radio. A typical Phone Patch device also provides for Transmit and Receive level adjustments.

Phone Patch units are not used all that much anymore. Fortunately, MFJ still makes the MFJ-624E Hybrid Phone Patch.

Setting up the MFJ Phone Patch was pretty straightforward. All that was required to work with our IC-9700 Transceiver was to set the internal jumpers in the MFJ Phone Patch to configure its microphone connection properly. The MFJ Phone Patch came with a cable to connect to the round microphone jack on the IC-9700 Transceiver. A connection between our audio amplifier to bring audio into the Phone Patch was made to complete the installation.

Testing On The Air

The MFJ Phone Patch was adjusted to achieve a good balance on the 2-wire Hybrid Interface to the telephone line and the Transmit and Receive levels were properly adjusted prior to on-the-air use. These procedures are clearly explained in the manual for the MFJ-624E and are easy to complete.

With these steps complete, we set up a telephone call and made several contacts using FM stateless on the air. We received good audio reports and could easily understand the downlink audio using a standard telephone receiver.

Becoming an ARISS Telebridge Ground Station

My initial purpose for adding Telebridge capability to our ground station was to enable it to be used to perform testing of the audio systems in schools that will be hosting Telebridge contacts. I am also going to apply to become one of the ARISS Telebridge Ground Stations in North America. We have an emergency backup power system here and our station’s location in our home makes it a good choice for situations where contacts need to be made at any time of the day or night. More to come on this in the future.

More About Our Ground Station

Here are links to some additional posts about our Satellite Ground Stations:

Fred, AB1OC

Winter Field Day 2020 Final Station Test

Source: Winter Field Day 2020 Final Station Test – Nashua Area Radio Society

Winter Field Day 2020 is almost here! A few weekends ago, several of us got our QTH to complete the final station test for our planned 5O operation in Winter Field Day (WFD). Activities including setup and testing of a new, Portable Networking Pod and three of our five planned Winter Field Day stations. We are planning to use the N1MM+ Logger in a networked configuration this year…

This article covers equipment and networking aspects of the Nashua Area Radio Society’s planned 5O setup for Winter Field Day 2020. All of our stations will use the N1MM+ Logger to support SSB Voice, CW, and Digital modes.

Fred, AB1OC

EME Station 2.0 Part 5 – Control Cables and Rotator Controller

Control Cable Junction Box on EME Tower

Control Cable Junction Box on EME Tower

Snow is coming to New England this weekend so we wanted to get the control cables run to our new EME Tower before the ground is covered with snow. The project involved installing a Utility Enclosure on our tower and running three control cables to our shack for the following devices:

Az-El Rotor and Preamp Switching Control Connections

Az-El Rotator and Preamp Switching Control Connections

We began by install some barrier strips and a copper ground strap in the Utility Enclosure. The copper strap provides a good ground connection to the tower and associated grounding system. The enclosure is clamped to the tower using two stainless steel clamps.

We ran three new control cables through the conduits that we installed between the tower and our shack and terminated them in the utility enclosure. We only needed 6 leads for control of the planned MAP65 Switching and Preamp System which will go on our tower later so we doubled up some of the higher current connections using two wires in the 8-conductor cable.

Green Heron RT-21 Az-El Rotator Controller

Green Heron RT-21 Az-El Rotator Controller

The final step was to hook up our rotator cables to a Green Heron RT-21 Az/El Rotator Controller in our shack.  We do not yet have our elevation rotator so we tested the M2 Orion 2800 Azimuth Rotator that is installed in our tower. The azimuth rotator is configured so that the rotator’s dead spot faces north. This is a good configuration of our planned EME operation.

With all of our control cabling in place, we are ready to begin preparing our Antennas, Elevation Rotator, H-Frame, and MAP65 components to go on our EME Tower. We’re hoping that the weather will cooperate and enable us to get these steps completed during this winter.

Here are some links to other articles in our series about our EME Station 2.0 project:

If you’d like to learn more about How To Get Started in EME, check out the Nashua Area Radio Society Teach Night on this topic. You can find the EME Tech Night here.

Fred, AB1OC

Winter Field Day VHF+ Preparations

Jamey AC1DC with Completed WFD VHF+ Mast

Jamey AC1DC with Completed WFD VHF+ Mast

We are continuing to make progress on our preparation for VHF+ Operations at Winter Field Day (WFD) 2020. We had a lot of fun on the VHF+ bands at WFD 2019 and we are planning to add some more bands for our operation this year. We’ve assembled a portable mast system to put us on 3 new bands…

Source: Winter Field Day VHF+ Preparations – Nashua Area Radio Society

We’ve been busy with preparation for Winter Field Day 2020. My part of this project is to increase our participation in operations on the VHF+ bands (6m and above). We are accomplishing this with a 30 ft push-up mast, some new antennas, and using Transverters for the 1.25m and 33cm bands. You can read more about our preparations and the equipment that we will be using on the VHF+ bands via the link above.

Fred, AB1OC