Why Ham Radio?

February 20, 2017 by AB1QB

Fred’s Truck with Antenna

Every so often, I drive Fred’s truck to work and people ask me what that big antenna on the back of the truck is for. I explain to them that it is for Ham Radio. But the reply is usually, why ham radio – isn’t that outdated technology? We have cell phones and IM, etc…what do we need Ham Radio for? So I thought I would put down my thoughts as a relatively new Ham about why I enjoy spending so much of my time with Ham Radio.

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Amateur Radio for Public Service

Public Service

The number one reason we still need Ham Radio along with all the other technology we now have is for public service. When there is a disaster and cell phones, television, etc are all not working, Ham Radio operators provide the critical communication.

Ham Radio operators help locally to keep hospitals and first responders in contact with each other to help those affected by the disaster.

Hams also use our ability to communicate around the world on HF bands to help family members around the world to get in touch with loved ones affected by a disaster.

Ham Radio operators have been on the scene helping in every disaster from the earthquakes in Nepal to the recent flooding in California.

Amateur Radio Cube Satellites

Technology and the Maker Movement

I only became a Ham 5 years ago but many of my fellow Ham Radio operators got their license when they were in their early teens and used what they learned to launch their careers. Many have had very successful careers in STEM fields, all launched by their interest in Ham Radio at a young age. As technology advances, so does the technology used in our hobby. We even have a nobel laureate, Joe Taylor K1JT who is a ham. Joe has developed weak signal digital communication modes that let us communicate by bouncing signals off the moon!

As technology has advanced, so has the use of it in Ham Radio. Most Ham Radio operators have one or more computers in their shack. Many also have a software designed radio (SDR), where much of the radio functionality is implemented using Software, we use sound cards to run digital modes, which are a lot like texting over the radio, and we use the internet extensively as part of operating. We can also make contacts through satellites orbiting the earth and even the International Space Station.

Most hams love do-it-yourself technical projects, including building a station, home brewing an antenna, building a radio or other station component. In my day job, I am a program manager for software development projects, but its been a while since I have built anything. As a Ham I taught myself how to code in Python and about the Raspberry Pi and I built the DX Alarm Clock.

QSL Card from VK6LC in Western Australia

International Camaraderie

One of the coolest things about being an amateur radio operator is that you can communicate with other hams all over the world. Ham Radio is an international community where we all have something in common to talk about – our stations and why we enjoy ham radio. The QSL card above is from a memorable QSO with Mal, VK6LC, from Western Australia, who was the last contact that I needed for a Worked All Zones award. I must have talked to him for 1/2 hour about his town in Australia and his pet kangaroos!

Amateur Radio Map of the World

Geography Lesson

I have learned much about geography from being on the air and trying to contact as many countries as I can. There are 339 DX Entities, which are countries or other geographical entities and I have learned where each one is in order to understand where propagation will allow me make a contact. I have learned a great deal about world geography. Through exchanging QSL cards often get to see photos from so many areas of the world.

DXCC Challenge Award Plaque

Achievement – DXing and Contesting

DXing and Contesting provide a sense of achievement and exciting opportunity for competition. Many Hams work toward operating awards. You can get an operating award for contacting all 50 states, contacting 100 or more countries, contacting Islands, cities in Japan, countries in Asia, or anything else you can imagine. Each of these operating awards provides a sense of accomplishment and helps to build skills. Contesting builds skills through competition among Hams to see who can make the most contacts with the most places in 24 or 48 hours. Contesting also improves our operating skills and teaches us to copy callsigns and additional data accurately.

Teaching a License Class

Teaching Licensing Classes – Passing it On

Recently I have joined a team of club members who teach license classes to others who want to get licensed or upgrade their existing Amateur Radio licenses. Teaching provides a way to improve my presentation skills and also helps me to really understand the material that we teach about Amateur Radio. It is always a thrill at the end of the class to see so many people earn their licenses or upgrades.

There are so many interesting aspects of Ham Radio which is what makes is such a great hobby. Getting your license can open up a world of possibilities. Upgrading to a new license class provides more opportunities to communicate over longer distances. Ham Radio clubs, including our local club, the Nashua Area Radio Club, provide many resources to help you get your first license, upgrade to a new license class and learn about the many aspects of our hobby.

Anita, AB1QB

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

February 20, 2017 by AB1OC

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

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:

A Kenwood TH-72A Full Duplex 2m/70cm HT
A Heil headset with a boom microphone to make using the HT easier
A pair of 2m and 70cm Low-Noise RF switched preamps from Advanced Receiver Research
A Mirage BD-35 2m/70cm amplifier (this amp produces about 25 – 35W out when driven by the HT)
A Diamond SX-400 Watt Meter and an MFJ Dummy Load for testing and monitoring
A RigRunner DC distribution block with voltage and current monitoring and a 4S4P A123 LIPO Battery Pack
An Elk 2M/440L5 Dual-Band Log-periodic Antenna

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 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

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

Giving Back To Amateur Radio

December 7, 2016 by AB1OC

Nashua Area Radio Club - 2016 Year In Review

Giving Back to Amateur Radio through the Nashua Area Radio Club

Anita, AB1QB, and I have spent a good deal of time this past year with the Nashua Area Radio Club here in Nashua, NH USA giving back to the Amateur Radio Service. Our work with the Nashua ARC has produced some of the most enjoyable and memorable times of our Amateur Radio experience.

Teaching Nashua Area Radio Club Hosted License Classes

In particular, our contributions to the work that our club is doing around helping people to earn licenses and introducing young people to the Amateur Radio Service have been most rewarding.

Abby, KC1FFX Operating a GOTA Station During Nashua ARC Youth Day - Givigin Back to Amateur Radio

Abby, KC1FFX Operating our GOTA Station during Nashua ARC Youth Day

We recently produced a 2016 Highlights video about our Club’s activities and the club’s contributions to the Amateur Radio hobby. We thought that some of our readers here might enjoy the video. You can view it on our club’s home page here. We hope that you consider giving back to Amateur Radio by volunteering your time.

73,

Fred, AB1OC

2016 ARRL Field Day!

July 8, 2016 by AB1OC

2016 Field Day Site Layout

I had the privilege of acting as the Field Day Incident Commander for the Nashua Area Radio Club this year. Field Day is the most important operating event for the Nashua Area Radio Club each year. We operated under our club callsign, N1FD and we were 7A here in New Hampshire, USA. We included some new antennas including a Three Element 40m V-Beam, a Satellite Station, and a 70cm Digital ATV Station in our operation this year. You can see some of the details which went into the planning of our 2016 Operation on our Club’s Tech Night Page.

The video above shows highlights from our 2016 Operation. As you can see, we had a lot of fun this year. Our club has 120+ members and we had a large turnout for Field Day. You can see more about our 2016 Field Day operation on our Field Day Page including photos, a score summary, and a recap presentation shared at a recent club meeting. I hope that you enjoy sharing our memories.

73,

– Fred, AB1OC

Dayton Hamvention 2016

June 1, 2016 by AB1QB

Anita Preseting in Contest Forum Fred, AB1OC, and I just returned from the 2016 Hamvention in Dayton, OH.

Our first day in Dayton was spent at Contest University – this was our 5th year in attendance but each year we learn more from the contesting experts. This year, we attended two presentations from Frank Donovan, W3LPL on operating techniques for the declining solar cycle and on 80m and 160m antennas. We also heard a talk from Val NV9L from Ham Nation on Log Analysis tools and another session on SO2R (Single Operator 2 Radio) Operating.

Slide from W3LPL Contest University Presentation

Friday was the first day of the Hamvention, and we spent most of the day visiting all of the vendor exhibits. We visited the Icom booth and looked at the new Icom 7851. It has an incredible display as well as one of the best receivers on the market.

Icom IC-7851 Display on a Large Screen TV

We also saw the new KX2 Transceiver at the Elecraft booth. It is even smaller than the KX3 and is perfect for SOTA and other portable operations. I would expect to hear some NPOTA activations using this radio.

Elecraft Kx2 on the Right, next to a KX3

Friday evening was the Top Band dinner, where we learned all about “Top Band Disease” from Larry “Tree” Tyree N6TR. Hams with this disease are nocturnal, and love the bottom of the sunspot cycle. They are constantly improving their 160m antennas – when you upgrade your receive antenna, there are people who can’t hear you, so you need to improve your transmit antenna – and the cycle continues…

2014 Amateur Radio Highlights

January 29, 2015 by AB1OC

Amateur Radio Highlights – our 2014 Readers Around The World

It is again time for our annual 2014 Year Amateur Radio highlights post. First, I’d like to thank our readers for their continued interest in our Blog. Our blog was viewed about 100,00 times in 2014 from 165 countries worldwide. You, our readers, have made 2014 our busiest year yet, and this provides Anita (AB1QB) and me with great encouragement to continue to provide content for our readers.

2014 was a very busy year in Amateur Radio for us. Our activities included a continued focus on station building, contesting, WRTC 2014, special events, providing presentations to help others in the hobby learn about new things, attending several HAM Events, progress on operating awards, and most importantly – time spent on the air operating.

microHAM Station Master Deluxe Antenna Controller

This year, we upgraded our fixed station to include a microHAM Station Automation system. This major project added some nice SO2R capabilities to our Multi-one station and automated the sharing of our antennas between our two SO2R operating positions. More of this project can be found here:

Eggbeater Antennas And Preamps SystemsOn Tower

Eggbeater LEO Satellite Antennas And Preamps Systems On Tower

We also added LEO Satellite capabilities to our station with the addition of some new antennas and electronics on our tower. This allowed us to make our first contacts through LEO birds with linear transponders. Our articles on this project include:

Our Mobile HF Station – Screwdriver Antenna

Our final major station-building project was constructing a state-of-the-art mobile HF station in our Ford F-150 pickup truck. We did this project in phases, starting with a simple setup using a 100W radio and HAM Stick antennas through the installation of a Screwdriver Antenna System for the 160m – 10m HF bands and concluding with the installation of an amplifier to enable high-power mobile HF operation. You can view the articles on this project here:

AB1OC Operating In the 2014 CQ WPX SSB

Anita (AB1QB) and I continued to be active in several contests this year. We both continued to develop our skills as contesters and our scores and place in the rankings reflected this. You can read more about our contesting activities and what we learned in the following articles:

WRTC 2014 Hollis Site Competitors, Support Team And Referee

We were also fortunate to host one of the WRTC 2014 competition sites. Along with our friend Scott Anderson, NE1RD, Anita and I acted as site managers for the only WRTC 2014 Competition Site in New Hampshire. You can read more about our WRTC 2014 experiences here.

13 Colonies Special Event QSL Card For K2K New Hampshire

Special event operations were a particularly fun part of our on-air activities in 2014. We operated as K2K, New Hampshire, in the 13 Colonies Special Event, W1AW/1, as part of the ARRL Centennial QSO Party, and as N1FD Celebrating the 35th Anniversary of the Nashua Area Radio Club. It’s great fun to operate in these events and the experience running the pileups that result continued to help Anita and me to develop our operating and contesting skills.

Introduction To The DXLab Suite

We prioritize devoting a significant amount of our Amateur Radio time to helping others in the hobby learn new things. In addition to writing this Blog, Anita and I try to create and deliver several presentations each year on a variety of topics of interest to the Amateur Radio Community. This year’s presentation included an update of our presentation on Amateur Radio Station Design and Construction and an Introductory Presentation on the DXLab Software Suite. We are always interested in working with Amateur Radio Clubs to deliver the presentation in person, where practical, or over the web.

Anita (AB1QB) and I with Bob Heil (K9EID)

We had the fortune to meet some of the legends in Amateur Radio this past year. Anita and I had the opportunity to get meet Bob Heil, K9EID and to appear on his Ham Nation podcast. Bob is an amazing gentlemen and we feel truly fortunate to have the opportunity to get to know him. We also had the opportunity to meet Fred Lloyd, AA7BQ, the President and Founder of QRZ.com. Fred visited our station and did an article about our station on QRZ.com. Anita and I both learned a great deal about HAM Radio and how it came to be what it is today as a result of the time these fine folks spent with us.

Joe Taylor’s WSJT Presentation At the ARRL Centennial Convention

Amateur Radio Conventions and HAM Fests were a major part of our Amateur Radio fun again this year. We were fortunate to attend and speak at the ARRL Centennial Convention in Hartford, CT USA this year – truly a once in a lifetime Amateur Radio experience. We also attended the Dayton Hamvention in 2014 where we had a chance to see all of the latest and greatest in Amateur Radio Equipment.

Our 2014 QSOs By Callsign

We were quite active on the air making almost 26,000 contacts between the two of us. As you can see from the graphic above, about 45% of our contacts were as part of Special Event Operations. We also made a little over 500 contacts from our mobile station, working over 100 DXCC entities in 2014 from the mobile.

Our 2014 QSOs By Band

We were active on all of the HF bands this year. We made our first contacts on the 60m band, and I was able to focus on the 6m band and earn a VUCC Operating Award (100 grid squares worked and confirmed) on that band. Anita and I made our first DX contacts in Europe on 6m in 2014. Anita took quite an interest in the 160m band, and she is working on a Worked All States Operating Award on this band. Our operating time using weak signal and satellite modes on the 2m and 70cm bands was limited to a few contacts this year. I did make my first contacts through LEO Satellites in 2014.

Our 2014 QSOs By Mode

We mostly operated in the SSB phone mode in 2014. Anita and I both continue to work on our CW skills, and we managed a little over 800 QSOs using CW in 2014. Anita was very active in the RTTY mode as part of her RTTY contesting efforts.

13 Colonies K2K New Hampshire QSL!

All of this operating resulted in quite a bit of QSL activity. We sent a total of almost 4,200 QSL cards in 2014!

We again made a video showing all of our contacts around the world in 2014. As you can see from the video, we were fortunate to work quite a bit of DX in 2014.

Fred’s 6M VUCC Operating Award

All of this operating helped Anita and me to make some progress on operating awards this year. In addition to earning a 6M VUCC, I completed a Worked All States Award on all 9 HF bands 160m-10m. I was also able to complete several nice regional operating awards (Worked All Europe TOP Plaque, Worked All VK Call Areas, and Worked All Africa) as well as upgrading my DXCC Challenge Award to the 1,500 Band Country level. Anita completed her JARL JCC Award (she worked 100+ Cities in Japan) as well as her Worked All States Triple Play Award (all states on SSB, CW, and Digital via LoTW).

Anita and I had a lot of fun with Amateur Radio in 2014. We look forward to another great year of HAM Radio fun in 2015. We hope to share some of what we learn and our experiences with our readers here on our Blog.

– Fred, AB1OC

LEO Satellite System Part 3 – Final Installation And First Contacts

September 19, 2014 by AB1OC

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 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 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

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

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)

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

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

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.

ARRL Centennial Convention This Week – Come Join Us In Hartford!

July 16, 2014 by AB1OC

ARRL Centennial

Anita (AB1QB) and I will be attending the ARRL Centennial Convention in Hartford Connecticut, USA this coming weekend. We are looking forward to seeing the vendor exhibits, Contest University and the many fine forum presentations which are scheduled.

Station Design Presentation

I will be doing a presentation on the design, construction and operation of our station at the ARRL Centennial event. My presentation is scheduled for Saturday, July 19th at 11 am in Room 27 at the Connecticut Convention Center. I will be presenting the complete story of our station from planning and design, through construction and finally how the station operates and performs. The presentation will include lots of high-resolution pictures and video including material on our shack, tower and antennas.

Updated Station Tour

The presentation will include lots of new material covering all of our recent projects as well as an updated virtual station tour.

Latest Antenna Projects

Some new topics will include our latest antenna projects and some information on our recently completed LEO Satellite System.

Station Automation Overview

The presentation will also include information on our recently installed Station Automation System from microHAM.

Current Station Performance

We plan to talk about how our station is performing against our original design goals and we’ll have some updated video too!

For those who are attending the ARRL Centennial Convention in Hartford Connecticut, I hope you stop by and say hello to Anita and me. We’re anxious to meet as many of our readers as we can at the event. For those who cannot make the trip, we will be taking lots of pictures and we plan to post a summary of what we saw here after the event.

– Fred (AB1OC)

LEO Satellite System Part 2 – Antenna Assembly And Ground Test

June 24, 2014 by AB1OC

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

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

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.

LEO Satellite System Part 1 – System Design And Electronics

May 16, 2014 by AB1OC

FUNcube-1 Cube LEO Satellite

We have realized all of the original design goals for our station except one – operation with Low Earth Orbit (LEO) HAM Satellites. Our next series of posts will be about realizing this operating goal. The team at AMSAT has been working diligently to get a new generation of small satellites called Cube Sats into space to provide additional “birds” for HAM satellite operators to use, so now seems to be a good time to add satellite capability to our station.

Icom IC-9100 Transceiver (courtesy Icom America)

Most recent LEO satellites use a combination of 2m and 70cm signals for their uplink and downlink frequencies, so we’ve decided to build an antenna system for satellite operation on these bands. Satellites that use these frequencies would be either U/V Mode (70 cm uplink, 2m downlink) or V/U Mode (2m Uplink, 20 cm Downlink) birds. We installed an Icom IC-9100 Transceiver some time ago for both VHF/UHF weak signal work as well as for future satellite operations. The IC-9100 provides 100w of Transmit power on 2m and 75W on 70cm. This is more than adequate for LEO Satellite operation. The IC-9100 also has some nice VFO tracking features to make operation with satellites that use linear transponders easier (more on this in a future post).

M2 Antenna Systems’ Eggbeater Satellite Antenna System (courtesy DX Engineering)

I have been working with the folks at M2 Antenna Systems to come up with a simple antenna system to allow us to work with LEO satellites. LEO Satellites do not require much radiated power to work but require a reasonably sensitive receive system. The design I have settled on will use M2’s Eggbeater Satellite Antenna System. This setup combines a set of omnidirectional 2m and 70cm antennas on a cross-boom to support U/V and V/U mode satellites.

M2 EB-144 Antenna Pattern (courtesy M2 Antenna Systems)

The “eggbeater” antenna uses a reflector (radial elements below the “eggbeater” elements shown above) to direct the antenna’s pattern upward. The resulting pattern is circularly polarized and omnidirectional. This is ideal for LEO satellite operation and does not require a complex rotator system to “point” the antenna.

M2 Antenna System 2M Low-Noise Preamplifier

While it does not take a great deal of radiated power to work LEO Sats, a fairly sensitive receive system is required due to the low transmit power used for the downlink on these birds. We are planning to mount the antennas for our satellite system at around the 90 ft level on our tower. This distance, plus the run from the tower to our shack, will result in a total feedline length of about 190 ft. To ensure that the feedline losses do not compromise the performance of our satellite system, we have decided to install tower-mounted Low Noise Preamplifiers (LNAs) on our tower near the antennas. We are using a 2m LNA Preamplifier from M2 Systems and 70cm LNA Preamplifier for Advance Receiver Research.

Preamp System Component

Mounting electronics on the tower is always a reliability concern. There are two issues to be addressed here. The first is proper sequencing control to ensure that the RF power going to the antennas during transmit does not destroy the preamplifiers and the second is to provide adequate protection from the weather. We chose to use M2 Antenna Systems S3 Sequencers to safely switch the LNAs to bypass during transmit (more on this below). We also decided to mount the LNAs and associated control interconnect points inside a NEMA enclosure. The picture above shows all the parts and components that make up the LNA preamp system. The components include (from top left to lower right) the LNA preamps, a NEMA enclosure purchased at our local electrical store along with stainless steel clamps to attach it to our tower, N-type feed-through connectors to pass the feedline connections in and out of the enclosure, a terminal strip for control cable and power connections, hardware to mount the preamps in the enclosure, LMR-240 coax for RF connections inside the enclosure, the M2 Antenna Systems S2 Sequencers, and N-connectors for the LMR-240 coax jumpers.

Completed Tower Preamp System

The picture above shows the completed preamp system ready to go onto the tower. The unit is designed to allow easy access to the electronics for testing and service on the tower should this be needed.

Preamp Sequencers

The picture above shows the M2 Antenna Systems S3 Sequencers that we are using to control the preamps (the S2 sequencers at the bottom control the tower-mounted electronics for our 2m and 70cm weak signal yagi antennas installed previously). We connected the S3 sequencers to our Icon IC-9100 Transceiver and (temporarily) to our new Satellite preamp system so that we could test the package before installing the electronics on the tower. We checked the SWR of the system in transmit mode using a dummy load as well the operation of the preamps in receive mode.

Andrews LDF5-50A Hardline Coax Cable

The final design decision for the hardware side of our LEO Satellite system is the choice of coax for our feedlines. The total length of our feedlines, including the connections between the tower-mounted preamplifiers and the antennas and the connection from our shack entry point to the radio, is about 190 ft. I set a design goal of 1.5 dB of total loss for this path. To meet this goal at 450 MHz (70 cm), I have decided to use a 7/8″ Hardline Coax (LDF5-50A) plus LMR-400UF Coax for the jumpers to connect the antennas at the tower end and the IC-9100 Transceiver at the shack end. We will also be using N-type connectors throughout the feedline system.

ARRL Satellite Handbook

We have been reading a lot to learn how to design and build our Satellite System. One excellent source of information on this topic is the ARRL Satellite Handbook. I can recommend this book as a great source of information for anyone considering the construction of a satellite system and those interested in learning more about satellite operations.

Our next steps will be to order the hardline and connectors and assemble our antennas. Once the materials arrive, we will install the antenna system on our tower. This will be the topic of the next post in this series.

Our HAM Station

Notes on the construction and operation of a multi-op Amateur Radio Station

Category Archives: Space