An 80m Broadband Matching System

January 28, 2018 by fkemmerer

Our Tower with 75m Loop

We installed a 75m loop for SSB operation on our tower when we built it. The loop is full size and is diamond shaped so that our lower SteppIR DB36 yagi can rotate inside of it. The loop is fed at the bottom corner about 20 ft up from the ground. It works great for SSB operation on 75m, but we have often wished we could use it across the entire 80m Band. This goal led to a project to create a matching system for the antenna. The idea was to use a set of loading coils in series at the feed point to create a good match in all segments of the 80m band.

EZ-NEC Model for 75m Loop

The first step in designing our 80m matching system was to build a model of our current loop using EZ-NEC. The model was then used to determine the correct values of a set of series loading inductors to match different segments of the 80m band.

Matching System Design Analysis

We also considered how likely different segments of the 80m band were to be used by profiling historical spotting data from DXSummit. All of this analysis led to the creation of a final design which is captured in the spreadsheet shown above. The final design requires our current 75m loop to be shortened to work well at the very top of the 80m Band.

Modeled Loading Coil Inductance Values

A set of 5 different inductor pairs can be used in series with the loop’s feed point to create a good match across the 80m band. The modeled values for the series-matching inductors are shown above.

Matching System Modeled SWR

Our microHAM control system can easily implement the switching of the various inductance values based on the frequency that a radio using the antenna is tuned to. The resulting modeled SWR for the final 80m loop and match combination is shown above. The design should achieve an SWR < 1.5:1 across the entire 80m Band except for the very top, where the SWR remains < 2:1. Also, the design optimizes the system’s SWR in the important CW DX, SSB DX, and Digital windows on the 80m band.

The layout of Components in Enclosure

With the design completed, we chose an enclosure and all components. Here are the details of what we used:

Barker and Williamson 2404TL 32 uH Airdux coil stock cut in half (3″ dia, 4 TPI)
Array Solutions RF-15 15/20 kW RF Relays
Balun Designs 1.5:1 Balun with eyelets
V22ZA2P Varistors (MOVs), 0.1 uF Capacitors, 1N4001 Diodes make up the 12Vdc relay control circuits
Outdoor NEMA Box Approx. 16″x12″x6.5″
DX Engineering Saddle Clamps to fit our tower

The first step in the construction was to lay out all of the components in the enclosure. Attention was paid to keeping the two series inductors at right angles to avoid coupling and to keep RF connections as short as possible. The relays were arranged to keep the leads connecting to the coils of roughly equal length. Finally, the control circuitry was kept as far removed from the RF leads as possible.

Enclosure Mounting Ears and Clamps

The matching system attaches to a tower leg via saddle clamps. We fabricated a set of mounting ears and spacer blocks to position the enclosure far enough away from the tower so that the antenna connections do not interact with the tower.

80m Matching System Construction

A summary of the completed matching system construction is shown above. The design uses a set of four double-pole double-throw relays to switch in different coil taps, which selects the loading inductance provided by the matching system.

We did a set of calculations and found that our relays would be subjected to a worst-case peak-peak voltage of about 2.1 KVp-p at the coil tap points.

The relays are arranged such that two sets of contacts have to be traversed to select any given coil tap. The relays we are using have a third pole which we are not using. We disassembled each relay and removed the internal contact wiring for the center pole, which improves both the coil-to-contact voltage rating and the isolation values of the relays.

These steps combine to improve the voltage rating of the system. This is an important design element given that the match will operate at legal limit power.

Completed RF Deck

The completed RF deck and control circuitry is shown above. The enclosure we chose came with a removable plastic plate that made mounting and wiring all of the components simple.

Loading Coil Mounting and Taps

The loading inductors are mounted using nylon hardware with the ends connected to the two antenna terminals on the sides of the enclosure. The coils use movable tap clips to allow us to fine-tune the match once the system is installed with the antenna on our tower. The initial clip locations are set to create the inductance values modeled during the design phase.

Relay Control Circuit Connections

The relay control leads use twisted pair wiring to minimize RF pickup. The control leads are routed away from the RF connections to minimize potential RF coupling.

Relay Control Circuit Details

The control circuits for each relay use a combination of a Diode, a Varistor (MOV), and a filter capacitor in parallel to avoid relay coil switching interference and to suppress control line noise.

1.5 to 1 Matching Balun

The matching system is designed to operate at 75 ohms which is close to the resonant impedance of our 75m loop. The current antenna uses a 1.5:1 Balun to match the loop to our 50-ohm coax feedline. We disassembled an identical matching balun (actually a 75-ohm balun plus a 1.5:1 unun) and used it without its enclosure to create a final 50-ohm match.

MicroHAM Setup to Control 80m Matching System

The final step in constructing our matching system was to program our microHAM antenna switching system to properly configure the relays in our matching system. This was quite simple to do using microHAM’s frequency-dependent antenna control capabilities. The microHAM system automatically operates the appropriate relays to create the best possible match as the radio which is using the matching system is tuned across the 80m band.

Unfortunately, we are in the middle of winter here in New England, so I will have to wait for warmer weather to install our new matching system on the tower and make the final adjustments. I am planning another article here when the final integration steps are done to cover the performance of the completed project.

Fred, AB1OC

Giving Back To Amateur Radio

December 7, 2016 by fkemmerer

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

Fall Antenna Projects – A New Low-Band Receive Antenna System

November 27, 2016 by fkemmerer

NCC-1 Receive Antenna System Control Unit and Filters

Anita and I like to take advantage of the mild fall weather to do antenna projects at our QTH. We have completed two such projects this fall – the installation of a Two-Element Phased Receive System and a rebuild of the control cable interconnect system at the base of our tower.

NCC-1 Receive Antenna System Components

Our first project was the installation of a DXEngineering NCC-1 Receive Antenna System. This system uses two receive-only active vertical antennas to create a steerable receive antenna system. The combination can work on any band from 160m up to 10m. We set ours up for operation on the 80m and 160m bands.

NCC-1 Receive System Antenna Pattern

The NCC-1 System can be used to peak or null a specific incoming signal. It can also be applied to a noise source to null it out. The direction that it peaks or nulls in is determined by changing the phase relationship between the two Active Antenna Elements via the NCC-1 Controller.

NCC-1 Filter Installation

The first step in the project was to open the NCC-1 Control Unit to install a set of 80m and 160m bandpass filter boards. These filters prevent strong out-of-band signals (such as local AM radio stations) from overloading the NCC-1. The internal switches were also set to configure the NCC-1 to provide power from an external source to the receive antenna elements through the connecting coax cables.

Installed Active Receive Antenna Element

The next step in the project was to select a suitable location for installing the Receive Antenna Elements. We choose a spot on a ridge that allowed the two Antenna Elements to be separated by 135 ft (for operation on 160m/80m) and which provided a favorable orientation toward both Europe and Japan. The antenna elements use active circuitry to provide uniform phase performance between each element’s 8 1/2-foot whip antenna and the rest of the system. The antenna elements should be separated by a 1/2 wavelength or more on the lowest band of operation from any towers or transmit antennas to enable the best possible noise rejection performance.

Received Antenna Element Closeup

The two Antenna Elements were assembled and installed on 5 ft rods which were driven into the ground. To ensure a good ground for the elements and to improve their sensitivity, we opted to install 4 radials on each antenna (the black wires coming from the bottom of the unit in the picture above). The Antenna Elements are powered through 75-ohm flooded coax cables which connect them to the NCC-1 Control Unit in our shack. The coax cable connections in our setup are quite long – the longer coax of the pair being approximately 500 ft. The use of flooded coax cable allows the cables to be run underground or buried. Should the outer jacket become nicked, the flooding glue inside the cable will seal the damage and keep water out of the cable.

Receive RF Choke

It is also important to isolate the connecting coax cables from picking up strong signals from nearby AM Radio stations, etc. To help with this, we installed Receive RF Chokes in each of the two coax cables which connect the Antenna Elements to the NCC-1. These chokes need to be installed on ground rods near the Antenna Elements for the best performance.

Underground Cable Conduit In Our Yard

We ran the coax cables underground inside cable conduits for a good portion of the run between the antenna elements and our shack. The conduits were installed in our yard when we built our tower a few years back so getting the coax cables to our shack was relatively easy.

Receive Antenna Coax Ground System

The last step in the outdoor part of this project was to install a pair of 75-ohm coax surge protectors near the entry to our shack. An additional ground rod was driven for this purpose and was bonded to the rest of our station’s ground system. We routed both of the 75-ohm coax cables from the two Antenna Elements through surge protectors and into our shack. Alpha-Delta makes the copper ground rod bracket shown in the picture for mounting the surge protectors on the ground rod.

Antenna Equipment Shelf In Our Shack (The NCC-1 Control Unit Is At The Bottom)

The installation work in our shack began with the construction of a larger shelf to hold all of our antenna control equipment and to make space for the NCC-1. The two incoming coax cables from the Antenna Elements were connected to the NCC-1.

microHAM Station Master Deluxe Antenna Controller

Antenna switching and control in our station is handled by a microHAM System. Each radio has a dedicated microHAM Station Master Deluxe Antenna Controller which can be used to select separate transmit and receive antenna for the associated radio. The microHAM system allows our new Receive Antenna System to be shared between the 5 radios in our station.

Antenna Switching Matrix

The first step in integrating the Receive Antenna System was to connect the output of the NCC-1 to the Antenna Switching Matrix outside our shack. We added a low-noise pre-amp (shown in the upper left of the picture above) to increase the sensitivity of the Antenna System. The blue device in the picture is a 75-ohm to 50-ohm matching transformer which matches the NCC-1’s 75-ohm output to our 50-ohm radios. The other two pre-amps and transformers in the picture are part of our previously installed 8-Circle Receive Antenna System.

Multi-Radio Sequencer

The Antenna Elements must be protected from overload and damage from strong nearly RF fields from our transmit antennas. In a single radio station, this can be handled via a simple sequencer unit associated with one’s radio. In a multi-op station such as ours, it is possible for a different radio than the one which is using the Receive Antenna System to be transmitting on a band that would damage the Receive Antenna System. To solve this problem, we built a multi-radio sequencer using one of the microHAM control boxes in our station. The 062 Relay Unit shown above has one relay associated with each of the five radios in our station. The power to the Receive Antenna System is routed through all 5 of these relays. When any radio transmits on a band that could damage the Antenna Elements, the associated relay is automatically opened 25 mS before the radio is allowed to key up which ensures that the system’s Antenna Elements are safely powered down and grounded.

Updated microHam Antenna System Diagram

With all of the coax and control connections complete, I was able to update the microHam system design information for our station and add the new receive antenna system to our setup. You can find more about the programming of our microHam system here.

NCC-1 Controls

So how well does the system work? To test it, we adjusted the NCC-1 to peak and then null a weak CW signal on 80m. This is done by first adjusting the Balance and Attenuator controls on the NCC-1 so that the incoming signal is heard at the same level by both Antenna Elements. Next, the B Phase switch is set to Rev to cause the system to operate in a signal-nulling configuration, and the Phase control is adjusted to maximize the nulling effect on the target signal. One can go back and forth a few times between the Balance and Phase controls to get the best possible null. Finally, the incoming signal is peaked by setting the B Phase switch to Norm.

Peaked And Null’ed CW Signal

The picture above shows the display of the target CW signal on the radio using the NCC-1 Antenna System. If you look closely at the lower display in the figure (nulled signal) you can still see the faint CW trace on the pan adapter. The difference between the peak and the null is about 3 S-units or 18 dB.

NCC-1 Used For Noise Cancellation

The NCC-1 can also be used to reduce (null out) background noise. The picture above shows the result of doing this for an incoming SSB signal on 75m. The system display at the top shows an S5 SSB signal in the presence of S4 – S5 noise (the lower display in the picture). Note how clean the noise floor for the received SSB signal becomes when the unit is set to null the noise source which comes from a different direction than the received SSB signal.

We are very pleased with the performance of our new Receive Antenna System. It should make a great tool for DX’ing on the low bands. It is a good complement to our 8-circle steerable receive system which we use for contesting on 160m and 80m.

Tower Control Cable Interconnects (Bottom Two Gray Boxes)

Our other antenna project was a maintenance one. We have quite a number of control leads going to our tower. When we built our station, we placed surge protectors at the base of our tower and routed all of our control leads through exposed connections on these units. Over time, we found that surge protection was not necessary and we also became concerned about the effects that sunlight and weather were having on the exposed connections. To clean all of this up, we installed two DXEngineering Interconnect Enclosures on our tower and moved all the control cable connections inside them.

Inside View Of Interconnect Enclosures

We began with a pair of enclosures from DXEngineering and we mounted screw terminal barrier strips on the aluminum mounting plates in each enclosure. The aluminum plates are grounded via copper strap material to our tower.

Closer Look At One Of The Interconnect Enclosures

The picture above shows one of the interconnection boxes. This one is used to connect our two SteppIR DB36 Yagi Antennas and some of the supporting equipment. The barrier strips form a convenient set of test points for troubleshooting any problems with our equipment on the tower. There are almost 100 control leads passing through the two enclosures and this arrangement keeps everything organized and protected from the weather.

With all of our antenna projects complete, we are looking forward to a fun winter of contesting and low-band DX’ing.

73,

Fred, AB1OC

Summertime Station and Antenna Projects At AB1OC/AB1QB

August 14, 2016 by fkemmerer

Summer is the time of year that many of us work on our antennas and improve our stations. Anita AB1QB and I did both at our QTH this summer.

Removing Lower SteppIR Yagi From Tower

Our SteppIR DB36 Yagis were due for some maintenance, so we took them off our tower. A special thanks to all the Nashua Area Radio Club members who helped us remove, recondition and reinstall our antennas! Matt Strelow, KC1XX of XX Towers, and Andrew Toth provided equipment and know-how to safely remove our two large SteppIR DB36 Yagis with help from the rest of us.

Lowering Antenna With Electric Winch

The SteppIR DB36 Yagis weigh almost 200 lbs each, and Matt used his electric winch to lower them.

Antenna Coming Down The Tram Line

The picture above shows the lower antenna coming off the tower. We used a Tram Line system to lower both antennas to the ground so that we could rebuild them.

SteppIR DB36 Antenna On The Ground

The SteppIR DB36 Yagis are quite large. They have 36 ft booms, and the driven elements are almost 50 ft from tip to tip! They completely fill up our backyard when they are both off the tower.

Element Pole Sun Damage

The rebuild process began with a careful inspection of both antennas. They were both in good overall condition, with some sun damage to the paint on the fiberglass element poles.

Disassembled SteppIR DB36

We removed all the element tubes and sweeps from both antennas for rebuilding. The picture above shows the disassembled upper antenna.

Reconditioned Stepper Motors Installed

All four Stepper motors on both antennas were replaced. These motors move metal tapes inside hollow element tubes to adjust the length of each antenna’s 4 movable elements. These adjustments are done automatically by controllers in our shack which receive frequency information from the radios connected to each antenna.

Reconditioned Element Sweep Poles

All element housing poles were cleaned, prepped, and painted with a UV-resistant clear coat to protect them from further sun damage. The poles were cleaned up like new.

New Element Sweeps Ready For Installation

All the new element sweep tubes (shown above) were assembled next. Each antenna has six sweeps.

Element Pole Preparation

The end of each element pole must be prepped with a tape system that ensures that the poles are seated properly, sealed to, and firmly attached to the sweeps. This process and the associated assembly and tightening of the element couplers was the most time-consuming step in the rebuild process, as it had to be repeated 24 times.

Rebuilt Element Assembly

Here’s a picture of one of the rebuilt element tube assemblies. The ropes support the element tubes and keep them aligned when the antenna is up. These elements are attached to the antenna motors with couplers and clamps.

SteppIR DB36 Yagi – Rebuild Complete

The picture above shows the lower antenna with all the element tubes reattached. There is quite a bit of additional prep work associated with adjusting all the supports and taping all the exposed areas of the antennas, which are susceptible to sun damage. Also, all the electrical wiring on the antenna must be checked to ensure good electrical connections and good overall condition of the wiring.

Ground Test Setup

The final step in rebuilding the antennas is to test their operation on the ground. This ground test is done to ensure that all the motors are working correctly and that the element tapes move smoothly inside the rebuilt element tubes.

Ground Test Results

Another important part of the antenna Ground Test is to confirm that the antennas have a consistent resonant frequency and SWR on all bands. The resonant frequencies and SWR levels are far from those measured when the antennas are on the tower at operating height. The idea is to confirm that a resonance exists and that its frequency and SWR readings are repeatable as the antenna is adjusted to different bands.

With both antennas rebuilt, it was time for Matt and Andrew to return and, with help from folks from our club, reinstall the rebuilt antennas on our tower. The video above shows this process. It is quite something to see! The installation took about 3 1/2 hours.

Updated SteppIR Controllers

The last step in the SteppIR DB36 rebuild process was to install the latest firmware in the associated SDA100 Antenna Controllers. There are some integration issues between the updated SteppIR Firmware and our microHAM system, but we are getting those worked out with help from the folks at both SteppIR and microHAM.

Icom IC-7851 With Display Monitor

I recently had a major birthday milestone, and Anita surprised me with a new radio – an Icom IC-7851. This radio is an upgrade/replacement for our Icom IC-7800. While the two radios are quite similar in their operation and interfaces, I did not want to install the IC-7851 until the SteppIR antennas were reinstalled and all of their upgrades were working properly with our current radios. With the antennas done, it was finally time to install the new radio!

Icom C-7851 Transceiver

The Icom IC-7851 has several important performance upgrades. The most impactful one is a new low-phase noise oscillator which significantly improves RMDR performance compared to the IC-7800. The IC-7851 is in the top tier of Transceivers in Sherwood Engineering’s tests. The receivers in the IC-7851 are very quiet, have excellent Dynamic Range, and perform great when close-in interference is present.

Icom IC-7851 Display Monitor

The Icom IC-7851 has a higher resolution and faster display. It also supports higher-resolution external monitors, so we installed an upgraded display monitor along with the new radio. The IC-7851 has a number of new networking features and supports stand-alone remote operation over a LAN and the Internet. We are planning to use these capabilities to add a second remote operating gateway to our station. More on this in a future article.

The rebuilt antennas and the new IC-7851 Transceiver have our station performing better than ever. The antennas are working as well or better than when they were new, and the IC-7851 has significantly better receive performance compared to its predecessor and is a pleasure to use.

We will be hosting the ARRL Rookie Roundup RTTY contest for our club members who have received their first license in the last 3 years next weekend, and we’re going to use the new radio and rebuilt antennas for the contest.

This project was completed in a little over two weeks and was a lot of work. I could not have done the project without the help of the many folks in the Nashua Area Radio Club. Again, a big Thank You to all the folks in our club who helped me with this project! I hope that many of you will be able to find some time to operate from our upgraded station.

Fred, AB1OC

2015 Nashua Area Radio Club Field Day Recap

August 21, 2015 by fkemmerer

We had the opportunity to be part of the Nashua Area Radio Club’s 2015 Field Day Operation. Ed, K2TE was our incident commander and he helped to club to put together a great Field Day Operation. We operated under our club callsign, N1FD as 8A. John, W1MBG put together the video above which is a really nice recap of our operation.

Field Day Tower and Beams

The club was very active in WRTC 2014 and, as a result, was able to purchase several of the tower and station kits from the WRTC operation. The heart of our Field Day antenna system was built around two of these towers. One was used for CW and 6m and the other was used for SSB. Both towers had tri-band beams and we used Triplexers and Filters to allow our stations on 20m, 15m and 10m to share the beams on each tower. The towers got us a long way towards our status as an 8A operation.

Wire Antenna Construction

My role in the setup part of our Field Day operation was to build our wire antennas. We began with a class covering how to build and tune Delta Loop antennas and we used the newly gained information from our class to build 40m and 80m delta loops at our Field Day site. We also put up a 75m inverted-V antenna in one of the tall trees at our site.

Operating Tents

We made good use of our WRTC station kits and other gear that our members brought to setup comfortable tents to operate from as well as a public information tent and a food tent.

Some Of Our Operators For The Nashua Area Radio Club

Despite the rainy weather on Saturday evening and Sunday, we all stayed comfortable and dry. Shown above is Dave, N1RF, Mike, K1WVO and Mike, K1HIF in our 40m SSB tent.

Field Day 20m SSB Station

John, W1MBG and I shared a tent which we used for both 10m and 20m SSB operations. The picture above shows our 20m station which was built around an Elecraft KX3 with a PX3 Panadapter and 100w outboard amplifier.

Mikayla Operating With Her Dad During Field Day

Our club has been doing a great deal of work on bringing young people and other new HAMs into the hobby via license classes, outreach to schools and other activities. We carried this work into our Field Day operations with a GOTA station and lots of opportunities for new HAMs and young people to get on the air. Shown above is Wayne, AA9DY helping his daughter Mikayla to make some contacts on 20m SSB phone.

Field Day Feast

Anita, AB1QB made great meals and snacks during our Field Day operation. The food provided us a great opportunity to take a break from operating and enjoy each other’s company. Anita and John, W1SMN organized our public information and outreach activities which were very successful. we had over 30 visitors from the general public during our operation this year.

We all had a great time during Field Day this year, and we’re looking forward to doing it again next year.

– Fred, AB1OC

LEO Satellite System Part 3 – Final Installation And First Contacts

September 19, 2014 by fkemmerer

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 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.

World Radiosport Team Championship 2014 Experiences

August 27, 2014 by fkemmerer

Hollis Site Competitors, Referee And Support Team

Anita (AB1QB), Scott (NE1RD) and I had the opportunity to serve as site managers for the WRTC 2014 competition site in Hollis, NH. Our site was one of 65 sites in New England USA (and the only on in the state of New Hampshire). This gave us a chance to be part of the WRTC 2014 event and to meet some of the competitors, referees and the event organizers. WRTC has been called the “Olympics of Amateur Radio” because it brings together the very best Amateur Radio Contesters in the world to see who is the “best of the best”. Here’s a summary of what WRTC is all about from the WRTC 2014 Website:

“The World Radiosport Team Championship (WRTC) is held every four years and consists of 50+ two-person teams of amateur radio operators from around the world competing in a test of operating skill. Unlike most on-the-air competitions, all stations are required to use identical antennas from the same geographic region, eliminating all variables except operating ability.”

Each competitor must qualify based upon results in selected contests over a period of 3 years. There were a total of 63 teams which participated in the event. It is a tremendous achievement just to qualify for WRTC. Each qualifying competitor selects a second person to make up their team. The competitors at our site were Julio Henriquez, AD4Z and Dan Thompson, W4UH. Our referee was Alex Orlov, RW4WR from Russia. We really enjoyed getting to know Julio, Dan and Alex. The stories that they shared and the information and tips they gave us a relatively inexperienced contesters will stick with us forever.

WRTC 2014 Competition Sites

The WRTC 2014 competition was held on July 12-13, 2014 as part of the IARU HF World Championship contest. A great deal of effort was put into selecting and building 65 competition sites for WRTC to ensure that they were as equal in terms of propagation, antennas and configuration as possible. WRTC provided all of the antennas/feedlines, generator power and a tent for each site and each team of competitors supplied their own radios and supporting station equipment.

WRTC Station Kit In Transit

Preparations for WRTC 2014 have been in progress for several years now including planning sessions, station and site tests, team formation and training. All in all, the event is a tremendous planning and logistical effort. Doug Grant, K1DG was the leader and chief evangelist for WRTC 2014. Doug and his team did a tremendous job in making WRTC 2014 happen.

Our part of the WRTC experience began with the pickup of the station kit for the Hollis, NH site on the Wednesday before the event. The station kit consists of a 40 ft Rohn 25G tower, beam/wire antennas, feedlines, generator, tent and miscellaneous equipment.

TX38 Tri-Band Beam Assembly

Ed, K2TE and our “beam team” were at the Hollis, NH site bright and early on Thursday morning to put up the tower and antennas. The heart of the WRTC 2014 antenna system is the TX38 Tri-Band Beam which was designed for WRTC 2014.

TX38 Yagi Installation On Tower

Here’s a picture of the assembled beam and tower ready to be pulled up and into place at our site.

Tower Going Up!

The picture above shows the tower going up. The Falling Derrick System that was developed for WRTC is quite ingenious and it raises the 40 ft tower and beam antenna with very little effort. Each beam team was specially trained in the use of this system to ensure safe setup and takedown of the tower and antennas at each site.

WRTC 2014 Site In Hollis, NH USA

While Ed and the team took care of the tower and antennas, Scott, Anita and I setup the tent, generator, feedlines and “crew tent” at our site. The picture above shows the completed site ready for our competitors.

WRTC Station Radios And Equipment

Julio, Dan and Alex arrived at our site after the site drawing at WRTC headquarters on Friday and proceeded to setup and test their station. As you can see, they brought quite a sophisticated setup! They used Ten-Tec Orion II radios, a microHAM band decoder and antenna switching system and PCs running the N1MM Logger to create a modern, state of the art multi-two contesting station at our site. WRTC competitors used a variety of different radios to compete in the event. You can find a summary of the radios and software used by the competitors here. The Elecraft K3 was the most popular transceiver and a combination of the Wintest and N1MM loggers were used most of the competitors.

WRTC Monitoring System

The WRTC 2014 organizers did some custom design work to facilitate the event. Shown above is the WRTC monitoring system. This system is used by the referee to monitor the power levels of each operator’s radio to ensure that the 100W WRTC power limit is not exceeded. The referees can also monitor the audio from each operator simultaneously and a recording of these audio streams for the entire contest period is also made. All of this is done in the interest of ensuring a fair contest and for judging purposes as needed when the event is complete. A device also monitors the logging streams from the competitors computers to create a live, real-time scoreboard on the web. The scoreboard uses an innovative data collection method developed by Dave Pascoe, KM3T and Bob Raymond, WA1Z to “sniff” the logging information being exchanged by the competitors computers. The data extracted in this way is fed via cellphone data connections to the WRTC headquarters to update the teams scores on the web in real-time during the contest.

The Big Moment – Our Station’s Callsign

On Saturday, just before the competition began, Alex our referee opened the sealed envelope which contained our site’s callsign which was W1T. As with all things about the event, the callsigns were not disclosed to the operators until just before the contest began to ensure that none of the operators specific callsigns were known to others.

Julio (AD4Z) Operating

Once the contest began, our team was all business. Julio is shown above operating CW. He is an amazing operator and can easily operate at 40+ WPM speeds!

Our site was one of the public access sites for the event and we had quite a few visitors from the press and local HAMs who were interested in seeing what WRTC 2014 was about. The event also received quite a bit of media coverage, some of which can be viewed here.

2014 WRTC Medal Winners

An award ceremony was held at WRTC HQ the following Monday to announce and recognize the winners:

Medal winners

Gold K1A 7,184,844 points

Daniel Craig, N6MJ – United States
Chris Hurlbut, KL9A – United States

Silver W1L 6,816,144 points

Rastislav Hrnko, OM3BH – Slovakia
Jozef Lang, OM3GI – Slovakia

Bronze W1P 6,421,383 points

Manfred Wolf DJ5MW – Germany
Stefan von Baltz DL1IAO – Germany

Award winners

Highest SSB (with >35% QSOs on CW)

K1M (IK1HJS/I4UFH) SSB – 2063 CW – 1233

Highest CW (with >35% QSOs on SSB)

N1S (LX2A/YO3JR) CW – 2391 SSB – 1302

Highest Multiplier

K1A (N6MJ/KL9A) 436

Best Accuracy

W1P (DJ5MW/DL1IAO) 1.0% error rate

The final results were very close with only 118,425 points separating the 3rd through 5th place teams. To give you an idea of how close this really was – only 6/10 of a multiplier or about one minute of operating time separated the 3rd and 4th place teams! Some of the operators achieved peak rates of over 300 contacts per hour. This is very impressive considering that Field Day style stations with 100W output were used by the competitors.

WRTC Tower And Antennas At Sunset

Our WRTC 2014 experience was a very memorable one. It was a great combination of amazing people, the best contesters in the world, great application of Amateur Radio technology and some of the best logistics and organization of a large event we’ve ever seen. Truly an Amateur Radio experience of a lifetime!

– Fred (AB1OC)

Our Tower From Space

February 13, 2014 by fkemmerer

Our Tower From Space (Courtesy Google Maps)

I recently had a look at our QTH on Google Maps and noticed that the latest satellite pass had picked up our tower. It is amazing to see the resolution of these satellite photos – our two SteppIR DB36 Yagi Antennas are visible in the photograph.

– Fred (AB1OC)

Amateur Radio For Young People At Sci-Tech

July 14, 2013 by fkemmerer

Sci-Tech In Frisco, Texas USA

I recently learned of the Sci-Tech Discovery Center in Frisco, Texas USA. This fine facility is dedicated to helping young people to learn about Science and Technology and to hopefully encourage them to pursue Science and Technology learning and vocations. A group of local HAMs in Texas has teamed up with Sci-Tech to install and operate a very nice Amateur Radio Station at Sci-Tech. I recently met with Barry Goldblatt, WA5KXX to tour the station at Sci-Tech and to learn more about what Barry and his team are doing with the Boy Scouts and other youth groups to promote Amateur Radio among young people in the Dallas, Texas area. The following is Barry’s description of his work and progress at Sci-Tech. I think that you will find his article interesting and enjoyable. The Sci-Tech HAM team is currently working to raise funds to create a more private area for young operators to discover Amateur Radio at Sci-Tech and to further expand the station’s capabilities. A link to a website where you can make a donation to help with this expansion is included at the end of the article (I suggest that you note in the comments that the donation is being made to benefit the Amateur Radio Station if that is your desire). I believe that the work at Sci-Tech truly represents the Amateur Radio community at its best.

– Fred (AB1OC)

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The McKinney Amateur Radio Club (MARC) and the Plano Amateur Radio Klub (PARK) teamed up over the past six months to install an HF-UHF station at the Sci-Tech Discovery Center in Frisco, TX. Sci-Tech is a science, technology, engineering, and mathematics (STEM) learning center for elementary and middle-school age students. The facility has hosted over 100,000 visitors in the past 12 months and provided outreach experiences for additional 165,000 students in Collin County schools. The teams completed the project on September 15, just in time for the station to be in operation for the Boy Scout Jamboree-on-the-Air (JOTA) on October 20-21.

The project began with a donation by David and Diana Brandenburg of the Brandenburg Life Foundation in February 2012. David, K5RA, has provided funding for amateur radio stations in schools and museums throughout the country including the Heard Museum in McKinney, Haggard Middle School in Plano and the Saint Paul School in Richardson. Additional funding for a WeatherBug commercial-grade weather station was provided by the Goldblatt Family Trust. The installation at Sci-Tech provides up-to-the-minute reporting of weather conditions on the Internet and is used by WFAA Channel 8, an ABC affiliate, as well as other news organizations that monitor weather in the north Texas area.

Tower Mount At Sci-Tech

The clubs went to work immediately on the antenna installation and station design. That was not an easy task. The Sci-Tech Discovery Center is located in a commercial tilt-wall structure with 50-foot walls. PARK President, Kip Moravec, AE5IB, designed an antenna mount that would clamp to the perimeter wall and allow the Rohn tower section to pivot down for easy servicing of the antennas, the rotor, and the weather station components. The mount was constructed using quarter-inch steel angle stock and weighed over 400 pounds. It took one full day to cut the steel and drill the necessary holes so the structure could be assembled and then powder-coated to protect it from rust and match the color of the building.

Once the antenna mount was complete, MARC President Walter Lemons, AE5IT SK, President of the McKinney club, along with Rusty Delaney, K5FEA, and other members of the team loaded it onto a flatbed trailer for transport. The team hauled the mount to the roof of the building and began the installation. It took two sessions the use of a 50 foot lift to position and secure the mount in place. The team then installed the Rohn tower sections and added a Force 12 C3SS 10, 15, 20-meter beam, a VHF-UHF vertical and the weather station components.

During these two sessions, other members of the team began drilling a three-inch hole in the building wall for the cable entry. Again, this was not an easy task, since the walls are eight-inch-thick concrete. The cabling run from the tower to the station measured 175 feet. Cabling included coax runs of LMR 400 for the HF-6 frequencies and LMR 600 for the VHF-UHF frequencies plus wire for the Yaesu antenna rotator, WeatherBug weather station and two runs of CAT-5 Ethernet cable. The CAT-5 cables are reserved for a future installation of HSMM equipment.

HAM Station At Sci-Tech

A second team that included Tony Campbell, W5ADC, completed the cabling and connected the radios for their first QSO on September 15. Rusty Delany, K5FEA, made the first VHF contact. Dan Howard, KE5CIR, and Michael Porter, KF5LDJ, from the Lake Area Amateur Radio Klub (LAARK) made the first HF contact with N1LS in Colorado on September 29 in preparation for the upcoming JOTA event.

This installation was extremely complicated and arduous because of the building structure and the fact that the teams were working during a hot Texas summer. The Brandenburg Life Foundation, the Goldblatt Family Trust and the Sci-Tech Discovery Center are extremely grateful to club presidents, Walter Lemons, AE5IT SK, and Kip Moravec, AE5IB, and the members of the McKinney and Plano radio clubs for their expertise and hard work. This installation would not have been possible without their help.

Sci-Tech Antenna System

In July 2013 Sci-Tech was provided with a much-needed expansion by the City of Frisco Community Development Commission (CDC) at their June 2013 meeting. The 3,800 square foot expansion will provide for more classroom and exhibit space. The expansion provides enough room so that the amateur radio station equipment can be moved to a permanent location. The new 60 square foot “shack” will feature sound-proofed walls and a glass door and viewing window. The enclosed space will allow Sci-Tech to expand its amateur radio programs and sets the stage for a special event station day later in 2013 or early 2014. There are plans to add more functionality to the installation including HSMM capability.

Sci-Tech currently opens the station to the public one day per month. Planning is underway to develop a radio exploration camp for young visitors during the summer of 2014. Ideas for other events include an all-night DX party and a Boy Scout One-Night Radio Merit Badge

More information is available about Sci-Tech by clicking here. Sci-Tech is a 501(c)(3) non-profit organization located in Frisco, TX that delivers innovative educational experiences for all ages in science, technology, engineering and math (STEM).

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Author: Barry A. Goldblatt, WA5KXX

Up The Tower Again

April 13, 2013 by fkemmerer

AB1OC On The Tower

Well, our 2m tower-mounted preamp system went on the blink recently so I decided to climb the tower and replace the preamp unit today. The preamp systems for our 2m and 70cm yagis are at the 95 ft level on our tower so the repair involved a climb to the top of the tower.

2m Preamp System

The climb took much more time than the repair did. The picture above shows the inside of the 2m preamp housing which holds the preamp itself plus the T/R relay which protects it during high-power transmit operation. A couple of screws and removing and reconnecting the cables were all that was required to change out the faulty preamp.

AB1QB Ground Crew

Anita (AB1QB) helped me as my ground crew on this one and she spent some time in the shack testing the new preamp to ensure that everything was working correctly. After a quick test, we buttoned up the preamp housing and I took a little time to enjoy the view from the top of the tower.

View From The Top

This was my first climb to the top of our tower and it was both exhilarating and tiring at the same time. It’s good to have the preamp working properly again. More fun with EME on 2m is planned for later today when the moon is on the horizon.

– Fred (AB1OC)

Our HAM Station

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

Category Archives: Tower Construction and Maintenance

An 80m Broadband Matching System

Giving Back To Amateur Radio

Fall Antenna Projects – A New Low-Band Receive Antenna System

Summertime Station and Antenna Projects At AB1OC/AB1QB

2015 Nashua Area Radio Club Field Day Recap

LEO Satellite System Part 3 – Final Installation And First Contacts

World Radiosport Team Championship 2014 Experiences

Medal winners

Award winners

Our Tower From Space

Amateur Radio For Young People At Sci-Tech

Up The Tower Again

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