“Tech Morning continues to meet every week at 10:15 AM, Mondays at the Pepperell Community Center.
“From week to week we engage in widely (and wildly) varying, ad hoc, discussions on topics of current interest. At times we have a major common project focus, as we had for many months with the Arduino Antenna Analyzer. Mostly though, we just ragchew on our radio interests and issues of the week.
“In a recent session we discussed a kit Peter, N1ZRG, found for building a nixie tube digital clock for those with a big time hankering to solder. It is made up of only discreet resistor-transistor and diode logic! Over 1,200 through-hole parts, with no IC’s.
“Another discussion we recently had was on propagation issues that are impacting our morning 40m CW nets. Since we are in relatively close proximity to each other (max ~17 miles), NVIS propagation is expected to be a determining factor in signal quality. As it is, George, KB1HFT, in North Chelmsford is barely heard by Peter, N1ZRG, in Pepperell, even though George is pumping 50 watts into a resonant Inverted V. George reports that on the same antenna his 1 watt 40 M WSPR signal has been heard in Antarctica by DP0GVN. Hmmm. No NVIS? We set out to investigate.”
Are you curious how to install your amateur radio into your motor vehicle? Join Sci-Tech Amateur Radio Society for its 2nd Tuesday Lecture Series at 7 PM. Radio guru Jeremy Breef-Pilz, KB1REQ, will be showing us how to perform a mobile installation.
Have you ever wondered what an antenna actually does? Why all those big pokey things on top of many tall buildings look the way they do? How we’ve engineered the ability to radiate electromagnetic waves across continents and oceans? If so, join us this Friday to hear about:
Antennas for Amateur Radio: Everything is a Dipole
(except when it’s a loop)
Friday, January 24th at 5:00 PM at MIT in room 4-270
Kiersten Kerby-Patel, University of Massachusetts at Boston
Hosted by the MIT Radio Society
Part of the IAP Radio Lecture Series <http://w1mx.mit.edu/iap/2020/
DINNER (Pizza) will be provided
TechNight is this Thursday, January 9, 2020, at the usual time and place: 7 PM, Grady Research building [in Ayer]. See the website www.DansTechNight.com for info and directions.
Our guest speaker will be physicist Bob Jackson, KE1JH. Bob’s talk is “Infinity, Q, and Transmission Lines, a Physicist’s View.” This will be about energy flowing in a transmission line, and characteristic impedance, among other things.
I will not be here for the meeting, I’ll be at the Consumer Electronics Show in Vegas.
From the ARRL Web, 01/02/20:
The Massachusetts Institute of Technology Radio Society (W1MX) and the Department of Electrical Engineering and Computer Science are hosting a lecture series in January that may answer some of your questions about such topics as radar techniques, interferometry, imaging, and radio astronomy, to antenna design and modern chip-scale RF devices. No prior experience with radio is necessary, and all are welcome.
All lectures will take place in the Green Building — MIT’s tallest academic building. Sessions will be live streamed and archived for later viewing.
The lectures kick off on January 10 with “The Next Generation of Weather Radar.” Other topics include “Lightning Interferometry” (January 13); “Radio Noises from the Sky” (January 15); “EDGES: Measuring the Early Universe” (January 22); “Antennas” (January 24), and “Chip-Scale THz Circuits and Sensors” (January 29). Lectures begin at 5 PM ET and conclude at 7 PM.
The club’s Daniel Sheen, KC1EPN, noted that the rooftop W1XM facilities in the Green Building are scheduled for removal as part of a renovation project. A capital campaign is under way to establish a new facility with improved capabilities for academic research and recreational activity.
From the Sci-Tech ARS Newsletter, January 1, 2020:
The American Meteorological Society’s 100th Annual Meeting will be held in the Boston Convention and Exhibition Center in Boston’s Seaport District from January 12-16, 2020. It will feature many informative talks and presentations. Among those is an invited presentation by the Ham Radio Science Citizen Investigation (HamSCI) entitled, “Space Weather Operational Resources and Needs of the Amateur Radio Community” on Tuesday, January 14 from 11:45 AM- 12:00 PM.
The authors include:
Nathaniel A. Frissell
Univ. of Scranton
Scranton, PA, USA
Philip J. Erickson, W1PJE
MIT Haystack Observatory
Westford, MA, USA
Ethan S. Miller
Johns Hopkins Univ. Applied Physics Lab
Laurel, PA, USA
Scranton, PA, USA
H. Ward Silver, N0AX
Scranton, PA, USA
R. Carl Luetzelschwab
Scranton, PA, USA
El Segundo, CA, USA
The presentation abstract follows:
“The amateur (ham) radio community is a global community of over 3 million people who use and build radio equipment for communications, experimentation, and science. By definition, amateur radio is a volunteer service, with the operators required to hold government-issued licenses that are typically earned by passing knowledge tests covering radio regulations and practices, radio theory, and electromagnetic theory. In the United States, there are about 750,000 licensed hams, ranging in age from very young to very old, and ranging in experience from neophyte to people with advanced degrees in radio engineering and science. Amateur radio operators are licensed to transmit on bands spread across the radio frequency (RF) spectrum, from very low frequency (VLF) up to hundreds of gigahertz. The purpose of these communications range from mission-critical emergency and public service communications to social contacts to highly competitive contests and achievement award programs. Many of these communications rely on trans-ionospheric paths, and therefore are heavily influenced by conditions in near-Earth space, or space weather.
The NOAA/NASA-co-chaired international Solar Cycle Prediction Panel has released its latest forecast for to forecast Solar Cycle 25. The panel’s consensus calls for a peak in July 2025 (±8 months), with a smoothed sunspot number of 115. The panel agreed that Cycle 25 will be of average intensity and similar to Cycle 24. The panel additionally concurred that the solar minimum between Cycles 24 and 25 will occur in April 2020 (±6 months). If the solar minimum prediction is correct, this would make Solar Cycle 24 the seventh longest on record at 11.4 years. In its preliminary forecast released last April, the scientists on the panel forecast that Solar Cycle 25 would likely be weak, much like the current Cycle 24. [Full story]
The Sudbury native has created a nationwide initiative called the Zero Falls Alliance to promote safe tower practices and “a vision of an always-safe amateur radio where every ham fully understands the potential risks – and has the knowledge and tools to keep those risks at bay.”
The first in the series aired on December 4, 2019. The second is scheduled to be shown on December 11.
Dan Pedtke, KW2T, writes:
TechNight is this Thursday, Dec 12, 2019, at the usual time and place: 7 PM, Grady Research building [in Ayer]. See the website www.DansTechNight.com for info and directions.
This month I had a request to talk about the various types of transistor amplifiers: Common Emitter, Common Base, Emitter Follower, Cascode, Darlington, etc. This came up due to the TNRadio using a variety of these, mainly for educational purposes, and from last months SPICE circuit simulation touching on some of these.
I’ll go over about 10 different transistor amplifier arrangements and talk about how they work and their characteristics, and where they are used. We might use SPICE to measure some of the characteristics.
We’ll also have a short presentation by Jim Wilber about the Pepperell CERT program he is involved with, getting ham radio to be involved with local FEMA authorities. He has gone through the certification program along with a couple other NVARC members.
Should be a good meeting. Hope to see you there, and that the weather cooperates.
As part of the new collaboration between WARS (Wellesley Amateur Radio Society) and NEST (New England Sci-Tech in Natick), Charlie has proposed a NEST High Altitude Balloon (HAB) project.
What are the goals?
NEST mission is to help youth with STEM projects. As you recall, Charlie has previously done balloon launches with Natick HS and now, he is leading this new effort for NEST.
The goals are to get young people involved in a project, which has Amateur radio (an APRS tracker device) with STEM learning. They will learn about project planning, platform testing, launching, tracking, and recovery of the balloon and its payload, and flight data analysis. The platform will carry up to 3 GoPro cameras, a commercial GPS tracker, and the APRS tracker. A 20-foot tether connects the platform to the HAB balloon, which is filled with helium or hydrogen, and is about 8 feet in diameter at launch. The platform will weigh less than 4 pounds.
As the balloon ascends, the APRS tracker will provide location info, pressure, temperature, altitude and a few more items in its telemetry. At around 90,000 feet after a 2-3 hour ascent, the balloon will have expanded to over 30 feet in diameter when it explodes and the package starts its return to earth.
The parachute will deploy and the downward trip will take 30-45 minutes. Hopefully it will not land on a roof, pond, or the Mass Pike!! It needs to be recovered to collect the photos from the cameras. The STEM team will write a report on the whole project.
Here is a breakdown of the expected cost of an HAB. The kit is obtained from High Altitude Science (https://www.highaltitudescience.com/) who has perfected the items for a youth team, supervised by adults (if you can call Charlie an adult!)
1. HAB kit – $ 750
2. Extra balloon $ 30
3. Helium or Hydrogen $ 150
4. 3 GoPro like cameras $ 150
5. APRS tracker $ 250
6. Batteries $ 25
TOTAL: $ 1355 (approximate)
Of course, subsequent flights can be done more cheaply if the platform is recovered successfully. Then, you just need a new balloon and more helium!
The project flyer is being designed and advertising to students will begin in late November through the end of the year. To give you a feeling of the project, here is a rough schedule as to the project activities:
1. November – Create flyer and start advertising
2. December – Sign up and order kit
3. January – start meetings, which are 2x/month at NEST
4. Late Feb/March – start assembly of the kit
5. March/April – flight planning and launch prep
6. May – tethered test prior to launch to ensure all systems are go
7. Late may – launch (likely from central or western MA)
8. June – data analysis and write report
The idea is not only to learn and have fun, but also to analyze the results and decide how the next flight should be done. For instance, radiation devices could be used or, perhaps, amateur live streaming of the flight and balloon burst could be added to future flights.
How you can help
I’d like to ask for your support in two ways. First, if there is anyone who would like to be involved in the meetings to learn, build, and assemble this platform, please let me know what you’d like to do. Second, I’d be grateful for any private donations of any amount or any general support of WARS. I know there are lots of worthy causes for your charity contributions, and I hope you can see the value of this STEM project for youth learning about ham radio and be able to offer some support – THANK YOU!
Bob Phinney, K5TEC, writes in the New England Sci-Tech Amateur Radio Society (STARS) newsletter:
The NESciTech (NEST) collaboration with Blue Hill Meteorological Observatory and Science Center (BHO) is now fully underway. A crew of eight volunteers arrived on November 9, 2019 at Blue Hill to install the antennas and repeaters for the new Blue Hill radio club that the BHO science center is starting with the help of Bob and Rusty at NESciTech.
Thank you Ted for doing much of the tower work, Bob D. for doing most of the repeater configurations and antenna setup, Jeremy for high quality cable connector terminations, and everyone for all your help running coax, hauling equipment, and supporting Blue Hill’s educational mission and STEM collaboration.
The Blue Hill repeaters will link back to the STARS repeater at NEST in Natick, so talking on one opens all of them. Burlington is by itself for now. Repeaters are open to use by all hams, and shared by Blue Hill Science Center and STARS. Please send any propagation reports to info@NE1AR.org.
Photo, left to right: Bob DeMattia, K1IW; Ted Reimann, W1OG; Jeremy Breef-Pilz, KB1REQ; Alex Dills, KB1SSN; Bruce Pigott, KC1US (kneeling), science center director Don McCasland, Eoghan Bacon, K2VUD; and Bob Phinney, K5TEC. Photographer, not in photo, Rusty Moore, K1FVK.
The PART kit building team is Andy, KB1OIQ; Steve, W1KBE; and Allison, KB1GMX. We recently received a very generous donation from an anonymous member of ten (10) DrDuino kits. You may remember reading about this kit in a recent issue of QST.
The PART kit building activity got started in KB1OIQ’s basement classroom on November 7th, 2019. There were five (5) kit builders: George, K1IG; Rakesh, KC1HTB; Niece, KA1ULN; Rich, AB1HD; and Scott, KB1WMH. The first session was spent soldering together the kit. The next two sessions will be Arduino programming lessons taught by Andy (KB1OIQ). The attendees will learn how to program switches, LEDs, potentiometers, a speaker, an ultrasonic distance measuring device, and those very colorful (and BRIGHT) LED strips. If there is time, we may also make a simple CW practice oscillator and a binary counter displayed on the LEDs.
There will be a future kit building activity using the four (4) remaining DrDuino kits (I built one). Additionally, this training will be a great prerequisite for the DDS VFO kit that we’ll unleash during a future session.
All things considered; the first session went really well. I’m really looking forward to the next two sessions!
TechNight is tomorrow night, Thursday, October 10, at the usual time and place; 7:00PM at the Grady Research Building in Ayer. See www.danstechnight.com for details and directions.
We have an unusually interesting program this month, with a rare guest speaker visiting us to discuss the technical aspects of the NASA Apollo spacecraft radio link. George Whitehead, W1BOF, is one of the few remaining radio engineers who worked on the design of the Apollo mission communications radios. This the radio hardware that did the communications between earth and the spacecraft, including the video of man’s first step onto the moon.
George worked at North American Aviation in Downey, CA from 1962 to 1967. This was the prime contractor for the Apollo Command and Service module. He worked in the Apollo Communications Subsystem Group mainly on the telemetry part of the radio system, the part that sent spacecraft status and astronaut medical information back to mission command. But sitting next to him was the rest of the designers of the radio who did the other parts of the design. He got to know the system quite well.
George will have some technical information for the projector, but it will be a technical discussion between George and I, where I’ll be asking him questions about the system.
And if you miss him here, he will be speaking at the [Nashoba Valley ARC] meeting one week later.
We’ll also talk a little about some progress on the radio.
Hope to see a good crowd for this one.
The Algonquin Amateur Radio Club meeting on October 10, 2019 features Andy Stewart, KB1OIQ, who will present on “Linux In Your Hamshack.” Linux fans will be interested in Andy’s Ham Radio Linux, a popular software collection he created for amateur radio users.
The AARC meetings are held at 7:30 PM in the library of the 1st Lt. Charles W. Whitcomb Middle School in Marlborough, 25 Union Avenue. Use Door #1 at rear of building.
The Northeastern University Wireless Club has announced a number of exciting projects for Fall 2019. If you want to join any of the projects below, contact their lead on Slack, and find their meeting times on the Google calendar.
First Meeting Tuesday 4pm
Contact: Jack Leightcap
Airights+ is working to improve the LED controller in the Wireless Club space. This team will have a good mix of software and hardware, with a lot of python programming as well as board design.
First Meeting Thursday 6pm
Contact: James Packard
The LED Flag is a device Wireless Club currently uses to advertise at club fairs and similar events. This team is looking to improve the device by overhauling the software, redesigning the user interface, and enabling the device to be battery-powered. This group is looking for hardware and software support! Support is available from the club if someone wants to learn about this but doesn’t feel confident to do it alone.
First Meeting Thursday 6pm
Contact: Thomas Kaunzinger
RFID is working on a device for Wireless Club that will allow for rapid attendance for club events using a Husky Card and RFID reader. Their goal is to create a device which allows for Husky Cards to be read, and the software to interface with and log this data. There will be board design, firmware design, and software design (probably including databases) for this project.
Crude Camera Sensor
First Meeting Tuesday 6pm
Contact: Henry Mayne
This group is looking to create a rudimentary camera sensor using photodiodes or a similar device. This project is still in the early stages of development with idea generation, so if you are interested bring your ideas! There will be significant hardware development and design required, as well as firmware/software to read the output from the sensor built.
MIT Lincoln Lab employee Brian Smigielski, AB1ZO, has been awarded funding to design a course in which participants will learn how to build a prototype High Altitude Balloon Carrying Amateur Radio (HABCAR).
“The [MIT Lincoln Lab] Technology Office wanted to create another kit building course where each kit would have a price point of about $400/kit,” writes Brian. “I had suggested a Build-Your-Own High Altitude Balloon Carrying Amateur Radio course focused on a long-endurance flight using WSPR and transmitting back telemetry (as well as other sensor related data) using the “invalid” WSPR messages which begin with a 0 or Q (that are now searchable on WSPRnet.org). Luckily Jon and I had our idea make it all the way through and were awarded funding for prototype development as well as course development.”
Assisting Brian with the project are: Jon Schoenberg, AA1FH, Paul Therrien, and Ben Martin, W1BPM. “Ben was a student in the amateur radio course who expressed interest in helping out.”
“We have been working pretty diligently since early winter 2019 purchasing COTS (Commercial Off The Shelf) parts, interacting with other hams who have helped accelerate our learning (Jared Smith N7SMI), and iterating our hardware/software designs. We expect our first launch will be on or about September 14.”
If all goes well, Brian thinks this will turn into a course for employees, then potentially for local area high school kids, boy and girl scout troops, or other STEM groups in the area.
Mark Pride, K1RX, writes on the YCCC Reflector:
To all Tower owners in the Amateur Radio Community – a must read! By Mark Pride, K1RX
Many old timers in the hobby that own a tower, perhaps in the air for 20, 30, 40 or 50 years, need to take this article seriously as it could provide life saving information to you and your ground crew. This is a cautionary article for all that have a tower no matter how long its been the air. What occurred at a NH amateur station recently provides a lesson for all of us tower owners. Although the article speaks to a Rohn 25 guyed tower product, it could be prove helpful to others.
K1JGA and K1EEE tower tragedy
A crew of amateurs gathered at the home of K1EEE to take down two 40 ft. Rohn 25 towers. The details of the tower which collapsed and its failure is provided below. It was a very unfortunate accident which took the life of Joe G. Areyzaga, K1JGA. The owner of the tower, K1EEE suffered multiple injuries but did survive. We all in the amateur radio community extend our prayers and condolences to the families affected by this tragic event.
One of two forty foot (40 ft.) Rohn 25 towers, with one set of guys at the 35 ft level was to be taken down. The base was the BPH 25 hinge plate on a concrete pad of unknown depth. This used tower had only been up 3 years.
NOTE: Following the accident, the owner learned one leg of the hinge plate had been previously repaired but the material used was not galvanized.
With the reasonable expectation the tower would support itself to 40 ft, the guy wires were disconnected from the anchors and the top section was to be removed. The top section to be removed had a rotor shelf and one torque assembly mounted at the 35 ft. level along with the three guy wires. The gin pole had not been raised at that point. The antenna, mast and rotor were previously removed.
At the time of the initial install, the tower was self supported to 40 ft until the first set of guys were attached per Rohn specifications. That may have been the case then, but after many years of exposure to the elements, one can no longer expect the same!
Prior to the start of the tower take down, the tower was thoroughly inspected and found to be in acceptable condition. The base was dry and free of any water. No obvious problems were found.
The general reason for this tower collapse was corrosion at the junction of the hinged base short legs (one leg previously repaired and welded as noted above) and the bottom of the lowest Rohn 25 section occurred primarily from the outside and some inside as well and thus weakened the structure. The first point of failure was the repaired and non-galvanized short leg of the hinge plate. When the guys were removed from their anchor points (necessary to remove the top section), the tower was free standing with the two climbers at 35 ft. It’s clear that the tower deflection from the vertical was extreme enough to make the overturning force at the base (the bending moment) great enough to cause base failure.
The proper installation of the hinge bracket (BPH 25) requires mounting it on a flat concrete surface, secured with bolts placed in the concrete, surrounded by a beveled edge for water run off. Normally, all of the hardware associated with the hinge plate are galvanized and able to withstand the wear and tear of Mother nature. However this base was slightly recessed where the plate sat and there were some gaps under the plate. This created the opportunity for water or ground contaminants to collect. It is presumed the previously repaired short stubby leg of the bracket began to corrode while sitting in water. Years of this kind of exposure slowly weakened the metal. Subsequent movement by climbers at the top of the unguyed tower led to breakage at the base.
NOTE: Rohn towers are very high quality and generally last many, many years with proper installation and maintenance. It is a very popular tower in the amateur radio community. And where tower sections join, they typically show little wear as water drainage occurs easily and there is a limited chance for collecting contaminants and held for long periods of time. Or where tower materials come in contact with the earth, the normal galvanizing process is more than adequate for a long lifetime. But what is noted here is areas that are in contact with the ground or areas such as the repaired leg of the bracket that can accumulate harmful materials and therefore become a danger over time. Clearly there are areas on a tower that are difficult to inspect however, the Rohn design usually lends itself to high levels of confidence that these blind areas are within acceptable standards if installed per the manufacturers specifications.
JGA Safety Guy Technique for Tower Take Downs in honor Joseph G. Areyzaga, K1JGA (SK)
When dealing with unknown tower installations that require removal, it is absolutely critical to err on the side of extreme caution. The technique described below is one approach and a simple one to help safe guard all involved.
A suggested safety procedure that should be applied during any tower take down of this type is attaching a set of additional guy wires at either the 10 or 20 ft. level prior to any work on the tower. By applying a set of guys near the base, further stabilization of the tower base can be achieved. Using this added set of guy wires reduce stress on the legs (twisting, flexing, bending) and prevent breakage at the very bottom of the section just above the concrete surface or surrounding areas. Then what would remain after the tower is taken down to the Safety Guy set becomes very manageable (10 or 20 ft. to be lowered to the ground).
And in honor of our friend and now silent key, Joe, K1JGA, I am naming this important safety procedure the “JGA Safety Guy Technique” with the hopes all of us will not forget Joe but more importantly, keep us all safe while our old towers are taken down. In particular, towers that have been up for our entire ham career and its maintenance history may be questionable require special attention. Of course if the base shows significant deterioration, corrosion and breakage, the tower should NOT be climbed! It should be removed by other means (cut down if the landing area is open and clear or by crane or similar).
The suggested collection of material that comprises the JGA Safety Guy Technique include:
Three (3) lengths of unbroken or spliced guy wire (3/16 inch EHS or larger) longer than the lowest guy to be sure it is long enough (DO NOT USE ROPE!);
Guy Grips for each end of the guy wire;
A come along at each guy anchor point for proper tensioning and;
A reliable heavy duty attachment device to connect to the existing anchor.
The attachment to the guy anchors should be done in a way that does not interfere with the existing guy anchor assembly (turnbuckles, etc.). If the JGA Safety Guy kit is to be used in multiple tower take downs of varying heights, use of the Guy Grips will allow full flexibility of locating the attach points where they are needed, without cutting cable. Just make the cable length longer than you might need to give you enough head room. One further consideration: Rather than just use this technique near the ground, consider always using it no less than 10 ft. below where you may be working I.E. erecting or dismantling a tower, place the JGA kit 10 ft. below the location you are either installing or removing the next section. Therefore, the guy lengths need to be approximately the same length as the longest guy (upper guy). This will assure maximum safety. With the guy grips, it is easy to relocate them, as you adjust the length of the temporary guy at each point on the tower.
As part of your annual maintenance plan, include keeping the base free of debris, dirt, trees, plants etc. to protect this area from any long term damage. Consider making one of these JGA Safety Guy kits for your club to be used as necessary.
Best to use the JGA Safety Guy Technique and find the tower base was just fine, than not use it and suffer a similar situation or worse! Stay safe!