September Club Meeting: W6GJB on Moble Contest Operation
Glen, W6GJB, is a retired aeronautical engineer. He graduated from Caltech in 1969. His career started with research on the aerodynamics of subway trains and ended with the design, development and flight testing of inflatable decelerators for landing heavy (up to 60 Ton) Mars landers.
Glen was first licensed in 1958 as WN6FQD and then WA6FQD. After a long gap he was re-licensed in 2008 as W6GJB. His interests are DXing, contesting in a limited sort of way, antenna experimentation, and county expeditions. He started building an operating trailer in 2012 and enjoys going out with friends for Field Day, CQP and 7QP each year. Continuous improvements to the trailer are aimed at making setup quick and safe for a crew of old fart hams.
CAKE Slices September 8
Our CAKE sessions are usually centered on technical topics, today was very different. Our discussions were concentrated almost entirely on a variety of operating and public service activities. In attendance were Gary K6PDL, Fred KJ6OOV. Don K6GHA, Peter K6UNO,.Bob K6XX, Glen KG0T and Reed N1WC. As usual these notes are a labor of love by Ron W6WO.
Don spoke very eloquently about the planning of an ambitious event he is deeply involved with.. It will provide show and tell exhibits of Ham Radio, Space exploration and Astronomy. It is aimed at attracting young people to exciting science. This is event is being planned and funded by ham radio clubs and others in this region.. It is scheduled for October 25th between 7-9 PM at Cabrillo College. Accommodation is limited so keep an eye on the SLV club web site and contact Don if you wish to become involved
Gary described some of his public service activity which included Ham communications in a recent major earthquake drill. He is regularly involved in providing communications at the State Fair and other Emergency Operations with the Sheriffs dept. Kudos to you Gary. His problem with RFI at home was not solved in the usual way with ferrite chokes. Ron suggested externally grounding coax shield(s) before they enter the home. A nearby copper water pipe would be a fair bet.
Peter K6UNO spoke about his interest in high quality audio. The challenge of achieving low distortion and high dynamic range is a familiar objective at RF. Peter is using a powerful PC-based spectrum analyzer 10Hz-50kHz. Glen brought two exhibits, one was a low cost software development platform using a LPC 804 chip. (Ron rues the day he gave up programming). The second item was a RF power amplifier using a pair of MRF 433 MP devices (12 Watt 30 MHz) with input and output transformers but no filter components, built on a 2×3 board with a generous heat sink. We thought Tom KW6S could tell us more about it. Contact Glen if you have an interest.
Bob K6XX spoke about his recent participation in the annual World Radio Team Championship in Germany. This event is designed to determine operator prowess by equalizing the technology (TX power, antennas etc) used by the competitors . It is very strictly defined and monitored, teams practice months ahead to literally get up to speed . If I heard correctly Bob’s team made over 4300 contacts, that’s about 20 seconds per contact for 24 hours.!!!!!!
Fred offered the following sage advice “don’t rush into using an electric fence as an antenna”! For a change Ron didn’t say much, he is currently exploring more capabilities of the N2PK VNA. Tom KW6S was at home operating in a VHF contest, Following our session we gathered in the parking lot and gave him a few points on 144, 440 and 1296 MHz .
Finally Ron had some very good news from Jimmy Koger.N1IPP; recently some new medication has literally given him a new lease on life.
That’s all for now so plan to join us on September 22. CAKE participants are friendly, items for discussion and questions at any level are welcome.
73 to one and all Ron W6WO
PS we haven’t been on any visits recently, does anyone have any suggestions ?
3D Printed Parts for Ham Radio
I’m One of the things that I keep telling myself that I need to learn how to do is 3D printing. This morning, I ran across a couple more 3D printing projects for ham radio that I thought I’d pass along.
printed_parts_for_portable_tape_measure_yagi/).The summary on Thingiverse (https://www.thingiverse.com/thing:3042505), which is a website where “makers” share their designs, says:
These parts are made for use with 1-in. PVC pipe and 1-in. Harbor Freight tape measure steel. You can use electrical tape to attach the element holders to the side of the pipe, and use the driven element bridge to give structural rigidity across the driven dipole element. I have used this with up to 5 elements on 2m with good success. When not using the antenna, just pinch the elements to remove them from the holders, and store them INSIDE the tube! you can add some end caps to make this ultra portable. Use these parts with any of the multitude of tape measure YAGI design guides online.
Here’s a look at an antenna made with these parts:
The element holders are attached to the boom with electrical tape in the photo above. While I haven’t tried it, I’d suggest that the antenna might be a bit more robust if you could screw or perhaps glue the holders to the boom.
There are lots of other cool amateur radio 3D printing projects available on Thingiverse (https://www.thingiverse.com/search?q=ham+radio&dwh=415b6d8da129c3c). Browsing through the list quickly, here are just two that look like they might be useful to me:
Last week, I attended a 3D printing class at our local maker space, All Hands Active (allhandsactive.org), and now I feel like I can finally attempt a 3D printing project. I’m thinking about starting out with the simple Soldering Fingers project. If that goes well, I’ll try a Raspberry Pic case and finally start using that in the shack. And, while these projects all seem pretty cool, I feel like I’m only scratching the surface.
Have any of you 3D printed anything cool for your ham radio projects? Is there another source of designs for ham radio 3D printed stuff besides Thingiverse?
When he’s not 3D printing enclosures for his ham radio projects, Dan blogs about amateur radio, writes exam study guides (www.kb6nu.com/study-guides), and operates CW on the HF bands. Look for him on 30m, 40m, and 80m. You can email him about your experiences with 3D printing at firstname.lastname@example.org.
Get your free copy of A Field Guide to Simple HF Dipoles
by Dan Romanchik, KB6NU
A link to A Field Guide to Simple HF Dipoles (http://www.dtic.mil/dtic/tr/fulltext/u2/684938.pdf) was posted to reddit recently, and I liked this document so much that I thought I would share it with you. It was originally written for the military, but is now available for free from the Defense Technical Information Center. The preface to this document reads: “Under project Agile, Stanford Research Institute has supplied several teams to assist operating personnel in improving the performance of field radio networks. In this work, it has been observed that U.S. military and civilian antenna manuals often contain misleading information regarding the operation of field antennas and tend to be overly complex. Consequently, this guide has been prepared to assist in training personnel concerned with the construction of simple HF antennas in the field.” I must say that A Field Guide to Simple HF Dipoles does this very well. It not only explains how dipole antennas work, it also does a very good job of describing the basics of radio waves and propagation. And it does this without getting overly technical. For example, below is Figure 10. It’s used to describe current flow in a dipole antenna. [[The illustration goes here. Download it from https://www.kb6nu.com/wp-content/uploads/2018/07/current-flow-in-dipole-antenna.png]] The Field Guide reads: “Electric current in a conductor consists of the flow of small particles called electrons. Figure 10(a) represents a dipole with electrons in it. When the transmitter is turned off, the electrons distribute themselves evenly throughout the dipole, as shown. All electrons repel each other and try to get as far from each other as possible; that is how they achieve the uniform distribution show in Figure 10(a). When the transmitter is turned on, the electrons flow back and forth from end to end as shown in Figures 10(b) and 10(c). First the electrons flow to the left and crowded at one end as shown in Figure 10(b). Second, since the electrons repel each other, the push off to the right and get crowded together at the other end, as in Figure 10(c).” It then uses this description to talk about voltage and current distribution along a dipole antenna: “The difference between voltage (volts) and current (amperes) in a dipole is also illustrated by Figs. 10(b) and 10(c). You can see that the maximum flow of current is going to be in the middle of the dipole. An observer at the center of the dipole would see the electrons rush past, first one way and then the other. The center is the maximum current point. Very little current flows near the end of the dipole; in fact, at the extreme ends there is no current at all for there is no place for it to go. However, at the ends of the dipole, there is a great change of voltage; when the electrons are densely packed, this represents a negative voltages, and when there is a scarcity of electrons, it represents a positive voltage. Thus you can see that the voltage at each end swings alternately positive and and negative. An end of the dipole is a maximum voltage point.” A Field Guide to Simple HF Dipoles is packed with all kinds of goodies like this. Download it (http://www.dtic.mil/dtic/tr/fulltext/u2/684938.pdf) right now.
When he’s not building dipoles or teaching ham radio classes, Dan blogs about amateur radio, writes exam study guides (www.kb6nu.com/study-guides), and operates CW on the HF bands. Look for him on 30m, 40m, and 80m. You can email him about your experiences with simple HF dipoles at email@example.com.
Field Day 2018 at Ben Lomomd CDF Camp
Youth CW Academy Program
The CWops club has added a new program to its popular CW Academy. For young people between 11 and 19 years old, there is a Youth CW Academy program focused on them. They learn in age-peer groups using the same method from CWA. The key advantage is they learn with other kids and are encouraged to get on HF CW and participate in contests and to ragchew with their age peers. CWops conducted two pilot semesters of YCWA and it works.
If you know someone in that age group who is interested in attaining CW skills and on-air competence, have them go to the regular CWA signup
There is a field for indicating age under 20 and another field for entering one’s age. If the under-20 field is asserted (“yes” reply), the application is automatically routed to YCWA for assignment. CWops is working very hard to keep CW vibrant. In 7 years, the beginner, intermediate and advanced courses have served over learners. Now, we are focused on increasing the number of younger CW operators and getting the increasing average age of hams to stop and begin going down from its current 60+ years.
If you have any questions, email me (firstname.lastname@example.org).
Mini Makers Faire at Cabrillo College
73, de Bob KO6XX
Is the internet, millennials or FT-8 killing ham radio?
By Dan Romanchik, KB6NU
Amateur radio bloggers love to write about the demise of amateur radio. To wit, we have:
* K0NR’s Is the Internet destroying amateur radio? (http://www.k0nr.com/wordpress/2017/11/internet-destroying-amateur-radio/)
* N0SSC’s Millennials are killing ham radio (http://n0ssc.com/posts/583-millennials-are-killing-ham-radio)
* PE4BAS’ Is FT-8 damaging amateur radio? (https://pe4bas.blogspot.com/2018/04/is-ft8-damaging-hamradio.html)
* NZ0T’s Did Joe Taylor K1JT Destroy Amateur Radio? (http://www.ei5di.com/jt.html)
Of course, none of these posts are really saying that the internet, millennials, or FT-8 has killed amateur radio. What they are saying is that all of these are changing amateur radio as we know it. Well, duh, the way we live our lives changes every day. Why should amateur radio be any different?
For example, Bob, K0NR, discusses how the operation of remote stations is changing the game of DX. Can you really claim that you worked a DX station if you rented time on a super station? I’ve written about that topic, too (https://www.kb6nu.com/dx-advisory-committee-wants-to-put-the-screws-to-remote-operation/).
There has also been much written about how FT8 is changing the amateur radio game. One blog post (https://ve7sl.blogspot.com/2017/10/160m-ft8-end-of-era.html), talking about the effect of FT8 on 160m operation, even goes so far to say that this is the “end of an era.” On DX World, the results of the poll, “FT8 – Damaging to Amateur Radio?” (https://dx-world.net/yes-or-no-a-poll-on-ft8/) show more than half of the respondents think that FT8 is damaging amateur radio.
I specifically used the word “game” in the previous two paragraphs because that’s exactly what’s changing. The physics of amateur radio certainly isn’t changing. Our transmitters are still generating electromagnetic waves like they have been for decades, and on the HF bands, anyway, those radio waves are bouncing off the ionosphere just as they have been for more than the past 100 years.
What’s changing is the human component. By that I mean what’s changing is how we think people should participate in the hobby. The hams that are complaining that the internet or millennials or FT8 is killing amateur radio are really just complaining that people aren’t participating in amateur radio the way they want them to participate.
Here’s where we talk about millennials. In his blog post, Sterling, N0SSC, suggests that setting up remote stations is one way to engage young people. He writes, “I believe that remote operating, and other internet-assisted means of ham radio operation, are critical to youth engagement.”
He’s also big on an idea he calls “ham radio hackathons.” He writes,
“A hackathon isn’t a coding competition. It’s explained well in this Medium article (https://medium.com/hackathons-anonymous/wtf-is-a-hackathon-92668579601). It goes even further than that, not limited to coders and engineers, but open to thinkers, doers, philosophers, system engineers, math people, teachers, students, artists, stakeholders…anyone with an interest in solving a problem with technology.”
I support both of these ideas, but I think that millennials (and, to be fair, it isn’t just millennials we’re talking about here, but any newcomers to the hobby) need to step up and get these things going. I don’t think it’s my job to try to get kids interested in amateur radio. I don’t even know if that’s really possible. What I can do, however, is be there to encourage and support kids (and anyone else that expresses a sincere interest in amateur radio).
For example, I’m not sure how fruitful it would be to set up my station to be remotely operable and then saying to some kids, “Hey, come and operate my station.” What I think would be more fruitful is to say to a kid, “Hey, come help me set up my remote control station, so that we both can use it.” Then, it turns into a learning situation, and we both gain from the exercise.
The same kind of thing has to happen with ham radio hackathons. The motivation has to come from the ground up, not the top down. I do hope that this idea gets off the ground, though, and I’m standing by, ready to support this effort however I can.
I think that millennials (I’m really getting tired of that term, by the way) need to grab the bull by the horns and take amateur radio in the direction they want it to go. Feel free to kill amateur radio as we know it. Make it better!
When he’s not trying to figure out how to save amateur radio, Dan builds stuff, blogs about amateur radio at KB6NU.Com, teaches amateur radio classes, and operates CW on the HF bands. Look for him on 30m, 40m, and 80m. You can email him about what you think is killing amateur radio at email@example.com.
What does ARES say about Volcanos?!
By Don K6GHA
I’ve been following the recent news in Hawaii, and through contesting I know a few folks in the southern part of the Big Island of Hawaii. I and a few local Amateurs around the bay, and in Santa Cruz, were concerned about some of the regulars that we talk to, or visit on an occasional trip to the islands. So I thought I would share a bit of what is going on, what ARRL is saying, and what local news is sharing.
You may know that the Leilani Estates, on the Big Island, is in the path of the lava flow, and is currently under evacuation, and headed toward the Ahalanui Park Warm Spings (soon to be known as a HOT pond instead of a warm spring!). Tom (KG6AO) has been over in the Islands in this location a lot. Thanks for the references.
Here’s a drone video: https://youtu.be/Gytkbx7Cf3U
Here’s a google map link: https://goo.gl/maps/35zhoczzyHr
I had heard of a few hams who may be in trouble based on the predictions of pending eruption, so I thought I would see how many hams were local to Leilani’s zip code, and within one area south. Doing a quick google search, I found a site that allows you to put in a zip code, and get back a list of call signs registered in that code. http://www.radioqth.net/ziplookup Amazingly, there are over 115 Amateurs local to that area of Leilani Estates. Take a look and see if you know anyone!
Right next door (next zip code south), there are over 120 additional registered Amateurs and club calls. This includes one of Santa Cruz’s past club members, Lloyd Cabral is KH6LC. He is one of Hawaii’s top contesters, so I was a bit more concerned about him. Talking with Tom (KG6AO) I found out Loydd is currently is in good shape, but I have heard that his water supply may be showing signs of Sulphur Dioxide intrusion. This might be because of the volcanic activity.
“Two informal informational nets remain open on the island of Hawai’i (“The Big Island”) in the wake of recent and ongoing volcanic eruptions and seismic activity, Pacific Section Emergency Coordinator Clement Jung, KH7HO, reports. No formal traffic has been passed, but frequencies are being monitored. “All normal communications, i.e., cell, land-line phones, Internet, and public safety, are operational,” Jung told ARRL.
The Kilauea volcano on The Big Island erupted on May 3, spewing lava and venting high levels of sulfur dioxide. An Amateur Radio net is open on 7.088 MHz (SSB), and the Voluntary Organizations Active in Disaster (VOAD) 146.720 MHz repeater (100 Hz tone) on Mauna Kea was activated after Hawaii’s governor issued an emergency declaration.”
You can tune in on 40 meters and listen if you want to hear the events as they unfold.
What would you do in a volcanic emergency?!?
Full House of Guest Speakers
By Don K6GHA
At our club meeting last Friday (April 20th), we had a trio of great presentations from club members, which kept the attention of all present!
It was a great evening covering a variety of subjects, and included a rousing Q&A session from the audience.
Jeff (AE6KS) kicked off a meeting with a presentation on his ADS-B receiver. This Raspberry-PI device captures aircraft beacon information and with software from Flight Radar 24 (https://www.flightradar24.com) allows you to see what your receiver can see! Pretty cool!
Glen (KG0T) asked a simple question… “What is SWR”. The answer was a little more complex, subjective, and educational! Taking a different approach, Glen shared his thoughts, calculations, and experince on what parts of SWR were important to focus on when considering its impact on your station.
Cap (KE6AFE) reminded us all that if the internet were to go down, with your radio, PC, and Winlink (https://winlink.org/ ), you can still have global email access! He recommends that everyone download Winlink Express (https://winlink.org/WinlinkExpress) and take advantage of the Forms that are included for emergency services and Radiogram messaging! Once you have downloaded it, send Cap an email!
I would like to thank Jeff, Glen, and Cap for jumping in at the last minute to present when a scheduled presenter couldn’t attend. It shows the professionalism, strength and breadth of knowledge in our club! Also a big thanks to Becky (K16TKB) for coordinating these great presenters.
Do you have an area of interest you would like to share? Contact the club Vice President, Becky KI6TKB.
CAKE Notes from April 28 2018
Those taking part were Gary K6PDL, Reed N1WC, Glen KG0T and Tom KW6S with Ron W6WO
The session was made special by the Home Brew projects shown by Tom. We have often seen his outstanding work but today what we saw was a collection, the like of which could hardly be surpassed. Tom admits he is a builder rather than a designer but tends to play down the exceptional engineering skill he always employs. The multi antenna switch was “best in show” and comprised a dense package of components, coax connectors, switches and wiring. The PCB traces were cut by hand using a Dremmel tool and “Dead-bug” construction was used; Manhattan would a better label to reflect the 3D nature.
Other projects were a high intercept amplifier, a HF-VHF transverter and a filter designed by Jim Tonne W4ENE (famous for his Elsie filter design software). Tom found it had more pass band loss than expected. Ron questioned the capacitors and will follow up withTom.
We had a fairly long discussion on the significance of the term “Low-dropout” as applied to linear DC regulators like the LM317. This is of interest to Ron who needs a very clean dual 12-5 volt supply for his N2PK VNA. This VNA is similar to a dual channel SDRreceiver with a dynamic range in the region of -140 dBc/Hz. Contrast this with the output noise levels delivered by linear regulators in the region of 20 to 40 micro volts RMS. A product made by OM3LZ was designed for this VNA and has exceptional performance and should be the way forward.
Ron showed graphs of the series inductive reactance, resistance and Q of a coil used in a 40m Hustler whip antenna. At DC the coil has a resistance of 0.5 Ohms which climbs to 500 Ohms at 10 MHz. Q decreases from about 100 at 50 KHz to less than 10 at 10MHz. We briefly discussed the amount of stray RF leaking through the shield of coax cable. A really good shield might be 98% so this at 1500W is potentially a 30 W noise source to adjacent receivers. It would be fun and quite easy to actually measure the degree of coupling between a pair of RG8, LMR cables etc.
The mystery item was a time-honored device about the size of a pencil with a ferrite tip at one end and a brass tip at the other, sorry no prizes. We touched briefly on the subject of maximum power transfer previously raised by Jim K9YC and will defer furthe discussion until the next time he is with us.
May 12 is our next regular session but I may have left for the annual visits back East by then. If so I wish you all a joyful and productive summer in whatever of our great hobby appeals to you. I hope you will continue these meetings in my absence and may yourhearts grow fonder.
73 Ron W6WO
The N2PK VNA
an International Ham Radio Success Story
Oscilloscopes, spectrum analyzers and tracking oscillators are scalar instruments which we have used
for decades so what's new? A VNA is distinguished by the ability to generate, detect and analyze
signals with very precise phase relationships. Prior to the mathematical analysis of electro-magnetic
fields by Clerk Maxwell, vector analysis was probably carried out by physical means.Today affordable
PCs can perform the complex math involved and custom software turns the data into a wide variety of
functions for analyzing the behavior of individual components, networks,transmission lines and
The VNA designed by Paul Kiciak N2PK is unique in several ways. First and foremost design details
and extensive documentation were made available to Radio Amateurs about 15 years ago at no charge.
It has been diligently supported by Paul with new versions as the technology evolved. It is designed as
a homebrew project for the serious builder and experimenter. The technical performance has been
compared to professional products from HP, Boonton and others and found to be very close indeed.
Paul's documentation begins with a few illustrations of precision. For example analysis of a leaded 3.3
Ohm ¼ watt 1% resistor at 40MHz had a resistance of 3.41 Ohms and inductive reactance of 3.3 Ohms.
The superior quality of the N2PK VNA has attracted and encouraged others to contribute their time and
expertise. The associated software and PCB designs are developed and supported by Hams elsewhere
in the US, England, Canada and Sweden. Paul likes to call it the N2PKetal VNA as it is truly an
international Ham Radio success story. Visiting Paul's web site N2PK.com is highly recommended.
I built mine about 14 years ago and used it extensively. One example of the incredible power of aVNA
and associated software is the measurement of common-mode rejection as described in the Nov/Dec
2010 issue of QEX. Recently my own VNA showed no sign of life and after verifying the DC supplies
were OK I concluded that new software drivers were required. For me this became a major challenge
but fortunately a most talented Ham coached me using TeamBuilder; once more proving that members
of our hobby help each other.
The VNA story is incomplete without describing the incredible software and to do so is now on my to-
Ron Skelton W6WO March 2018
“Alexa, help me with ham radio”
By Dan Romanchik, KB6NU
I have had an Amazon Alexa for nearly a year now. Mostly, I just use it to listen to internet radio stations or tell me a joke, but I think it has more potential than that. For example, I’ve written before about how I’d like to develop an Alexa skill to control my IC-7300. I haven’t gotten around to that yet, but, Joe, N3HEE, has just published an Alexa skill called Continuous Wave. It’s designed to help you learn Morse Code.
To use this skill, you have to first enable it. Once enabled, say, “Alexa, open Continuous Wave.” This opens the skill at the main menu. You can then say any of the following at any voice prompt…
- Common words
- Random words
- Call signs
- Quick Brown Fox
- Stop – To end your session.
I’ve just played around with this app for a short time, but I’ve found it to be quite entertaining. It does, however, have one big drawback. You can’t set the speed. It’s currently limited to sending at 20 words per minute only.
Also, the learn function could use a little refining. When you give the command “learn,” it asks you for a character, sends that character three times, and then asks you for another. If you could set the speed at which the skill sends characters, it could teach a character like the K7QO Code Course, first sending the character slowly, then ramping up the speed.
Overall, though, I think this is a great first shot at a usable Alexa skill for teaching Morse Code. I hope this is the first of many versions of this skill.
Other ham radio skills
While I was poking around on Amazon, I decided to see what other amateur radio skills might be available. Here are a few that I found:
- Ham Exam. Ask Alexa to ask you questions from the Technician Class question pool.
- Ham Lookup. Allows you to look up amateurs by call sign. Information is provided from the callbook.info database.
- Ham Radio Propagation Forecast. Reports the latest forecasts directly from HamQSL (run by N0NBH).
- ARRL Audio News. Adds ARRL Audio News to your Alexa flash briefing.
Building your own voice app
The Continuous Wave Alexa skill was developed using tools found at VoiceApps.Com. Two other websites—Pullstring and StoryLine—also have tools to help you build voice apps. And, Amazon has an online tutorial that will teach you how to build an Alexa app. I’m just getting started with these tools, so I can’t recommend one over the others, but they do look like they’ll make developing voice apps easier.
Since I’m currently in the process of updating my No Nonsense Technician Class License Study Guide, it occurs to me that I should also develop an Alexa skill for drilling students on test questions. I guess you could call them audio flashcards. Stay tuned for that.
When he’s not trying to figure out how to build voice apps, Dan blogs about amateur radio at KB6NU.Com, teaches ham radio classes, and operates CW on the HF bands. Look for him on 30m, 40m, and 80m. You can email him about the voice apps that you like at firstname.lastname@example.org.
CAKE Notes for April 14 2018
Ron arrived 5 minutes late and found the following well known subject-matter experts fully engaged in the sunny patio area of The Abbey. Glen KG0T, Don K6GHA, Gary K6PDL, Peter K6UNO, John N5HPB, Ward AE6TY and Tom KW6S. We were shortly joined by Jim K9YC and Cap KE6AFE. Sitting at the end of the long table made it more difficult than usual for Ron W6WO to hear every subject being discussed.
Don mentioned a Makers Fair to be held at Cabrillo College on May 5 and items from the Ham community would be welcome, contact Don for more info. The emphasis would be to show home-brew hardware /software items but also the excitement of modern Ham Radio in action. One suggestion was a sdr radio transmitting JTxx modes with PSK reporter or WSPR net showing a map of connections. Similarly we could demo Ham satellite and Balloon activity. Ron may be out of town on May 5th but offers assistance ahead of the event. Don reminds us that Field Day is soon approaching.
Once more John demonstrated his varied talents for designing and building just about anything. Today he showed a very neat QRP end-fed antenna tuner and in particular we admired his torroids. John is a mine of information about sources including Metric components and PCB fabrication. Decades agoTom KW6S established his reputation for R&D of many items Today it was a neat antenna selection switch. Tom has an Antenna farm in a small back yard which results in complex interaction between antennas and their feed lines. One indication of this issue was a copper shield included in his selection switch.
The topic of shielding often comes up and is currently of interest to Ron where a second N2PK VNA is under construction. Here the challenge is to have noise levels on the 5 and 12 VDC power sources so low as to not degrade the 100 dB+ dynamic range of the VNA. As we all know switching power supplies are noisy and require shielding from electric and possibly magnetic fields. The question we discussed was the choice of material to be used as a shield. Copper is commonly used because electrically induced currents are constrained by virtue of the skin-effect. Magnetic fields are only constrained by magnetic materials such as steel. Ron suggests a shield using tin plated steel could possibly benefit from the conductivity of tin and the magnetic permeability of steel. Can anyone propose an
appropriate test to quantify shield effectiveness?
The topic of noise was introduced by Jim in an entirely different context. It was asserted that applicability of the maximum power transfer theorem between a radio and an antenna was dubious. This resulted in a spirited discussion which amounted to debating whether a) Max power transfer is generally irrelevant b) Relevant only in the transmit path and c) Relevant in both directions. Thanks to Jim for this stimulating topic and welcome further discussion on this important subject at a future CAKE session. Warren’s NR0V assessment would be appreciated.
Cap showed us a list of our complete membership and a separate list of those who have not paid their dues. Frankly the high % of the latter is disappointing.
To all readers, please come and join us, or send in a question to Ron at any level of complexity All with be treated with respect at a future CAKE session.
73 Ron W6WO
Reminiscent of John Reihart’s break though in 1922/3
First USA – EU amateur QSO on 2200m, used QRP Labs Ultimate3S transmitter at both stations
It’s always nice to be able to report unusual uses of the well established Ultimate3S QRSS/WSPR/etc transmitter kit. The majority of constructors use the kit for WSPR. But it can transmit lots of other modes too! CW, FSKCW, DFCW, QRSS, Hell, Slow-Hell, JT9, JT65, ISCAT, Opera, and PI4. In all their various flavours. DFCW is very slow CW, sending Morse characters but with both “dit” and “dah” having the same duration; to differentiate between them there is a frequency shift so that the “dah” is typically 5Hz higher than the “dit”. It has a very high signal to noise ratio when long symbol durations are used.
Chris 2E0ILY and Paul N1BUG report the first ever USA – EU amateur radio QSO on 2200m band (136kHz band), on 26-Mar-2018. They used DFCW mode with 60 second dits and a frequency shift of 0.25Hz permitting a very high signal to noise ratio. 60 second dits in normal CW would mean about 1 word per HOUR!
Chris and Paul both used their Ultimate3S kits to transmit the DFCW messages. Antennas are necessarily electrically short on 2200m, and so typically high powers are used. Paul N1BUG says he uses a home-made single FET Class E power amplifier, with 175-200W output; the EIRP is estimated at no more than 0.5W. His antenna is a 27m tall vertical with 3x 33m parallel top hat wires spaced 1.5. The receiver is a 9m tall low noise vertical feeding home made band pass filter, pre-amp and Software Defined Radio. Paul says:
“We used an old technique of night by night transmission sequencing and completed the QSO in four nights which is the minimum possible with this method. This QSO would not have been possible without Chris’s kindness and dedication nor without my trust U3S!”
“The receiver is a modified Softrock Lite II. The oscillator has been reworked to provide a suitable LO for 2200m reception, the front end filter reworked and significantly augmented. It is preceded by a 2N5109 preamp and BPF.”
More details are on Paul’s website http://www.n1bug.com/lfmf/
The pictures below show Paul’s Ultimate3S, and Chris 2E0ILY’s transmission mberswith the “O” signal report as received by Paul N1BUG.
Congratulations to Paul N1BUG and Chris 2E0ILY on this achievement!
CAKE Notes March 24 2018
We welcomed Mike AJ4NR for the first time and were pleased to haven Richard K8SQB back with us. New minds and voices add so much to our discussions.
Gary K6PDL attends regularly as does Glen KG0T. Gary evidently knows a great deal about “drivers” and offered Ron some suggestions on how to proceed to update those associated with his N2PK Vector Network Analyzer. Unusually our session today included several topics concerning test instruments. Richard showed his newly purchased MetroVNA which is an attractive product about the size of a smart cellphone. It has a most useful frequency range from 0.1 to 256 MHz and gave an impressive demo of a short whip antenna SWR. We are keen to hear more about it in due course.
Ham radio Workbench has been mentioned previously and Mike has recently acquired one of their products, here is a summary of what is included. George from the Ham Radio Workbench states: “Every ham radio workbench needs an oscilloscope, waveform generator, voltmeter, data logger, logic analyzer, and spectrum analyzer. The Analog Discovery 2 includes all these and more in a compact USB connected device. These features are essential for designing and debugging audio amplifiers, filters, logic control circuits, power supplies, etc. The compact size makes it easy to take your workbench with you to the repeater site, DXpedition or the Field Day site”. We keenly await hearing more from Mike. In stark contrast we recalled the huge cost of early test gear,computers and memory.
Gary is enthusiastic about his hand-held Digital Mode Radio (not Digital Radio Mondial ) for talking around the world via a network of digital repeaters.. I think this would fit in well as a presentation on the alternatives such as Echolink, DSTAR, IRLP etc…
As is now the custom there was some intense discussion on Raspberry Pi and like products. Glen is our subject matter expert and mentioned a new
version , the Pi 3B+ It was seen as a fine way to enter the world of uproc programming at low cost. Ron met the inventors of the first 4 bit chip in the mid 70s and remains an interested listener to these discussions today.
There has never been a CAKE meeting without some discussions on antennas. True to form today Glen said he had found an EZNEC model of a small loopwhich Ron has been looking for. Richard had several questions including options for HF antennas while traveling, Ron expressed his opinion that a
telescopic fiber pole to support an inverted VEE is a simple and effective option for regional communications. A vertical quarter wave with some above ground “counterpoise” wires of some sort can be quite effective for DX This could include other features such as a base inductance and a series inductance at about 2/3 from the base. Such an antenna would be only 3dB less efficient than a full half wave radiator. Contact Ron for more info if interested.
Ron mentioned he was disappointed by the way the QEX Editor rejected two recent draft articles. Their policy to provide no further communications
is the antithesis of Hams trying to encourage one another. The Editor of QST may also have reasons for rejecting articles but gives much more help
in understanding the requirements. In short QST issues are likely to include construction details,list of materials etc.
That’s all the news fit to print 73 BCNU in 2 weeks if not before
Bonus When are you likely to find the first description of a VNA to measure common-mode rejection ?