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June Meeting Date Change, June 14

and Speaker Announced

At the last board meeting it was decided that it would  be best to move the June meeting date up a week to accommodate Field Day activities.  Our guest speaker for that month, Ray Rischpater (KF6GPE), is agreeable to moving the date as well. Here is a bio and summary of his program for June 14:

The Automated Packet Reporting System (APRS) has seen a lot of use since its advent in 1984, and is the most popular digital mode on VHF today, providing real-time telemetry, position reporting, and messaging. A lot has changed since 1984, however — there’s an internet backbone for your traffic, satellites when you’re not within range of your local digipeater, and the possibility of working APRS using just a soundcard and PC, or with a stand-alone radio or your smartphone. In this talk, I’ll show you how to get started if you’re not already on the air with APRS, and maybe show you a thing or two you didn’t already know if you are!”

And the bio:

I’m a software engineer and author with twenty-five years of industry experience and sixteen books to my credit. Beginning with software development for mobile platforms, I’ve done work in several areas, including mobile, web services, building tools for mapping and geospatial engineering, and applying machine learning to geospatial processing problems. When not writing for or about software development, I enjoy writing, making music, hiking, and photography with my family and friends in and around the San Lorenzo Valley in central California. When I’m able, I also provide public service through amateur radio as the licensed Amateur Extra station KF6GPE.


Getting loaded (antenna-wise, anyway)

By Dan Romanchik, KB6NU

A couple of years ago, I homebrewed a “Cobra” antenna (https://www.kb6nu.com/yet-another-new-antenna-the-cobra/). It’s a doublet antenna, meaning that it consists of two elements connected to a center insulator, where it connects to a feedline. The unique thing about the Cobra antenna is that each element consists of three parallel conductors connected in series.

My antenna uses a lightweight, three-conductor rotor cable that used to be available from Radio Shack. The feedline is 450 Ω ladder line that connects to an antenna tuner to give me multi-band operation.

Connecting the conductors in this way is is supposed to provide “linear loading.” Somehow, running the conductors in parallel is supposed to increase the antenna’s effective length. My antenna is only 73-ft. long, but it easily tunes up on 80m.

The ARRL Antenna Book has a short section on linear loading. It says that linear loading is a “little understood” alternative to inductive loading that can be applied to almost any type of antenna. Furthermore, “…it introduces very little loos, does not degrade directivity patterns, and has low enough Q to allow reasonably good bandwidths.”

As I mentioned, I’ve been using this antenna with good results for a little more than two years now. When I first put it up, someone mentioned the concept of linear loading to me, but not being an antenna guru, I didn’t ‘give it much thought. About a week ago, though, I ran across a link to the page Short Ham Antennas for HF (https://www.hamradiosecrets.com/short-ham-antennas.html). That got me thinking about the topic again.

This page describes a way to build a linearly-loaded dipole antenna with a feedpoint impedance of approximately 35 Ω. This allows you to feed it with coax instead of the ladder line that I use. The author uses 390 Ω ladder line for the elements. He says it’s commonly available, but I don’t think I’ve ever seen 390 Ω ladder line. You could probably use 450 Ω ladder line by adjusting the element lengths a little.

At that point, I started Googling. The next linear-loaded antenna design that I ran across is a design from M0PZT (http://www.m0pzt.com/40m-linear-loaded-dipole/). He built his elements from some sturdy wire and homebrewed spacers made from PVC pipe. He’s used this design for the 40m elements of a fan dipole covering the 40m, 20m, 15m, and 12m bands. Only the 40m elements are linear-loaded.

I also found a design for a linear loaded vertical antenna for 40m and 80m (https://www.qsl.net/pa3hbb/ll.htm). This antenna is only 7.736m, or 25.4 ft. tall. Of course, it requires a good radial system to work well, but it will work a lot better for DX than a low doublet or dipole.

Finally, there’s an eHam discussion on linear loading (https://www.eham.net/ehamforum/smf/index.php?topic=84418.0). Unlike a lot of eHam discussions, this one is quite civil. It’s worth reading if you’re interested in the topic.

So, if you’re thinking of getting loaded, errrrr, I mean loading your antennas, here’s a method for you to consider. It works!


 

Congratulations to Gary Watson, K6PDL

Congratulations to Gary Watson, K6PDL, for his volunteer communications workon our behalf.  For his work with County OES, Gary is scheduled to be recognized with a Outstanding Volunteer Award at the County Board of Supervisors meeting at 10AM on March 16th.  And Gary has just received his Certificate of Successful Course Completion for the ARRL’s advanced course, “Public Service and Emergency Communications Management for Radio Amateurs (EC-016).”  Gary is our first local ham to complete this training course.
Now Gary qualifies as Level 3 in the new 2019 national “ARES Plan.”
Thanks, Gary!
73, Cap KE6AFE

 

Notes from the CAKE meetingCAKE Crumbs for April 13 2019

Glen KG0T, Peter K6UNO and Ron W6WO met in comfort at the Abbey. The close-knit trio provided an opportunity for some intense discussions.

Glen is now well known for the breadth and depth of his knowledge in the field micro processors . The word “field” seems quite appropriate as they seem to be appearing like mushrooms. Glen brought seven types mounted on a breadboard and proceeded to describe how they compare in terms of speed, languages, ease of development and system software. The one item they had in common was their purchase cost being in single digit dollars. Ron commented that in his case the cost of programming labor would be prohibitive. Glen hinted that he was developing a presentation on uProcs to deliver at a future SLVARC meeting. Stay alert for details

Peter returned to a previous CAKE topic of software for printed circuit board (PCB) layout and fabrication. Peter showed a recent book on KiCAD -pro which is evidently a powerful well documented product. More details can be found on txplore.com and a PCB fabrication firm called OSHPark.

Peter asked how Ron’s VNA exercise was pr proceeding. The best way to respond is to quote Lao-Tzu (a 6th century Chinese philosopher and writer). “The further one pursues knowledge- the less one knows” In this instance all was going well until my home-brew short circuit calibration standard was measured giving the result of 0.0007 Ohms. A value of 0.007 would have been cause for celebration as it indicates a precision needed to make accurate ESR measurements- however one extra zero seems unealistic and suggests all is not well.

Glen posed one of his insightful and deceptively simple questions -”what makes a VNA the instrument of choice for measuring impedance ?”Leaving aside the question of accuracy my best answer is that it combines all the needed elements of a programmable signal source having precise frequency and phase , a vector voltmeter, phase sensitive detection, analog-digital conversion and digital signal processing together with a comprehensive graphical user interface.That said even high-end   Rhode and Swartz VNAs have trouble measuring capacitor ESR.

A VNA provides the same degree of dynamic range, precision and upgrade potential which makes a SDR the choice for Amateur communications. The VNA I made was designed by true experts N2PK and G8KBB who have a high regard for entry level users while satisfying the professional demands of others. Our conversation included some terminology relevant to VNA measurements such as reflective loss and dissipation loss .

At his point in time I would like to inform all readers that I am about to leave the area for my annual trek to GA and KY with a possible side trip to the UK ( while it stillhas the U ) with an open ended return date, most likely in August

73 all round Ron W6WO

 


30th Annual Strawberry Fields Bike Ride

Volunteers Needed

We are looking for volunteers for the 30th annual Strawberry Fields Bike ride from around 8:00 am until the around 15:30 (depending on the shift) on Sunday, May 19th.

Operators novice & experienced are invited to join us! If you’ve never participated in a public service event, this is an easy one. We provide safety and situational awareness for the race at four rest stops.
If you can make it, please let me know so I can provide a count of available operators to the race director.

Please reply with: *Name: *Call: *Email: *Phone: *Favorite assignment (if any):
*Did you sign up on the website?:  *T-Shirt size:
(There is no guarantee of T-shirts or if we’ll have the correct sizes but let us know anyway)The event organizers are asking that we also sign-up on the Strawberry Fields site:  https://cyclistsforculturalexchange.redpodium.com/strawberry-fields-forever-xxx-volunteers-2019 . Under “Volunteer Team” select “Radio”. If you sign up on the website please let me know.

Feel free to forward this if you know someone that’s interested but may not be on the reflectors.
For more information about the event browse to https://www.cyclistsforculturalexchange.org/sff

Thanks & 73
Dan  N6RJX

CAKE Notes for March 9 2019

The heavy rain did not deter Peter K6UNO or Glen KG0T from joining Ron W6WO at The Abbey.

We discussed the way methods for designing and fabricating Printed Circuit Boards have evolved from crude techniques involving tape and chemicals . Peter spoke highly of KICAD 5.0.2 which is open source software that automates component placement, routing and ordering of components. There are several choices for board fabrication PCB Express being just one of many. Expert help is an advantage to becoming familiar with such powerful software, Peter has found folk at APCircuits very helpful.

We discussed how to handle Surface Mounted Devices (tip: order a few extra as they tend to take wings). Soldering them to a PCB is not as onerous as may be thought. It was generally agreed that working in a good light was important as was using a very fine tip to a temperature controlled iron. A wooden toothpick is popular for holding a component in place. Ron believes that it is of utmost importance to have surfaces clean and preferably those that have been “tinned” in advance. Using a microscope seems to be a personal preference . Even now the simple use of VeroBoard and Dremmel tools is expedient.

Problem solving has also evolved over time and Glen recalls the days of using a “bed of nails” to access test points. Finding problems in software without detailed documentation has probably become more difficult over time. In contrast fixing the loss of network access was simply a matter of locating an obscure on-off switch.

Ron has progressed in gaining knowledge of his Vector Network Analyzer and showed some results from making measurements of capacitors. For those with a VNA here is a simple exercise. After instrument calibration make reflection-mode measurements of resistance and the reactances inherent to your Open-Source-Load standards. My standards are home-brew, so it would be helpful to compare results. Glen asked how can measurements avoid errors due to the resistance incurred by test probes making contact with the device under test. The solution comes from using a technique invented by Lord Kelvin in the 1800s known as the Kelvin 4-point method. This is possible using a two port VNA to measure S21 parameters. Ron will post an image of the technique to Short Skip and provide measurement data in due course.

Better Kelvin picture

On March 6th George Badger W3AB and Ron attended a full day seminar on RF measurements put on by Keysight technologies in Santa Clara, analog and digital topics were presented . Rosenfell detection was mentioned in the context of noise reduction. I note this topic is mentioned in a recent software update for the Anan SDR radio, it (Warren ts) finding out more.about it. Both George and Ron have reasons to make a follow up visit to Keysight. Incidentally the ride in George’s Tesla model 3 was quite intriguing. Imagine driving over the hill in rush hour without having to manually apply the brake.

That’s all for now BCNU March 23 , assume at the Abbey unless other arrangements are selected.

Following the advice of Bob Marley I wish you Positive Vibrations Ron W6WO

 


CAKE  Notes for Feb 23 2019

Our regular “small group” participants  Reed N1WC, Gary K6PDL,  John N5HPB, Kerry K3RRY , Peter K6UNO and Glen KG0T joined Ron W6WO. It was a cool morning which prompted us to sit in comfortable armchairs – comfort at some expense of easy listening.

Gary mentioned the challenge of training VE (Volunteer Examiners) due to turnover of participants. Some of us have a modicum of teaching experience so it could be useful to show  some of the material used in the VE sessions. The demise of Yahoo groups  seems to have encouraged migration to “groupsio”  QRPlabs  is one example.

John never ceases to amaze us with his multifaceted interests and talents- today he described what it takes to find tiny neon bulbs from the 1950s. He found some but only a few were in working order. The group suggested the glass seal had failed releasing the neon gas. Ron related a similar situation where the fluid in a VHS tape-head cleaning product had failed.. Use of a Q-tip to manually clean the heads was recommended. John astounded us once again by his ability to design useful items with 3D printing. Not content with his printer John is now building one of his own design.

Glen is making good progress with his knee surgery and we much appreciate his  effort to take part in our sessions. Glen’s micro-processor Dejour is called Blue Pill (nothing to do with blue-tooth). Glen likes this item as the on-board cost was <$2 shipped, supports Linux and includes a debugger. How about a presentation at a Club meeting Glen? There was some conversation about the history of computer memory and once again the evolution is simply incredible. Adding a 30m element to a 40/80m Butternut vertical came up but we decided to defer discussion. Kerry showed a very cool push button switch with internal colored lights.

Peter is well known as an audiophile and has loaned Ron a copy of an excellent book entitled  “Linear Audio”. It goes to great length to show how audio quality can deteriorate due to power dissipated  in capacitors. At DC and AF these losses are mainly due to the dielectric  material, Polyethylene derivatives are popular dielectric materials. The concerns at audio for power output, efficiency and quality are similar to those at RF but the choices of component technologies can be quite different. Quiz  What typical insulation resistance should be expected in a quality AF/DC capacitor 1, 10, 100, 1,000, 10,000  MOhms ?  What typical Equivalent Series Resistance ESR should be expected in a quality RF capacitor 1,10,100,1000,10,000 mOhms ?

Ron reported some progress in measuring ESR which wastes power in battery- powered devices such as RF beacons and  medical implants. The expected growth of all manner of IOT devices will emphasize the importance of ESR in determining battery life. Incidentally the typical battery in a pacemaker is expected to last about 8 years. How many ampere hours would that be ?   

We discussed a question Don K6GHA had sent in. This concerned the ability to remotely control a relay to switch a single AC power supply between his water pump and crank up tower motor. The group were sure this would be possible but.wanted  more details on what Don was trying to  avoid.

Our next session is on March 9th. which coincides with the Flea-market so we can look forward to some interesting items. 73 BCNU  March 9th   

PS Ron is still looking to share a ride to SJC on March 6th to attend a Foresight seminar on RF,


 

Frank Carrol Jr K6BDK SK,  Bob Perry K6GDI SK

Sadly, two prominent local HAM radio operators have passed away recently.

Frank Carroll, Jr. (K6BDK) passed away in Bend, Oregon on January 26, 2019.  His service will be held Saturday, April 13 at 2pm at the Santa Cruz Memorial Park on Ocean Street Extension in Santa Cruz.  A reception will follow at the Santa Cruz Elks Club on Jewell Street.  Donations in Frank’s memory may be made to the Partner’s in Care Hospice House, Bend, Oregon.  Here is the link to the website: https://www.partnersbend.org/get-involved/donate-to-bend-hospice/

Bob Perry (K6GDI) was a regular voice on the K6RMW repeater, and an active member of the South County ARES and other emergency communications efforts.  He passed away on February 14, 2019, according to his long-time friend Bob Wiser (K6RMW).  No further information is available at this time.

Both will be greatly missed.

73,
Becky
KI6TKB

Photos from SCCARC Annual Holiday Celebration

Saturday December 15 at the Capitol Ihop.

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David Shoaf KG6IRW, SK

I am very sad to announce that one of our club members is SK.

David Shoaf (KG6IRW) passed last Thursday, Nov. 29th after a short, but valiant, battle with cancer.

Our thoughts, prayers, and condolences go out to David’s family, his wife Sharon, and David’s son, and grandchildren.

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Davidl appeared at a CAKE meeting in October, and Ron (W6WO) commented on how everyone was delighted and happy to see him attend the meeting. David had a way of making a conversation light up, especially when he talked of the hobby he enjoyed, and the equipment he supported. Always an ambassador of fun, David’s contribution to any conversation was appreciated, and interesting.

I met David around 2011 when he attended the K6BJ Club meetings, and he soon became a semi-regular at CAKE meetings. Elecraft soon occupied much of his time,  where he became their chief support and event manager.

Through a series of conversations, David and I came to find out that we had crossed paths many times in life. From our shared background working at Hewlett Packard (David for over 20 years), at events when he was representing Elecraft (Dayton, Friedrichshafen, and Visalia), and at his other passion of playing at local musical events, like Bocci’s Cellar and other locations around town. One of my favorite times to say Hi to David was as a runner in the Wharf-to-Wharf 10K race. My annual visit to him was punctuated by a quick wave, and a shouted ‘73’ as I ran past, while he played for the participants, and waved back.

David spent his time helping others. Setting up an HF station, giving inspiring talks to the club on a variety topics like Amplifiers and upcoming digital technologies. In one talk on JT-65 (I still have the link to his slides), not only did he tell us about it, he actually went to peoples shacks (including mine) to get them up and running! All you had to do was ask. 

Storytelling by David was still one of the greatest joys in being around him. His smooth voice incorporated a warm southeastern style, with a little mischief. It was his signature on (and off) the air. When you got him talking, you also found out about his audiophile and engineering background, and his joy just talking to folks. David always had an ease and grace in making you feel like you were his friend, even if you only just had met him. There we many stories told at events, but none where so special to him when he proudly talked about his son as a pilot in the Air Force, and David working him on HF while in flight.

I’ll miss a David as a Ham, a musician, but most of all a friend.

It is unknown at this time if a celebration of life will be held, but please let everyone know if there will be one.
I am sure there will be some wonderful stories, good laughs, and warm friendships continued and created. Something David would enjoy.

73, de Don K6GHA
SCCARC President

K6GHA@arrl.net


Some Images from the December 8 CAKE Meeting

Rene K6XW and old rectifier

Rene K6XW and old rectifier

The CAKE group dec 8 2018

The CAKE group dec 8 2018  The seated group from L-R are Richard K8SQB Tom KW6S Fred KJ6OOV Eric WA6HHQ Ron W6WO and Vic AE6ID

W6WO ESR Test Board

W6WO ESR Test Board

Fine 60s era amp shown by Rene K6XW

Fine 60s era amp shown by Rene K6XW

 


Field Day 2018 at Ben Lomomd CDF Camp

 
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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!