Author Archives: OCRA Website Admin

OCRA General Membership Over the Air Meeting June 10,2020

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In compliance with The State of North Carolina’s revised health requirements for preventing the spread of Corvid-19, this meeting could not assemble at our normal gathering place in Efland, NC. Instead it was replaced by a virtual event that made use of the 442.150MHz repeater and ZOOM. This novel functional linking together of a club repeater with Zoom, a popular and widely used video conferencing platform, made it possible for all members of the club to both attend and participate in a virtual meeting. The club gives its special thanks to Dan, KR4UB, our treasurer/website manager, and Mark, KR3AM for spearheading and providing continuing support for this initiative.

MEETING (7:30 PM): The meeting was convened at 7:30 P.M. by club president David W4SAR. The check-in process proceeded smoothly. Callsigns from 32 stations attending stations were recognized.

Introductory Announcements:

  1. Dan KR4UB: We currently have 105 members on the club roster, 75 of which have paid up dues. In addition, new apps have been placed on the club website. One of these is for Zoom conferencing. The club has purchased a site license to use this product
  1. David W4SAR: The club is looking for ways to continue offering its program of volunteer-administered license testing for members in the wake of the pandemic. One approach to solving this problem might be to search out opportunities for collaboration with other clubs to accomplish this important function remotely in a shared fashion. David also reaffirmed that the club will continue to practice social distancing in all of its activities. .

Discussion:

  1. David W4SAR: The main topic for this meeting is to discuss how the club’s participation in field day will be impacted by the recent rule changes proposed and adopted for the event by the ARRL. Before launching that discussion It is important to recall that the rule changes were made to encourage and allow broadened participation of League members and clubs from their home stations rather than stations grouped together in a “field” setting which has traditionally been the desired format. In fact, in past years club rules have dictated that participating stations operating from their homes and obtaining power from commercial mains (Category “D” stations) could only earn contact points for exchanges with traditional non-D stations operating in the field. The new rules recently placed in effect only for field day 2020 permit category ”D” stations to work and earn contact points through exchanges with all other categories of stations participating in the event.
  1. Questions and Comments from Membership

This section contains a synopsis of the commentary offered by club members following David’s introduction.

  1. Wilson W4BOH – Offered operating space to anyone wishing to set up a station at his home. This kind offer is a continuation of Wilson’s generous hosting of the field day operations for OCRA and DFMA members for many years.
  2. Howie WA4PSC – Offered to provide an Elecraft KX3 for someone needing an HF rig for SSB or CW operation in the contest.
  3. Aurora KN4VXB — Announced her interest in making satellite contacts during Field day. She would like to work with others to build a station capable of doing that. One of her planned projects is to build a tape measure antenna for satellite work.
  4. Bill N8BR – Offered the use of his IC7300 for someone needing an HF rig for CW or SSB operation during the contest.
  5. Bruce N1LN – Offered suggestions on how the club might best organize its overall effort during this year’s revised event. Historically speaking field day efforts involving DFMA / OCRA groups during past years have been highly coordinated. Stations for each band have been planned, organized, equipped, set-up and staffed under the tutelage of a Band captain who has overseen its operation throughout the entire weekend event, and ultimately helped our club president in the preparation of a composite club log for submission to the ARRL. However, the operation we are contemplating for this year is comprised of a group of autonomous stations separated by relatively long distances each focused on earning as many points as possible in a contest effort for which many of us have little experience. There are no band captains to organize operators, attend to equipment needs, design and set up stations for individual bands, or coordinate logging. Many of us may be very good operators but are lacking in the knowledge or equipment needed to get the whole job done. To help to alleviate some of these issues I am volunteering to contact those of you planning to operate in FD to determine any equipment needs you may have or special assistance you may need to get your planned operations up and running. That information will be posted on the club website. We also need to know what resources you might have available to help others participate more effectively in this effort. Please note that we have only about 2 weeks to not only get our planning done but to implement it as well.
  6. David W4SAR: As a point of clarification, logging for field day operations this year will be done and submitted to the ARRL on an individual basis by each participating category D station wishing to contribute to a club score. Please study the current rules for field day and procedures for submitting logs found at ARRL.org or on your club website. In order for your QSO’s to count toward our combined club score please indicate your affiliation with OCRA/DFMA when you submit your log.

After a number of closing comments the meeting adjourned at 9:17 PM.

Bill N8BR/s

OCRA-DFMA Fox Hunt – Aug. 1 2020 – Save the Date!

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Fellow Hams,

I had a good response to my survey and both the on-foot and vehicle based fox hunt events are a go. Thanks so much to everyone who responded!
I am happy to announce that there is one day that works for all interested participants.

Mark your calendars for August 1 for the OCRA-DFMA fox hunt event. For those of you who indicated interest in making or loaning transmitters, I will be in contact soon.

Best,

Aurora (KN4VXB)

Communications for coordination during the  August 1st Saturday Fox Hunt will be held on the OCRA 442.150 repeater.  Further details will be posted.

Fox Hunt Proposal

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from Aurora, KN4VXB

Fellow Hams,

I mentioned this idea to at the Zoom OCRA meeting today, but I don’t think it got broadcast on the repeater, and I wanted to share the idea with the larger group:

Like many, I was sad that field day won’t be happening as usual, and I was trying to think of a group activity that could be done while maintaining social distancing. As preparation for eventual recovery of my own high altitude balloons, I would like to improve my skills at finding hidden APRS trackers.

The logical combination of these two ideas is a Fox Hunt! For those who don’t know, a fox hunt is a scavenger hunt for hidden radio transmitters.

I am happy to be the organizer for this event, but as I am am new to this, I would like an experienced advisors (or two) who would be willing to assist. I recently ordered a small APRS transmitter that I am willing to let the group use for the event, if needed. I have a few questions:

1. Would you be interested in participating in a club fox hunt?
2. Have you done so before? If so, what did you like/not like about what you did before?
3. Do you have equipment we could use for the event, such as APRS transmitters or extra antennas/HTs for folks who don’t have them?
4. Should we have prizes or simply bragging rights? If prizes, how should that work?
5. Would you be willing to help me organize?
6. Do you think late July or early August would be a reasonable time to do this? (I’m starting grad school in mid-August, so if I’m organizing, I’d like to have this done before then.)

Thanks in advance for feedback and ideas!

05/13/20 Update:
Thanks everyone who gave me feedback on my idea!  Based on feedback I’ve gotten so far I’d like to amend my original proposal in a few ways.  I propose we have TWO events over the course of a day or weekend:

  • Event 1: An early- to mid-morning (before it gets too hot) on-foot search for transmitters at a park or large private property.  From the feedback I got, a 2-m transmitter that sends out a string of Morse code would be better than an APRS transmitter, as I originally proposed.  I think this may be fun to do in teams of 3-4 people to make it more social.  Maybe one experience person and 2-3 newbies per team?  Perhaps a capture-the-flag type event where each team hides transmitters that the other teams have to find?  For public health reasons, team members that are not from the same family must stay more than 2 m apart, which should be easy to do.
  • Event 2:  A late morning thru afternoon fox hunt in vehicles to find a hidden person transmitting from an undisclosed location.  The ideal fox would place themselves in an unlikely place where they can work the repeater, but not be heard on the input.  For 50 minutes out of every hours, the “fox” must answer questions when asked by repeater users on the club repeater.  Since this activity can be done in air conditioned vehicles, this event will allow folks who don’t want to slog through the woods or be out in the heat to participate.
If this sounds ok, I will work on putting together a more fleshed out description of events for the group to review and an online survey to figure out who is interested in doing what.  I will plan to only organize events that people actually want to do, and are willing to help out with preparations for.

Best,

Aurora

OCRA Club Over-the-Air Meeting 442.150 Repeater with Audio Linked Zoom Conference

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Monday, May 11th, 2020
7:30pm to 8:30pm
Description:
Our next monthly membership meeting for OCRA will be Monday, May 11 at 7:30 pm.  Since Orange County still restricts all gatherings to 10 persons or less, the Efland Baha’i Center remains closed.

We will hold the meeting over the W4UNC 442.150+ repeater, PL 131.8

Additionally, we will have a Zoom meeting held simultaneously, so that those who cannot access the repeater may still participate. We have been experimenting with audio links between Zoom and the repeater, so it should work well.

Hope to hear you there!

See the OCRA Club Meeting Notice posted on the OCRA/DFMA groups.io Message Board for the OCRA Zoom Video Conference Log-in Information.

73,

Dave Snyder, W4SAR

========================================

 

 

Bill, N8BR on the OCRA Monday Night 10M Net via Video Conference

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Remember the HF phone patch that used to be commonplace in the ham shack years ago?  How about a video conference HF patch?  Or for that matter, flip a switch and it’s a video conference to VHF/UHF patch?

Bill, N8BR does not have an HF station at his QTH, but that did not stop him from listening to the net and Dan, KR4UB passing on his comments to the net.

Dan hosted a video conference and invited Bill to join the OCRA Monday Night 10M Net on 28.450 via video conference.  Ham station audio is fed into the computer running the video conference application. A simple switch of the video conference microphone device driver setting from the normally used Logitech HD camera microphone to the computer line-input brings the ham radio receiver audio and Dan’s Heil headset microphone audio into the video conference.

© 2024 photo by KR4UB, OCRA Inc

Much of the equipment used and shown below has origin in other usage and has morphed into a small home audio studio serving multiple purposes. This application is a good example of the versatility it can provide.

The video conference “audio patch” application demonstrated here might could be built using some of the audio interfacing devices found in today’s ham shack for computer sound card driven amateur radio communication modes. However, if undertaken getting the audio chain correct might still require use of external audio mixers, attenuators, and additional isolation and perhaps impedance matching transformers, and instrumentation to get the sound right.

W2IHY Technologies Equalizer Function

The ham radio connections in this setup uses a W2IHY Technologies Equalizer that has multiple microphone inputs, one used for the Heil Headset microphone and a second input is used for the video conference inbound audio feed.  The internal microphone amplifier gain is adjustable to ensure appropriate drive level to the selected ham transmitter with the output fed via an internal isolation transformer for RFI protection. The output is switch selectable to one of  two ham station transmitters, in this case a Yaesu 8900 VHF/UHF and the Elecraft K3s transceiver. The phone jack output is an outbound (ham transmitter mic input) audio monitor output that is also connected to one of the Roland Monitors as described below. The equalizer interconnection ports available for all audio outbound to the ham radios are shown below.

 

Roland CM-30 Studio Monitor Function

Two Roland CM-30 Mini-Cube Studio Monitors in an interconnected stereo link configuration provides multiple audio channel mixer inputs as shown below on the one of the two units. One of the CM-30 units is used for all inbound (video conference incoming audio & ham radio receiver audio) feed mixing. Outbound (ham transmitter microphone inputs & video conference outbound) audio is separately mixed in, permitting audio from all sources to be monitored on the Heil headset as a final control operator quality check. Roland, a major manufacturer of musical instruments and sound stage equipment describes the CM-30 as a multi-purpose portable mixing monitor for the home-studio and portable live monitoring onstage applications.

 

 

A Jensen two channel isolation transformer previously used in a home theatre application is used to provide RF & ground loop isolation between the ham station and computer audio connections.  Braid ground strapping bonds all equipment to the common station ground.

A recently added connection for the video conference audio output will permit that feed to be mixed into the Elecraft HF or the Yaesu VHF/UHF mic input so video conference folks have half-duplex two way audio communications and can join the rag chew. None of this will be automatic and will require the control operator to set up the “audio patch” and operate the PTT control, the same as was required by the FCC back in the days of “phone patch” operations.

Inbound, Outbound, Mixing, Attenuators, etc, etc

Does the above discussion of all the inbound, outbound, audio mixing sound like one giant circular loop?  Not surprising… Ever wonder why speakerphones, telephone handsets, cellphones, bluetooth headsets, hearing aids and now video/audio conferencing…. any accoustic environment where speakers and microphones are in close audio proximity doesn’t turn into an enormous squealing audio feed back loop?  You’ve probably heard that many times with public address systems. What’s the magic?  What invention took place and has been deployed in telephone systems from the beginning?  The telephone hybrid transformer, used in bidirectional audio paths where two audio directions are combined in to a single audio channel. This function is essential in today’s world of communication devices and typically done with digitial signal audio processing. The mixing and combining of audio paths described in the above setup had to be done in a way to avoid generating an audio feedback loop at several possible points in the circuit.  The bidirectional processing or half-duplexing of conference audio by a video conference service is also a necessary ingredient.

The Nearby HT / Repeater Echo Effect

You’ve probably have experienced this effect in ham gatherings when you transmit on with your HT into a repeater and someone close to you has their HT volume turned up on the same repeater you are using.  You’ll hear your own voice coming through being delayed in time or an outright audio feed back squeal occurring. The delayed audio echo effect is caused by an audio delay line in the repeater controller for the purpose of removing squelch noise bursts at the beginning and end of every transmission into the repeater and also for masking DTMF repeater control tones sent to the repeater.  The OCRA 442.150mHz repeater is programmed to use a 70 msec audio delay to accomplish the above purposes. Sounds short, but very disorienting to hear your own voice delayed in time as you try to speak!

The conference to repeater audio bridge described in this article can have similar echos in the video conference side when repeater radio transmissions are recirculated from radios in the video conference. Video conferences can be more vulnerable as downloaded video conference applications typically provide a microphone audio AGC (automatic gain control) that if checked will adjust your computer/conference device microphone gain on the fly to make all voices at the same level in the conference. This is a good thing for the conference, but stray radio audio can be problematic.

However, the effect can be totally eliminated by proper audio protocols being practiced by those in the video conference. Those procedures will be described in a separate article.

While the equipment used here may border on overkill, hopefully the above audio discussion explains the necessity and there are advantages especially in the ability to measure, set and monitor audio levels at the key points in the audio chain. Among other uses, this setup has been used for some years as the final over the air audio level checks before a newly built repeater is deployed to a difficult to reach site such as the OCRA 442.150 mHz repeater located high up on the TV tower.

The setup is also used for periodic repeater checks and troubleshooting when repeater problems have arisen. The computer can do extended VOX triggered recording of the repeater to catch intermittent problems and spectrographic analysis software can be helpful on certain types of repeater issues.

Useful Software for Proper Audio Setup

Two computer applications were used to adjust the audio levels for optimum quality. The first program called Spectrogram, used in a vast range of fields, was written many years ago by Richard Horne, an Electrical Engineer working for the U.S. Navy. The second program Goldwave, a professional digital audio application was used to analyze historic recordings of the Moon landing, including establishing the “missing word” from astronaut Neil Armstrong’s famous line.

In summary, the building of this setup has been heavily influenced by other audio interests & needs, but also by experience in building the OCRA repeaters for the last 20 years. Mentoring by Danny, K4ITL in the early days of repeater building taught what it takes to set up repeaters to have excellent audio quality.

Dan, KR4UB

Bug Refurb – Another Piece from the Old Novice Station

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from Bruce, N1LN

Another piece of the old novice station finished today.   The bug is one that my long ago SK uncle, W2NAD, gave me after I first got my ticket.  Since then I modified it into a paddle to use with a keyer I built from the ARRL book, Understanding Amateur Radio.

Now about 56 years later, it is a bug again!

© 2024 photo by N1LN, OCRA Inc

I lost the original weights so I made one out of a large galvanized bolt.   I cut the head off with a hack saw, drilled it / tapped it and DONE!

© 2024 photo by N1LN, OCRA Inc

He also let me borrow his HQ-129X, which is why I purchased one to go with my DX60 / HG10 combo.

 

DFMA / OCRA 2020 Field Day Cancelled due to COVID-19

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There will not be a joint DFMA / OCRA 2020 Field Day (FD) event due to COVID19 related issues. Safety first. The ARRL has not changed any rules regarding FD 2020 at this time. If you want to participate in FD 2020 you may due so as you wish from your home. Please refer to ARRL FD 2020 rules and apply them to your own operating conditions.

Dave, W4SAR

Polycomm (Obi) 202 as a shack telephone service solution

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By Charles McComas KN4PTU

I like having a wired desk phone in my home office/radio shack for use during conference calls and long waits for tech support. The clarity and functionality of a landline desk phone is much better than the average cellular connection. Until the last few months this was handled quite well by a VPN connection to my employer’s Cisco VOIP system. After I retired, I started looking for a new solution. In a perfect world, I would have gotten a POTS (Plain Old Telephone Service) line, as the reliability of the old analog copper wire system is unmatched by the newer VOIP (Voice over Internet Protocol) telephone services. Unfortunately new POTS lines are not available and all telephone service providers are rapidly changing existing lines to VOIP.

Checking with AT&T, my current ISP (Internet Service Provider), it would cost me a $100 setup fee and around twenty dollars a month for a phone line. I have had great experiences with the knowledgeable AT&T technicians in the past but a $100 service call to plug in a patch cable is a bit steep.

In my net surfing I came across Obi, who makes a range of ATA (Analog Telephone Adaptors) devices and phones. I ordered an Obi, now Polycom Obi202 ATA  (Photo 1) as it has a second phone line port that I plan to use for the fax function on my multi-function printer.

Picture of the Polycom Obi202

(Photo 1) Polycom Obi202

The back of the unit (Photo 2) has the two phone line (RJ11) connectors, a USB port for future functionality and two RJ45 connectors, one for Internet in and one for Internet out.

Back of the Obi202 showing the connections

(Photo 2) Back of the unit.

I will be installing the device in my hallway coat/telecom closet (Photo 3).

Photo of the interior of the hallway closet, showing the AT&T fiber modem, and cables and equipement mounted on the walls above the coat rod.

(Photo 3) Telecom closet.

I used a piece of masking tape to make a template for the mounting slots (Photo 4).

A piece of masking tape on the back of the unit with marks on it to indicate were the mounting slots are located.

(Photo 4) Marking the mounting slots

I drew a level line with a torpedo level and stuck the tape to the line (Photo 5).

Template tape stuck to backer board following the level pencil line.

(Photo 5) Tape template and level line

Drilled the holes for the mounting screws (Provide your own) and screwed them in (Photo 6).

Installed mounting screws on the backer board

(Photo 6) Installed mounting screws

I connected the provided patch cable to an open Ethernet port on the AT&T modem (Photo 7).

Back of AT&T fiber modem, showing were the patch cable is attached

(Photo 7) Modem Ethernet ports.

and to the Internet in port on the device (Photo 8).

Ethernet patch cable connected to the Internet in port on the Obi 202

(Photo 8) Patch cable attached to the Obi 202

A four-wire phone cable with RJ11 connectors goes from the Phone 1 port on the unit to a surface mount block in the closet (Photo 9).

Single jack surface mount block with a RJ11 keystone connector with a phone line coming from the Phone Line 1 port on the device.

(Photo 9) Telephone line cable connected to the surface mount block.

. The cable from the block is spliced into the house’s original telephone service cabling and provides a dial tone to every telephone outlet in the house.

Before installing the power supply, I mark it with a paint marker to identify what equipment it is used for and the output voltage (Photo 10).

Unit power supply with the purpose and output voltage marked on it.

(Photo 10) Power supply

This comes in handy later to match up equipment with a power supply or to clean out a drawer that is overflowing with old power supplies.

The power supply is connected to an open outlet on the server rack PDU (Power Distribution Unit) and to the device. We have power and blinking lights (Photo 11).

Obi 202 connected and powered up

(Photo 10) Connected and powered up.

An Aastra 480e, analog desk phone, is connected to the phone jack in my office. I have a dial tone and I dial the special number provided in the instruction and do a echo test (Photo 11).

Phone sitting on desk

(Photo 11) Desk phone in place.

The next step is to set up a account on Obitalk.com. Once you have done that, you start the setup for a new device. On the phone connected to the ATA, you dial the number provided on the setup page and the Obitalk back end server identifies the device and you will see the device listed on your account web page

With a Obitalk account you can call and talk to other Obitalk accounts for free, but to call outside of the Obitalk network you need to have a account with a VOIP service provider. Obitalk supports most of the major home and small office VOIP providers as well as Google Voice. I have used Google Voice since before the technology was bought by Google and have been satisfied with the service. Best of all it is free for calls in the U.S. and Canada. But if you think that Google already knows too much about your life, you can go with one of the other VOIP providers. Also a big Warning, 9-1-1 service does not work with Google Voice. However you can add 9-1-1 service from another provider to your setup in Obitalk and still use Google Voice. Another concern is what Google gives for free, can be taken away in an instant, so I would not use a free Google Voice account for a phone number that is tightly tied to your business or where you can’t take an outage for a day or two. If you pay for G suite, those worries are about nil as Voice is part of G suite

Since I used my Google account to set up my Obitalk account, it had already configuring the Polycom Obi 202 to work with Google Voice. I made a few selections on what phone line to use for inbound and outbound calls and that was it. Configuration took less than 10 minutes and the total time I spent on the installation was about a hour. Most of that time was bringing in and then putting up the tools I used to install the device in my closet. Voice quality is very good. Reliability is too soon to tell.

Inside of the closet with the completed installation on the right wall

(Photo 12) The finished installation

OCRA Board Meeting Minutes – April 7th, 2020

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Meeting Held by Video Conference

Present:

  • Dave W4SAR
  • Karen KD4YJZ
  • Bill N8BR
  • Nick KA1HPM
  • Dee KU4GC
  • Dan KR4UB
  • Wilson W4BOH

Agenda for Monday April 13th Over-the-Air Club Meeting

  • Monday’s Meeting will take place on the repeater—it will provide membership an opportunity to communicate in a round table discussion. To make it work will require a well-controlled management. Dave will direct the meeting.
  • Dan will review membership. There are now 72 members in the club. 20 are new. A high number need to pay dues, but these folks will not be identified to the club in an open meeting. However, our website will have a corrected current list of paid up members.
  • Nick will comment on the activities of Chatham Auxcom. That organization is on standby with a 48 hour notification of activities. They are not holding meetings at the EOC due to Covid-19 social gathering restrictions.

Following Dan’s enquiry Dee announced that DurHamFest for this year has been cancelled. Durham schools are closed for the rest of the current school year.

Dave announced that VEC duties with exams are on hold for now. This is a good thing since the exam team is in general composed of older folks who are most severely affected by the virus. ARRL is talking about the use of remote testing but in the mean time we will follow local regulations that currently govern meeting location and size of meetings.

A discussion of the current status of field day ensued. As of now the regulations are the same as they were last year, and will remain so until the ARRL makes a final decision. Dave believes the event will likely be cancelled. Discussion ensued concerning the potential problems involved with activities such as decontamination of mikes, keys and operating positions for participating stations as well as maintenance of social distancing issues. Dan will solicit comments on field day from the club.

Dan suggested that he has thoroughly enjoyed the few events that the club has presented by video conferencing, and suggested that we consider using more of this technology to both promote our club to potential new members as well as to better serve existing ones. His comments catalyzed considerable enthusiasm among the group. Specific suggestions that arose from the discussion included using this technology to:

  1. Recruit new club members
  2. Broaden participation at meetings by members living too far away to permit regular attendance
  3. Engage speakers from other clubs and relevant organizations to give presentations at our meetings without asking them to travel long distances.
  4. To present our club members with opportunities to more effectively collaborate with their counterparts in contesting, dxing, operating, public service and other important areas of our hobby.

The foregoing discussions culminated in the unanimous decision by this committee to present the membership with a motion to:

“Empower Dan, KR4UB, our website administrator,

  1. to research the basic strategies our club should use in order to most  effectively interface its mission with current best practice technologies for video conferencing.
  2. supervise the allocation of club funds to acquire the equipment, supplies, and subscriptions needed for the club to be able to utilize these technologies”.

Bill, N8BR – Club Secretary

OCRA Monthly Meeting – Monday April 13th @ 7:30pm via the 442.150 Repeater. NO Meeting @ Efland Baha’i Center

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As the Efland Baha’i Center remains closed due to the State and County directives that will not permit gatherings, we will hold our monthly OCRA meeting over the air on the W4UNC repeater (442.150+, 131.8 PL). This will be via a directed net, similar in format to the AUXCOMM/ARES nets held on Saturday mornings, I as club president who usually runs the meetings, will act as net control, with someone else as a back up. We will commence this net at 7:30 pm on Monday, April 13.

When checking in, give your call sign and name only, I ask that we dispense with the “what I’ve done with ham radio lately comments” we usually do with introductions, we’ll have rag chew opportunities later in the net.

After all attendees are checked in, we will have brief officer’s reports. We will have brief pauses for any members to make queries or give brief comments, via the net control.

Our agenda at this time is:

AUXCOMM/ARES

Volunteer Exams

Field Day

Any other items?

There will be a pause after each agenda item, again for any member queries or comments, going through the net control.

Following the completion of the agenda, we will have a roll call checkout, as we do with the Saturday nets, where members who wish to continue a rag chew are welcome to do so.

Hope to talk to many of you there, stay safe all!

73,

Dave Snyder, W4SAR

Quaradoodles from the Land of Magic

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Wilson, W4BOH

I’m really no less busy, but have used quarantine as an excuse to do a few fun things. Do you have a Kill-A-Watt, the great little $25 power meter. I do, but it’s been used almost entirely for measuring current drawn for various devices. But wait, there’s more! It does the obvious frequency, voltage, current measurements, but also POWER FACTOR (cosine of the phase angle between voltage and current). AND CUMULATIVE CONSUMPTION since last started.

© 2024 photo by W4BOH, OCRA Inc

Here’s the tie to Covid: When I really think ahead, I can imagine power blackouts, short or long, leading to thoughts of generators to run things around the house. Of course there’s been lots of generator talk concerning Field Day too. So what’s my main concern about power? The weather is so nice that HVAC is not of interest. It’s too much load for to support for very long anyway. Next comes BEER! I like warm beer, but the same fridge also keeps our hamburger, bacon, etc., so it’s very important. Well, we just got a new fridge, a Frigidaire.  

BTW, are you old enough to remember when lots of people called any fridge a Frigidaire? That’s the reward for being early to a big market. I don’t remember not having a fridge, but I vividly remember neighbors who didn’t and, most interesting, the old man who drove an old wagon, pulled by an old horse, through our neighborhood. Houses using ice had a little sign they hung by their front doors to tell the iceman how much to leave. He would carry the ice in and put it in your icebox, if you wanted. He had bags of coal too. We kids would go along and chat with the old guy and eat ice chips from the bed of the wagon. I don’t think there was a sanitation grade on the wagon.

The previous fridge was a Whirlpool, a mechanical mess and a power hog. Maybe they are better now, but I wouldn’t bother with them. Getting back on track now…. Would it be practical to run the new fridge from a generator and/or batteries? YES, since it runs at an incredible low current of ONE AMP, 120Watts! Now, that’s way low power for any generator (although the inverter models idle down pretty well) and the efficiency of gasoliine use would be poor. So what to do?

There are lots of inverters available these days and even real sine wave models are reasonably priced. I don’t know, but a 500W model would likely handle the 3A or so starting current of the Frigidaire. SO what does the Kill-A-Watt tell us, besides the one Amp running current? I ran a 100 hour test period, four days, during recent temperate weather, with the kitchen running around 70 degrees F most of the time. Over the 100 hours we used 5KWh, so the average load is 50 Watts and the running time was 40 hours. That’s about 1.2KWh/day, costing about $55/year around here. And how does that relate to batteries? It’s almost exactly the rated capacity of the big AGM batteries we got from Adriano last year, 120Ahr at 12VDC.

But you don’t want to run your batteries all the way down, so we can think of two batteries we recharge once a day.. The problem then is to choose a reasonable charge rate and charger. A conservative charge rate of C/6 would be 20A per battery or 40A needed from the charger. That’s only about 500W, still low, but better. The Honda 2200W generator claims to use 0.17 gal/hr at 1100 W. That’s 21,250 BTU from gasoline to make 1.1KWh or 3750BTU of electricity. An efficiency of 18%, gas in to electricity out, NOT SO GOOD. Let’s call it 15% at lower load. Making electric heat from gasoline is NOT a good thing! Assuming we can get 15% at 500W (wildly optimistic), we need 11350 BTU of gasoline to make our 1700 BTU (0.5KWh) of electricity. That’s about 0.1 gallon! It’s also about a beer can full.

That seems too good to be true, to me, but it’s what the numbers say, if Honda isn’t lying. It’s 20 cents, if gas is $2/gal and you’re getting about 6 cents worth of power, if you got it from the grid. That shows that you can’t beat the power company, unless you get some PV panels! And don’t forget, you’ll have to run like that for 5 hours to get your batteries back up, costing you about a buck. What ho, that’s $365 for a year, versus the $55 running on the grid, but your beer is cool and your steak doesn’t spoil!

And we neglected the $1000 for the generator and the $200 for the inverter, but we won’t charge for them, because we need them for Field Day!

Or you could run off the 12V battery in your Prius, but that recharge would be much less efficient.

Now, I did this quickly, for fun, so feel free to point out my errors. There’s some rounding and some assumptions, so we’re looking for 25% accuracy, at best. If I’m in that range, I’m happy, but I still worry about the Honda claim.

73,

WL

DFMA Club Over-the-Air Meeting, Tuesday April 7th at 7pm

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DFMA will not be having in-person meetings until further notice due to the Covid-19 pandemic.

Fortunately, our hobby supports communicating from a distance. Instead of our usual monthly meeting at Bullock’s, we’ll have a special net. The net will be at 7pm on April 7th, our usual meeting time, on the linked 145.45- and 147.225+ repeaters (both have a PL tone of 82.5). You can also check-in over the Internet via Echolink/SVXLink to the WR4AGC-R node. The format of the net will be check-ins (in place of our usual introductions), officer reports, and a rag chew round table discussion.

Jack, KM4MBG, 4/3/20

OCRA-DFMA Saturday Morning Breakfast, rather Video Conference

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from Jack, KM4MBG & Chris, KK4VBE

Reminder tomorrow, April 4th, after the 9:30am Orange County Auxcomm net on the 442.150 repeater

There will be a Saturday morning video conference to help fill the void left by the cancelation of our celebrated ham breakfasts due to the Covid-19 pandemic. That net usually doesn’t last long, so we’ll try to start at 9:45am local time.

Directions for Joining:

Make sure you have a computer with good microphone and speakers (a headset often works well). There is no software to install. Use your web browser to go to URL address posted in the video conference announcement note on the OCRA-DFMA Joint Email list at the appointed time.

Thanks to Chris, KK4VBE, for hosting the server. Hope to see y’all online.

And more from Chris,

If you do not have a computer with a camera and or mic but have a smartphone you can still join in on the video call. You will need to install the Jitsi app form the app/play store.

IOS App Link https://itunes.apple.com/us/app/jitsi-meet/id1165103905
Google Play: https://play.google.com/store/apps/details?id=org.jitsi.meet

Then at the appointed time click the link in the recently posted note on the OCRA-DFMA Joint Email list and your web browser will open and give you the option to launch the app.

73, Chris KK4VBE

Earlier note from Jack, KM4MBG,

  • WHO: As some of you know, there are various HAM groups in the area that meet on Saturday mornings for breakfast.
  • WHAT: At least one of these groups organized a virtual meeting March 28th among themselves. We had also talked about doing a virtual meeting on the DMFA net.
  • WHEN: Originally, I had called for the club’s virtual breakfast meeting to be at the same time as one of these other gatherings, but decided to defer to next Saturday, April 4th.
  • WHY: Those of use who are not introverted [1] need some socialization time. In addition, those of us who are not working from home or are unhappy with the remote collaboration tools that our workplace is using, wanted an excuse to play with technology.
  • WHERE: This wasn’t asked, but it fits the theme. For the first meeting, we’ll be using the Jitsi Meet browser application. I’ll send out more details and a reminder next week.

Many thanks Jack & Chris!