Techncal Mentoring and Elmering Net – February 19, 2015

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Last Thursday’s Technical Mentoring and Elmering Net proved to be as enlightening as ever. Eric (K6HMD) is looking to add a VHF antenna to his BMW and after checking with the manufacturer and their warranty conditions he’s decided to do so as discretely as possible. Suggestions by Levi (K6LCM ) and Dave (K9KBX) included a lip mount bracket with tape added as a buffer to scratches and a window mount bracket. Magnetic mounts were also discussed but the window mount seemed to win over the conversation as it can be removed when not in use and offers the least invasive way to route the coax.

The discussion shifted to circular polarization as Garrett (AG6RQ) posed the question as to how it works. According to Shackmaster Dave (K6HWN) circular polarization is where the electric and magnetic wave continually rotate 360 degrees every cycle. The AARL Extra Class License Manual (Tenth Edition page 7-11) describes circular polarization as “to generate electromagnetic waves in which the orientation of successive wavefronts rotates around the direction of travel”. It goes on to say that as the twisted, circularly polarized wave passes the receiving antenna, the polarization of its fields will appear to rotate. The rate at which the polarization changes and the direction of the rotation, right-handed or left-handed, is determined by the construction of the antenna. To best receive a circularly polarized wave, the structure of the receiving antenna should match that of the transmitting antenna. Lastly the manual states that it is particularly helpful to use circular polarization in satellite communication, where polarization tends to shift with the orientation of the satellite and the path of its signal through the atmosphere.

Tune in to the SBARC Technical Mentoring and Elmering Net this Thursday February 26th and see what interesting questions will arise or ask some of your own! The net is broadcast each week on 146.79 and 224.08 both with minus (-) offsets and PL 131.8. All club members and visitors are encouraged to check in to the Technical Mentoring and Elmering Net each week and join in with questions and /or answers to and contribute the knowledge of new and seasoned amateur radio operators alike.

Bill Talanian’s Presentation at the February 2015 General Meeting

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Bill Talanian discusses the vast communications infrastructure available to SBARC.

Bill Talanian discusses the vast communications infrastructure available to SBARC.

If you missed the February 2015 General Meeting, you really missed out on a good presentation. Bill Talanian W1UUQ gave us a great presentation on the various repeaters we use in the Santa Barbara area. Most of us probably have no idea how sophisticated how Club communications backbones are, but in an hourlong presentation that went by way too fast, Bill gave us plenty of detail illustrated with pictures about the unbelievably sophisticated infrastructure we all take for granted when we press the transmit button on our radios.

Starting with  the main repeater site on the Mesa, Bill took us on a guided tour through it’s humble beginnings with a couple of leaky shacks and equipment covered with blue tarps, to the sophisticated communications center it is today. His tour continued give us a behind the scenes look at La Cumbre Peak,  Santa Ynez Peak, Broadcast Peak, UCSB, and Santa Cruz Island.

Most of us think our repeaters are only for 2m, 220 and 440 voice communications. Not so fast. Bill showed us many of the other things he and a handful of volunteers maintain on a constant basis. These include weather stations, APRS digipeaters, AIS reporting for maritime purposes, aviation, and many other things.

One of the more interesting aspects of the presentation was how Bill and others have bartered and wheeled-and-dealed over the years to get the club access to literally hundreds of thousands of dollars worth of top quality equipment, towers, and whatever else it has required to make us a first class club. He is a master at horse trading and scavenging and fruits of his many years of work are largely unknown. If you missed this meeting, you missed one of the best presentations we have had. The amazing number of resources available to the club made possible through Bills hard work truly deserve our appreciation.

You can listen to audio recording of the the meeting below. The presentation is 1 hour 37 minutes and you will need to stay on this page to ensure you do not interrupt playback.

Free to a Good Home – Hy-Gain HF Antenna

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Hy-Gain HF Antenna. This is an antenna that was used by a now silent key ham. It was disassembled a few years ago and stored by another ham friend. From the part numbers on the antenna it appears to be a Hy-Gain TH-3JRS or TH-3MK4 10/15/20 meter tri-bander. One element is slightly bent and may need to be repaired.

This kind of antenna is $400 to $500 new but the person who is storing it is willing to give it away free of charge to someone who can put it to use.

Please contact webmaster@sbarc.org if you are interested, and we’ll put you in touch.

Technical Mentoring and Elmering Net – February 12, 2015

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Well last night proved to be another successful Technical Mentoring and Elmering Net, there were 14 total check-ins and Shackmaster (K6HWN) made for 15 participants. First up Jim (KJ6ZJX) had a question about his 10 meter antenna and would it be long enough to tune other HF bands. I asked him what kind of antenna, vertical, dipole, etc. and Jim responded dipole. After a discussion with other members of the net it was determined that he has enough room and copper wire to go ahead and construct another longer wire antenna and use it on the lower bands.

Answer to last week’s puzzle: Eric (K6HMD) heard back from ICOM and indeed he’d set the transceiver into a self-calibration mode and band scope setting that emits 100 KHz spaced band markers for frequency tuning. So Shackmaster had it pretty much correct except that newer rigs use digital calibration modes rather than crystals. Congrats Shackmaster!

I had a question about a mathematical equation being used in the Extra Class license manual. In order to calculate effective radiated power (ERP) from an antenna you first need to calculate the total gain which includes losses due to feed lines, duplexers and circulators and add back in the antenna’s gain. The total gain turns out to be 1 dB. So now that plugs into this equation: EIRP = 200 W x log-1 (1/10) = 200 log-1 (0.1) = 200 (1.26) = 252 W. My issue is that no matter how I plugged the numbers into my scientific calculator I couldn’t make it work. Eric (K6HMD) commented that it seemed a little bit of an “old school” way to present the problem but he came up with the answer. With the calculator you enter 0.1 and press the anti-log function which gives you the 1.26. Thanks Eric! If I do get this question on the Exam I’ll be in good shape!

The remaining discussion was about the new digital HTs that several of the club members have picked up and are experimenting with. Brian (K6BPM), Levi (K6LCM) and Eric (K6HMD) all were very helpful in explaining the new technology and their experiences with it so far. The Yaesu FT-1DR is a hand-held digital / analog transceiver utilizing Yaesu’s C4FM/FDMA technology for digital communications and it’s also capable of 144/430 MHz FM as well. You can read more about it here SBARC and here Yaesu. It’s supposed to be on sale right now for around $299.95, about a $100.00 discount.

All club members and visitors are encouraged to check in to the Technical Mentoring and Elmering net each week and join in with questions and /or answers and contribute to the learning experience of new and seasoned hams alike.

ATV Special Modes Net – February10, 2015

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We had a great turnout this week with 9 check-ins to the net. Several Club members have recently purchased new Yaesu digital VHF/UHF radios, so this net is becoming the place to come to learn about this exciting new twist on day to day FM voice communications. Everyone that has experienced using this special digital mode cannot stop raving about the clarity and total lack of noise. Often, when two or more members go off to another frequency to experiment with digital, it is difficult to get them to come back! As we continue to experiment and test we’ll devote a portion of this net to talking about digital FM each week.

During the past couple of nets we have also been talking about operating with JT65. To many, this low power, weak signal mode seems somewhat boring, so we talked about some of the finer points this week. Low power, weak signal operating can really become an art form if one takes the time to explore it deeper than face value. Once you learn basic operation, it is not unusual to hear about operators using incredibly small output wattages in the sub-1W range and making thousand mile contacts.

We also talked about using JTAlert, an add-in product for JT65 that adds a lot of additional functionality and convenience to the two major JT65 applications. JTAlert can be freely downloaded at http://hamapps.com/. If you are a JT65 user, this is a useful addition to your setup. It offers a full macro system, callsign lookups, log book interface, and even allows user to user real time chat.