Technical Mentoring & Elmering Net
Technical Topics and Advice for New Hams
Thursdays from 8:00 to 9:00 PM on the SBARC Hub linked repeaters.
The Technical Mentoring and Elmering Net is dedicated to teaching. We discuss technical topics related to ham radio at ALL levels of expertise, with very special emphasis on helping any new ham any way we can. Remember you are an expert in your field of endeavor, so its no shame if you are just a beginner in ham radio. In fact, a great question for the net is “ WHAT are you guys talking about?”
There is no “lecture topic”, meaning that we are completely question-based, so its great if you have a list of questions ready. We take check-ins at the beginning, and throughout the net, so you can join (and leave) anytime you want to. Usually we discuss some technical topic for awhile, then leave breaks for people to jump in with a different question. Often several very expert hams are on, with possibly some listening ready to help with something they know, or to answer up to net control asking “who wants to answer that question?” The net is very informal and friendly, and also helps any new ham with even non-technical ham radio questions, like correct operating procedure, etc.
You’ll find recordings of the net in the SBARC Audio Archives.
Net controllers, see the TM&E Net preamble and script wiki.
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.
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.
There were some interesting discussions on last night’s net including K6HMD Eric’s issue he’s been experiencing with his iCom IC-7600 transceiver. It seems that Eric was attempting to set up FM split mode operations to access the K6TZ 6 meter repeater when he began seeing unexplained signals every 100 Khz at the same amplitude on the rigs spectrum analyzer. Even changing bands didn’t help. After a fair amount of troubleshooting Eric finally opted to reset the rig to factory specifications and the problem was solved, no more weird signals. Shackmaster Dave (K6HWN) offered a very plausible cause for the anomaly, while Eric was trying to set up split mode operations he may have pushed a button on the rig enabling the crystal calibrator. The calibrator would emit signals at specific intervals to calibrate the rigs frequency output by. Eric’s perusal of the operating manual didn’t offer up any information about a crystal calibrator being on-board the rig so he’ll contact the manufacturer. Tune in to the next Technical Mentoring and Elmering Net and hopefully learn the answer to this puzzle!
Other discussions involved HF noise and troubleshooting, automatic gain control and signal to noise ratios.
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 edification of new and experienced hams alike.
Dave K6HWN conducted a great discussion on station grounding. Steve KI6HGH provided a lot of technical information as did Theo KK6YYZ who is a licensed electrician.
You can read more about the Technical Mentoring and Elmering Net here.
Listen in next week on Thursday at 8:00pm for another great discussion.
