Category Archives: Tech Mentoring Net

Well, last Thursday night’s net (4/16/15) was yet another successful one with 11 check-ins plus net control (K6HWN). The net began with Garrett (AG6RQ) asking what the difference is between an antenna tuner and a matching network is. John (A6GLJ) was the first one to respond with the fact that what an antenna tuner really does is when it’s placed between the coax and transceiver it keeps the transceiver happy with the SWR level so it can deliver the maxim power to the load (antenna). If the transceiver detects too high of an SWR level it will restrict the amount of power output as to not damage the final amplifier stage. Cyril (AF6GW) offered up that maybe if the tuner was placed between the coax and the antenna it would be more of at true antenna tuner. Dave (K6HWN) agreed with Cyril except that it might be called an antenna impedance compensator, which is really what it does by changing the length of the antenna or the matching point. Cyril made a point that sure, the tuner might make the transmitter happy but the fact is that you still have the same feed line loss or bad antenna paring. Don’t you wish you had tuned in? If so you can listen to the audio archive here. John (AG6LJ) mentioned that this topic is one of the issues they’re currently dealing with using the fractional wave loop antennas. They’re really not designed to work on 12 meters, they can go with a solid state amplifier to about 200 watts, however with the impedance matcher/antenna tuner they can run full legal power. It basically tricks the system into working yet it’s not fully efficient but you can get the power out and at end of the day it works. Also discussed at this point was the concept of grid dipping in historical tube amps, and reversing the leads on an SWR meter to ascertain reflected power going back to the transceiver. (You can review the audio here). Next Levi (K6LCM) had some follow-up regarding his attempt to use a Heil adapter to connect a headset with a boom mic and headphones to his rig. He was having trouble getting audio to the radio. (Solution can be heard here). Now Cyril had some follow-up to a previous net’s question regarding suitable coating material for antennas, wires, enclosures, etc., that won’t affect the performance… Continue reading →

Last Thursday night’s net (4/9/15) was another successful one with 12 check-ins plus net control (K6HWN). The net began with John (A6GLJ) reminding everyone listening that Jerry’s (KK6FNP) single loop fractional wave antenna is for sale. Jerry is upgrading to a double loop fractional wave antenna and the single loop is making a trip to Arizona where the inventor of the technology will go over it and certify its well-being. The asking price is $2,000.00 USD and you can contact Jerry at (805) 896-4484 (no blocked numbers please) or jerryfarwest@aol.com. The antenna is described in greater detail in a swap net listing here at the Swap Net Listings. Paul (KF6CIH) had listened to part of an ATV Special Modes net and had a question about how one can send computer data over the radio. Brian (K6BPM) was present on-air and being the net control for the Special Modes net happily went over some concepts with Paul and invited him to join the net if he’d like to learn more and participate. The net airs every Tuesday night at 8:00 PM to 9:30 PM on 146.79 linked to 224.08 and everyone is welcome to check-in. Next Brian (K6BPM) asked a question that he and I (K6FLD) were curious about. I’d mentioned to Brian that when using my MFJ-969 antenna tuner that I thought I noticed enhanced signal reception when the antenna was tuned properly on a band. Brian and I (before I had ever used an antenna tuner) had thought that receiving wasn’t affected by tuning the antenna, only the SWR and transmit quality. Shackmaster Dave (k6HWN) explained that yes, indeed the receive will peak as well as the process is reciprocal in that what’s good for transmit is good for receive. Likewise, if you have loss on input you’ll also have loss on output. Signals will definitely peak on receive in fact you can tune it approximately by peaking it on receive noise and you’ll be close on transmit and SWR. Ken (KA6KEN) commented that it sounded like Brian had talked himself out of the idea that an electrical adjustment was being made during tuning when in fact you do, it’s just that you have passive components making a passive adjustment and you need not transmit for that to be beneficial. Tune in to the SBARC Technical Mentoring and Elmering Net next Thursday at 0800 and see what interesting questions… Continue reading →

Last Thurdsay night’s net (3/26/15)was successful with 14 check-ins plus net control (K6HWN). The net began with Yishen (KK6MJF) asking about apartment /dorm room antenna solutions. Apparently he’s not allowed to remove the screen from his window to extend a wire or any other type of antenna and was looking for another solution. Brian (K6BPM) offered probably the most practical solution, a magnetic mount car antenna attached a piece of “weldable” sheet metal (ground plane) about 12′ X 24″ placed on the window sill. This method works well for Brian at his office and might work well for Yishen too. Shackmaster Dave (K6HWN) offered his experience of using tops of cookie tins or mounting to the top of metal filing cabinets. Another solution Dave offered was the use of a gain antenna rather than the rubber ducky. All great suggestions. Justin (K6LPZ) offered some of his experiences with handhelds and antennas. Over the years he’s found that bigger and more is better when it comes to VHF antennas. At one point he had a full length whip antenna reduced from a 239 connector down to BNC connected to his handheld transceiver and he could hear just about everything and his transmit was as good as could be expected with 2 watts. Eric (K6HMD) asked if random wire antennas can be dangerous voltage wise and Dave answered that transmitting at high power it might be a problem but at lower power settings probably not more than any other antenna. There could be high voltage at the end where the antenna tuner transforms it down but again at lower power settings he probably wouldn’t worry too much about it. Eric offered some friendly advice to Yishen that of he went with a random wire setup not to get too close to it if everything’s indoors. Yishen’s next question was regarding whether or not he should worry about grounding the antenna he’s planning to use and Dave asked a few questions including the radio Yishen would be using and the kind of antenna he’d be using. Depending on the type of antenna and what bands he’d be on it might improve the antennas performance if t were grounded. Levi (K6LCM) asked about a 72 ft end-fed antenna at 40′ high he purchased from Brian, it works good on 80 meters but it’s noisy, in fact he’s been switching between two antennas for transmit… Continue reading →

Last Thursday’s Technical Mentoring and Elmering Net included discussions about Levi’s (K6LCM) quest to research his grandfather’s ham call, K1ELJ. He contacted AARL and they indicated that they could help but he hadn’t heard from them as of Thursdays mentoring net. Levi asked all who were listening if they had any databases, knowledge or other resources that could help him with his search. Harry (K6PDQ) said he has a QRZ CD ROM from 1995 but Levi didn’t think his grandfather renewed his license after the 1960’s. Lee (W6QYS) mentioned that he has 1960 and 1967 AARL call books and Justin (K6LPZ) said he has many old books and would take a look for K1ELJ. Brian (K6BPM) brought up www.hamcall.net which Levi thought he may have tried. A couple folks found the call and K1ELJ but is was assigned to someone other than Levi’s grandfather so he’s going to do further research make sure he’s looking for the correct call. Good luck Levi! Then the focus was on Ken’s (K6KEN) question as to why Dave (K6HWN) was operating as W6HUT. Dave filled him in on the fact that Reg Dawe (W6HUT) was a friend and mentor to Dave and many local hams back in the day and now the call is registered to the Reg Dawe Amateur Radio Association. The call is used during the Reg Dawe Memorial Cuckoo Net every weekday morning at 0800 and during the Technical Mentoring and Elmering Net every Thursday evening at 1800, as a gesture to remember Reg’s good naturedness and  mentoring to so many hams that he came in contact with. Ken also inquired as to the use of Reset, Break, and “Mine” that he’s become accustomed to hearing during our nets. Dave explained “Break” is a standard ham term meaning the breaker needs to relate priority traffic of different degrees including life threatening emergencies. “Reset” is used when a comment is lengthy so that the repeater isn’t timed out and listeners know there is still more content to follow. The K6TZ repeater will time out if a carrier signal is not dropped within 3 minutes so that if a radio is being keyed accidentally or a malfunctioning radio is transmitting out of control the repeater isn’t locked out to all other traffic. The term “mine” was derived by Dave (K6HWN) after he begins a transmission and it’s become quite useful in our nets…. Continue reading →

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… Continue reading →