We had four (4) VNAs to look at Thurs the 28th, two brought in by Mike KI5YX, one from Kenny KJ5EKW, and a little one from Rich WA5ZQG. They all worked (if you knew how) but Rich’s had only the 3 inch screen. ZQG also brought in the MFJ, demonstrating it on a 2M/440 dual band antenna to Anthony KJ5PUZ (who is reealy new – only 1 radio so far).
If you want more on VNAs or missed this one, the TARC club is having a VNA program Tues June 2nd at Keplinger Hall room 3140 Tuesday night at 7.
In the photo above, an MFJ SWR analyzer sits beside a Tiny SA spectrum analyzer and a VNA, the 50 or 60 dollar solution to figuring out your antennas.
The MFJ SWR analyzer is easier to use at first, as they say, a much easier learning curve, but it costs $250 and up so wouldn’t you like to know how to use the cheaper (and quicker to display a chart) VNA thing.
Field Day isn’t that far off, only another 6 weeks to make sure the generator works and the LifePo batt is charged. Everybody at the meeting had the rules (1.4 MB ‘Field Day 2026 Packet’ from the ARL) and we discussed whether to go to one of the local clubs and help out their Class A stations or stay home and work Class 1D or 1E, or both. Rules have changed over the years, you no longer have to stay on a band for an hour, and clubs working like 3A or 4A can have a free GOTA station As Well As a VHF/UHF station to talk to locals on their HTs. (Can’t log people who go home after helping the club.)
John KI5OYW has a QRP rig and an 80/40 fan dipole at home. We advised him, and Tom WA5MAZ who lives not far, said he’d help out with a local test of John’s station. (OYW is also on 2M and 440.)
Rich ZQG brought in specs from a home made 4A power supply; an 8A (maybe more) Motorola that’d served a school bus program for a quarter century (renewed by Rich), and a 20 Amp Kenwood (those pictured above). The 4 Amp weighed 3.1 lbs in a small aluminum chassis, and the Kenwoood at five times the capacity, weighed 5x as much, 14.8 pounds. Inexplicably, the mid size Motorola was 16.9 pounds. Oh weight, they do have a reputation for reliability. One detail on the Mot, it did not have a variable resistor to adjust voltage, instead 2 resistors in series, possibly custom selected at the factory to produce 13.8 out from the series regulator. (Variables can fail at the sliding contact after decades.) Rich said when he got it, no longer working, the two resistors had drifted a bit and the output was 15.5 Volts. (3 to 4 decades under the dispatcher’s desk.)
Tom WA5MAZ (ex KJ5NMH) is making sure his old Motorolas are up to spec, and bot this Gertsch FM deviation meter in Muskogee for 75 bucks. It’s old, full of tubes, and needs to be at a particular temp to be in spec, so comes with A Mercury Thermometer that contains Hg. It’s a normal thermometer reading from minus 20 to 70 deg C. It goes in horizontally, the hole next to the phones jack to sense the temp of the crystal oven. Hey, trivia question: Is human body temperature really 98.6 deg F, and the answer is No, it was originally ‘around’ 37 deg C and the equiv F is 98.6 which implies an accuracy that is excessively precise. Back to radios: Tom has also installed one of the Mot mobiles in his white van with a brand new Mot 5/8 wave antenna on top. That rig has a custom designed Freq and PL tone signal injector (to make the old xtal rig work). It includes a green digital 1 to 16 readout to select one of 16 channels programmed with local freqs. Late Note: He drove it out to 41st and Sheridan for the Saturday night Simplex Net on .55 and heard everyone.
Larry W5LQF brought in some old ceramic plate mounted cheese slicers (variable capacitors) plus a genuine Dan Bosco Electronics ‘Stetho Tracer’ from the early 60s, a pen size demodulator and audio amp that lets you trace signals through a radio receiver. Don Bosco also made a similarly packaged simple square wave signal injector (that put out lots of harmonics) for ten bucks. The demodulator looked the same, pen sized, but came with accessories like a 20 dB attenuator, an earphone, and cost a hundred a fifty bucks, an armful back in the 1950s. Larry’s example looked pristine and had the original paper manual.
Mike KI5YX brought in a TEKTRONIX 2224 digital storage scope to show. Nxt mtg is 2nd Thurs in May. See you on 146.91
Last year at Green Country, I thought there were a lot of books, old Radio Amateur’s Handbooks and Callbooks etc. This year I noticed quite a few Kenwood 520 HF rigs (plain 5 band 520, the 6 b 520S, and economy model 520SE without 12V capability and lacking plugs for the 10 Watt 6M or 2M trans verters. The one above is 6 band 520 SE with matching tuner and speaker. You’ll never find the two transverters (bc they didn’t make very many). No price on this one. The others varied up to $250, but you might’ve gotten the one from Earl WB5UUW for a hundred or less. Estate sale, and no condition stated. I did see one Kenw 820, the eight hundred dollar expensive alternative, worth it at the time bc it was single conversion (to 9 Mc) versus double conversion (600 kc wide at 9, and then crystal filter at 3395) which made the 820 noticeably quieter on 10M (without so much conversion/mixing noise).
A Yaesu 101B was there also, same vintage as the 520 but with Sweep Tubes in the final, an 11M band, and AM mode available (only one reason for that – CB). Sweep tubes bring the plate out through the pins on the base, so there’s a little capacitance there which reduces gain on 10M – less of a problem on the Kenwoods bc they use S-2001 tubes (like the 6146A) with a plate cap that makes them usable up through 2M freqs. It was marked $100 and the LandLiner phone patch another $50. Oh, on the tables selling tubes you could buy 6146 types for ten ($10) bucks.
You always need a spare power supply and there was an Astron 20 marked $100 and a more capable Astron 35M (with meters) for $150. I liked the MFJ 4035 with meters going to 35 Amps marked $10.
I know the bad part is in here somewhere. I’ll just keep replacing parts until it starts working.
This is why you go to a Hamfest. Say you’re thinking about a Coax Switch for your station. , Go to the Fest and you’ve got your choice of dozens, 2 position, 4 position, 5 (one for ground).
Tom WA5MAZ (ex KJ5NMH) brought in some old Motorola stuff again, a tube type portable 2M rig from back before you were born. He made this 90V power supply to test the tiny jelly bean size tubes to find (surprisingly) they all worked. Listen on 146.91 Wed and Friday at 7 to hear the old rigs work (and be aware he has also synthesized both Crystals and PL tones to do so.)
Rich ZQG reviewed the BA club program from a few days ago, summarizing Emergency Power by suggesting a 100 Ah LifePo battery; five hundred dollar Harbor Freight generator (not the Inverter type because they make RF noise), and a $130 Hbr Frt solar panel.
Back in the 1950s the FCC license test had requirements like ‘Draw a 5 tube radio schematic.’ We reviewed a schematic of one using 50L6, 35Z5, and some with 12 Volt filaments, and decided, Yes, it’s possible for five tubes to work, and even cover the HF range as did the Hallicrafters S-38 (made in the 1950s).
We meet 2wice a month, 2nd and 4th Thursday, at Scott’s hamburgers downtown Bixby 7 to 8:15PM.
Tom NMH has switched back to his old callsign, WA5MAZ from the mid 1960s. At the Thurs 03.26 meeting he brought in two (2) Motorola handy t – well, back then they were more like lunch boxes, the one from 1958 mostly transistors (except driver and final tubes – little ones, 1W out), and the other from 1948, one year after Shockley and the other two guys invented the point contact transistor, It was all tubes, a bunch of them, like 19 little ones, mostly mounted in replaceable/fixable modules like the one shown above, part of the crystal multiplier chain that makes 146 Mc from a crystal in the 12 Mc area. Tom has used the old ‘Lunch Box’ Motorolas on the 146.91 repeater. It’s a little trick to do that since Int’l Crystal Co. doesn’t make crystals any more, and that’s another story about Tom, using a freq synthesizer chip to program not only a 12 Mc crystal, but also a PL tone. We asked him, Why don’t you just buy a Baofeng, but I guess he likes to display his talents
Kenny KJ5EKW brought in a heavy 14 VAC transformer and asked about making a power supply. The linear Astrons start with a little more voltage that comes out around 21VDC. One idea was to use the 7812 type regulator chip which can regulate with as little as 2 Volts difference. (14VAC times 1.414 yields 19.7; less 1.4 for loss in hte bridge rectifier; now 17.3; less maybe a Volt of ripple with a large (80,000 uF) filter capacitor; down to 16.3 that could be regulated to the 13.8 – 14.0 DC range.
We were going to compare RX sensitivity on Chinese H/Ts, but instead, we spent most of the hour measuring TX output and using a Spectrum Analyzer (Tiny SA on Ebay for $68) to check for spurious output. Shown above is an anomaly, second, third, and fourth harmonics that weren’t there.
Two Baofeng UV5Rs (the x3 model) measured 5.3 and 5.4 Watts out on 220. That’s good. They were bought about a year ago on EBay. Deb and Sam, DBE and BJR, both had Baofeng UV25s that output at stated ratings.
Every transmitter has a Low Pass filter on the output to restrict spurious at higher freqs. FCC spec is a 40 dB reduction. Deb DBE’s TID Radio H8 showed the second harmonic at negative 50 dB, similar to Mike KI5YX’s Japanese HT at negative 53.
Rich ZQG related a story from the beginning of WWII how Leo W0GFQ and friends were able to mass produce crystals for Army tank radios, their first contract spec 60,000 xtals in a few months from a small town (Council Bluffs) in Iowa that enabled our guys to communicate faster and more easily than the opposition using tunable radios. Their secret technique was not allowed to be kept secret back then so other Americans were later able to do the same.
Entering the outbuilding behind the house you were greeted with an enormous Ham collection of a lifetime, and atop shelves on the far wall, dozens of 2M cavities (those round things on the top). Motorola experts would know if those stacks of radios were Maxars or Mocoms, but all the rest of us could do was look in amazement and then turn to another group of items to ask, Are these dummy loads, only to be told by an expert, No, isolators, or circulators. What’s that. There was a small stack, maybe half a dozen, of Kenwood commercial UHF mobiles. You could find familiar Ham items too such as MFJ accessories. And parts. Parts. Parts. And a scope or two. And . . . .
Tom KJ5NMH found a 1960s era HT-200 handie, a dual freq model (Motorolas in those days were often single, dual, or sometimes 4 freq variations) and took it home for a pittance (and put in a home made freq synthesizer – also PL tone synthesizer – that he designed himself.) (It’s the size of a crystal can, not quite an inch square.) Here are two boards he has made recently, the postage stamp size freq and tone generator that fits inside an H/T, and the slightly larger multi freq board for mobile rigs.
Kenny KJ5EKW and Rich WA5ZQG each found what appear to be new in box 220 rigs (Chinese) and are working on antennae for them. Paul WB5ANX was prominent among volunteers helping to make the sale successful. At the end of the morning, although many items were taken, the sale had made only a dent in the inventory.
Both Mike KI5YX and Phillip KI5PFV brought their new Baofeng DMR HTs, the new DM32 model with lots of memories and larger size. In the Amateurish (see what I did there?) pic below, Mike’s 55 dollar black and green HT is on the right. Phillip spent $67 to get the clear plastic see through model (and some extra antennas and stuff).
As advertised, Mike YX also brought along his Baofeng programming computer. Kenny KJ5EKW had his new TD Radio H3 Plus (2 of them for $80) that had somehow gotten into BRICK mode. Mike tried resetting it to factory specs (didn’t work) and then reloading the firmware. The radio (in BRICK mode) didn’t respond. Lesson learned: Careful when buying radios that offer BRICK mode. Mike put a variety of 2M and 440 freqs in the other one.
Kenny EKW won the Silver Plated door prize (see pic above) although a condition of winning was to donate two bucks to another club (RSGB does not have a Treasurer).
Deb K5DBE brought her new MeshTastic Node, an 89 dollar RAK WisMesh pocket V2 with internal battery, GPS, and small LCD display. You talk to it through an App on your phone. Deb set it up herself (with guidance from Jeff AI5ME) and has been reading texts from all over town. See the pic above – the green HT thing on the left. No PTT button, and no speaker. Your PHONE.
Next mtg is Thurs 26 Febr, 7PM at Scott’s hamburgers in downtown Bixby. Left side, way in back..
Mike KI5YX brought in a 220 J-Pole made with 3/8 in copper pipe (2/3 the length of a 2M J-Pole). The ‘U’ at the bottom was about 13 in tall, and the half wave radiator above was around 26 inches. There used to be a 220 Net on one of the 220 repeaters, but not lately.
The slightly revised meeting format allows a brief Show and Tell from each person prior to the Tech subject program. Mike held up the copper J-Pole and the rest of us had a few comments. A common concern on antennas was the advertised gain figures, often distorted by ISOTROPIC gain; ground reflection gain, or plain lies. Next mtg is on Lincoln’s BDay, Febr. 12th.
Tune in Wed and Fri on the B.A. 146.91 repeater at 7PM for the Conspiracy Net where you can talk on a variety of subjects.
Radio Society of Greater Bixby 