Radio Items Picked-up at VWS Winterfest 2024 Hamfest

As always, click on image for a better view

Above you can see what I picked up at the Vienna Wireless Society's 2024 Winterfest Hamfest. 

-- On the left in the blue box is an MXM Industries SuperRX/TX 40 transceiver. It is a kit from a Texas company.   Superhet receiver with IF at 455 kHz.  Crystal controlled CW transmitter on 7040 kHz.  The oscillator works, but so far no receive signals.  I will have to troubleshoot.  Does anyone have a schematic? 

-- Behind the MXM there is a nice box marked "Diode Detector" I opened it up and there is just a solid state diode and a 50 ohm resistor to ground.   Box may be useful. 

-- I got a couple of books: "Weekend Projects" 1979 from ARRL, and "A History of QST -- Volume 1 Amateur Radio Technology 1915 - 2013" 2013 from ARRL. 

-- On top of the Weekend Projects book you see a "Crystal Holder" from Gross Radio of New York City.  W1UJR has some good history on this company:  https://w1ujr.com/written-word/gross-radio-company-circa-1931/  This device seem to be intended to hold in place a raw piece of quartz!  Cool. 

-- To the right of the books there is a serious-looking VFO.  One dollar!  Deal!  It is a CB VFO, but the markings say it puts out 5.44 to 5.99 MHz.  So it should be useful.  The dual speed dial is very nice.  

-- Above the VFO is a nice step attenuator from the "Arrow Antenna" company of Loveland Colorado. 

-- Further to the right are some Electric Radio and Antique Wireless Association magazines that Armand WA1UQO gave me.  Really nice.  The AWA mags have a very thoughtful piece (warts and all) on Jean Shepherd.  And the ER pile has an article by Scott WA9WFA that mentions my work on the Mate for the Mighty Midget receiver.  Thanks again Armand! 

-- I also got some ADE6+ surface mount mixers.  The price was right! 

Thanks to VWS for putting on this great hamfest! 

Does Matching Matter? (Diode Matching for Diode Ring Mixers) -- Nick M0NTV Finds the Answer (Video)

In this video, Nick M0NTV takes on a hot topic in ham radio homebrewing:  The matching of diodes in diode ring mixers.   How should the matching be done and -- more controversially -- is this matching necessary?  

I won't spoil it for you by giving the answer.  Watch Nick's video to find out if it matters.  (But a hint appears below.)

I think it is great that Nick has taken the trouble to look carefully at this issue, and has found info that will be of great use to  homebrewers.   And I really liked Nick's response to the fellow who suggested just going out and buying a commercial diode ring:  Nick replied that he homebrews because he likes to, and because he wants to know how these circuits work.  FB Nick. 

I was also pleased that Nick gave some much warranted recognition to Pete Juliano for his idea regarding the placement of a trim pot on a diode ring.  This idea made it into the Experimental Methods in RF Design book (under Pete's old call: W6JFR).  Page 6.56. 

Part III: Curious Marc Repairs an All-Discrete Freq Counter: DO NOT ATTEMPT REPAIR OF CAVITY RESONATOR

I love all the "DO NOT ATTEMPT" warnings.  Wow, even HP got so skittish about this stuff.  Marc has a great sense of humor and notes that, "no cavity resonators were harmed in the production of this video."   I like the description of the mixers and the photo of the mixer antennas.