Mike WU2D's Video on the SimpleX Super Receiver -- Part II

 Another FB video from Mike WU2D.   

But you know,  I too find myself kind of opposed to front panel on-off switches.  I power my rigs with small DC supplies.  I just turn on the supply when I want to use one of the rigs.  I don't have or need a switch on the front panel of the rig.  

I especially liked Mike's use of the gate dip meter and, of course, the Q meter.  FB OM. 

I must say I have a preference for the first version, but only because I dislike the regenerative circuit in the second version.  I do like the newer-style coils -- I have one in the BFO of the Mate for the Mighty Midget receiver.   

Thanks Mike for the sideband inversion factoid in Part 1!   The Hallas Rule -- words to live by. 

One word of caution.  I used 6U8s on my Mate for the Mighty Midget receiver.  I had good results, but WA9WFA had a lot of trouble.  We eventually concluded that the 6U8s didn't age well.  And they were quite long in the tooth.  We found (from the tube guys) that 6EA8s aged better and were a good and easy sub for the venerable (perhaps TOO venerable) 6U8s.  I switched tubes in my rig and it did seem to work better.  BTW, this is the receiver that I use to listen to the Old Military Radio Net on Saturday mornings.  

Here is the story of our switch from 6U8s to 6EA8s: 

https://soldersmoke.blogspot.com/2022/02/6ea8s-in-mate-for-mighty-midget-and.html

SimpleX Super Superhet Receiver -- A Great Video from Mike WU2D

Here is another great video (and project) from Mike WU2D.  I'm a big fan of homebrew superhets.  And wow, Mike presents a band-imaging superhet!  Two bands for (almost) the price of one!  I have FIVE homebrew dual-band band-imaging transceivers around me.  Believe me, once you have the experience needed to build an SSB transceiver, a dual-bander is the way to go.  Five bands seems like a bit too much.  But two seems to be at the sweet spot.  

I wrote to Mike reminding him to talk about the sideband inversion problem.  This rig will invert the 75 meter signals,  but this is easily resolved by just shifting the BFO frequency.  I also pointed out that many of today's builders will be detered by the need to scrounge for parts.  Where oh where is the BOM OM? 

Thanks Mike! 

Pil Joo's Homebrew Superheterodyne Ham-Radio Receiver

It is just very cool to see someone build a superhet and get it to work.  For so many years amateurs were told that "homebrew receivers are too hard."  Even simple regens or direct conversion rigs were sometimes seen as beyond the abilities of amateurs.  But here we see another reminder of this not being true.  Even a superhet -- which is a lot more difficult than a direct conversion receiver -- can be homebrewed by an amateur builder.  Three cheers for Pil Joo! 

He wrote on the SolderSmoke Facebook page: 

I finished my first super het receiver. It's for the 40m band. It consists of: bandpass filter, tuned amp, diode ring mixer, wide band amp, crystal ladder filter, wide band amp, then SA602 + LM386 combo. I learned tons as i put all the components. First two amps are my design. The third amp is bga2866. The bandpass filter is what i posted a few days ago. I planned to make another one but with 2.5db insertion loss i thought it was good enough.

The result is actually quite good. I can hear everything a local kiwisdr can hear. Now, I have lots of ideas about how i can improve, but that will be another radio.

Pil Joo

Basic Radio Circuitry -- a 1971 film

This 1971 training film is pretty good.  I like how they break the RF circuitry into just four components, then describe the AM receiver stage by stage.  The way they handle diode (envelope) detection is exactly right.  But their description of how mixing moves the incoming signal from the broadcast band to the IF is overly simple, and sort of just repeats the hetrodyne story from music. Real mixing is, of course, more complicated than that, but too complicated for a 15 minute film. 

Homebrew Receiver -- AG5VG's 20 Meter "Mythbuster" Receiver

Michael has the receiver done and is wisely heeding Farhan's advice about pausing to enjoy the homebrew sounds.  

I was pleased to see someone else using the FT-101 VFO.  Great piece of gear.  

On to the transmitter!  

AG5VG's Homebrew 20 meter Superhet (with a CW rig Coming) (Video)

 Michael AG5VG finished this receiver last weekend.  He hopes to build a CW transmitter using an output of the Si5351.  Obviously I defer to Pete on that one.  Good going Michael.  I think it sounds great and looks even better.  

CuriousMarc Visits Cape Canaveral -- Lots of Space History (and some ham gear)

I like all the CuriousMarc videos, but I especially liked this one. Marc and company visited some of the very early launch sites and bunkers at Cape Canaveral.  If you thought Apollo tech was crude, take a look back at what they used in Mercury and Gemini.  Wow.  

I spotted two ham radio receivers.   In the first bunker at 10 minutes 28 seconds we see an old National HRO Sixty with the classic HRO dial, much like the one given to me by Armand WA1UQO. (Thanks again Armand!) Note how they attribute one of the early launch disasaters to two diodes in the power supply that shorted due to launch vibration.  I hate it when that happens.  

In the second bunker we see a Hammarlund HQ-140 at 19 minutes 7 seconds.  This was apparently being used as a Frequency Standard (or maybe a time standard?) perhaps receiving WWV at 10 MHz.  I note that the frequency knob shows it set for the AM broadcast band... 

Charlie ZL2CTM's New Receiver

It is truly a thing of beauty.  

I really like that variable capacitor.  (Where did that come from?  How can I get one?)   

Charlie's calculations on each of the stages is -- as always -- really nice.  

I like the J-310 infinite impedance detector,  Charlie's use of solder wick,  the wooden base, and his decision to keep the circuitry visible.   

I also like Charlie's decision NOT to put that VFO in a metal box.  Too often we see projects that try to convince us that the receiver just won't work unless everything is hermetically sealed in submarine-like boxes.  Not true!  And Charlie's receiver demonstates this.   

Charlie is clearly keeping up the Kiwi tradition of fine homebrewing exemplified by the Tucker Tin 2,  ZL2BMI's DSB rig,  and many other FB HB projects from ZL. https://soldersmoke.blogspot.com/search?q=New+Zealand+DSB

Thanks Charlie!  Be sure to check out the rest of his YouTube channel: https://www.youtube.com/@CharlieMorrisZL2CTM

Justin's Receiver -- A 40 meter Superhet from AC8LV

 

FB Justin!  I really like the board that you are using as a base for the project.  And you have some great mentors in Nick and Loren.  

It is wonderful that you have that receiver working.  But I would tweak and peak quite a bit before taking on the transmitter.  Get a decent outside antenna -- even a dipole or a 1/4 wave with counterpoise would be a big improvment.  Like this one:  

https://soldersmoke.blogspot.com/2023/03/an-antenna-for-high-school-direct.html

And try to square away the grounding on the board (maybe some copper tape from Amazon) and the power supply you are using (I hope it is not one of those noisy wall warts).  When  you are experimenting, it can be useful to power varous stages with 9V batteries -- this is a good way to find out where noise is coming from.  If your AF amp is squealing at 12 volts, you need to break the feedback loop that is leading to oscillation.  Often the feedback is through the power supply.  Finally, try to get that homewbrew crystal filter working -- if the bandpass is uneven, you just need some impedance matching at the input and output.  

Great work Justin!   Keep at it.  73  Bill 

Bill,

I am sending video and pictures of my 40m  superhet that I built. I have it on the floor in an extra room in the house. The antenna is a stock vhf dipole that came with my rtl sdr which I use as a spectrum analyzer. In one of the clips I am receiving RW7K. I have been working on the station for the past year with help from Loren Moline, WA7SKT through texts when I have a problem. The LO / VFO is from Nick Woods Videos.

Next, I will build an outdoor antenna and the transmitter section. I first started homebrewing at the beginning of the pandemic, but this is by far my largest accomplishment. I would like to thank you and Pete for the soldersmoke videos which have been a great inspiration.

I will send more updates when the transmitter section is finish along with a much longer description of the projects

Thank you

Justin Elliott
AC8LZ

Bill, Pete, and Dean 

Thank you for the compliment. Pete, I want you to know, I’m a huge fan and I enjoy the one-liner jokes. I enjoy your contributions to the videos when you’re on Dean. 

Here are pics / videos of my superhet. 

The bandpass filter is a homebrew version of qrp labs design for 40m, I had to add an extra capacitor to get the bandpass where I wanted it. It is 6.9mhz to 7.32mhz. 

Mixer / demods are ade-ask.

The rf amps are kits i bought online, assembled, then used the schematics to replicate. They are the W7OI created and which have been mentioned on the channel

The LO/VFO are arduino driven from Nick Woods (M0NTV) YouTube channel. I believe episode 26

The crystal filter was built for 9MHz, but when I swept it I found the bandpass was saw toothed, so I used a commercial filter that Loren Moline WA7SKT sent. 

The audio amplifiers are a Common Emitter Amp I found on YouTube, I can’t recall the channel and a commercial amplifier, which I can now reproduce as I have the schematics. 

The speaker is a 2W 8 ohm speaker. 

...

Justin Elliott

AC8LZ

Nate KA1MUQ's Amazing Thermatron Receiver

https://natesbasement123.blogspot.com/2024/02/thank-you-bill-dean-grayson-pete-and.html

Wow, some really wonderful work is taking place in Nate KA1MUQ's basement in California. 

-- I really like the pill bottle coil forms.  I wonder if Nate faced suspicion (and possible arrest) in the pharmacy when he asked for the pill bottles.  (I got some suspicious looks when I went I asked for empty pill bottles while building my thermatron Mate for the Mighty Midget receiver back in 1998.) 

-- The variable capacitors are also quite cool, as is the big rotary switch.   Is that for band switching? 

-- Oh  man, all on a plywood board.  Frank Jones would approve!  

-- Indeed Nate, that beautiful receiver NEEDS an analog VFO.  And we need to hear it inhaling phone sigs, not that FT8 stuff. 

-- Please keep us posted on your progress.  And of course, one hand behind your back OM.  Lots of high voltage on those thermatrons.  

Thanks Nate!  

Videos from Mike AG5VG -- His Homebrew BITX Rigs

Here are two great videos from Mike AG5VG showing his two homebrew receivers in action.  (The transmitter portions of Farhan's circuit will come later.) See yesterday's post for more details. 

On the video above (40 meters) 

-- I love that speaker.  

--  The enclosure and the reduction drive for the VFO is really great.  FB OM. 

-- Very cool that Mike captures a 40 meter QSO with "Wild Bill" ZS6CCY in South Africa, someone who we've spoken to many times, often on the long path, sometimes from Mozambique. 

-- I like how Mike demonstrates the effect of removing the antenna.  You can definitely see what we mean when we say you should be able to "hear the band noise."   

  

Above you see the 20 meter receiver in action.  You can see one of the physical benefits of using a wooden base:  You can easily mount connectors, switches and tuning controls using just pieces of copper-clad board screwed into the wood.   This is what I am doing with my latest BITX 15-10 rig. 

For the tuning of the VFO, it looks to me as if Mike has a large "main tuning" control in the center, with a smaller "fine tuning" or "bandspread" control off to the left.  Does that smaller control work with a varactor diode or with a smaller variable cap?  Also, to the right of the main tuning control we see a 3 pole switch.  Is that switch putting additional L or C into the VFO circuit to move the frequency around?  These techniques would all be quite valid;  Mike demonstrates that there are many ways to skin a cat (or tune a VFO!) 

Mike:  Please send more info. 

F6CRP's FB Homebrew Receiver

I like F6CRP's homebrew receiver.  I like the way he presents it (block by block) and I like the inclusion of the W7ZOI IF board. The JF3HZB VFO is quite cool (even though it is digital),   We have posted about this VFO several times: 

 https://soldersmoke.blogspot.com/2022/05/who-is-jf3hzb-creator-of-that-nice.html

Denis has a very nice station and workbench: https://www.qrz.com/db/F6CRP

He also has some very nice videos on his YouTube channel: 

https://www.youtube.com/@radiorider8249/featured

Thanks Denis! 

Nine Homebrew Transceivers by Walter KA4KXX (and some QRP and QRO RC planes)

 

Our friend Walter KA4KXX in Orlando recently sent us this really cool "family photo" of his homebrew rigs.  Be sure to see the key that explains the photo (below) FB Walter.  Thanks too for the model airplane pictures. (Click on the images for better viewing.) 

Walter wrote: 

I recently realized that I am now operating nine homebrew transceivers, which would fit nicely in an “aerial” photograph, so I grabbed my stepladder and everything did fit well in the frame.  Six of them come from the BITX side of the family, with #1 and #7 direct conversion and #9 a single conversion superhet but using the NE602.  More basic information is included in the sketch.

I tried a Si5351 VFO once in the dual-band rig #4, but by the time I built the QRP Labs kit with so much closely-spaced soldering, and then added sufficient filtering and amplification to properly drive a 50 ohm load, I was exhausted!

These nine were created during the past eight years, and were preceded by eight more transceivers that I can document, but those have all been disassembled, with many of the parts being used in these later rigs.  I build my transceivers to be operated often, and since 20 Meters has been hot lately, for example, my POTA Hunter log shows over 300 CW and SSB contacts in 2023 alone, so rig numbers 7 - 9 have been earning their keep lately.

In summary I have created a lifetime total of seventeen transceivers so far, and although I am nowhere near the fifty-plus tally of Pete N6QW, I did spend a lot of years instead homebrewing many radio-controlled model airplanes of my own design.  Two photos show one example that I flew in the 2011 Blue Max Scale R/C Contest at the Fantasy of Flight Museum in Polk City, Florida against some stiff QRO competition.

—Walter KA4KXX

The Awesome Homebrew of Will KI4POV

 

Will's homebrew station is really something.  The rig (it truly qualifies for this term of praise) is amazing all by itself  (see below), but a look at Will's QRZ page reveals other ingenious inventions and techniques:  There is the clock made from panel meters.  And the method he uses for making aluminum project boxes.  He even made an N0WVA regen receiver.  That's the one I used in my ET-2.   Fantastic.  

Will really needs to share his homebrew skills with others.   I hope he is soon in a local high school teaching students how to build things.  Thanks Will!  

Bill and Pete,

Just wanted to send a note to update you on the latest projects here. The last time I emailed, I mentioned wanting to build a superhet, which you (rightfully) discouraged, pushing for a DC receiver.

Well, I finished the superhet at the end of last year. I had most of the receiver working long before then, but got bogged down in an AGC system. The final receiver is a 5 band si5351a controlled single conversion superhet loosely based on Todd, VE7BPO's design with several modifications. I used a 9 Mhz IF instead of 4, I used a digitally controlled LO and BFO, and as mentioned, I added an AGC system, which ended up being the most challenging (and most interesting) part. The final AGC system I ended up with used the detector and amplifier side of Wes Hayward's "full hang" AGC from SSDRA, but I didn't have the IC IF amplifiers with variable gain, so instead, it fed a PIN diode attenuator circuit to control the IF gain. The final result worked great, but I nearly pulled my hair out getting it to work. I originally intended to build the receiver for 40 and 20 meters, but it ended up covering 80, 40, 30, 20, and 15 since I used the filter relay board from QRP Labs which had 5 slots.

After I got the receiver running, I decided I needed a matching transmitter, so I  built up a simple CW transmitter to match. It uses an si5351a VFO driving a 74HC04 hex inverter as the buffer amplifier. The trick here is that by driving all the inverter gates in parallel, the output impedance is ~14 ohms broadband, suitable for driving a BJT PA without any need for matching transformers. The PA is 3 2N2222s in parallel with heat syncs putting out about 2 watts from 80 - 15.

The part I'm most proud of is that I have the arduino for the receiver connected to the arduino for the transmitter through a serial line. The receiver sends it's current frequency to the transmitter so that the transmitter can track the receiver's frequency as you tune (like a transceiver). I'll attach a few pictures of my homebrew station below. The transmitter is on the left, receiver is on the right. The box on top of the transmitter is my homebrew keyer. Next up on my build list is a solid state T/R switch.

Bill, I've enjoyed following the updates on the school DC receiver build. My local club is wanting to do some youth outreach, and I'd love to get them involved in building. I'm the only builder in the club though, so I don't know if I personally have the manpower to make it happen. Also, thanks for the recent info and pictures of Cuban homebrew rigs. I grew up listening to Arnie Corro, so I love seeing their resourcefulness and ingenuity. Makes me want to take apart some old electronics.

Pete, I'm enjoying following the 10M SSB project. With the uptick in propagation, I've been bitten by the 10M bug, and I'm thinking a 10M rig may have to be on my project list for this year.

73,

Will - KI4POV

KI4POV's Clock

KI4POV's N0WVA Regen

Fixing Up An Old Homebrew Rig -- Barebones Superhet and VXO 6 Watter

 

I'm not exactly sure why I pulled this old rig off the shelf, but I'll write up what I did -- I often use this blog as a kind of notebook.  I can look back and easily see what I did on my last encounter with the rig. 

The receiver is Doug DeMaw's Barebones (aka Barbados) Superhet.  This was my first superhet receiver. I built in in 1997.   The transmitter was my first real homebrew project -- it is the VXO 6 watter from QRP classics.  I built it in the Dominican Republic, probably in 1993 or 1994.  I built the power supply so that I could say that the entire rig is homebrew. 

This rig is getting a bit long in the tooth:   The receiver is built with 40673 Dual-Gate MOSFETs, an some of the transistor cans have gotten rusty.  The frequency readout on the receiver is the top of a coffee can fitted onto the reduction drive behind the tuning knob from a Drake 2-B (not MY 2B!). 

Here are two 2013 videos that I did on this receiver: 

https://soldersmoke.blogspot.com/2013/03/video-of-my-barebones-superhet.html

-- I put the crystal filter back in CW mode.  I had widened it so that I could listen to 20 meter SSB, but I decided to go back to its original configuration.  When I built the receiver in 1987, I didn't characterize the crystals -- I just used the capacitor values that Doug DeMaw had in his article.  I pretty much did that again this time, just putting caps that are close in value to what Doug had.  DeMaw used color burst crystals at 3.579 MHz.  So I guess this would be a GREAT receiver for the Color Burst Liberation Army!  

-- I used My Antuino (thanks Farhan!) to check the passband.  Here is what it looks like.  I just put the Antuino across the 10k resistors on either side of the input and output transformers.  The coil cores had become very loose -- I just tried put them in the right place.  I may need to put some wax in there to allow them to better stay in place. I think they could have used toroids instead -- that would have been easier. One of the transformer connections was open -- they don't work well that way,  once I fixed that, the passband looks like this: 

-- Each of the horizontal divisions is 500 Hz.  The passband is not pretty, but it is OK, and I  didn't feel like doing too much work on this to get it in better shape. 

-- The filter peak was a bit lower in frequency than expected.  I found that trimmer cap C3 in series with the BFO crystal would not allow me to lower its frequency sufficiently.  So I moved C3 to a position in parallel with the crystal.  With this mod, I could get the BFO frequency to 3578.69.  This produces a 690 Hz tone when the received signal is at the peak of the IF passband.  Opposite sideband rejection is quite good. 

March 2013 Rebuild of the VXO 6 watter

-- I didn't have to do any real work on the transmitter.  The RF amplifier in the transmitter had served for a time as the RF amp in by 17 meter DSB rig (I had added a bias circuit, which I removed when I put the amplifier back in Class C).  Some time ago I rebuilt the oscillator circuit (which had been literally cut off the board when I used the amplifier in the DSB rig). 

-- I did have to reconfigure the muting circuit -- the T/R switch in the transmitter switches the antenna and also -- through a two wire circuit -- cuts off 12 V DC to the transmitter when in receive mode. 

-- For sidetone I just put a small piezo buzzer through a 1k resistor between 12 V DC and the key line. 

It all worked fine -- I talked to three stations on the high end of  the 20 meter CW band. 

Phase Noise and all that

Our friend Dave K8WPE has been listening to old podcasts.  He recently came across those in which Pete and I were talking about phase noise.   He asked for some resources on this topic.  Here is what I sent him: 

 Receiver performance expert Robert Sherwood explains it this way: 

Old radios (Collins, Drake, Hammarlund, National) used a VFO or PTO and crystal oscillators to tune the bands. Any noise in the local oscillator (LO) chain was minimal. When synthesized radios came along in the 70s, the LO had noise on it. It is caused by phase jitter in the circuit, and puts significant noise sidebands on the LO. This can mix with a strong signal outside the passband of the radio and put noise on top of the weak signal you are trying to copy. This is a significant problem in some cases: You have a neighboring ham close by, during Field Day when there are multiple transmitters at the same site, and certainly in a multi-multi contest station. You would like the number to be better that 130 dBc / Hz at 10 kHz. A non-synthesized radio, such as a Drake or Collins, has so little local oscillator noise the measurements were made closer-in between 2 and 5 kHz. 

http://www.sherweng.com/documents/TermsExplainedSherwoodTableofReceiverPerformance-RevF.pdf

Rhode and Schwarz have a good oversight video with great graphs that explain the fundamentals,  See above or here:  https://www.youtube.com/watch?v=hfgaEjf1154 

I think a lot of the fretting about advanced receiver performance measurements are really kind of over-the-top, and mostly of interest to advanced builders who want the very best performance from their receivers.  Most of the rest of us are happy if we can hear the band noise and separate the desired signals from the QRM.  But I must admit that as time goes on, I find myself getting more and more finicky.  I start to worry about gain distribution and dynamic range.  But I don't worry so much about phase noise because I am more of an LC oscillator guy and don't make much use of the PLL devices (like the Si5351) that do produce more phase noise. 

I've had many articles on the blog about about phase noise.  Here they are: 

https://soldersmoke.blogspot.com/search?q=%22phase+noise%22

W1VD's Boatanchor Receiver Tests

I've been trying to get more rigorous in my evaluation of receiver performance.   My HQ-100 is tuned to Radio Marti, and it sounds great.  But how great is it really?  And what about all the receivers and transceivers I have built?  How good are they?  

Our friend Dean KK4DAS is about to start the rehabilitation of his dad's old HQ-170A.   A search for that receiver led me to Jay Rusgrove's very interesting measurement and analysis of old tube type radios.  Jay's results appear in the links below.  More important is his very clear description of how the tests were done and what the results mean (link below). Also included is one link showing a discussion of Jay's work.  

Jay notes: 

The decision of which boat anchor receiver(s) to own is seldom based on performance alone. A combination of favored manufacturer, period of manufacture, features, collectability or even just 'looks' often rank higher on the priority list than receiver performance. Even if one were interested in performance specs much of the available information is subjective as few receivers manufactured prior to the mid 70s have undergone standardized testing. Hard data on minimum discernable signal (MDS), blocking and two-tone IMD dynamic range is interesting to some operators and important in an historical context as it shows the progression of receiver development.

Jay designed the very first real transmitter that I homebrewed (The VXO 6 Watter from QRP Classics). Jay has been mentioned many times in the SolderSmoke podcast and blog:    

Jay's results:   http://www.w1vd.com/BAreceivertest.html

Jay's methods:  http://www.w1vd.com/Receivermeasurementbasics.html

Discussion: https://www.antiqueradios.com/forums/viewtopic.php?t=96872

Mr. Carlson's Grand Receiver Restoration Project -- Your Input Sought (video)

Mr. Carlson (VE7ZWZ) is launching a series of videos on the restoration of some old boatanchor receivers.  I have been working on an old HQ-100, so this all resonates well with me. 

He asked for viewer input on which of these receivers he should work on first.  I voted for the SP-600 because I wanted to see how difficult it really is to change out the infamous Black Beauty capacitors.  My second choice was the R-390, but I warned Mr. Carlson that he might need a chassis crane for that one.  No kidding.  Really.   

I look forward to watching the series.  Thanks in advance Mr. Carlson. 

Level UP EE Lab Builds a Superhet Receiver

I was really glad to have stumbled across Darren's YouTube channel: 

(46) Level UP EE Lab - YouTube

Heck, he has an S-38E on the shelf above his bench.  He is clearly one of us.  What is his callsign?  

This morning I watched the first and last of his 10 videos on his superhet receiver project.  Very cool.  Lots of good info in there.  And there is something for everyone:  Arduinos and Si5351s, along with a lot of standard analog circuitry.  The first episode appears above. 

The variable bandwidth filter looks very interesting. And there was a nice shout-out to Charlie Morris and one to Hans Summers. 

I really like his effort in episode 10 to measure Minimum Discernible Signal using commonly available test gear.  This helped me in my effort to get more rigorous and serious about receiver performance measurement.    

Darren has many other excellent projects on his YouTube channel.  My Hammarlund HQ-100 receiver started giving me trouble this week, and I was debating whether or not to fix the old thing.  Darren's channel provided the inspiration I needed.  It will be fixed!   

Please subscribe to Darren's channel.  And spread the word about his videos.  We definitely want him to make a lot more.  

Thanks Darren! 

SolderSmoke Podcast #236 -- Bill's 17-12 Rig, Pea Shooter, VFO Wisdom, Temp Compensation, Need Code for Max2870, Making Enclosures, MAILBAG

ARC-5 R-23 Nav Receiver Parts

SolderSmoke Podcast #236 is available!

http://soldersmoke.com/soldersmoke236.mp3

Winterfest!  Many Boatanchors.  Lots of old good analog test gear.  Talk with Dean KK4DAS.  Met up with Armand WA1UQO and Charles AI4OT. 

Pete's Bench: 

-- Looking for help in software development for MAX2870 board.  

-- Tapped Capacitance Impedance Matching

-- The Pea Shooter (See N2USD's version in videos

 below).

-- Tribal Knowledge on Making Enclosures

Bill's Bench: 

-- 17-12 Band Imaging SSB Transceiver.  It works on both bands. 

-- Plan for Glowing Numerals (N6QW has been there and done that!)

-- WU2D's videos on VFOs.  

-- Temperature Compensation:  HT-37 capacitor.  FT-101 VFO,  even in the ARC-5 receiver! 

-- Trying to get more rigorous about receiver design.  Gain distribution, IMD, Dynamic Range, etc. 

-- Do I need a true RMS audio voltmeter?  Or can I get the same info from freeware audio spectrum analyzer and soundcard?

-- 6EA8s replace 6U8s in MMRX 

SHAMELESS COMMERCE DIVISION:   We have a sponsor!  

PARTS CANDY out of Chicago produces quality test leads for your bench.  The guy who runs the company is Carlos, and he is one of us.  He is an electronic tinkerer. See the ad on the left hand column of the SolderSmoke blog.  Just click on the picture of the test leads and you will be taken to Carlos's ebay store.  Go for it. 

Mailbag

Walter KA4KXX in Orlando -- Diodes in BITX Bilats -- Why?  Farhan says To prevent reverse junction of off transistor from conducting and clipping waveform. 

Tony G4WIF -- Audio test gear and G3ROO paraset

Todd K7TFC Pine boards, TIAs and 12 meters

Dean KK4DAS  Ceramic Variable Oscillators on 40.   Juliano Criteria? 

Mike WU2D   VFOs and Temp compensation. ARC-5s

Chris KD4PBJ   A really nice parts care package -- Thanks Chris! 

Steve M0ECS.  Inspired by SS, moved something off the Shelf or Box of Shame. 

Jason KD2RKN Building a DC receiver.  It is all our fault. 

Chris Mannon in Indiana joining the CBLA

KC4GMH is listening! 

Ed N2XDD has been armed with a 3.579 MHz crystal.  

Harvey Wa3EIB working on his museum 

Tim AG4RZ is BACK IN THE SOLDERSMOKE! 

Fred KC5RT -- an old friend -- recommends Bangood RF sig gen for 88 bucks. 

Shlomo 4X4LF listening and homebrewing from a Kibbutz in Israel. 

Chuck KF8TI was a Peace Corps Volunteer in the Philippines.