Karl K5KHK's, Junkbox (but really nice) Direct Conversion Receiver (with a rebuilt AF Amp)

Karl K5KHK wanted to build the receiver from junk box parts.  But he did not have the needed AF transformer in his junkbox.  So he designed an AF amp that would not need a transformer.  That's great, but the circuit was a lot more complex than the one we designed for use by beginners.  And we advised others to search for the needed transformer and to use the circuit we had prescribed. Thus the original "Honorable Mention" category.  But this is no big deal.  Karl has made great contribuitions to the radio art, and his circuit will, I think, be of use to those who want to build a different AF amp AFTER they complete the basic receiver.  

NOTE FROM 28 March 2024:  Karl found the right kind of AF transformer! He went the extra mile and re-built the audio amplifier using the transformer.  FB Karl.  You Honorary Mention status has been removed!  Welcome to the full Hall of Fame! 

Here it is with the simple AF amp that we are using:      

Karl writes:  

First Light! I know, I am a rebel and cannot follow instructions, but I wanted to do this from my stash (OK, mixing worlds here, that's what fiber artists call their junkbox of fiber, but I did join my wife this morning at a fiber fest). I do not have an output tranformer (I do have a few 600:600Ohm transformers). So here are my three answers:

 

1. Biggest challenge was to find a way to replace the output transformer. I did have a few baggies of BD139/140, so I researched small amplifiers wiith a complimentary output configuration and found one in  John Lenk's "Handbook of Simpified Solid State Circuit Design", which apparently goes back to a Motorola application note (based on ancient transistors). After some noodling and heavy LTSpice'ing, I had something that looked like it would work, and it did, even though without anything connected, it blasted me with the local AM talk radio station (and some RF oscillation). A few strategically placed 0.01uF capacitors tamed the beast. What also helped with the design is that I found a schematic online without much comment (besides one who said "this will not work") that was based on the same design with more modern transistors. 

2. I learned a lot about how to keep strong RF from messing with my AF amplifier, and that without having to put it into a shielded box. 

3. I've started on two modules for Pete's PSSST transceiver when he first published it, but stuff got in the way, and I am motivated to pick it up again. 

So again, the complete receiver was build with parts from my junkbox. This means that I had to make substitutions. I have for example a 5.1V Zener diode for the oscillator. It does produce enough power to drive the mixer, even with that lower voltage. I had smaller toroids on hand (-37 vs. the -50), so I had to do some math for the BPF to figure out how to wind them. I had no  silver micas, and also no NPOs of the correct values, so a couple other values added up to almost exactly what I needed.

Thanks Karl, and congratulations! 

 

Clip Leads Made with FAKE WIRE! Buy Good Ones from PARTS CANDY!

We don't see many videos about clip leads,  but this one fits in well with our esoteric subject matter. 

Carlos of Parts Candy (our sponsor) responds: 

Interesting video. Yes the clips we make are nickel plated steel but the wire is tinned copper. When I was making custom orders I made some custom clip lead sets using 100% copper clips for a few people who really needed the low resistance. In most applications the steel clips should be fine. The resistance for 12” clips is about 12mOhms and the 32” clips are around 24mOhms, iirc.

The bottom lines:  1)  Don't scrimp with a crimp -- get a good solid soldered clip-wire connection from Parts Candy. 2) Parts Candy wires are not fake.  They are tinned copper 3) The metallic composition of Parts Candy clips does not degrade performance. 4) But if a customer really needs copper clips, Carlos can make them too. 

Parts Candy web site:  https://www.partscandy.com/

More Background on the Mythbuster II Rig (and a short video)

Above is a short clip of me hearing an old friend on the new receiver.  TRGHS. 

A couple of guys on Facebook asked for a schematic for this rig.  I don't really have one -- as you will see it is a collection of different circuits from lots of different sources.  I was also thinking that if you need a schematic for a rig like this, you probably shouldn't try to build a rig like this.  But in an effort to be nice, I supply here some background info on some of the circuitry and parts sources.  And no, I don't have BOMs nor Gerber files.   

More info on the Yaesu VFO is here:

https://soldersmoke.blogspot.com/2021/07/mythbuster-video-3-using-vfo-from-yaesu.html

The VFO is kind of high in frequency. But it is very stable. I can't really take credit for this -- the credit goes to Yaesu. But I like the circuit because it is all analog and all discrete component. It even has a split stator temperature compensation variable cap! At Pete's recommendation, I originally bought these boxes thinking that I'd just get the anti-backlash gears and the reduction drives. But the sellers always sent the entire VFO boxes. They even come with a "clarifier" circuit which I now use as an "up 5-10" feature that lets me work the DX-peditions on 20.

As for the tape, I got mine from Amazon. It has conductive adhesive:
https://www.amazon.com/gp/product/B07QQJ4MX1/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

The boards for the IF Termination Insensitive Amplifiers come from Todd K7 TFC at Mostly DIY RF:  https://mostlydiyrf.com/tia/

The little LM386 boards that I have been using are available here: https://www.amazon.com/dp/B00LNACGTY?ref=ppx_yo2ov_dt_b_fed_asin_title  I precede it with one stage of AF amplification from the original BITX 20 sechematic.  I put a 10K pot between this stage and the LM386 board. 

Here is the Amazon source for the 1/8 inch plywood that I will use for the case (I have used up all the pandemic treadmill packing material):  

https://www.amazon.com/dp/B0D5VCBBP4?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

"The New Essential Guide to Electronics in Shenzhen" A Book Review by Jenny List (with a video from Shenzhen)

This new book looks really good.  Great electronics info, with lots of cultural and linguistic wisdom. 

https://hackaday.com/2024/03/13/review-the-new-essential-guide-to-electronics-in-shenzhen/#more-668397 

Jenny's review brought to mind an older SolderSmoke blog post about Shenzhen. In this 2012 video  Bunnie Huang in Singapore talks about getting parts in that city: https://soldersmoke.blogspot.com/2012/08/singapore-knack.html

Thanks to Jenny, Naomi, and Bunnie.  

The TinySA Ultra Spectrum Analyser (video)

I got mine this week, and I've been playing with it.  When I spoke to Dean KK4DAS, I asked what he thought the first thing I did with it was.  He guessed that I tried out the greatly improved Resolution Bandwidth.  Good guess, but not quite:  I tried out the  "listening" feature on this SA.  You will recall that the plain-vanilla, non-Ultra TinySA required a hardware mod to allow for listening.  Dean had told me that the Ultra came with a headphone jack.  Indeed.  I fired it up and was able to listen to 1220 AM and also to the FM broadcast stations in the area.  With the FM stations, I'm guessing I was using a form of slope detection (IMSAI guy says it detects AM).   I tried to see if I could see/hear stations on the ham bands -- so far, no luck.  I'm not sure why, but I will work on this.  

The IMSAI guy video (above) does a great job in comparing the TinySA Ultra to a "real" spectrum analyser.   I think it compares very well.  

One note on where I got mine:  I ended up getting it from R&L Electronics, the recommended U.S. dealer for the device.  I had tried getting it (cheap) through AliExpress.  This didn't really work out.  The tracking info from AliExpress showed that the box had made it to my local post office, but I never got it.  It may have been that they just didn't take the complete mailing address from PayPal.  In any event, I was able to get a refund from PayPal, so no loss here.  R&L turned out to be a great source. 

Ultra, of course. 

Boom! Small Electrolytics Blow-up in a Big Way. MAGIC SMOKE RELEASED!

It doesn't take much.  Like if you put 12 volts across a little electrolytic rated at 10 volts, WATCH OUT! The tranquility of your workshop could soon be very suddenly disturbed.  Even with the proper polarity, they will BLOW-UP.  The MAGIC SMOKE will be EXPLOSIVELY RELEASED. BOOM! 

And speaking of capacitors, Rogier PA1ZZ sends this: 

https://jupitercondenser.com/collections/audio-capacitors

But don't blow these ones up.  Some of them are 75 dollars a pop!  

Apex Surplus in Los Angeles

The Polaroid camera for the Tek 'scope was pretty cool.  And the comments about the Simpson 260 made me feel good about finding one at a recent hamfest, but I don't think mine is an extremely rare Model 2.   

Open Circuits: Cutting Open Components for a Look inside -- First Chapter Free

 

Bob KD4EBM sent me this: 

“…. Eric Schlaepfer (@TubeTimeUS) and Windell Oskay (co-founder of Evil Mad Scientist)’s latest book, Open Circuits, is a celebration of the electronic aesthetic, by literally opening circuits with mechanical cross-sections, accompanied by pithy explanations and illustrations. Their masterfully executed cross-sectioning process and meticulous photography blur the line between engineering and art, reminding us that any engineering task executed with soul and care results in something that can inspire feelings of awe (“wow!”) and reflection (“huh.”): that is art. …”

https://www.bunniestudios.com/blog/?p=6558

I saw on Hack-A-Day today that the first chapter of the book is available as a free download: 

https://nostarch.com/download/OpenCircuits_Chapter1.pdf

Many of our favorite parts are dissected in that chapter.  The innards of a ceramic disc capacitor, for example, are shown above.

Thanks Bob! 

Great Technical Info and Tribal Knowledge from GQRP

Thanks to Tony Fishpool G4WIF for sending us this link.  

https://www.gqrp.com/tech.htm

There is a lot of great tech info and Tribal Knowledge on the GQRP page.  This is all related to our discussion of how to set up an electronic workbench or workshop. 

Thanks Tony and thanks to GQRP. 

Where Do You Think This Variable Capacitor Came From? What Piece of Gear Did it Come out of? Is it in the Old Catalogs?

 

In an effort to stop the slaughter of innocent Heath QF-1s (for their very nice variable capacitors), I bought this thing on e-bay.  Here is the info I have: 

https://www.ebay.com/itm/255622418189

I checked the resonance of the cap and the coil:   It tunes from about 10.140 MHz to about 13 MHz.   The cap is nice -- brass vanes and with the linear tuning shape.  I don't know about it being from a Hartley oscillator -- no signs of a tickler coil.  There seems to be some sort of a pass-through cap from "Faradon" of Camden N.J.  

Update: 

It tunes from about 9 to 138 pf. The coil that it had on the back of the cap is about 1.6 uH and is tapped (Hartley style). The capacitor is marked on the back: "Licensed Under Pats. MC 15257781258423"

From the e-bay ad: 

"Here's a great project part.  These were likely a VFO assembly for some RF equipment from the late 1920's or 30's.  Essentially it's 4" Type A Velvet Vernier dial (standard 5:1 reduction drive) with a variable capacitor.  The variable condenser is a high quality ceramic frame with brass plates and looks suspiciously like a General Radio house part (also in Cambridge at that time). The variable condenser looks like a SLF shape or similar, about 135pF.  It has a ceramic frame and has an insulated shaft, which was critical to keeping hand capacity down back then.  It appears to be wired for a Hartley oscillator, probably 10 MHz+ give or take (not measured).

The vernier is in excellent condition--smooth, without backlash or sticking.  There are no chips in the skirt and the numbers and nice and clear--these were obviously well cared for over the years.  They have the the hard-to-find dial markers!

There is a rigid metal panel to which the vernier assembly is attached, and this in turn supports the condenser frame.  I suppose you could just that in a project box with an appropriate sized hole for the shaft and have an instant shielded enclosure for a VFO, or maybe screw it to the side of a breadboard.  You can also remove the vernier assembly from the panel and use it separately (e.g., to fix up an old NBD).  Lots of possibilities.  

There is a loose sheet-metal collar behind the rigid panel that friction-fit a (now missing) can that went over the whole assembly. It's easy enough to unscrew the front and remove this piece.  Everything comes apart if you want, including the unobtainium dial pointer."

So where do you guys think this very nice cap came from?  Who made it?  Was it salvaged from a piece of radio gear?   Does it appear in any of the old catalogs?  

Electronics Manufacturing in New York City -- Limor Fried and Adafruit (video) -- "TRUST YOUR TECHNOLUST"

The Radio Gods seem to be directing my attention to my hometown: New York City.

I was recently in the city, observing the placement of various IBEW - WYKSYKDS stickers.  And as I work on my old Hammarlund HQ-100 I note that both the HQ-100 and I may have been produced on Manhattan island at about the same time (me definitely, but the HQ-100 may have been built in Mars Hill NC). 

This morning Jim W4JED reminded me that Limor Fried, MIT Engineer and founder of Adafruit,  is producing a lot of amazing electronics items right in NYC, on Manhattan Island, down in Chelsea.  Thanks Jim.  FB Limor!  

Watch the above video.  I really liked the sign Limor has above her workbench: 

"TRUST YOUR  TECHNOLUST."  

 Indeed.  Back to the HQ-100. This IS a case of technolust.  I'm not quite satisfied with the alignment.  And it bugs me.  I technolust for perfect alignment.    (Steve Silverman -- I think we should add technolust to the SS lexicon.) 

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. 

Troubleshooting Apollo: 23 MHz Crystals in a NASA Ground Receiver

More amazing Apollo stuff from CuriousMarc. 

Here we see them struggling to find the proper frequency for one of the oscillators in a dual conversion UHF receiver from the Apollo program.  For the VCO, they needed a crystal in the 23 MHz range. They faced the same questions we face:   Series or parallel?  Load capacitance?  Fundamental or overtone? 

It just so happens that at this moment I have on my bench the 17 meter SSB transmitter that I built some 20 years ago.  And the VXO in it uses crystals in the 23 MHz range.  TRGHS. (More on the spur problem with this rig soon.  The solution does involve the 23 MHz VXO.) 

Very cool that CuriousMarc found a manufacturer still willing to produce custom-made crystals. JAN flashbacks!  LapTech Precision in Canada: https://www.laptech.com/index.php

The video above is Episode 8 in the Apollo Comms series.  If you go back one episode, you can watch Marc and his assistant troubleshoot the NASA Apollo UHF receiver.   They use very familiar troubleshooting techniques.  This reminded me a lot of what we do with older, potentially modified gear.  They were able to figure out what was wrong and  how a mod had changed things.  This set the stage for the crystal replacement selection we see in Episode 8.   Here is Episode 7: https://www.youtube.com/watch?v=87qA41A_Ies

Note:  The frequencies in this Apollo receiver were listed in Megacycles, not Mega Hertz. 

Thanks to Bob Scott KD4EBM for alerting us to this. 

Repairing My Maplin Audio Waveform Generator

I picked this generator at the Kempton Park rally in London many years ago.  I use it quite a bit, not only for circuit testing but also as an easy way to get my homebrew BITX rigs to send a signal so that I can adjust my antenna.  I just plug this thing into the mic jack, crank in a small amount of 1 kHz audio, and I am ready to minimize SWR. 

It never gave me any real problems until last week.  I opened it up and examined the circuitry for the first time.  Lots of mystery chips in there. Fortunately they are all socketed.  Thank you Maplin. 

Even without really knowing how each of the ICs work, it was easy to troubleshoot. See the schematic in the article that begins on page 21 in this .pdf: 

https://worldradiohistory.com/UK/Mapelin/Maplin-Projects-Book-48.pdf

My Rigol scope showed a good signal going into and coming out of IC8, the LF351 op-amp.  From there the signal goes to IC5 a 4066BE.  But nothing was coming out of IC5.  Thus IC5 was my lead suspect.  I put in a quick order to Digikey.  A couple of days and a few bucks later the chips (as always, I ordered several) were on my doorstep.  Within a few minutes IC5 was replaced and the generator was as good as new. 

One annoying problem with this generator is that it has no automatic shut-off circuitry.  So if I forget to turn it off, I soon have to buy two 9V batteries. Tony G4WIF suggested a simple timer circuit.  I may do that soon.  Or, given that we are already on the IC dark side with this project, there is this: https://www.youtube.com/watch?v=C4C2H_3BU3o&feature=youtu.be 

I recently find myself replacing a lot of chips in various rigs and devices in my shack.  It seems that chips go bad more frequently than discrete transistors or even tubes.  But maybe I'm just using older gear with older, more fragile chips.   What do you folks think? 

Homebrew Resistor Kit -- Drew's Mouser BOM

I put the resistors in parts envelopes and cardboard boxes

Hi Bill,

You mentioned wanting to get a resistor kit.  If you'd like, I can

help you do what I did.

First, I looked at:  https://en.wikipedia.org/wiki/E-series_of_preferred_numbers

Then I noodled about it a bit.  And looked at mouser.

A tiny bit of code put together a copy and paste list of part numbers

that I pasted onto mouser's BOM order form.  And bob's your uncle.

In my case, a particular manufacturer's 1/4 W metal film 100 ppm as

they were 1.9c @ 100 pieces.  I created a copy and paste BOM for E6

over 4 decades plus E3 for a 5th and 1M and 49.9 ohms. Less than $2

per value for 29 values.  Not a bad price for the size of the resistor

kit.  I also figured if the value gap was too large, I could fill it

in with the other half of the E12 series.  (E6 series is every other

E12 series value.)

This could be tweaked.  Perhaps fewer resistors in each value.  Or add

some more special values or whatever.

Mouser was kind enough to cut tape and put each value in a flat

plastic baggy with a label as to what was inside.  Sorted in a file

box, it's a snap to grab a resistor.

Perhaps this is something I should post online to share?  Maybe

someone else already has?

On my todo list is to construct my self a homebrew BOM of capacitors.

If you're interested, I could update this and let you know what Mouser

can do for you.  It may not be your preference, but it is an

interesting option.

Best regards,

Drew

n7da

--------------------------------

Drew:   Your message caused me to think about what I really need in a resistor kit.  I have been using some other resistor kits, but I end up using ALL of certain values and NONE of others.  Your message made me realize that there is valuable data in those old kit packages.  

I took a look a them this morning.   It seems I use the following values:  4.7, 10, 47, 100, 220, 330, 470, 1k,  2,2k, 3,3k, 4,7k, and 10k.  That's about it.  So maybe I just need to go to mouser and order, 50 of each.  I'm thinking 1/4 or maybe 1/2 watt? 

The packaging you describe sounds great.  How can I get Mouser to do that for me?  

I don't think I need the more sophisticated approach you used, but I'm sure we have listeners who could benefit from it. 

Any further suggestions?  

Thanks again,  

73  Bill 

-----------------------------

Hi Bill,

Sounds very good.  It turned out to be simple for me to order a
ridiculously well stocked resistor kit, but doing something custom is
actually a great idea.  If you want both 1/4 and 1/2, get both.  (I
figured I could always make a 1/2 W resistor out of 2 1/4 watt
resistors.)

The packaging is just what they do.  No extra charge other than their
regular shipping and handling.

So, I did this in late 2018.  When ordered, two values were
backordered, but they shipped them out a month or 6 weeks later or
something.  Checking now, 660-MF1/4DC1000F (a 1% 100 ohm metal film
1/4 watt), I see it is out of stock with an ETA of June 1st for 10K
they are ordering.  The other P/N that was backordered was
660-MF1/4DC1503F.  Who knew 100 and 150K ohms were extra popular?
150K is in stock right now BTW.  Maybe it's random what they run out
of?

Best thing is you copy and paste your list of P/Ns and quantity for
each and bam Mouser will tell you pricing and if anything is
backordered, etc.  If you don't like what you see, change your list
and try again.

I actually thought about what I wanted, then looked at Mouser to see
what they had and what the pricing was on it.

So, from this particular resistor family, I see the pricing is what it
was a couple of years ago.

if you order 50 pieces of that 150 or 100 ohm resistor, that is:
50*$0.055 = $2.75 for 50 resistors.

If you order 100 pieces of that 150 or 100 ohm resistor, that is:
100*$0.019 = $1.90

IT"S CHEAPER TO ORDER 100!  Well, at least for this resistor family
and for Mouser's price breaks.  You have to look at the price breaks
versus volume.  And of course, understand the minimum you need and the
maximum you can store in your lab.  :-)  Don't be ordering 10,000.
:-)

So, price breaks for these they show:

Qty.    Unit Price
1    $0.23
10    $0.055
100    $0.019
1,000    $0.014
2,000    $0.009
10,000    $0.008
25,000    $0.007

You can see that there's a good break at 10, 100, and 2,000.  The
quantity with a good break really depends, so you would have to look
at different vendor product families to see.  I don't think I looked
very long.  I probably knew I wanted 1/4 W (may have considered 1/8 or
1/2, don't remember).  I also think I knew I wanted metal film.  When
I saw the pricing on these at 100 pc and with 1% tolerance (so I could
double out to E12 series and have it make sense if it turned out to be
useful for me), I stopped shopping.

Here's the full BOM I ordered.  The top part is some extra parts I
wanted and those couple of special resistor values.  The lower part
was generated by just a few lines of python:

-----
G6K-2F-Y-DC12|8
1N4007FFG|100
1N4448|100
2N3904TAR|100
2N3906TAR|100
2643000101|100
2643002402|25
2673002402|25
2661000101|25
1C10X7R104K100B|50
1C10X7R103K100B|50
ECA-1HM101|25
ECA-1HM100|25
TIP29CG|5
TIP30CG|5
1N5355BG|10
PR01000104700JR500|10
PR01000102200JR500|6
MF1/4DC1800F|20
MF1/4DC2400F|20
MF1/4DC36R5F|10
FC2053-440-A|100
MF1/4DC16R5F|20

MF1/4DC10R0F|100
MF1/4DC15R0F|100
MF1/4DC22R0F|100
MF1/4DC33R0F|100
MF1/4DC47R0F|100
MF1/4DC68R0F|100
MF1/4DC1000F|100
MF1/4DC1500F|100
MF1/4DC2200F|100
MF1/4DC3300F|100
MF1/4DC4700F|100
MF1/4DC6800F|100
MF1/4DC1001F|100
MF1/4DC1501F|100
MF1/4DC2201F|100
MF1/4DC3301F|100
MF1/4DC4701F|100
MF1/4DC6801F|100
MF1/4DC1002F|100
MF1/4DC1502F|100
MF1/4DC2202F|100
MF1/4DC3302F|100
MF1/4DC4702F|100
MF1/4DC6802F|100
MF1/4DC1003F|100
MF1/4DC1503F|100
MF1/4DC2203F|100
MF1/4DC3303F|100
MF1/4DC4703F|100
MF1/4DC6803F|100
MF1/4DC49R9F|100
MF1/4DC1004F|100
-----

So, your BOM (4.7, 10, 47, 100, 220, 330, 470, 1k,  2,2k, 3,3k, 4,7k,
and 10k) would be the following.  Added the 4.7 by hand and deleted
the other values by hand.  Qty 100 each.
-----
MF1/4DC4R700F|100
MF1/4DC10R0F|100
MF1/4DC47R0F|100
MF1/4DC1000F|100
MF1/4DC2200F|100
MF1/4DC3300F|100
MF1/4DC4700F|100
MF1/4DC1001F|100
MF1/4DC2201F|100
MF1/4DC3301F|100
MF1/4DC4701F|100
MF1/4DC1002F|100
-----

Mouser.com.  Services & Tools button.  BOM Tool button.  Login (they
want account for the tools.  I can't complain.)  Upload spreadsheet or
copy and paste.  In this case, copy and paste.  In fact, copy right
out of this draft email and into their tool.  Next.  Then they ask me
for a name for the BOM and if I only want RoHS.  (RoHS is up to you.
I picked only RoHS, because I know all these parts are RoHS and it
won't warn me about lead poisoning or anything.)  Process BOM.
Blammo.

I had the 4.7 wrong, but they figure it out.  Ouch.  Pricey.  Maybe
you don't need so many, but $4.6 for 100.  Parallel a couple of 10
ohm, you'll have less parasitic L in your emitter circuit.  Change the
BOM before you click the add all to cart.  No problem.  Or maybe 4.7
is worth the extra money to a high roller such as yourself.  :-)

2 parts are at 0 inventory.  The 100 we knew about.  470 as well with
6K arriving 15June.  Yes, those ETAs are perhaps questionable.  Dunno.
They will ship you what they have and ship the rest later AT NO EXTRA
CHARGE.  :-)

A third part is at 123 pc inventory.  Act now before they are all out!
:-)  220 ohms.  6K due end of June.

The above would be $25.50 plus less than $10 for their cheapest
shipping option.  Not a bad price for a well stocked CUSTOM kit and
it's really easy to do.  And these are good parts with specifications
and tempcos etc. all in the data sheet.  Sure, you don't need it 99%
of the time, but if you wanted it, because you were doing something
fussy, you have it.

You could cut that price down quite a bit if you went carbon or wider
tolerance.  (Who needs 1%?  This is electrical engineering, not
mechanical engineering!)  Or maybe another manufacturer.  It's easy to
browse on Mouser and figure out those other options quickly and what
it may do to help you out.  Of course, when you get to a price of
$0.00, you still have the flat rate cheapest Mouser shipping as the
floor on what price you can achieve.

Mouser will also give you a print and email with price, part number,
description of everything in your custom kit.  And each pouch is
labelled.  Crazy!  :-)

Another crazy thing is with these BOMs is that you can easily share
them with others.

Best regards,

Drew
n7da

SolderSmoke Podcast #224: Mars. Spurs. Bikes. SDR. NanoVNA. Antuino. MAILBAG

SolderSmoke Podcast #224 is available:

http://soldersmoke.com/soldersmoke224.mp3

1 August 2020

--The launch of Perseverance Mars probe with Ingenuity helicopter.

--China’s Tian Wen 1 on its way – radio amateur Daniel Estevez EA4GPZ is listening to it! 

--Sci Fi Books:  Mars Trilogy by Kim Stanley Robinson.  No skip on Mars :-(

--We have some sunspots!  SFI now 72 and the Sunspot number is 23. 

Bill's bench: 

--Conquering Ceramic Spurs in Q-31   Roofing filter -- sort of 

--NE602 for a Q-75 converter – Gilbert Cell. 

--Measuring low power levels out of NE602.  Antuino better than 'scope . 

--NanoVNA   Really cool stuff.  SDR in there. 

--Building a 455 kc LC filter from QF-1 rubble. Using LTSPICE, Elsie... 

--Reviving my bicycle AM radio – The “All Japanese 6”

--Understanding L Network impedance matching. 

--Bill’s new resistor kit from Mouser. Thanks to Drew N7DA. 

SHAMELESS COMMERCE:  PATREON, AMAZON SEARCH.  THANKS

Pete's Bench: 

--Lockdown Special 

--BPF work on SDR Rig

--I U W I H 

Mailbag:

VK3HN Summit Prowler 7

VK2EMU “The Stranger”

SM0P  HB uBITX in Dubai

AE7KI  Worked him in VK from London

ON6UU  EA3GCY’s 4020 rig

KA4KXX A Simpler Mighty Mite

W9KKQ M19 DMR

KD4PBJ Radio Schenectady

W3BBO 12AU7 Regen

KE5HPY Another 12AU7 regen

N5VZH Ne602 Converter

KY3R Wall Art

G4WIF  Spectrum Analyzer in your pocket

W2AEW  Talks to UK Club

KK0S Sent 455 Kc IF cans

KL0S Making 9Mhz filters

VU2ESE  Diving into simple SDR schemes

Dean KK4DAS  Amateur Radio Astronomy

The Ceramic Spurs (not a rock group)

Paul Taylor VK3HN's magnificent AM receiver was the inspiration for my Quarantine-31 Shortwave Broadcast receiver.  Like Paul I decided to make use of ceramic filters at 455 kHz for selectivity.  I started with the +/- 3 kHz filters that Paul used, but I found them kind of narrow for SW listening.  So I went with some wider ceramic filters that Bruce KK0S had sent me.  But I misread the specs that Bruce sent.  I thought they were 10 kHz wide filters. I realized later that they were +/- 10 kHz -- really twice as wide as I needed.  So I went back to Mini-Kits in Australia and got some +/- 6 kHz filters.  12 kc wide should be just about right, I thought. 

The bandwidth was right, but I started noticing a problem:  I could hear strong SW broadcast stations at two places on my dial.  This brought to mind an admonition from R.A Penfold, author of "Short Wave Superhet Receiver Construction" (1991 Babani Publications).   He advised keeping a few standard 455 kc IF cans in the circuit because, he warned, the ceramic filters have spurious responses, spurs that the IF cans can help knock down.  

Penfold was right.  Look at the filter response curve on the right (above).  There is a nasty spur at around 640 kHz.   This was the cause of my problem. Here is why: 

Suppose I was tuning Radio Marti's big signal on 9805 kc.  My VFO would be running at 9350 kc. 

9805-9350=455.  Great, but... 

With that spur at 640 kc, I could tune down to 9620 kc on my dial.  My VFO would be running at 9165 kc. 

9805-9165=640.  Bad.   That 640 kc difference product would make it through to my detector and AF amp.  I'd have Radio Marti showing up in two places.  I didn't like this. 

I thought about putting a series LC circuit tuned to 640 kc at the output of the ceramic filter.  This looked like a possible solution, but on the bench it looked like I would have trouble getting a circuit of sufficiently high Q.  

So rummaging around in my junk box I found an old Murata CFM455B filter.  This filter is quite broad, but it does not have the spur at 640 kc.  I could use it as a kind of roofing filter just ahead of the +/- 6 kHz filter.  Putting it there would allow me to avoid having to build additional matching circuits for the 455B filter.  

+/-6kc filter upper left,  455B wide filter to the lover right. 

I'm happy to report that this fix works.   The 6 kc filter provides the needed selectivity, and the broader 455B filter knocks down the 640 kc spur. 

Beware the Ceramic Spurs!  

Q-31 with can for first IF amps and filters open

SolderSmoke Podcast #222 Antennas, Phasing, VFOs, 2-Bs, 6 years of N6QW, MAILBAG

After 46 years, finally a dial skirt

SolderSmoke Podcast #222 is available:  

http://soldersmoke.com/soldersmoke222.mp3

No travelogue but… SolderSmoke Almanac!

Memorial Day in U.S.

End of Ramadan so Eid Mubarak! 

#222 marks SIX YEARS of Julian-ismo.  He started on SS 161.  Thanks Pete. 

Thanks to all who sent good wishes on Billy's graduation.  He heads to Boston and the lab in a week or so.  Very proud. 

------------------------------------------

Bill was on Ham Radio WorkBench Podcast  

 ----------------------------------------- 

PETE'S WORKBENCH

-- Antenna Ideas -- Don't Buy that $165 dollar dipole!  It is just wire!   

-- THE PHASING RIG. Does this point to a need for meditation?  Or at least some temporary disengagement? Tribal wisdom from Pete. 

-- DEAN KK4DAS's rig.  The Furlough 40.  Troubleshoot.  Tribal knowledge. 

-------------------------------------------

-- SHAMELESS COMMERCE DIVISION:   AMAZON BOX -- SEARCH FOR ANYTHING OU WANT THERE.  

-- PLEASE PUT COMMENTS ON THE SOLDERSMOKE BLOG POSTS. 

-- PLEASE CHECK OUT THE SolderSmoke YOUTUBE VIDEOS. 

------------------------------------------

BILL's WORKBENCH

n  Shortwave dials and exotic locations.  Java!  

n  Galaxy V VFO Project. Series-tuned Colpitts.  

n  DRAKE 2-B.  Hayseed Recap. Put the skirt back on the old rig.  Reduction drives?   

SHOPPING BAG: 

I got a replacement for the Xtronics 4000 soldering station.  Yaogong worked! 

https://www.amazon.com/gp/product/B078WB9Z2R/ref=ppx_yo_dt_b_asin_title_o02_s01?ie=UTF8&psc=1  

Ordered screws and stuff from McMaster -- Came very fast! 

Working on a resistor kit from Mouser. 

MAILBAG: 

VK2BLQ's Phasing RX with an HRO dial.  Cool Retro.  

Adam N0ZIB -- Cool station.  TFT screen Aluminum welded box. FB. 

Karl G7AFT    BITX 40 doing USB and LSB by changing the VFO freq.  Pete's trick! 

Jerry KI4IO  out in nearby Warrenton.   Hope to be able to meet up soon. 

Keith N6ORS's Hot Mustard Phasing Board. 

Mike N5GTF'd FULLY INDOOR Quarantine Receiver.  Need a slogan for the antenna!

Nick M0NTV's Bread Bin 80 Quarantine rig

Bruce KC1FSZ   Quarantine 10 -- Brave man in solar minimum. But I hear 10 is opening.

Talking to Grayson Evans KJ7UM  TA2ZGE about Collins 9.9 MHz transformers.

Talking to Alan Wolke W2AEW about Drake 2-B stuff  Was there a reduction drive?

Paul VK3HN about Ceramic filter spurs.

Peter VK2EMU notes no animals were harmed in the making of my videos.  But many electrons were agitated. 

N6QW Phase Shift Success -- It aint over 'till the fat lady sings