N6ORS's Franken-SDR Superhet

Of course, I love it.  MOSFETS!  NE602's!  10.7 Mc IF cans!  Cycles, not hertz! And a Tayloe Quadrature Sampling Detector made from junkbox parts from the Reagan administration. FB Keith.   And the frequency display is icing on the cake.  

Bill:

I thought the group might find my new Franken-SDR interesting.
It is an SDR with a superhet front end. 

I wanted to play with an SDR but I didn't want to get a kit or buy
parts, so I scrounged through he drawers and found a mux chip
cd-4016 circa-1980 some old 7400 logic that is probably per-1980.
This could make a QSD but only very low frequencies. Well I thought
how about at IF frequencies?

The frontend is a MOSFET mixer (1975) , the 10.7 IF is a dual gate MOSFET
(1975), the second mixer is a NE602, the IF cans are all stagger tuned to
give a bandwidth of 50kcs.
The only thing modern is the DDS but I old-time-ifyed it with BCD switches.

Keith N6ORS

VK6FTH did something similar: http://www.vk6fh.com/vk6fh/SDRradio.htm

Understanding the "O" (organic) in OLED

That's the one I'm using.  Less than 1 inch on each side.  No back light.  8 bucks shipped:
https://www.amazon.com/gp/product/B00KRZY7PW/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1

Here is a thorough description of the technology:

https://en.wikipedia.org/wiki/OLED

Boatanchors! HT-37 to HT-37 contact with W1ZB

Jerry W1ZB and I met up on 40 a week or so ago.  He was running a Hallicrafters  HT-37.  This spurred me to clear up the T/R problem that had knocked me out of the competition on Straight Key Night  (I'm sure I would have won!).  One spray of DeOxit D5 on the HT37 relay contacts was all it took.  Jerry and I set up a schedule for this morning on 40 minutes.   Above you can see a short video of the first part of our HT-37 to HT-37 contact.

Jerry has an amazing collection of beautiful old tube radios.  Check out his QRZ.com page:
https://www.qrz.com/lookup/w1zb

BTW:  Speaking of old rigs talking to identical old rigs:   Last night on 40 I worked TI2NF in San Jose, Costa Rica.  He was running a Collins KWM-2 to a Collins 30-L1.  It was real nice to talk to somebody who was using an unusual rig.  Right after we finished, VE3OCZ called  TI2NF.   VE3OCZ was ALSO running a KWM-2 to a 30-L1.   TRGHS.  

Great Interview with Farhan Re BITX 40 and BITX History

W5KUB has a really good interview with Farhan.  There are several spots where the Skype connection gets quite choppy, but hang in there -- it gets better.  Farhan provides a lot of good info on the history of the BITX rigs, his design philosophy, and the importance of the EMRFD book.  He also talks about how the BITX 40 Module is produced.  And he talks a bit about possible future rigs.  Great stuff. 

I was very pleased to hear that Farhan is trying to eliminate the need for his FT-817 (he currently needs it for its general coverage receiver) so that he can have a completely homebrew hamshack.  FB! 

NE602 Si5351 OLED "Whole Foods" Receiver

This is one of those projects that sort of just happened.  First I built an Si5351/Arduino synthesizer with a small OLED I2C display (program by Thomas LA3PNA -- thanks Thomas).  Tom Hall AK2B up in New York helped me get the Si5351 VFO and BFO going -- thanks Tom.  Then, over the holidays I decided to build a rig of some sort around the Si5351.  I started with a superhet receiver using an NE602 as the mixer and another as the product detector.  I power the NE602 with an 8 volt regulator from W8NSA -- thanks Jim.  I made a 4 crystal 11 MHz Cohn filter using crystals left over from a BITX project.  The software from AADE helped me design the matching networks to match the filter to the 1500 ohm impedances of the NE602s.   I built the circuits on a milled board sent to me by Pete Juliano N6QW -- thanks Pete!   I put a dual tuned circuit at the front end, going into a MOSFET RF amplifier.   For audio amp I have an LM386.  The whole thing is screwed down to a barbeque grilling plank from Whole Foods -- thanks Whole Foods!  (This seems appropriate -- the "O" in OLED is for "Organic"!)

It sounds nice.  I may eventually try to put some relays in to switch the NE602s and the filter around to make this a transceiver.

Straight Key Night -- Bandscan from WA6ARA (audio)

WA6ARA SKN Station

Mike Herr WA6ARA was on 40 meters with old gear this Straight Key Night.   Mike was receiving with a venerable Heath HR10B.  One of his favorite QSOs was with Keith W6SIY; Keith was running Conar twins that had the kind of "swing" that stirs up the kind of memories that SKN is all about.  FB.  Mike made a bandscan recording of what 40 sounded like, and he made another of W6SIY's beautiful signal.

You can listen by clicking on these links:  

http://soldersmoke.com/SKNBANSCAN.mp3

http://soldersmoke.com/SKNQSO.mp3

My own SKN effort was cut short this year by technical difficulties.  The HT-37's relays stopped doing their thing.  Probably the relay drive tube going soft.  But I did manage to make two great contacts on 40:

WA6URY is in Los Angeles.  This was a very timely contact -- my wife and I went to see the movie "La La Land" on New Year's eve -- the film features a lot of beautiful LA scenery.  Dan was running a kilowatt to a 2 element Yagi on 40.  He too owns an HT-37 and a Drake 2B.  He was on a straight key "with dirty contacts."  FB Dan, thanks.

And then I worked W1PID!  Wow! Jim is well known for his operations from field locations and for his intrepid participation in many of the radio adventures of Michael Rainey AA1TJ.  Jim was on the Maine sea coast expedition when Michael was attempting to cross the pond with his voice-powered radio.  On SKN Jim was in New Hampshire running 35 watts to a Windom off-center fed dipole.  His Morse key is a Kent.    TRGHS.   Thanks Jim.

Happy New Year!

W1PID Maritime Mobile

Homebrew SSB in Germany: DK7IH

Pete WB9FLW alerted us to the work of Peter DK7IH, a very talented homebrewer who recently followed the lead of Pete N6QW in building some really small SSB transceivers.  Here is his Micro QRP SSB rig:

You can see more of his fine work here:

https://radiotransmitter.wordpress.com/

https://www.qrz.com/db/DK7IH

Have you guys noticed how many Peters there are among homebrewers, especially among SSB homebrewers?  Just from recent mentions on this blog:

Pete Juliano N6QW
Pete WB9FLW
Peter Parker VK3YE 
Peter DL3PB
Peter W1UO
Peter GW4ZUA
Peter G6GNR
Peter VK2EMU
Peter VK2TPM
Peter HA5RXZ
Peter DL3JIN