Fast Radio Bursts and the Molonglo Radio Telescope (with video)

7,744 circular dipoles on 843 MHz  feeding 176 preamplifiers and 88 IF amplifiers!

Read about how the Molonglo Radio Telescope has recently been used to study the mysterious Fast Radio Bursts:
http://www.sciencealert.com/confirmed-mysterious-radio-bursts-detected-by-astronomers-really-are-coming-from-outer-space

There is a Grote Reber connection:
https://en.wikipedia.org/wiki/Molonglo_Observatory_Synthesis_Telescope

SolderSmoke Podcast #195: (We need some help!) BITX, 60, SSB History, Tribal Socketry

SENDING IT BACK

SolderSmoke Podcast #195 is available.  Link appears below (scroll down)

We’ve got a problem:   Pete Juliano and the QRP Hall of Fame  :-(  PLEASE HELP!

BENCH REPORTS

Pete Releases Smoke (wiring harness)

Pete's DifX on 60

Architecture and Dual Conversion (uBITX:   uses ALL THREE clocks on the Si5351)

The Big Kahuna

ON HACKADAY with Philco SB100 SEE!  QRP!!!!!

BITX60

Cap Stack Hack mod (with leads)

Let the smoke out of an Si5351 (shorted output) Several actually.

(Same day delivery zone for Amazon -- but no drones or parachutes yet.)

Installed scanning switch

Observations on 60.  All the weird bands have a 6 in them: 160, 60, 6

The good:  100 watt limit, wire antennas 
The bad:  Kind of cliquish-- like 75, not much of a CQ band.  Channels.  Not much activity.

Met Josh KE8CPD on 40.  BITX 40!

TRIBAL KNOWLEDGE:

Socketry:  How to keep BNC jacks from spinning loose?

Do you heat shrink?

Feel Tech Sig Gen might not have blocking cap at the output.

Speaking of which, when I spoke of the Ne602, I mostly meant blocking caps, not bypass caps.

How come they don't have a cable TV channel devoted to radios?  They have HGTV? Why not HBTV?

REPORT FROM WINTERFEST

Bad weather.  Tailgaters wimped out!

Combined forces with Armand WA1UQO.

Met up with Charles AI4OT.

Acquisitions:  1/4 phono jacks, carbon mic, vero board, disc caps, weather radio,

LARGE collection of Electric Radios from Armand.  Wow.

Electric Radio notes:   1st Fifty Years of Sideband 1991 articles by Jim Musgrove K5BZH

Why LSB on 75? -- so AMers couldn't follow to top of band

W2, W6, W8s liked phasing, W3, W4, W0 more into filter rigs.

Early SSB guys turning on carrier and talking AM hams into SSB RX.

Kelvinator Refrigerator rigs.

A reading on the homebrewing of SSB rigs.

Tony Fishpool on QSO Today!  Pete mentioned prominently.

Good Hacks from ND6T on BITXHacks,   Stockton Bridge

MAILBAG

LINK:  http://soldersmoke.com/soldersmoke195.mp3

ND6T's Very Cool Power Meter (and drawing)

Don's drawing is so good, I just couldn't resist posting it here.  It is part of an article he did for the BITXHACKS blog describing how to add a Stockton bridge forward/reverse power meter circuit to your rig.  Check it out: 
http://bitxhacks.blogspot.com/2017/03/nd6ts-forward-and-reverse-power-meter.html 

N7SUR's Nice SSB Filter -- Nail Polish Stuff Adds Soul to the New Machine

That's a beautiful graph, don't you think?  In addition to the very pleasing results, I liked Bob's methods:  the "by hand" collection of the data points using an AD9850, a 'scope and a notepad (see below); the filing down of ceramic disc caps;  the use of nail polish hardener -- all this adds a definite artisanal element to this project and puts more soul in the new machine.

Like Bob, I too kind of bailed out on the Q calculation when I was doing this.  But as I recall there is a variation on the G3UUR method that yields this parameter too, right?

Bill:

I'm reluctant to share this with you because the results appear too
good.  I've attached a graph showing my four crystal, 11Mhz
filter measurements.  The graphed points are read values using my
AD9850 DDS VFO feeding to a TEK scope.

A TIA amp was used for input and output of the filter.  My development  software was the Steder-Hardcastle software as presented in November 2009, QEX.

I am now practiced in the black art of filing off the tops of disc
ceramic caps to "adjust" their values.  This black art also involves
the mysterious qualities of Sally Hansen Nail Hardener.

Let me share my method for developing the filter.

I've built CW filters before but this was my first effort at SSB
bandwidth which is less forgiving.

The G3UUR oscillator method (see page 3.19 in EMRFD) is a simple and
effective filter design method. but it does not provide a measure for
crystal Q, a value which impacts filter insertion loss.

So I decided to choose crystals with proven pedigree. These were 11 Mhz crystals from Mouser, part number 20-HCA1100-S.  A lot of ten costs $5.  These were the crystals selected by Jim Kortge, K8IQY, for use in his 2N2/20 rig.

For software, I use the Dishal package that can be downloaded from the ARRL and other sources.  This package was the basis for the
Steder-Hardcastle article in November 2009, QEX. The "Xtal" pull down
menu provides entries for an individual G3UUR oscillator.

Simply put, all critical filter input values are generated by reading
the change in crystal frequency as an additional capacitor is added
into the oscillator circuit.

I suggest starting with a 4 crystal filter. Only two capacitor values
were required for my filter.  Five capacitors were required--two series
and three shunt.

Start by reading the "open switch" frequency for each crystal.  Sort
the crystals into increasing frequency order and choose the four with
the most narrow frequency span.

Using the pull down menu measure the individual crystal measures for
Lm, Cm, and series frequency.  Average these across the four crystals.

The Lm or Cm and series frequency are placed into the Dishal software
main menu.  Also enter the average Cp which is the measured capacitance across the crystal leads.

Finish up the main menu entries by entering the number of crystals (4), and the desired bandwidth--generally 2.4 to 2.9 Khz.  Finally enter the acceptable ripple, which is often 0.1db.

Let the software calculate the filter values.  Expect some odd
capacitance values.  By changing the filter bandwidth--say from 2.4 Khz to 2.35 Khz I can move one of the capacitance values to a standard value.

The software also displays the input and output impedance.  If the
filter is centered between two TIA amps, this filter impedance must be
transformed to 50 ohms in the amps.  This provides the transformer
winding ratios.

The Dishal software has always given me good results.  But I haven't
compared its results to Ladpac--especially GPLA.

Bob -N7SUR

Pete's 60 Meter DifX

Oh man, run -- don't walk -- to the N6QW blog and check out Pete's amazing 60 meter DIFX transceiver.  DifX is another N6QW contribution to the lexicon: it refers to a transceiver that has an architecture DifFERENT from that of our beloved BITXs.  Pete means no disrespect to the BITX -- he just sees the value in sometimes doing something different.  I understand this completely -- I myself am on my FIFTH BITX   (three scratch-built and two modules) and definitely felt the need to do something different. (That's why I built the OLED NE602 rig.)  

Once again Pete Juliano shows himself to be a man ahead of his time: Anticipating FCC approval of a VFO tune-able segment in the band, Pete has made Channel 3 on his rig tunable with a rotary encoder.  Hopefully, we will all soon need this.  Pete is already there. FB OM.

My reaction to 60 meters has been very similar to Pete's.  We will talk about this on the next podcast (this Saturday).  

Pete's blog has a great description of the new rig, complete with a really nice video.  Check it out:

http://n6qw.blogspot.com/2017/03/a-new-line-of-transceivers-difx_23.html

A Slovakian Al-Fresco Digi-Tia Homebrewed In France (and an improved AD9850 VFO)

Hello Bill and Pete,

Thanks for the podcast! My normal occupation is more computers and
software but your podcast got me motivated to melt some solder. So I
want to share a bit of what has been cooking on my bench.

I used to have a Yaesu FT-450 but sold it - I am living in a tiny rental
apartment in France without any place where to put a proper antenna so
it was only collecting dust. And where is the fun in operating a
factory-made rig, right?

So I have been working on this instead:

http://janoc.rd-h.com/archives/541

This "al fresco" rig is "half-DigiTIA". Half because there is no
transmitter part (I don't have a French license and I am too lazy to do
the paperwork and convert my Slovak one).  The purple modules are TIAs,
as designed by Wes Hayward, using 3x 2n3904s, only built using SMD
components to keep them small and tidy.

VFO & BFO are Si5351 + ATMega328, with an OLED module and code adapted
from Pete N6QW. It uses 11.997450 MHz IF because that's where most of my
12MHz crystals actually matched.

The 40m bandpass filter is taken verbatim from the BitX 40 design - I
have only changed the coils to use toroids instead.

For audio I have used LM386 with a NE5532 opamp as a low noise preamp
because the audio was a bit low. The TIAs don't have a lot of gain and I
have only an indoor magnetic loop for antenna so had to compensate for it.
I have another, a bit older project that became quite popular - firmware
for the AD9850 DDS VFOs using an Arduino and a character LCD. It is a
much improved replacement for the one from Richard, AD7C.

http://janoc.rd-h.com/archives/502

Perhaps it could be useful to someone.

Keep up the good work and 73!

Jan OM2ATC (at the moment "in exile" in France)

An Si5351 Ham Sandwich from China (with video)

Ernesto Marquez alerted me to the offerings of CRKITS -- Chinese Radio Kits:

http://crkits.com/  Their Si5351-Arduino Pro Mini "sandwich" is quite interesting.  Here is a video on the device:

I must say, that nice little sandwich seems to be crying out for an organic slice of OLED.... How about it Adam?

While there is, of course, an enormous amount of electronics coming out of China,  I haven't seen much that comes from actual Chinese radio amateurs.  But CRKITS is the work of a real Chinese ham.   Adam Rong (Rong Xinhua) BD6CR seems like a very interesting fellow. From qsl.net:

About BD6CR/4

Adam Rong (Chinese name: Rong Xinhua), BD6CR/4 was first licensed in 1996 while in university in Hefei, Anhui province and now holds Class 2 Chinese amateur radio license (FCC Amateur General license equivalent). After graduation from university, he moved to Shanghai and call sign changed to BD6CR/4 in July 2003. Adam is now living in Pudong new district with his XYL and their son.
Adam holds a Master of Engineering degree in computer architecture and is an Engineering Program Manager in computer hardware industry. In spare time, Adam has written a lot about ham radio for magazines and papers, mainly about QRP, homebrew projects, APRS (Automatic Packet / Position Reporting System) and ham radio software applications. Adam has also translated two ARRL's books into Chinese for Post and Telecom Press in China, including part of the ARRL Handbook and ARRL's Low Power Communication: The Art and Science of QRP by Rich Arland, K7SZ.
You can contact Adam by email, or track Adam's real time position on Google map by clicking this link.