An NE602 SSB Design from China: The KN-Q7 by BA6BF

Allison KB1GMX alerted us to this rig.  Pete and I had been discussing with her various designs for SSB transceivers.  I recently completed an NE602 rig.

I really like the KN-Q7 (click on the picture above for a closer look).  The T/R switching is much simpler than my use of three DPDT relays.  It even seems simpler than the Epiphyte's switching of the BFO and VFO frequencies.  I also like the analog VFO and BFOs inside the 602s, but I think Pete would use an Si5351.  The AF amp muting circuit is kind of neat. 

I questioned the need for the extra IF amp for the receiver.  My rig just uses the two NE602s and an AF amp circuit from the BITX40 module (2N3904 and an LM386), and with this I can hear the band noise floor on 40.   But Allison points out that different bandpass and crystal filter have different losses, so with these components some additional gain may have been necessary. YMMV.

Here is the kit manual:

http://www.qsl.net/bd6cr/knq7amanual.pdf

Here is a video of VK2TPM putting his KN-Q7 on the air:

It is interesting that Peter notes a need for additional mic gain.  Some of the NE602 rig designs run an electret mic right into the NE602 balanced modulator with no mic amp. For a few days I had my amplified D-104 mic running into the NE602 in this way.  I too found that I was having to "loud talk" into the mic.  I put an LM741 mic amp in there and it fixed the problem. I wonder if later versions of the KN-Q7 included a mic amp.  I will check on this later.  

Three cheers for designer Shi Ke, BA6BF!

Still Photos and Slow-Motion Video from Shenandoah Rocket Launches

The above slow-motion video of launch #3 is pretty cool.    You can very briefly see a bit of the yellow parachute deploying. The best video from this flight is at the end, as the rocket floats over the farm buildings and comes perilously close to landing on top of one of the silos.  I put some snap shots at the end. Five other launch videos are available here: https://www.youtube.com/user/M0HBR/videos

SNAP SHOTS

Launch crew visible -  N2CQR with hat, Billy to his left. Randy's son (next to Billy) launches the rocket!

Smoke trail back to the launch pad.

MECO! And you can see the smoke trail up to the rocket

The view across the Shenandoah Valley.

Skyline Drive runs along that ridgeline

Here is a hunk of flame-proof wadding ejected by the rocket.

We were afraid it would land on the silo.  It was close.

GREAT BALLS OF FIRE! And a smoke trail.  

Part of the deploying parachute is visible.

SolderSmoke Podcast #196 Rockets, Pete's EXPULSION, SDR, DiFX, '602 rigs, T.O.M.

View from rocket. I'm in front of the swing-set, with hat on. Billy to my left.

SolderSmoke Podcast #196 is available.
5 May 2017
http://soldersmoke.com/soldersmoke196.mp3

Shenandoah Rocket Launch -- With video!

Pete and the QRPARCI HOF: We thank you for your support! 

Note the strange seasonality of these kinds of events... Always in the Springtime...

April is the cruelest month. Especially the FIRST DAY!  

Feel Tech Follow-up -- the DC blocking cap issue.

HBTV?  Roku Challenge? 

A tube of Desitin?  Why?

SDR Misadventures. 

SDR on a tablet  Just like WA7HRG

Pi Day   More RaspPi Linux observations  TOO HARD

The problem of Si5351 and updated libraries -- old sketches don't work!

My SDR question: If we go with direct sampling, no need for I and Q at front end  No image problem, right?  But why is there often a digital I and Q in the direct sampling receivers?

BITX MODULE

Getting RF in through the DDS jack.

Electric Radio:  Reading from the history of SSB.  And from the T.O.M. article

Joe Carr K4IPV : Homebrew Hero from Falls Church Va.  Any more info on him?

Pete's newest DifX

Pete's new digital scope.

Bill's NE602 RIG, Epiphyte History.

He put AADE crystal filter impedance match circuits in backward  That's why he needed RF amp. Duh.

The perils of a crowded box 

Building RF amp board (BITX Module design) for the NE602 rig.

NE602s do not put out a lot of power. uW

BITX Module Amp circuits very stable.

Chassis as the heat sink.

Mic amp?  We don't need no stinkin' mic amp!  But yes, we do. 741 on the way.

Parts on e-bay very expensive!  Back to the hamfests. On to Manassas!

Congrats to Tony Fishpool G4WIF, who received the Don Cameron, G4STT, Award for an outstanding contribution to low power amateur radio at the RSGB AGM meeting in Cardiff.

MAILBAG

Rocket Key-Chain Camera Video!

This project started almost 5 years ago when Billy, his friend Ben and I built a nice BIG Estes Model Rocket that Elisa had bought me for my birthday.  Here is the original post about this:
http://soldersmoke.blogspot.com/2012/09/video-model-rocketry.html

Building the thing was no problem, but finding a place to launch it was.  Model rocket launches are prohibited inside the Washington DC beltway, and when you get outside the beltway it is hard to find a suitable open field. Out rocket camera sat in a box.  We said "someday" for five years.

Yesterday I was going out to the Shenandoah Valley of Virginia picking up Billy after the completion of his freshman year in college.  I decided that yesterday would be the day.  I used Google Maps to look for places with a big open field near the highway.  I recharged the key chain camera.

At the first of my possible launch sites we found lots of fields, but also lots of fences, and cows and horses who might not like our noisy rocket.  We were about to give up hope when I spotted a farmer at work.  I explained the situation to Randy.  He agreed to let us launch, but wanted us to do it from his nearby house so that his family could watch.  This was very nice of them.

After one failed attempt, WHOOOSH!  That D12-3 engine really pushed that thing up there!  The family loved it.   It was  great.  The parachute deployed perfectly.  Billy would run across the field to retrieve the rocket (you can see him running up to get it in one of the attached videos).  When we got home I was amazed to find that the little camera had worked perfectly on all three launches. 

The Waters Edge Rocket Research Society would be so proud of us.  VIVA LA WERRS! VIVA!

Color Code Violation -- Almost as Bad as Breaking Ohm's Law!

A cautionary tale:   How would you read the color code on that little resistor?    It was plucked from a strip marked 2.2 ohms.   And indeed it is red-red-gold.  2.2 ohms, right?   But no,  my friends. On the DVM it reads 2.2 kilo ohms.  2200 ohms.  Believe me, that makes a big difference when it is in the Vcc line of your driver!  It took me a while to find out WHY that driver wasn't driving very well.  

This turned out to be one of those very satisfying trouble-shoots --  the problem was elusive and it wasn't all my fault.  But I should have MEASURED the resistor value before soldering it in. 

Here is the scary part:  The next resistor from the same strip was marked the same way, but measured 2.2 ohms.  Be careful out there. 

How LCD Displays Work (Video)

8 Bit Guy does a great job de-mystifying the LCD displays that we have been using.

An Old but Cool DiFX: The Epiphyte

I've been hearing about this rig for many years.   It first appeared in the September 1994 issue of QRPp, the journal of the NORCAL QRP club. A condensed version of that article appeared in SPRAT 81 (Winter 94-95). The designer is Derry Spittle VE7QK from Vancouver, British Columbia.

The name always puzzled me.  Here is the explanation:  It started with the Neophyte: A very simple direct conversion receiver that many of us built.  The Neophyte was mostly an NE602 and an LM386.  In the Epiphyte, a crystal filter and a second NE602 were added, turning the Neophytes into a superhet receiver and -- with some additional circuitry -- an SSB transceiver.  The Oxford English Dictionary reportedly defines an Epiphyte as "a plant that grows on another plant"(see picture below).   The Epiphyte grew out of the Neophyte.

And this plant grew in British Columbia, which seems -- like Australia and New Zealand -- to be fertile ground for simple phone rigs.  I'm pretty sure the "Wee Willy" DSB rig also came out of BC, and it may have had a similar purpose:   allowing for portable contact with the BC Public Service Net on 75 Meters.  

There are many features of the Epiphyte that I like:  There is a simple 455 kHz filter and a ceramic resonator BFO/Carrier oscillator. The original design featured a VXO-like circuit using a ceramic resonator at 4.19 MHz.  And it ran off AA batteries (as did the NE602 DSB rig I took to the Dominican Republic).

Unlike my NE602 rig, the Epiphyte made an artful use of the fact that NE602's can be set up to have TWO inputs and TWO outputs.  Where I used DPDT relays to switch inputs and outputs from both NE602s,  OM Spittle left all the inputs and outputs connected, and simply switched the VFO and BFO signals.  Ingenious.  

There were updates and improvements.  The Epiphyte 2 and 3 featured increased power out (5 watts vs. 1 Watt).  Version 3 has an IRF-510 in the final, driven by a CA3020A chip.  That chip is capable of 70 db gain.  Wow. 

In 1996 NORCAL and G-QRP donated 50 EP-2 kits to radio amateurs in third world countries. Very nice.

In 2000 NORCAL did a kit of the EP-3 -- it sold out in 24 hours.  Here is a nice article on the EP-3:
http://www.norcalqrp.org/files/Epiphyte3Mnl.pdf

And above we have a video from Japan of an EP-3 in action.