Von:         n4so@juno.com (charles  k brown)
Betreff:     Re: Pixie Text
Gesendet am: 25.Sep.1999 15:59:51 EDT
Abgeholt am: 26.09.99  18:31


The following is a saved text file.
Any questions should go to the source.
From: Casey Ray <clray@usc.edu>
Date: Thu, 23 Sep 1999 08:42:27 -0700
Subject: Re: Pixie II

The following was received from Ed Loranger//we6w@qsl.net
WE6W

Hope it helps.

-----PASTE ---
> 
> I ran across your webpage and was intrigued with the Pixie II QRPp
> tranceiver you presented.   I purchased the parts kit from Halted
> electronics (my junk box is pretty sparce these days), and have been
> delighted with it.  I noticed the circuit is described  as a 160-10m
> tranceiver, with a change of one inductor and crystal all that's needed
> for switching bands.  Although I am coordinated enough to build the
> radio, I am not smart enough to design a circuit.  Could you by any
> chance give me the inductor values for the bands other than 80m and 40m
> (I CAN figure out which crystals to use!).  Thanks!

Basically 50 Ohms reactance for the components.  I just now wrote
a quick program and have it for you:  (Exact Values for QRP Freqs.


     Band       CW                 SSB
     ----    ---------------   ----------------
     160      1.810              1.910 
                                 1.843 (Europe)
      80      3.560              3.985
              3.710 (Novice)     3.690 (SSB EU)
      40      7.040              7.285
              7.030 (Europe)     7.090 (SSB EU)
              7.060 (Europe)
              7.110 (Novice)
      30     10.106
      20     14.060             14.285
      17     18.096
      15     21.060             21.385
             21.110 (Novice)    21.285 (SSB EU)
      12     24.906
      10     28.060             28.885
             28.110 (Novice)    28.385 (Novice)
                                28.360 (SSB EU)
       6     50.060             50.885
                                50.285 (SSB EU)
       2    144.060            144.285
                               144.585 (FM)
Output filter for WE6W Contest Pixie, p. 38 of QRPp Journal
This is one inductor and two capacitors in a PI network.  
Both filter caps are the same.  Data is for CW operation.   
> 160m = 4.4 uH, .00176 uF
> 80M = 2.23 uH, 894 pF
> 40m =  1.5 uH  470 pF  
> 30m =  .79 uH, 315 pF
> 20M =  .57 uH, 226 pF
> 17m =  .44 uH, 176 pF
> 15m =  .38 uH, 151 pF
> 12m =  .32 uH, 127 pF
> 10m =  .28 uH, 113 pF
> 6M  =  .16 uH,  64 pF

Obviously there might be a little
bit of tweaking on the coils to adjust
the match to your transistor, but it
is not that difficult.  Also, you might want
to add a Bandpass tank circuit on the output to
clean up the signal if you get above 20 Meters.

Just link couple to the tank about 2 or three
turns from the bottom.  That way the 50 Ohm
taps won't desensitize the 'Q'.

we6w@qsl.net
Enjoy.  And 72 de Ed/WE6W
> 72s,
-- 
-Ed  AR Millennium Q's=>1200/2000  QRP-L#1068 Old NC#2227
72, Ed WE6W, A-1 OP; http://www.qsl.net/we6w  Santa Rosa, CA 
QRP-Z#106 AR#112 HI-QRP#64 ARCI#9397 ARS#275



Casey, here's some other information to help you with
MODS:
ENJOY!!  All my best, 72/Ed we6w

Dmitry, Here's my understanding that has survived the test of time:

This is all My words/work.  So I can answer more specific
questions if you have them.  There is about 4 emails I
have that I think will really help you.

Also, if you have the Spring 1998 issue of QRPp magazine by
Norcal QRP Club, check out my article there on my CONTEST PIXIE!
Notes:
QRPp Journal
WE6W Contest PIXIE by Ed Loranger, p. 24-25.
we6w@qsl.net
Enjoy, Dmitry.  --Ed Loranger WE6W/QRP

---------  Begin Old email discussion --------
Good Morning Ron.  I thought over your questions and decided I had
just better explain the circuit for you.  


Ok.  The basic pixie2 consists of a crystal controlled oscillator,
a second transistor providing:
Mixing, Detection, and RF Amplification.
An LM386 Audio Amplifier, a Low Pass output Filter in a PI configuration.

OSCILLATOR:  Colpitts oscillator, single frequency set by installed
crystal.  Broadband design and components allow any crystal from
at least 3Mhz to about 22Mhz to be used to set the 2N2222A or 2N3904
transistor to the crystal frequency.  Any crystal above or below
this range will require a change in the two feedback capacitors
attached to this transistor.

The output of the oscillator is capacitively coupled to the second
transistor which serves to MIX, Amplify, and DETECT (convert to audio),
signals entering the Base and Collector.

MIXING:  The second transistor is biased near cut-off when the key is
up.  You'll see that a 10K ohm resistor is in the emitter lead. When
key is down, the resistor is bypassed to direct current and the
transistor
has high Gain and sufficient DC current to amplify the RF entering the
transistor Base junction.  A 100 micorhenry choke from Base to Emitter
allows base bleeder bias to keep the transistor stable.  Signals
entering the Collector mix with the oscillator thereby producing
harmonics. 
Signals close to the oscillator frequency result in a difference that is
in the
audio range.  these are fed to the Audio AMP.

RF Amplifing: The second transistor also amplifies.  The crystal
frequency enters the Base.  When you key down, bypassing the 10Kohm
resistor, the
transistor now has MUCH current to work with.  The 15 to 22 uH inductor
on the collector provides an RF load.  The transistor DC current is 
strobed at the oscillator frequency and developes a voltage across the
load inductor.  The output filter isolates and lowers the impedance of
the 15 uH inductor to that of the antenna, also the filter is of
low-pass design, where all frequencies above the oscillator frequency
are attenuated.

(NOTE:  A band Pass filter can be used too.  But the input/output must
be carefully coupled so as not to load the filter or broadbanding occurs
and efficiency rolls off quickly.)

DETECTING:  When the key is up, the FINAL transistor is nearly biased
off and works as a diode, mixing the two signals, Base/Collector, and
the difference of these two signals result in a DC audio wave heterodyne
that is fed to the audio amplifier.

OK!  That's how it works.

Modifications:  The frequency you operate on is set by the crystal. 
This is a single frequency rig.  It is possible to vary the particular
crystal operating frequency by changing the crystal capacitance, either
by adding a capacitor load to ground, or a series inductor to ground
which
tunes out the crystal capacitance.  Some people use both.

Since the oscillator contains non-tuned feedback in the form of two
100 picofarad capacitors, it operates as a simple voltage divider.  The
signal at the oscillator transistor enters the base, and is fed back
to the base with an amplified in-phase portion of the oscillator output.
Due to reduced gain above 22 MHz, the oscillator begins to fail at those
higher frequencies, and below 3 Mhz, insufficient in-phase signal is
coupled and/or fed back to the oscillator input (Base).  So for lower
frequency operation, the 100 pF caps should be increased to a reactance
similar to what the 100 pF have at say 7 MHz.

The only other limitations are the output transistor load coil, and the
PI filter network.  The filter has two capacitors to ground, and an
inductor in series with the antenna.  A pixie2 built for 3.579 Mhz needs
the stock capacitors and a 2.2 uH inductor.  For 7.040 or whatever 40
Meter pixie2, you need a 1 uH coil.  (Obviously the frequency of the rig
is
set by the crystal as explained earlier).  So for a 80 meter rig you
should have a 80 meter xtal installed, and the output filter should
have the 2.2 uH inductor.  A 40 meter rig has a 40 meter xtal, and the
output filter now has a 1 uH inductor instead of the 2.2 uH inductor.

Other frequencies:  As a frequency spotter for tuning other rigs, you
don't need really good output power efficiency.  Just change the crystal
and
leave a 1 or 2.2 uH inductor in the final.  But to operate, say on 10
meters,
Get yourself a 10.116 xtal, modify the PI network to use capacitors of
perhaps 100 ohms reactance to ground, series inductor of about 100 Ohms,
and output capacitor of perhaps 100 ohms.  The load inductor on output
final should be changed to have 500 or so ohms reactance at 30 meter
band.

So you see, it isn't too mysterious.  just compute the reactance values
of the PI filter, the Output Load inductor at the collector, and install
the xtal for the band these are valid for.

Coil Reactance formula: Xl=2*PI*F*L  (Primary units Hertz, Henry's)
Capacitor Reactance formula: Xc=1/(2*PI*F*C)  (Again Primary units.)


Now!  If you still have any more specific question we can
begin anew.  I will try to do a line by line explanation.

This is fun!  I really do enjoy circuit design and hope
I can help you further if necessary.

Keep in touch.  Happy Holidays Ron.
--------  End of Old email discussion. --------
we6w@qsl.net
-Ed, we6w



OH!  Here's another email I wrote up:

Nick Franco wrote:
> 
> Ed,
> 
> Enjoyed your post on the mods you made to your 3rd Pixie.  I've built
> about 5 or 6 of these little gems and tried in my very limited
> understanding of circuits, to make some mods.  Most didn' work.   I do
> use a manual switch for RIT or TX offset.  I agree with you; it's nice
> to be able to TX on either switched freq.
> 
> I get tons of AM broadcast RFI;  I have no sidetone;  I'm not happy
with
> the offset and trying to hear the other party.   I like what you
> mentioned but don't understand most of it.  I do not have QRPp, but
> maybe I should break down any finally join NorCal.  I figured I live on
> the opposite side of the USA.  Now that NEQRP is gone, I guess I should
> stay in touch with these articles.

QRPp and QQ magazines are well worth it!  (I have no financial
association.)


> 
> Well, I would love to add some of the things you mentioned but don't
> have a schemo or any other info than your printed post from QRP-L.  If
> you get a chance, could you explain the 60pF cap in the RIT switch area
> and also the blocking out of the AM junk.  I was about to build the
W1FB
> version with the audio filter and the auto-switching offset, but maybe
I
> should continue to experiment with my old faithful some more.  You've
> introduced some fresh ideas for me to try.
I have the UPDATED/CORRECTED W1FB schematic on my web page.  (See sig.
below)
OK.  You've got a XTAL.  For a NO-RIT rig, just ground one end of the
crystal, the other end to transistor Base input as shown on the
original Pixie2 schematic.  (also on my web page.)

Instead of directly grounding the crystal, you can ground it THROUGH
a .001 capacitor.  .001 uF is a low impedance at the RF frequency, and
you still get a single freq., no-Rit pixie2.

RIT:  Permanently ground the crystal through a smaller capacitor,
say 50 to 60 pF.  This raises the xtal frequency about 600 hertz.
So a 7040 xtal == 7040.6 KHz.  Connect a SPST switch such that allows
you to parallel a .001 uF cap across the 60 pF, thereby totally
providing an excellent ground to the xtal.  The crystal now operates
at it's proper (Lowest) possible frequency.  There you have it.

A smaller, say 30 pF cap will provide 1Khz offset or so.  Just remember,
the well grounded crystal operates on the lowest frequency it was
designed for.

AM BC BAND:  Get Ferrite Chokes.  They are the size of 1/4 watt
Resistors.
Do NOT use wirewound molded inductors, they are miniature antennas!
The ferrite chokes I use are 5 millihenrys and have a green paint drop
supposedly revealing their value in millihenrys. Green=5.

Looking at the schematic you see the KEYING LINE and Ground; SPEAKER
LINE and Ground, POWER Positive Line and GROUND, a 1 Kohm resistor
feeding reduced current/voltage to the LM386.  Also, the Detected
Audio from Q2 line goes to the audio input pin 2 or 3 of LM386.

OK.  Place a RF CHOKE: Audio Output; Key Jack; Detected audio to
LM386 Pin 2; Power Supply Positive line.  Next; add small Ferrite
bead to Positive Voltage line going to each Transistor.  

The Following is probably Optional:
This next part is Tricky!  I wanted a stable 5.62 volts to the LM386
and decouple it from the power supply (Car Battery).  On the Pin 6 side
of the 1 Kohm resistor (R5), put a 5.62 Volt Zener Diode.  Change R5 to
500 ohms, or parallel another 1 Kohm as I did.  Put in 250 uf to 470 uF
electrolytic capacitor from pin 6 to ground of the LM386.  YOU WILL
GET IMMEDIATE IMPROVEMENT IN AUDIO AND BC INTERFERENCE REDUCTION!!!

Add 100 ohm resistor from D1 switching diode Cathode to Keying line.
This suppresses the now SURGING current from 470 uF powersupply
capacitor.
Without the 100 ohm resistor, the keying device has to pass too much
current to be reliable.  My keying relay contacts stuck sometimes...
Also, some current flow is possible thru D1 and the 10KOhm emitter
resistor
and the Q2 amp gets stuck in Self-Transmit mode!

OK!  Mine works FB and although I still get a small amount of BC
interference from the AM station about 2 miles away, I find it
disappears when I touch the enclosure.  So it is just stray capacitance
and when I put the lid on my PC BOard constructed/soldered enclosure,
I expect all BC qrm to be gone. 


> 
> My Pixie is a 40/80 dual band switchable and I beefed up the 2
> transisters to a 2222 and a 2219 can type for the amp.  I get about 1
> watt out on a 12vdc battery.  I'm very happy with the output and I do
> make some contacts but copy is very rough.  I've checked into the
Klites
> net on Sunday eves but that's a tough one and usually rely on my Icom
> for that.

I tried the 2219 and it is FB.  Currently using a 2n5109.  But the
2n2222A works well too.  But I put in a bigger socket that fits
the 2n2219 and 2n5109 so I'll keep those.

> 
> Thanks for the post,
> 
> Nick - KF2PH
> QRP-L # 13  

Thanks for your input.

I hope I have helped!
we6w@qsl.net
Vy 73/72 -- Ed Loranger, we6w


Here's some email from another person:
ently threw together a Pixie to play with, and put it
on 20 meters (but that's another story).  Haven't had a QSO
with it yet (last weekend was one of *those* weekends..),
but I did get to listen a bit, and geez, I guess I've been
spoiled by good crystal filters.  What with all the digital
stuff going on up several kHz, and rag chews down around 14.050,
I had quite an earful!

  I got to looking at the datasheet for the LM386, and a little
circuit labelled "Audio Amp with Bass Boost" got me thinking
that it would be easy to add some filtering to the thing.

  So it's as simple as this: 

   - Change the 10uF cap between pins 1 and 8 to 4.7uF.
     (This puts the low freq -3dB point at about 200 Hz)
   
   - Put a 2k ohm resistor and a 6800 pF cap in series, and
     wire the unconnected ends between pins 1 and 5 (the
     output).  This rolls off the high frequency gain.  The
     upper -3dB point is about 1.6 kHz

   - I also tried reducing the output coupling cap from 10uF
     1 uF.  This reduces the gain below 200Hz, but the value
     you need will depend upon your load (I had 500 ohm headphones.)

  The result is still no 6 pole crystal filter, but it's an
improvment, and doesn't complicate the rig very much.  The center
freq of the resulting "filter" is about 600 Hz.  If that's too low
for you, try a 2.2 uF cap between pins 1 & 8 and reduce the 6800pF
cap to 4700 pF.

Here's another email I sent to another guy:

More info...


Ok, the stock pixie2 uses about 20 to 25 milliamps and is capable
of running off of a 9 Volt transistor battery.  I'm not sure, but
another problem develops with the 741 in this circuit due to the
additional current demands.  Try the thing on a pair of 9 Volt batteries
in parallel to check that.

Explanation of what I did and why I changed the 1 Kohm.

This is a bit complicated, but when I hooked the stock pixie to the
9 volt battery I noticed a few things.

  1)  The LM386 Motorboated as the battery voltage got to about
      7 volts.  The spec sheet on the LM386-N1 recommends it run
      between 5 and 12 volts.  

      1A)  7 volts should have been fine, I deduced the LM386 was
           being starved for current.

  2)  The LM386 is a good detector for AM BC band.  I decided to 
      further decouple the LM386 from the power supply by putting
      a 5.62 volt zener to ground on the LM386 side of the 1 Kohm.
     
      2A)  I lowered the 1 KOhm to 500 ohms by parallelling another
           1K.  This allowed me to stabalize the LM386, decouple the
           Battery and Leads from RF, and supply more current as 
           needed.

  3)  The LM386 had problem with strong signals and I observed problems
      with audio on CW peaks.
      
      3A)  I added a 470 uF electrolytic to pin 6 of the LM386 to serve
           as a current reserve for those peaks.  This also improved
           audio response SIGNIFICANTLY, and eliminated more BC
           interference.

  4)  The mods ran too much current through the diode on key down.  Also
      the idle current through the 10 Kohm resistor - Diode - to power
      supply was too much and this turned on the power transistor as
      if you were keying.  (BAD PROBLEM!)

      4A)  I put a 100 Ohm resistor on the Kathode (Key) side of
           the diode.  This reduced the current through the key
           contacts during key down, also kept the output transistor
           from turning on.

  There you go Bill.  I hope this helps.  It was a lot of work,
  but very worth it!  I have a very quiet pixie2 and works FB.  The
  audio is strong enough to drive a speaker and the key clicks are
  virtually non-existant.  The 470 uF bypass cap on the LM386 was
  totally amazing.  Really helped the circuit in three ways: Audio
  quality, LM386 stability, Reduced BC interference to to RF detection
  of the current starved LM386.

Let me know how it works as you go.

Best of luck.  we6w@qsl.net
-Ed


-- 
72, Ed WE6W (CW only/VP-0); http://www.qsl.net/we6w  Santa Rosa, CA 
QRP-Z#106 QRP-L#1068 AR#112 NC#2227 ARCI#9397 QAA#006
-- 
-Ed  AR Millennium Q's=>1200/2000  QRP-L#1068 Old NC#2227
72, Ed WE6W, A-1 OP; http://www.qsl.net/we6w  Santa Rosa, CA 
QRP-Z#106 AR#112 HI-QRP#64 ARCI#9397 ARS#275


One more thing Casey.  You will probably find that
a 2N3904 might not oscillate at 10 Meters.  A 
selected 2N3904 or 2N2222A might work.  You may have
to find a 2N5179 to use for the oscillator.  And be 
sure to change the 100 pF feedback capactors to something
around 47 pF or so.  You may get too much offset if
you use a capactor switched in/out for XIT, so play
around with that a bit too.  

Gotta run.  Have fun!  72/Ed we6w

----END OF TEXT COPY----
73 de Casey
AD6DI

The following is a saved text file.
See SMiTe, the SMT version of the Pixie near the end of this file.
From: k4wz@juno.com (RON L TODD)
Date: Sat, 15 Mar 1997 17:13:46 EST
Subject: PIXIE II

HSC SELLS THE PIXIE II   FOR 9.95
PHONE NR.    1-800 -442-5833
HSC//
Halted Specialties Co.
In Santa Clara, Sacramento, and Rohnert Park, CA
408-732-1573, 916-338-2545  707-585 7344 respectively.
Web:  http://www.halted.com
Fax for orders:  408 732-6428
Source:  Nuts and Volts magazine.  Full page ad on page 3.
Ask HSC for information.


RON TODD K4WZ@JUNO.COM  OR K4WZ@WORLDNET.ATT.NET
FISTS #2109,  ARCI # 9273,  QRP-L # 924
NNNN
From: "Mark A. Arvidson" <arvidson@swbell.net>
Date: Thu, 30 Oct 1997 15:38:56 -0600
Subject: RE: Pixie2 Revision File
Howdy, gang,

I finally got a quick (only a few hours work) web page put up to
display Frank Matthews' (KC4FKX) Pixie2 Layout in a .gif file.  It's at:

http://www.geocities.com/capecanaveral/lab/3955/pixie2.html

The site is, of course, always under construction.  Perhaps I'll actually
add 
more to it some day. :^)

Mark A. Arvidson, KB0SPQ
arvidson@swbell.net

The following are Old text files but relate to the PIXIE II>

Frant Matthews was sending out a revised Pixie board.  You need to email
him at the following:
From: fmathews@norfolk.infi.net (Frank Matthews)
To: "Low Power Amateur Radio Discussion" <qrp-l@Lehigh.EDU>
Date: Fri, 28 Nov 1997 17:06:43 -0500 (EST)
Subject: Re: Pixie Board & PC materials from Frank Mathews
Brian,

I usually sent out the orders within 24 hours of reciept. I
received yours today (Friday) about 2pm and it was at the post office by
3pm (within an hour!). Upon seeing your post I wondered why you seemed as
though you had been waiting a long time......so.......I pulled your
envelope and there it was.....a postmark of what appears to be November
8.
Wonder why it took so long.......upon further examination I saw where the
zip code and "upc code" had been scratched through and corrected. You had
written the zip code as 22321 instead of 23321.
Be assured yours is on the way and should be in Arizona probably by
Wednesday. Sorry you had problems.

Frank Matthews
Technology Education Department
Oscar F. Smith High School
Chesapeake, VA 23320
fmathews@norfolk.infi.net
KC4FKX     QRP-L #1079  CQC #434   NorCal #2232  AK/QRP #199
Grid Square FM16
nnnn
Also Old text files...
From: Bruce Hopkins - KL7JAF <kl7jaf@polarnet.com>
Date: Thu, 4 Dec 1997 21:55:05 -0900 (AST)
Subject: PIXIE 2 Kits...

Hi Gang...

     For those that have been chomping at the bit to get a Pixie 2 kit, I
just talked to HSC Electronics and they had just received 50 kits and
were
awaiting documentation before shipping them out... At the time of my call
(12/2/97) they said about half the kits were already spoken for...  I
ordered two and also ordered some 3.5759mhz crystals at about .85 a
piece... Their order number for those that can't wait for the surface
mount
version or prefer to work with full size components is:  1-800-442-5833

I'm looking forward to the surface mount version of the Pixie 2 and
wonder if anyone has an update on when to expect them out ???  Be the
first
kid on the block to have a dedicated Pixie 2 on each band from 80 to
10m...
Put them all in one tin, use diode switching, one keyer and a DDS DC to
Light vfo... Boy the nights are long up here in the Frozen North !!!


72 / 73 / oo's - Bruce - KL7JAF

Web Page:     http://www2.polarnet.com/~bhopkins

"Alaska QRP Club" - Web Page:    
http://www2.polarnet.com/~bhopkins/akqrp
nnnn

SMiTe--  Surface Mount Technology version of PIXIE II
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

From: "Bob Kellogg" <ae4ic@nr.infi.net>
Date: Sun, 7 Dec 1997 00:20:38 -0500
Subject: Announcing: The Knightlite SMiTe

Announcing the Knightlite SMiTe:

It's the revised and modernized Pixie II!

You ask:
Does it have QSK?  Of course - that's a feature of the basic Pixie
design.
Does it have receive/transmit offset? - Certainly!
Does it have a VXO? - Of Course!
What is the maximum output?  About 250mW, output is at least 100mW with
9V
supply.   
What frequency does it operate on?  80M, the crystal is 3.6864
(Knightlites
net frequency)
Why is it the called the Knightlite SMiTe?

Thought you'd never ask that one.
1.  It's a very small transceiver.  Small as a mite.  (board 1" X 1-3/4")
 
2.  It uses Surface Mount Technology 
3.  It's the Knightlites attempt to SMiTe a mightly blow for those who
embrace new technology, eager to try, eager to learn, eager to test,
eager
to crusade for the causes of right, justice and chivalry.

How much will it cost?
The price will be $10 for the kit plus $3 shipping.  Those who order
multiple kits will pay for just one shipping fee.

What do I get for my Ten Dollars?
The kit includes the board and all parts on the board.  The only other
parts needed are jacks for antenna, phones, key, and an enclosure.  We'll
include some extra parts so you can do some practice soldering.

When can I get one?
That's a really good question, and I'd like to thank you for asking that
one.  At this time, I've proposed that we appoint an investigative
committee to look into the problems associated with bringing this project
in on time.  Evidently there were certain unresolved problems with the
design as we received it.  This, of course, was not our fault, but
never-the-less we had to spend considerable time and resources
determining
the root causes of the problems.  It turned out that the basic design has
been in the public domain for some time, and we could not pinpoint those
responsible for the original work.  I must hasten to point out that the
original design used different parts, therefore we can't assume that the
design, per se, was faulty, only that we saw several areas where
improvement was needed.  We must, of course, produce a product which is
acceptable to the general public and especially to the taxpayers.  So,
our
course has been to redesign and improve the product to the best of our
ability with the resources we have at hand.  Our team has been working
nights and weekends to try to bring this product ot you, and we will not
relent until every american who wants his own Knightlite SMiTe is able to
purchase one.       

In other words, I don't know.  We haven't ordered the boards, yet.  Most
of
the parts are on their way.  
Our design guys, Gary, N3GO, and Todd, KB0HQU, have really done a great
job
of simplifying (!) and improving the Pixie circuit.  (the switching
transister has been replaced with a diode)  We think we're building the
final test versions now.  Probable availability after the first of the
year.  

Man, I really appreciate the job NorCal does, and what the NJ club did
with
the Rainbow Tuner.  We were hoping to be ready a month ago!

One thing that has surprised me.  I've never tried Surface Mount before. 
--And when I looked at that first board and package of parts I thought
"What have I gotten myself into?  -- This thing is tiny!"  Didn't know if
I'd be able to see well enough to solder those little "grains of sand" in
place.  Well, tonite I populated most of a board in about 2 hours, and at
least half time was spent salvaging parts from a couple of other boards. 
-- And it was fun!    The hardest part was overcoming my initial
uncertainity about handling the small parts.  After this project, I
certainly am not going to shy away from surface mount stuff.  In fact,
I'm
laying in a supply of parts.

Our first batch will be 100 kits.  If you want to get on the list for the
first run, send checks to me, made out to Bob Kellogg, not the
Knightlites.

Will keep you posted.

CUL,
Bob Kellogg, AE4IC, 
4708 Charlottesville Rd.
Greensboro, NC 27410
pixiedes.txt
nnnn

This last file is NOT the Pixie but a similar low parts count
QRP radio called the Tuna Tin 2.  Info is on the ARRL Web site
http://www.arrl.org/members/
Graphics, schematic diagram and discussion by W6TOY.
Also:
Hendricks, "Tuna Tin 2- Back to the Future", QRPp Journal,
Spring 1998, page 49-55.
                 Tuna Tin 2 Parts List

                 Resistors (all 0.1 W 5 % carbon film) 

                 1 - 4.7 kohm
                 1 - 47 kohm
                 1 - 220 ohm
                 1 - 100 ohm
                 1 - 1 kohm
                 1 - 8.2 kohm
                 1 - 56 ohm 

                 Capacitors (all monolithic) 

                 2 - 0.01 &micro;F
                 2 - 0.1 &micro;F
                 1 - 100 pF
                 1 - 270 pF 

                 Capacitors (silver mica or monolithic--watch voltage 
rating) 

                 1 - 240 pF
                 1 - 220 pF 

                 Capacitor (electrolytic) 

                 1 - 10 &micro;F @ 25 VWDC 

                 Other 

                 1 - 22 &micro;H RF choke
                 1 - 4 :1 transformer (T1): 16 turn primary, 4 turn 
secondary on a FT-37-43 core
                 1 - output coil (L2): 19 turns #26 wire on a T-37-2 
core
                 1 - SPST toggle switch
                 3 - phono jacks

see tunatin3.txt

nnnn
From: "Doran, Dennis D" <Dennis.Doran@med.va.gov>
 Ken,
 
 Part 2 - My understanding of the Pixie, in all of it's various
 forms (Pixie, Tixie, Knightsmite, Dixie Pixie), is that the 80
 meter version is pretty consistant.  The KnightSmite (80 meter
 pixie) seems to be the final word on the 80 meter version. The
 40 meter version, seems to have the most mods done. For the
 80 meter version, the following values for the output filter
 are listed:
 
 (2) caps - 820 pf
 (1) inductor - 2.2 uH ** That inductor is not a wound torroid, but
                          just the common of ferrite inductor that
                          looks like a resistor. It has been suggested
                          that winding the 2.2 uH inductor on a T50-2
                          core would improve filtering.
 
 For the 40 meter version, there are TWO sets of values for the output
 filter network:
 
 SET ONE:
 (2) caps - both 470 pf
 (1) inductor - 1 uH  ** Either a 1 uH ferrite inductor OR 14 turns of
                         wire on a T50-6 core for improved filtering.
   
 SET TWO:
 (1) cap - 390 pf 
 (1) inductor - 1.5 uH  
 (1) cap - 560 pf

 Which one works better?   I have no idea----yet. 
 
 Actually Ken, I would like to hear both a Pixie and a 49'er side-by-side
 just to hear the difference.  
 
 I hope this answers you question. But, you are talking to someone who
 is still trying to figure out - in a QRP antenna tuner, what the 
 difference is between: inductor in series with antenna, or capacitor in
 series with the antenna.  Maybe one of these days.......
 
 73,
 dennis
 WB8WTU

From: "Robert C. Mazur" <rmazur@tbaytel.net>
Date: Sat, 25 Sep 1999 12:42:33 -0400
Subject: Re: Pixie 40m pi-filter values

G'day Charles,

The Pixie pi-filter for 40m should be 470 pf caps for input and output
values with a 1.2 uH inductor. The W1FB mod uses 390 pf and 560 pf for
input
and output values and I believe dropped the inductance down to around 1.0
uH
or so. But, my textbooks all use 470 pf caps, so I'll stick with the
books.

72/3
Bob, VA3ROM

Subject: WE6W Contest Pixie2 ready for Novelty Sprints!
From: we6w@juno.com (Ed Loranger)
Date: Sun, 20 Dec 1998 12:56:41 EST

The Pixie2 engine is all warmed up gang.

TWO Notes: I have bypassed the 100 Ohm feedback
resistor between pins 1/8 of the LM386 for
additional Volume on my less than sensitive
earphones.  The extra volume lets in more
AM BC station.  So what did I do to fix this
little annoyance?

Well, yesterday I reporte I modified my output
inductor.  This is truly important.  Not only
does a tuned coil with powdered iron slug allow
you to tune the BC station out of the picture,
you will get a better match to your output
transistor.  I found that the pixie2 I have
can put out 990 milliwatts with the slug in
one position.  Unfortunately, this maximum
power point is also a maximum BC station
location as well.

With the slug tuned to minimum/impersceptible
QRM from the AM BC stn, the pixie2 cranks
out an ozone depleting 600 milliwatts.

I added 100 pF to the coupling capacitor
from the OSC to the final transistor, this
increased the output power by about 50 milliwatts,
but also introduced a small chirp.  I was told
it was minimal, but removed it right away.

Anyway, try a few different tuned-slug coils
for you pixie2 output filter and see if one
will fit your situation.

QRpp'in Santa Rosa CA, and loving it!
72, Ed WE6W QRP-Z#106  http://www.qsl.net/we6w
Enjoying Ham Radio every day!  Santa Rosa, CA.

___________________________________________________________________
