Sunday, October 29, 2006

Halted Pixie2

G3XBM's pixie article is a good summary for Pixie2 kit. You may refer it for the kit construction.

WA5ZNU contacts on pixie2

WA5ZNU wrote the blog for the contact K6WAY on pixie2. He got the calling CQ on 7.040KHz which is the crystal by pixie2. He got the bad QRM from the AM station but had the contact. Nice article.

Saturday, October 28, 2006

PicoKeyer

ARRL site has the article about picokeyer in PDF format. It's very simple and ultra low power that can be used for QRP rigs including pixie2.
It's uses PIC12F629 chip and has some parts to interface to it.

The binary code of picokey has been stored here. You can get the binary code for the picokeyer.

Bandpass filter on pixie2


Pixie2 bandpass filter is C6, C7 and L3 to filter out the frequency that should be selected. For example, if you would like to use pixie2 for 7MHz, they would be C6,7: 820pF and L3: 1.0uH.

Thursday, October 26, 2006

Inside of the pixie 2 kit



I opened the kit package. Here is the parts that I got.










  • Crsytal
  • Board
  • BNC Connector
  • Two 2N3904 transistors
  • Diode
  • Battery plug
  • Inductors
  • Capacitors
  • LM386
  • Registors
  • It's very simple and you may construct it soon if you have the solidering iron and solider.

    2N3904 is a power(Pd) with 625mW. I'll replace them with PN2222A. Other source recommends 2N2222A for a better power. If I can get it, I'll use it for pixie2.
    MPS2222A is another choice for pixie2 transistors.

    I have several 2N4401 and 2SC1815 transistors and would like to try them for pixie2, too.

    Pixie2 photos by JE2CDC page

    Here is another pixie-2 . It may be made by Kenneke Communications. They are selling Pixie II CW Tranceiver .

    Wednesday, October 25, 2006

    Got the pixie2 kit


    I got the pixie 2 kit today and opened the package. The picture shows the kit, battery connector and crystal. It's very small board and should be easy to build it.

    LM386 to get 74dB (Pixie 2 audio amp.)

    JF1OZL describes the LM386's circuit with a higher gain. The LM386 gets 40dB as an original circuit provided by the data sheet (10uF pin1-8 connection). This article describes 74dB gain with the circuit.

    If you didn't get enough audio gain on pixie 2, you may change to the circuit to get the higher gain.

    Tuesday, October 24, 2006

    eHam.net review for pixie 2

    eHam.net has the review pages for pixie 2. There are 26 reviews about pixie 2 and the average is 3.2/5 which means that it's not good. You should read those reviews before you construct pixie 2 kit.

    HSC Electronic Supply

    HSC Electornic Supply sells pixie2-KIT as $9.95. This is a good offer to those who would like to have the pixie-2 as a kit. You may build it by yourself because it's easy to construct on the board.

    Monday, October 23, 2006

    Pixie 2 by M0DAD

    M0DAD writes the article of Pixie 2. He mentions that the T1 transistor should be swapped with the better gain of it (e. g. 2N2222) instead of 2N3904.

    Monday, October 16, 2006

    Zero Beat operation by K3NG

    K3NG wrote a good article about An 80 Meter CW Five Watt QRP Tranceivert. In the article, there is the section about the opeartion:

    Operation
    As this rig has a direct conversion receiver, signals can be heard on both sides of zero beat. In other words, when tuning up the band, you will hear a signal with a high frequency beat note, decreasing as you tune up. The beat frequency continues to get lower until reaching zero beat (dead on the transmit frequency of the other station). Tune further up, and the beat reappears as a low frequency and increases frequency as you continue to tune upwards. This characteristic of direct conversion receivers require a little more thought when tuning on stations and attempting a QSO. Since the transmitter frequency is negatively offset (TX frequency is 600-700 Hz below the RX frequency), one needs to tune on the “high side” of zero beat in order to have the transmit frequency fall within the other station's receiver pass band.


    This is a good description of zero beat on the direct receiver.

    The article of "Listen to AMATEUR RADIO Signals!" also describes the zero beat by direct conversion on the receiver.

    Sunday, October 15, 2006

    pixie2 modification on Kenneke Communications

    Kenneke Communcations provides the memo for pixie2 modification. It describes the change of Q2 to 2N2222A to increase the output power and the addition of 0.01 uF capacity to ensure RF noise to be bypassed adequately.

    It describes the AC BC Band interference to install ferrite chokes. The memo uses 5 mH. It uses 5.62V Zener Diode to be stabalize the power line to LM386. R5 to 500 Ohm and put 250 or 470 uF capacitor from pin 6 on LM386 the GND. It will get immediate improvement audio and bc interference reduction. IT recommends as follows:
    1. Definately the RF choke going to the audio input of LM386.
    2. RF Choke on headphone/spkr jack center lead.
    3. RF Choke to keyed line.
    4. RF Beads on each line to oscillator/PA resistors.
    5. Shielding between stages.
    To eliminate the surging current, add 100 ohm from D1 diode cathode to key line.

    Friday, October 13, 2006

    RixPix by KE3IJ

    The modification of Pixie 2 has been done by Rick Anderson. It calls RixPix. It uses four transistors for audio amplifier instead of LM386 and has the audio filter. The final transistor is 2n3503 to get the higher power than pixie2.

    Thursday, October 12, 2006

    SPRAT pixie 2 article

    SPRAT has the good article of pixie 2. You may refer this article to understand pixie2 and its origin.

    Reduce BCI and add sidetone to Pixie2

    LA3ZA has the article to reduce BCI and add sidetone to Pixie2. You will use Pin 2 of LM386 to connect diode to the ground instead of pin 6 diode. I will try to use this approach.

    The article describe the sidetone of pixie2. Output of sidetone is going to pin 7 of LM386. I'd like to use this sidetone, too.

    Wednesday, October 11, 2006

    G3XBM's pixie2

    There is the article of pixie2 written by G3XBM. It describe the pixie2 kit well.

    Circuite Swamp has the good explanation page of pixie2. They have the layout of the board. You may refer this page to build pixie2 with the board.

    Monday, October 09, 2006

    Zero Beat of frequency

    Zero beat is always needed to contact other station. AF8X wrote zero beat indicator. It uses LM567 op-amp to indicate the zero beat. The original article was described by WI5W in March 1992 QST magazine.
    Another zero beat indicator is called "CW Zero Beat Detector" by Jerry Henshaw, KR5L.

    K3WWP shows the zero beat circuit using LM567. It is from a letter sent by W6OWP, he mentioned.

    Jackson Harber Press offers the kit of zero beat called "Son of Zerobeat". It has 7 LEDs which graphically inidicate the frequency of a received CW audio tone.

    K6XX, Bob Wolbert wrote the visual CW tuning indicator on the Web. It uses XR-2211, FSK/Tone Decoder. LED illuminates as you get within about 25Hz of a signal. It will flash on and off a bit with the incoming signal.

    Dixie Pixie2 (Modified pixie2)

    The page of modified pixie2 exists. It calls dixie pixie2. VXO and reducing key chattering has been equipted.

    Sunday, October 08, 2006

    pixie2 article by JJ1SLW

    JJ1SLW describes the good article about pixie2. He contacted JA stations from Californica with pixie2, too.

    Saturday, October 07, 2006

    pixie2 mod by JA9MAT

    JA9MAT shows the web page of modified pixie2. He added VXO, AF LPF, sidetone and RIT. It's useful to make the enhanced pixie2.

    Friday, October 06, 2006

    Press-n-Peel

    Press-n-Peel is an interesting technology to make a printed circuit. I'd like to use it sometime future.

    Kenneke Communications

    There is the memo of pixie2 on Kenneke Communications site. It's useful for me.

    Wednesday, October 04, 2006

    Pixie2 tips by WE6W

    WE6W has a nice tips for pixie2. The RIT should be always equippted with the rig. Audio improvement can be applied to my pixie2. If you can put Zener diode in parallel, it's also stable to operate it.

    Anyway, it's considerable to build pixie2.

    Monday, October 02, 2006

    Zero Beat for QSO

    WD3P describes a nice article about Zero Beat for QSO.

    VXO for Pixie2

    The original pixie2 doesn't have the mechanism of variable frequency. The crystal oscillates only one frequency on both sending and receiving time. Typical operation of CW needs to support the CW band for 40m.

    VXO (Variable Xrystal Oscillator) is a good option to support the variable frequency for the CW band. The super VXO has two X-tals in parallel and gets the wider range of frequency change with a variable capacitor like trimmer. My first design of frequency converage is 7000KHz-7030KHz, therefore, two 7030KHz X-tals will be used. Inductor and capacitor parameters will be decided to cover the frequency range.