sabato 7 marzo 2020

How to trasform a 40 m Pixie into a 20 m Pixie


These are the changes identified on the scheme; they have not yet been tested, but welcome if anyone wants to do so.

First of all the general schema of the "Frog" Pixie with the changes:




The changes on the output filter:



The change of the crystal, near the mixer-oscillator NE602:


Changes in the input resonating filter: the ceramic resonator at 7023 khz is replaced by an inductor that resonates with the capacitor (22 pF) at 14060.
All must to be tested.



73 de IZ3AYQ

mercoledì 26 febbraio 2020

lunedì 17 febbraio 2020

1 BJT Transceiver by HA4OO

This is an incredible micro transceiver: only 1 transistor, and less tha 100mW of power for a QRPx RIG. Very essential; only a few components.
Some QSO have been done on the first skip on 20 m during last ARRL contest.




73 de IZ3AYQ

giovedì 26 dicembre 2019

Testing on the air the "Shorty Multy"

I tested for a month (from 22/11/2019 to 22/12/2019) the "Shorty Multy" on the air, to verify the possibility of making QSO with this short antenna, first of all in 40 meters. It was easy to do it, and the answer was generally the first time. On 40 meters i was QRO (10 watt); on the other bands i was QRP with less than 5 watt ( usually 3 or 2 or , 1,8 watt).






73 de IZ3AYQ

domenica 22 dicembre 2019

The SHORTY MULTY

My new antenna used with good results on 40m, 20m, and 15m. Here is the schema.


The antenna in the origin was an OCF (off center feed dipole), of 21 meters; this is a simulation of the OCF (not linear loaded):


The OCF was too long for my balcony, so i tried a new configuration: now it is a 23,4 OCF dipole, linear loaded. The center of the cable is attached to the vertical part, that is the aluminium tube.
I use it with my micro Bitx, with 10 Watt on 40 m, 3 watt on 20 m and 1,8 watt on 15 meters with very good result (in 20 m and 15 meters i work QRP, with less of 5 watt !!!). I use a Kenwood AT-130 antenna tuner to tune it.

In the next post i will report my testing.

73 de IZ3AYQ

domenica 15 dicembre 2019

QRPx

QRPx: collegamenti radio con potenza inferiore ai 100 mW. Difficile ma possibile! Molti appassionati abbassano la potenza fino a livelli di 80 mW, 50 mW, fino a 10 mW o 1 mW per collegamenti sfidanti.
Ancora meglio, costruiscono in modo minimale un trasmettitore con pochissimi componenti e bassa potenza, come quello che segue, denominato "Vanguard", di Oleg Borodin, RX3G (ex RV3GM):



Oleg lo usa con una Yagi 3 elementi, ma essendo la potenza di circa 80 mW, anche supponendo 6 dB di guadagno, che equivarrebbero a 320 mW sul radiatore isotropico (circa 4 dB di guadagno sul dipolo), è una grande sfida fare questi collegamenti.

La pagina del Club 72 è molto interessante, perchè questi circuiti sono usati e non sono solo un esercizio di semplicità:

Link al Club 72


Ci sono anche altri trasmettitori analoghi, ne documento qualcuno:






Ed aggiungo il famoso MMM (Michigan Mighty Mite):




73 de IZ3AYQ


martedì 3 dicembre 2019

Simple audio amplifier

Simple audio amplifier with TDA2003

This audio amplifier can be easily used with rigs like Pixie, or Microbitx to reach the audio output power of about 10W. Very easy to do, you can find kits for about 1 or 2 euro in the Internet. Vcc can reach 18 V.

 73 de IZ3AYQ