Monthly Archives: February 2017

P2N2222A for the Pixie

Posted on February 27, 2017 by robert

On Semiconductor has a variant of the old 2N2222A in a plastic case called the P2N2222A and characterizes it as a small signal RF amplifier.  I picked up a few samples and ran three of them through the Pixie.  In … Continue reading →

Posted in Pixie, Projects, QRP | 1 Comment

7-Pole Filter + Pixie

Posted on February 26, 2017 by robert

A friend of mine, Paul K1YBE, gave me a QRP Labs 40-meter Low Pass Filter Kit.  The kit came with three T37-6 cores, some #28 wire, 4 caps, a tiny PCB, and a couple of headers. Normally used with one … Continue reading →

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Better Q == Better Response

Posted on February 26, 2017 by robert

Yesterday I replaced the inductors in my original 40-meter LPS with larger cores that wound up having about twice the Q.  This morning I replaced the ceramic caps with silver mica caps.  The old caps had a Q around 80.  The … Continue reading →

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Does Size Matter?

Posted on February 25, 2017 by robert

There’s a joke in there somewhere… Yes, size does matter when it comes to Toroid diameter (which also has an impact on winding geometry), maximum wire size, etc.  All things which impact the Q of the circuit. I went back … Continue reading →

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A New Transistor for the Pixie

Posted on February 21, 2017 by robert

Of course the Pixie final transistor, Q2 S8050, gets darned hot, and I’ve blown one out in the past just holding the key down more than a few seconds.  With my Pixie + Red Core Filter, I was seeing about … Continue reading →

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Passing Pixie!

Posted on February 21, 2017 by robert

After experimenting with T37-6 yellow core inductors, it was time to change to the T37-2 red core.  These have a lower operating frequency, up to 10 MHz, and it is possible that they might have a higher attenuation on 14 MHz … Continue reading →

Posted in Gear, Pixie, Projects, QRP | 1 Comment

Pixie PLUS 5-Pole LPF

Posted on February 20, 2017 by robert

My Pixie produces about 500 mW of output power when driven by a 13.8 volt supply.  The total input power to the board is about 1.5 watts.  As I’ve mentioned the Pixie only suppresses the 2nd harmonic by about 10 … Continue reading →

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A 40 Meter LPF for the Pixie

Posted on February 20, 2017 by robert

As I mentioned the 40-meter Pixie QRP rig has pretty horrible harmonics, well above the maximum allowable FCC limit (-43 dBc).  One Pixie was about -9 dBc, and the other was about -20 dBc. The output filter in the Pixie … Continue reading →

Posted in Gear, Pixie, Projects, QRP | 2 Comments

Pixie Varibility

Posted on February 16, 2017 by robert

Given the dismal harmonic supression of my first Pixie kit, I was excited to test another. While still not passing, it is isn’t absolutely dismal. The readings were taken with a 40 dB external attenuator.  So the fundamental is actually … Continue reading →

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QRP Still Rules the World; even on 80 Meters

Posted on February 13, 2017 by robert

Yesterday I decided to set my radio up on a QRP (5 watt) beacon mode on 80 meters (I used a propagation mode called WSPR, transmitting once every 10 minutes).  I let the rig run from about 4:45 PM local time … Continue reading →

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