Humorous Article on this Receiver

WN5Y Special Receiver

Let's talk about the old days. When you could hook up your receiver to a long wire and not blow out the front end. Keep your coffee warm by placing it on the top of the receiver. And on cold days, warm up the shack with 18 or so hot tubes plus power supply, etc. And, last but not least, a super hot RF amplifier that gave you the confidence that you could hear the weakest of DX signals.

There are no lightweight static-sensitive devices in this design. The first three active stages of the receiver produce heat! The output stage (loudspeaker) uses two large transistors with heat sinks, so you can effectively disturb everyone in the house! The transmitter power supply will have to share duty with this one. Don't even try your QRP power supply.

Last, but not least, a super hot RF amplifier. The 2N5109 with 50 ma of bias pushes all the signal that a diode mixer can handle. Every stage is 50 ohm impedance and stages can be added or subtracted at will. Two designs are presented: a single 2N5109 that has good dynamic range, or a push-pull 2-2N5109 that combines great sensitivity with dynamic range, IMD, and distortion. Heat sinks are required! Throw those mosfets in the trash!

Let's unleash some design features:

1. Use all the current you can. Dynamic range is achieved easily with current hogging active devices. Use a respectable audio amplifier so you can say "arm chair copy OM" and not be lying. This makes the receiver less susceptible to outside influences. Change to circuits that use the most current. Use the brightest, most current hogging displays available. At night, I can read my logbook from the light of my frequency display.

2. Amplify your signals. Bring in the noise level and place it where you want it. The human mind (with ears) can hear signals 10-15 dB below the noise level. Give yourself a chance!

3. Use a separate receive antenna, like a small loop or a helical dipole, with a strong RF amplifier for excellent low noise reception. I will admit (in this sentence alone) that with some antennas the RF amplifier needs to be switched out, depending on the noise level of the band, especially on 80 and 40 meters. If you can't switch out your RF amplifier, use a smaller antenna.

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Last Update: 01/20/2000
Web Author: David White, WN5Y