Ramsey Electronics HR20 manual Using Your Receiver, Tuning SSB Signals, CW Operation

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USING YOUR RECEIVER:

In your first tests, you might feel that tuning in CW and SSB stations by turning the control shaft seems tricky. Don't despair! The addition of a simple knob to the final version of your kit will result in more comfortable tuning right away. Also, the larger the knob, the easier tuning is. Even smoother control can be accomplished by a vernier dial, which will also provide calibration marks. Finally, if you intend to use this receiver only for monitoring or working a very specific frequency range, you can add a resistor in series with the tuning control to achieve the bandspread you want for your own application. For details, please see the upcoming section, Notes to Experienced QRP Builders.

We want you to enjoy this economical receiver, whether you use it for portable listening or as a base for easy experimentation. Isn’t it amazing the performance that can be achieved with just two IC chips?

•TUNING SSB SIGNALS

As you know, the protocol for the 160 - 80 - 40 Meter Bands is Lower Sideband (LSB), with Upper Sideband (USB) used for 20 - 18 - 15 - 12 - 10 Meter SSB. To check or ‘scan’ a given band for SSB signals, tune your HR20 up from the low end for USB signals and down from the high end for LSB.

•CW OPERATION

A direct-conversion receiver lets you hear equal ‘sidebands’ on either side of the zero-beat ‘null’ of the exact frequency of the signal to which you are listening. Therefore, when adjusting the frequency of your companion Ramsey QRP transmitter, be certain that you have in fact tuned to the other station’s lower sideband. The two stations will actually be several KHz apart. Because this receiver’s oscillator is not shared with a transmitter, as in transceivers, there is no need for separate RIT (receiver incremental tuning).

•ON THE AIR TRANS-RECEIVING

Let’s assume that you plan to use this receiver together with a Ramsey QRP transmitter, which provides an RF protected receiver antenna jack. While the receiver will be protected from RF damage from the transmitter, do not expect to monitor your own signal on this receiver while transmitting unless you are a QRP design expert and do not care about future factory service from Ramsey. Even with the circuit protection, the RF signal is just too much for the SA602.

The transmitter signal overpowers the SA602, disrupting the internal oscillator. However, the receiver can handle the output of a crystal oscillator or VFO for frequency spotting purposes.

A better operating arrangement will consist of a T-R switch, either a manual switch or break-in delay relay circuit. This switching circuit can disconnect the

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Contents ALL Mode Receiver KIT Partial List of Available Kits Ramsey Transmitter Kits HR20 Amateur Receiver KIT Introduction Ramsey HR-SERIES Amateur ReceiversAbout Direct Conversion Receivers Circuit Description Capacitors Parts Supplied with the HR20 KITLEARN-AS-YOU-BUILD Receiver Assembly Strategy HR20 HR20 Parts Layout Diagram Receiver Assembly HR20 HR20 Initial Testing of Your HR20 Required for Initial Testing and AlignmentAlignment Alignment Hint for ALL Direct Conversion ReceiversUsing Your Receiver Tuning SSB SignalsCW Operation On the AIR TRANS-RECEIVINGSpeaker Operation More Audio Power Another WAY Adding AN LED Power on IndicatorTroubleshooting Tips Alternate Power Sources General Notes for Experienced QRP BuildersBandspread and Tuning Range Other Methods of Dial Calibration Frequency StabilityDirect Frequency Readout LM386 Audio Output HR20 Construction Notes Ramsey Kit Warranty Factory Repair of Assembled Kits Total Solder Points Estimated Assembly Time HR20 Amateur Receiver KITRequired Tools Additional Suggested Items
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