© 1999 QRP2000 Design Team

Specification of the QRP2000 Receiver

The performance of the QRP2000 is largely determined by the R2/T2 modules which were designed by KK7B and described, most recently, in the ARRL publication QRP Power. Apart from adding a PRA10 pre-selector/RF pre-amp and other published modifications we have added little to the basic design Our contribution has been the DDS VFO and PIC Control board/Firmware plus the integration of the modules to make a working radio. As implemented it covers all ham bands from 1.8 to 29.5 MHz. Modes available are USB/LSB and CW.

We used a Rohde and Schwarz Radiocommunication Analyser model CMTA 94 to measure the following performance on our prototype:

Receiver :-
Band Sensitivity for 10 dB SINAD (Pre-selector in)
1.8 -117
3.5 -117
7.0 -117
10.0 -117
14.0 -119
18.068 TBA
21.0 -116
25.0 TBA
28.5 -118
Sideband suppression varies from better than 40dB on 7.0 to better than 35db at 28 Mhz.
But please read observation in Hardware description regarding problem observed in synchronizing the two DDS Chips!!!.

SSB selectivity 3Khz at -6db and 5Khz at -60 dB.

CW selectivity 600Hz at -6dB and 1200 Hz at -60dB.

In practice this is not a DX competition performance however it compares well with standard commercial transceivers like the ICOM 725. The clarity of the audio must be heard to be believed. The receiver has no AGC so when tuning the band the AF volume control will require adjustment to cope with varying signal levels. There are some spurious responses in the prototype. For example 25Mhz (ie the 100 Mhz clock divided by 4). The prototype has poor screening so spurii are to be expected. We will re evaluate the spurii when the "Show and Tell" model is complete.

In Europe there is no sign of Broadcast band interference or spurious responses resulting from them. We used a full size 80 meter dipole during our listening tests and a BC348 tuning knob!. The receiver is unusually quiet.
 
 
 
 
 
 
 

Transmitter :- TBA