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SM5BSZ

Joined: Sat, Apr 4th 1998, 00:00 Roles: N/A Moderates: N/A

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Receiver testing W1RFIAdmin on 19/10/11
The purpose of receiver testing is to find a couple of numbers by which one can predict the outcome of a direct comparison of two radios on the same. Is one better than the other?

Today we can compare radios under difficult interference conditions by use of wideband recordings. SDR softwares can be tested directly and analog receivers can be tested by use of a (good) SDR transmitter that generates RF on a suitable ham band from the recording.

Not only the usual problems, selectivity intermodulation and reciprocal mixing show up. Also other problems like AGC sensitivity to pulses and poor sound quality for strong SSB signals become evident.

This page: http://www.sm5bsz.com/lir/agctest/agctest.htm has loudspeaker output files from these transceivers: TS-520, R-4C, FT-1000, FT-2000, FTDX-5000, K3, IC-706MKIIG, IC-7000, FT-221R and IC-202. The following SDR softwares are tested: Linrad, Winrad, WRplus, SpectraVue, HDSDR, SDR-radio, Rocky, PowerSDR, G31DDC, perseus.exe and SDRMAXIV.

High performance SDR hardwares are ideal in this test but low cost hardwares have limitations. These low cost SDR hardwares are tested: SDR-14, Softrock, AFEDRI SDR.

It is interesting to note how a low cost SDR like Softrock outperforms old radios like R-4C and FT1000 as well as modern low cost radios like IC706MKIIG and IC7000.

In the near future anyone interested can perform qualified receiver testing by use of a laptop and something like this: http://www.sdr-one.com Just play a 96kHz .wav file to the unit by use of whatever audioplayer. A small set of test files would be enough to rank receivers with respect to dynamic range below 50 kHz frequency separation.

73
Leif, SM5BSZ

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