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From: Jay A Beamer@4H-MAILC05
To: smtp:TenTec@contesting.com
To: <tentec@contesting.com>
Date: 10/8/97 12:59PM
Subject: Re: [TenTec] Estimating receiver passband re
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From: Jay A Beamer@4H-MAILC05
To: <tentec@contesting.com>
Date: 10/8/97 9:53AM
To: smtp:tentec-request@contesting.com at GATEWAY
Subject: Re: [TenTec] Estimating receiver passband re
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hello all and Gary,
Only my opinion, but comparing the results of another with your own results
would be an unfair comparison based on one element of your test set-up. Since
your test set-up uses a speaker and microphone, the results will be different
even though the receivers are the same due to the difference in frequency
response of the speaker and the microphone. Even if an individual used the
same
receiver, microphone, and speaker, one individual could not duplicate the
results of another individual because of the difference in acoustics where the
test took place. Guess all this will depend on the accuracy one is attempting
to
achieve, but to base performance on one's test results versus anothers would
be
unfair.
If all receiver testing took place in the same environment, then the relative
results would be of value.
Just my 2 cents.
73,
Jay, KM6VX
Hi All,
I write the morse column in the NZART Journal "Break-In". Recently, I've
been
comparing and publishing the passband responses of various commercial
transceivers.
I do this by
1. tuning the receiver to HF noise only (empty frequency on 20m say);
2, digitizing the audio noise from the receiver;
3. finding the power spectral density of this digitized audio noise, which is
the response of the complete radio.
For digitizing, I use GoldWave, which is shareware software obtainable from
http://web.cs.mun.ca/~chris3/goldwave
This samples using a standard PC soundcard. I sample for 10 seconds at 8
kHz,
digitize to 16 bits. Because most of us listen to CW via the speaker, I
sample
through that, with a high-quality microphone.
Regards,
Gary, ZL1AN.
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