Re: [linrad] OH0 June 12: Rx/Tx measurements

[Richard Hosking <richardh@xxxxxxxxxxxxxxxx]

A friend of mine(Rod VK6KRG) devised a test using a "comb" of strong 
signals across the band of interest.
The mixer performance is affected by the total energy it has to absorb 
from unwanted signals and a single strong interfering signal may not be 
as rigorous a test as some HF band conditions, or multiple pager signals 
on 148 MHz, or even TV line oscillator noise for example.
I think he used a sharp square wave oscillator at about 20 KHz followed 
by a bandpass filter at the band of interest to give multiple strong 
signals at 20 KHz spacing. With this setup, even signals at -5 to -10 
dBm were enough to overwhelm a good mixer. The idea has been (or will 
be) in QEX - some of the details above may be wrong but you get the idea

Richard

Leif Åsbrink wrote:

> Hi All,
>
> Like for last years VHF meeting I will bring equipment
> this year to measure dynamic range properties of amateur
> transceivers.
>
> Those of you who go there and have a modern rig (one that
> is still available on the market) please bring it if you
> can. I am interested in collecting data from several different
> units of the same model for a Dubus article about typical 
> performance of modern amateur equipment.
>
> The big problems are sideband noise in Tx and Rx as well as
> keying clicks and splatter in SSB mode. I am interested
> in collecting more data like what you can find here:
> http://antennspecialisten.se/~sm5bsz/dynrange/rig_compare.htm
>
> 73
>
> Leif  /  SM5BSZ
>
>
>
>
>  


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