Tom Said....
Look at close-spaced receiver tests at:
http://www.w8ji.com/receiver_tests.htm
The cheap (old technology) K2 receiver which isn't especially well-designed
equals or beats all of the receivers on that page.
Folks,
I am quite a neophyte when it comes to hands on design considerations of
radio receivers, but I regularly listen to Eric WA6HHQ, and his partner in
Elecraft give talks in the Central California Region about their wunderkind,
the Elecraft K-2. He really explains the MANY considerations that went
into it's design, and is justifiably proud of the result. For what it is, (
a VERY Low power consumption, robust, receiver, cheap, easy to build, easy
to manufacture, modular, multi accessory, capable..etc etc.. Look for lots
of additions to it coming up...
I would say it is an amazing accomplishment. It also brings me back to the
days when I assembled SB 101s and SB 301/401 Heathkits...
The receiver holds it's own against almost all modern ham trascievers...
--Pat aa6eg@hotmail.com
>From: "Tom Rauch" <w8ji@contesting.com>
>Reply-To: Tom Rauch <w8ji@contesting.com>
>To: <amps@contesting.com>, "Zyg Skrobanski" <af4mp@mindspring.com>
>CC: "Ian White, G3SEK" <g3sek@ifwtech.co.uk>
>Subject: Re: [Amps] Why hasn't solid state replaced tubes?
To: <amps@contesting.com>
>Date: Tue, 4 Mar 2003 18:07:15 -0500
>
> > Does a transmitter with poor 3rd order IMD therefore have any noticeable
>distortion in the voice quality due to the speech intermod products within
>the audio bandwidth?
>
>Why would it have audible distortion? The garbage being measured is already
>20-30dB down, is outside the passband of the receiver fileters, and the
>receive detector and audio system already has IM products. Not only that,
>many locations have high noise levels masking IMD that can be heard in
>quiet locations.
>
>There is also a BIG difference between off-frequency products and
>distortion that you can hear inside the passband. The same is true for
>keyclicks. What you hear inside the passband is not related to actual
>bandwidth. This is why information is generally not reliable when we ask
>random operators how we sound, or if our rigs are clicking or splattering.
Ironically, the most meaningful test of IMD performance for SSB is also the
simplest - just tune away from the signal, using a good receiver
that isn't being overloaded, and notice how far away you have to go
before the splatter dies away into the noise.
Using the (meaningful) receiver method, I have heard terrible, very wide,
signals transmitted from "high end" transceivers, and excellent, no
splatter, signals from the so called "cheap" transceivers!
If you look at measured performance, price has little to do with results.
If you listen to sound files on the keyclick page, you'll see top of the
line radios have terrible clicks. Price has nothing to do with quality.
>
>73 Tom
>
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