Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site brl-tgr.ARPA Path: utzoo!watmath!clyde!burl!ulysses!mhuxj!houxm!vax135!cornell!uw-beaver!tektronix!hplabs!hao!seismo!brl-tgr!jcp From: jcp@brl-tgr.UUCP Newsgroups: net.ham-radio Subject: Re: some questions about UNIDEN CR2021 Message-ID: <4806@brl-tgr.ARPA> Date: Fri, 28-Sep-84 00:36:51 EDT Article-I.D.: brl-tgr.4806 Posted: Fri Sep 28 00:36:51 1984 Date-Received: Wed, 26-Sep-84 06:31:17 EDT References: <12141@sri-arpa.UUCP> Organization: Ballistics Research Lab Lines: 20 The Antenna Adjust knob on the CR2021 probably does what most antenna tuners do, control a variable capacitor or inductor (probably the latter), forming 'transformer' which is used to match the input impedance of the radio, (probably 30-50 ohms) front end, to the impedance of the antenna (which varies with frequency, and for a short whip is probably several hundred ohms). From comparing the 'sound' of the filter on the CR2021 with my McKay Dymek DR-101, I would suspect 4Khz/8Khz as the filter widths, although it could be 3/6 as well. The 'narrow' is definetely less than 5Khz, which is a standard 'station spacing' on shortwave. The RF attenuator acts like about 10db per step, (which is pretty standard for attenuators). The 'fine tune' knob controls the frequency of the BFO, which is totally divorced from the IF tuning frequency generated by the digital synthesizer. I suspect getting it to act as fine tuning on AM is difficult. -JCP-