Path: utzoo!utgpu!CUVMA!SWL-L Date: Wed, 21 Feb 90 00:07:35 EST Reply-To: Don Liu <@BBN.COM:liud@guille.ece.orst.edu.ece.orst.edu> Sender: Short Wave Listener's List Comments: Warning -- original Sender: tag was From: Don Liu <@RUTGERS.EDU,@orstcs:liud@guille.ECE.ORST.EDU> Subject: Sangean 803A hints X-To: swl-l@cuvmb.cc.columbia.edu To: UofToronto LAN redistribution Message-ID: <90Feb21.223557est.58764@ugw.utcs.utoronto.ca> Newsgroups: bitnet.swl-l Distribution: ut Approved: devnull@gpu.utcs.toronto.edu Recently I fixed several minor problems of my new Sangean receiver. I am posting the followings in hope that some of you may use it as reference. The problems are: 1) Inacuracy in the synthesized frequency 2) Audible "hiss" 3) Crossmodulation (that is, strong local stations interference when using a good antena) My fixes are: 1) open the back cover and remove the top PC board. Set the bandwidth switch to "narrow" and tune to a weak yet clear signal. Adjust the tunable capacitor to center the frequency (very easily done). 2) Since the volume of this radio is ample, I reduced the audio gain by 50%. This cures the hiss, makes the volume control smoother and results in a better audio quality. The max volume is still enoughly big. To do this, reduce increase the two feed-back divider resistor from 100 ohm to 200 ohm. They are in board labeled B, and are connected to the audio amp pins 3 and 12 thru two 100uf caps. (symetric since there are left and right channels) 3) You may have crossmodulation if you find that a good antena would make reception worse. reduce the RF gain will help reduce the cross modulation, but the redustion is often not enough. There is a 68 ohm resistor connecting the RF gain potentiometer to ground. Shorting this resistor will increase the gain control range greatly thus fixing this problem. Another surgury I have done to my radio is to install 4 lead-acid batteries into the battery compartment and connect the "+" to power jack input. This way, a 24-hour charging will give me 3 month of play. The battery I used are 2.5 amp-hour type and is of same dimension as the D cells. I got them from a local e-junk store. Happy SWLing!