tag:blogger.com,1999:blog-2257458838727315711.post1933663445224829705..comments2024-03-21T00:37:26.331-07:00Comments on K6JCA: Improving the Selectivity of the R-105A ReceiverJeffhttp://www.blogger.com/profile/04853314106806116765noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-2257458838727315711.post-293225420464232712013-11-06T16:19:00.762-08:002013-11-06T16:19:00.762-08:00I was unable to find an easy way to open the IF tr...I was unable to find an easy way to open the IF transformer cans to remove the capacitors. These transformers are designed to be overcoupled and the passband is to be aligned with a "double hump" frequency response. The 6 kHz mechanical filter works fine and you should buy as many of these as you can. <br /><br />Beware the .01 mica bypass capacitors. I found the receiver lacking in gain and sensitivity with zero volts on V-104 pin 6. <br /><br />Hint: on old radios with a problem, feel all the tubes. If you can keep your fingers on a tube you are probably near the source of your problem. <br /><br />Cliff, WB6BIH<br />Cliffhttps://www.blogger.com/profile/12260106617333818520noreply@blogger.comtag:blogger.com,1999:blog-2257458838727315711.post-31765862169294952962012-09-24T13:16:35.736-07:002012-09-24T13:16:35.736-07:00Jeff, another method suggested in electric Radio A...Jeff, another method suggested in electric Radio Article in from May 1991 by Walt Hitchins kj4kv suggests that lowering the coupling cap value between IFs will narrow the bandwidth down as well. <br />Thanks you for posting this information, just picked up 2 R-105a's this weekend and 1 that had a hb supply showhorned in the dynamotor area even works.. Welcome to send me an email at kd3ht@epix.net if you'd like a scan of the ER article.<br /><br />Steve, kd3htSteve Gajkowskinoreply@blogger.com