[Milsurplus] [Glowbugs] Narrow AM mech filter ?

[Glen Zook]

The wider the filter the better for AM up to around 10 kHz.  Of course, you can tune the receiver so that only 1-sideband of the AM signal is received and, as such, the bandwidth can be halved.


In the SB-300, Heath used a 3.5 kHz filter for AM and this was a little too tight for most people.  Then, they went to a 3.75 kHz filter in the SB-301 which helped some.  However, in the SWL version, the SB-310, Heath used a 5 kHz filter and that worked very well.


I do have an 8 kHz filter available that I sometimes use in my Collins 75A-4 receiver when I want to use it on AM.  That filter works very well.  I have the 3.75 kHz filter in my Heath SB-301 and it is "OK" for voice.  However, when the 41-meter shortwave stations (7200 kHz to 7400 kHz) are received, the music, etc., is constrained. 

Glen, K9STH 
Website: http://k9sth.net
 

      From: Hubert Miller <kargo_cult at msn.com>
 To: "milsurplus at mailman.qth.net" <milsurplus at mailman.qth.net>; "armyradios at yahoogroups.com" <armyradios at yahoogroups.com> 
Cc: "tetrode at googlegroups.com" <tetrode at googlegroups.com>
 Sent: Sunday, January 31, 2016 9:04 PM
 Subject: [Glowbugs] Narrow AM mech filter ?
   
#yiv0839254176 blockquote.yiv0839254176cite {margin-left:5px;margin-right:0px;padding-left:10px;padding-right:0px;border-left:1px solid #cccccc;}#yiv0839254176 blockquote.yiv0839254176cite2 {margin-left:5px;margin-right:0px;padding-left:10px;padding-right:0px;border-left:1px solid #cccccc;margin-top:3px;padding-top:0px;}#yiv0839254176 .yiv0839254176plain pre, #yiv0839254176 .yiv0839254176plain tt {font-family:monospace;font-size:100%;font-weight:normal;font-style:normal;}#yiv0839254176 a img {border:0px;}#yiv0839254176 body {font-family:Calibri Light;font-size:14pt;}#yiv0839254176 .yiv0839254176plain pre, #yiv0839254176 .yiv0839254176plain tt {font-size:14pt;}Speaking of mechanical filters, what would be the narrowest one for AM voice and CW working?As specifically, in the TR-9 trans-receiver. I think the filter in it is wider than it has to be. There isonly one, one-size- fits-all  filter in the set. 
  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/milsurplus/attachments/20160201/25170f4a/attachment.html>