Racal RA17L. - UK Vintage Radio Repair and Restoration Discussion Forum

George G4EUF · 8th Jan 2016, 5:16 pm

Hello again, and a Happy New Year to everyone,
Firstly, can I thank " Racal Rob" and the other gentleman amateur who responded to my last posting with offers of help.
I now have a working 37.5mHz after a lot of replacement of SM caps in the filter, the replacement of the SM caps in L28 and L33, I could not understand why there was an external 220pf coupling cap attached to L33 and only after removing L33 did I find that the internal cap had been shorted out for what ever reason I don't know? the short has now been removed and a new SM cap fitted and the filter realigned.
I would like to put a few thumb nails on this site to show the response on the SA of the filter alignment, however, I am unsure as to how to do this?
I have uploaded some pictures, however, unsure if these will be shown?
If they do appear the first shows the filter response at 1mHz bandwidth with 3 mv injected at TP1 and the SA at TP3 with V5 and V9 removed and the vertical at - 106 dbm. the 4th picture is with a 3mHz horizontal and again at -106 dbm. As my HP sweeper has gone on the blink, ( typical when you need a piece of test gear!) I have used the FM O/P on the sig gen at 30kHz dev.
Any comments very much appreciated. Regards, George, G4EUF.

Station X · 16th Jan 2016, 2:47 pm

Thread closed as OP was disappointed by lack of response.

8th Jan 2016, 5:16 pm	#1
George G4EUF Tetrode Join Date: Oct 2010 Location: Loughborough, Leicestershire, UK. Posts: 84	Racal RA17L. Hello again, and a Happy New Year to everyone, Firstly, can I thank " Racal Rob" and the other gentleman amateur who responded to my last posting with offers of help. I now have a working 37.5mHz after a lot of replacement of SM caps in the filter, the replacement of the SM caps in L28 and L33, I could not understand why there was an external 220pf coupling cap attached to L33 and only after removing L33 did I find that the internal cap had been shorted out for what ever reason I don't know? the short has now been removed and a new SM cap fitted and the filter realigned. I would like to put a few thumb nails on this site to show the response on the SA of the filter alignment, however, I am unsure as to how to do this? I have uploaded some pictures, however, unsure if these will be shown? If they do appear the first shows the filter response at 1mHz bandwidth with 3 mv injected at TP1 and the SA at TP3 with V5 and V9 removed and the vertical at - 106 dbm. the 4th picture is with a 3mHz horizontal and again at -106 dbm. As my HP sweeper has gone on the blink, ( typical when you need a piece of test gear!) I have used the FM O/P on the sig gen at 30kHz dev. Any comments very much appreciated. Regards, George, G4EUF. Attached Thumbnails

16th Jan 2016, 2:47 pm	#2
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,290	Re: Racal RA17L. Thread closed as OP was disappointed by lack of response. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.