- 1. [Amps] SB-220 6 meter conversion parasites (score: 1)
- Author: Steve London <n2icarrl@gmail.com>
- Date: Thu, 16 Jul 2015 14:38:15 -0600
- Finished the SB-220 6 meter conversion, but it seems to have major parasitic oscillations. A little background - I basically followed the 2008 QST article, except I have the original relay in it. I d
- /archives//html/Amps/2015-07/msg00048.html (7,528 bytes)
- 2. Re: [Amps] SB-220 6 meter conversion parasites (score: 1)
- Author: Alek Petkovic <vk6apk@bigpond.com>
- Date: Fri, 17 Jul 2015 06:55:55 +0800
- Hi Steve. What brings you to the conclusion that its a parasitic oscillation? Have you measured the frequency? It sounds more like the amp is simply taking off, in which case, no amount of fiddling w
- /archives//html/Amps/2015-07/msg00049.html (8,787 bytes)
- 3. Re: [Amps] SB-220 6 meter conversion parasites (score: 1)
- Author: Steve via Amps <amps@contesting.com>
- Date: Fri, 17 Jul 2015 14:40:57 -0400
- Hi Steve, I agree with Alex...you're not describing parasitic oscillations (i.e. oscillations at some random frequency.) You're describing a high power oscillator! Remember the difference between an
- /archives//html/Amps/2015-07/msg00050.html (9,675 bytes)
- 4. [Amps] SB-220 6 meter conversion parasites (score: 1)
- Author: Roger Parsons via Amps <amps@contesting.com>
- Date: Sat, 18 Jul 2015 14:15:14 +0000 (UTC)
- I hate to admit this, but I had very similar symptoms with an amplifier when I mis-wired the TX/RX relays... 73 Roger VE3ZI _______________________________________________ Amps mailing list Amps@cont
- /archives//html/Amps/2015-07/msg00054.html (6,638 bytes)
- 5. [Amps] SB-220 6 meter conversion parasites (score: 1)
- Author: "Jim Thomson" <jim.thom@telus.net>
- Date: Sat, 18 Jul 2015 17:50:09 -0700
- Finished the SB-220 6 meter conversion, but it seems to have major parasitic oscillations. A little background - I basically followed the 2008 QST article, except I have the original relay in it. I d
- /archives//html/Amps/2015-07/msg00056.html (8,170 bytes)
- 6. Re: [Amps] SB-220 6 meter conversion parasites (score: 1)
- Author: Bill Turner <dezrat@outlook.com>
- Date: Sat, 18 Jul 2015 19:50:52 -0700
- -- ORIGINAL MESSAGE --(may be snipped) REPLY: 300 ohms is a little high. Most designers use from 50-100 ohms. You need to fine the "sweet spot" for the value. If it is too high, the circuit becomes e
- /archives//html/Amps/2015-07/msg00057.html (8,043 bytes)
- 7. Re: [Amps] SB-220 6 meter conversion parasites (score: 1)
- Author: Colin Lamb <k7fm@teleport.com>
- Date: Sat, 18 Jul 2015 20:13:43 -0700 (GMT-07:00)
- Without any other more sophisticated instruments, use a grid dip meter in absorption mode to learn what frequency the oscillation is. Knowing that, you can solve the problem. Perhaps it is near 50 MH
- /archives//html/Amps/2015-07/msg00059.html (8,212 bytes)
- 8. Re: [Amps] SB-220 6 meter conversion parasites (score: 1)
- Author: Steve London <n2icarrl@gmail.com>
- Date: Sun, 19 Jul 2015 11:03:01 -0600
- First, I want to thank everyone for their comments and suggestions, which were mostly sent privately. They were very helpful. The parasites/self-oscillation is fixed. That simply involved changing th
- /archives//html/Amps/2015-07/msg00060.html (9,448 bytes)
- 9. Re: [Amps] SB-220 6 meter conversion parasites (score: 1)
- Author: Bill Turner <dezrat@outlook.com>
- Date: Sun, 19 Jul 2015 13:58:44 -0700
- -- ORIGINAL MESSAGE --(may be snipped) REPLY: There is a better way, IMO, to do the conversion although it's too late now for Steve. But for anyone else considering this, it can be done while still u
- /archives//html/Amps/2015-07/msg00062.html (7,992 bytes)
- 10. Re: [Amps] SB-220 6 meter conversion parasites (score: 1)
- Author: "Hardy Landskov" <n7rt@cox.net>
- Date: Sun, 19 Jul 2015 20:21:00 -0700
- Hi All, In my opinion the 2008 article has another glaring mistake, and that is the plate RF choke. It has way too many turns to be inductive at 6 meters. Believe me, about 20 turns of #22 wire will
- /archives//html/Amps/2015-07/msg00064.html (10,477 bytes)
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