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1. [Amps] FM Amp. (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Sun, 22 Dec 2002 22:47:18 +0100
I don't know about 4-400 but for sure I've seen the 3-500z in FM 88-108. It was when in italy exploded the private radio phenomena, just during the middle seventies. I remember the dish with the larg
/archives//html/Amps/2002-12/msg00246.html (8,088 bytes)

2. [Amps] Re: [Amps] various parasitic sources... chassis, tubes, etc... (score: 1)
Author: i4jmy@iol.it (i4jmy@iol.it)
Date: Wed, 6 Nov 2002 11:08:46 +0200
Luck doesn't matter so much here. Tubes like 8877 are inherently good under this perspective and do not require VHF suppressors, other tubes aren't stable and suppprssors must be installed, that's al
/archives//html/Amps/2002-11/msg00051.html (9,513 bytes)

3. [Amps] Power ratings N/BNC/SO239? (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Sun, 10 Nov 2002 23:26:23 +0100
...hmmm... if 15Kw is a CW signal, or a carrier, I wouldn't do that, expecially if the cable is a small one. The 7-16 is typically a precision 1KW UHF TV connector, not exactly a big power one. We u
/archives//html/Amps/2002-11/msg00161.html (7,386 bytes)

4. [Amps] Re: [Amps] EIMAC Confusion (score: 1)
Author: i4jmy@iol.it (i4jmy@iol.it)
Date: Wed, 13 Nov 2002 10:52:50 +0100
Mark, I think you did not understand how does it work. As the word says, the plate dissipation is the energy dissipated, not the total power involved. If a tube FM amplifier (typically a class b) has
/archives//html/Amps/2002-11/msg00197.html (8,223 bytes)

5. [Amps] 8877 dissp (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Fri, 15 Nov 2002 00:12:52 +0100
All considered, when an amplifier has good protections (fast) with reflected power, plate and grid current, the actual risks for mistuning errors and errors in general is quite limited. I'm talking i
/archives//html/Amps/2002-11/msg00229.html (8,943 bytes)

6. [Amps] A general question about why anodes get hot (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Wed, 18 Sep 2002 20:20:36 +0200
In my experience with broadcast FM transmitters, solid state mosfet amplifier are not so much better than a tube PA plate efficiency already when the device is alone, I mean a single pushpull unit.
/archives//html/Amps/2002-09/msg00131.html (8,578 bytes)

7. [Amps] Re: [Amps] suppressors (score: 1)
Author: i4jmy@iol.it (i4jmy@iol.it)
Date: Mon, 5 Aug 2002 17:15:30 +0200
s in over in A politically correct answer would say that each amplifier needs its own suppressor, most likely you find in amplifiers all sort of suppressors or no suppressor at all. Often suppressor
/archives//html/Amps/2002-08/msg00071.html (7,418 bytes)

8. [Amps] Re: [Amps] Re: [Amps] suppressors (score: 1)
Author: i4jmy@iol.it (i4jmy@iol.it)
Date: Tue, 6 Aug 2002 09:30:20 +0200
1500 (1, 8877) is the only HF amplifier I know of that has no I do not deal with Ham products, but in some medium (line tuned) and big power (cavity) VHF amplifiers, ceramic tubes from YC236 (8877)
/archives//html/Amps/2002-08/msg00082.html (6,809 bytes)

9. [Amps] Re: [Amps] Changing 3-500z to 8877 (score: 1)
Author: i4jmy@iol.it (i4jmy@iol.it)
Date: Wed, 21 Aug 2002 14:54:20 +0200
Not the greatest idea. Adding to the already notices made by others, I like to point out also: 1) As is, the HVPS in an SB220 is too low and small for an 8877. 2) Replacing the internal HVPS with an
/archives//html/Amps/2002-08/msg00176.html (8,927 bytes)

10. [Amps] Press, Cool Stuff... (score: 1)
Author: i4jmy@iol.it (i4jmy)
Date: Thu, 22 Aug 2002 20:00:11 -0400
-- StripMime Report -- processed MIME parts -- multipart/alternative text/html audio/x-midi application/octet-stream -- StripMime Errors -- A message with no text/plain section was received. The enti
/archives//html/Amps/2002-08/msg00211.html (6,365 bytes)

11. [Amps] Re: [Amps] RF choke selection (score: 1)
Author: i4jmy@iol.it (i4jmy@iol.it)
Date: Tue, 2 Jul 2002 18:15:38 +0200
I was reading all posts but I didn't see one that pointed out that a choke working inside an amp could be easily wrong in another. A "parked" resonance can infact easily move (enough to disturb) when
/archives//html/Amps/2002-07/msg00047.html (9,792 bytes)

12. [Amps] Your ideal HF mobile amp. (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Sat, 1 Jun 2002 15:40:01 +0200
It depends by the desired power level. A too low impedance leads always to poor results, my opinion is that over 500W and solid state PA it's not the best to run 14VDC. A DC-DC converter to a minimu
/archives//html/Amps/2002-06/msg00006.html (7,424 bytes)

13. [Amps] Strange Problerm (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Sat, 8 Jun 2002 15:32:45 +0200
Also in the case 237 V AC is made with one leg of a 380V 3 phase and the neutral (very common here in europe) the transformer windings are isolated to each other and coupled magnetically. 73, Mauri I
/archives//html/Amps/2002-06/msg00058.html (12,546 bytes)

14. [Amps] Re: [Amps] Driving Impedance (score: 1)
Author: i4jmy@iol.it (i4jmy@iol.it)
Date: Wed, 12 Jun 2002 16:08:21 +0200
A tetrode can be grounded grid. Polarization requirements are not the same than dynamic circuit and have nothing to do with the amplifier configuration. Stated it, and generally speaking, why to both
/archives//html/Amps/2002-06/msg00078.html (9,016 bytes)

15. [Amps] RE: [Amps] 8877 Max Grid Current (score: 1)
Author: i4jmy@iol.it (i4jmy@iol.it)
Date: Tue, 18 Jun 2002 17:47:36 +0200
A brand new and optimal 8877 (years ago, rarely later) was typically 40- 50mA for 1.8Kw of output power at VHF (broadcast) with 4Kv HV (loaded). As the tube was aging, the RF power decreased and driv
/archives//html/Amps/2002-06/msg00140.html (9,102 bytes)

16. [Amps] Interaction, antennas. (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Sun, 12 May 2002 16:45:20 +0200
If you keep antenna elements 90° off, one antenna beams 90deg the other, the minimal spacing can be much smaller or interction minimized, unless the boom is the disturbing element (rare). When al
/archives//html/Amps/2002-05/msg00136.html (7,838 bytes)

17. [Amps] power combining? (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Sun, 12 May 2002 22:39:42 +0200
If impedance and phase are correct there's no problem to parallel two amps like it happens with antennas, put in parallel and then match to the load. This perfect impedance and phase between two PAs
/archives//html/Amps/2002-05/msg00142.html (7,706 bytes)

18. [Amps] Re: [Amps] triband/warc interaction: G3JVC (score: 1)
Author: i4jmy@iol.it (i4jmy@iol.it)
Date: Mon, 13 May 2002 17:31:55 +0200
Sorry guys, but coupling doesn't change if the element is above or in the same plane of the other. It only changes and reduces, the coupling, if the elements are normal to each other or the distance
/archives//html/Amps/2002-05/msg00172.html (8,321 bytes)

19. [Amps] Nonsense (score: 1)
Author: i4jmy@iol.it (i4jmy@iol.it)
Date: Thu, 16 May 2002 13:30:02 +0200
Tecnically, sub-harmonic is a pure nonsense. It shouldn't be a term used to identify a frquency product that's obtained by specific and peculiar situations. It would be bad and didactically misleadin
/archives//html/Amps/2002-05/msg00233.html (6,627 bytes)

20. [Amps] Re: [Amps] Nonsense (score: 1)
Author: i4jmy@iol.it (i4jmy@iol.it)
Date: Thu, 16 May 2002 15:17:48 +0200
Hi leon, sorry, to point it out but your sarcastical reply and the hetherodine example doesn't fit. Take a simple oscillation (any kind) and explain us how a sub harmonic oscillation of can be produc
/archives//html/Amps/2002-05/msg00238.html (8,987 bytes)


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