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21. Re: [Amps] LK500 various (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Tue, 30 May 2006 15:33:02 +0100 (BST)
Not sure how typical this is, but many of the outlets in my house have a 3 wire feed from ganged breakers with one socket on each of the 120V wires and a common neutral. The house is about 25 years o
/archives//html/Amps/2006-05/msg00507.html (7,849 bytes)

22. Re: [Amps] Safety grounding - was Mains Isolation Transformer (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Wed, 5 Jul 2006 05:30:52 +0100 (BST)
This is probably a silly question, but it intrigues me: I can understand why ranges, heaters, AMPLIFIERS and other high power devices need a 240V supply, and I can understand why in North America tha
/archives//html/Amps/2006-07/msg00199.html (9,051 bytes)

23. Re: [Amps] 3CX800A7 Orientation (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Fri, 18 Aug 2006 03:05:03 +0100 (BST)
"At 25C air temperature, a Papst 4600 family axial 120mm fan meets the flow rate for about 700W diss. provided you take care with the airflow design...." Funny you should mention that Steve - that is
/archives//html/Amps/2006-08/msg00535.html (8,239 bytes)

24. Re: [Amps] cooling tubes (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Wed, 7 Feb 2007 03:11:47 +0000 (GMT)
I cool a single 3CX800A7 in my modified MLA2500 with a Papst fan which has the same dimensions as the original, but considerably higher output and can work against a higher back pressure. Works quite
/archives//html/Amps/2007-02/msg00108.html (7,429 bytes)

25. Re: [Amps] Switching PS for filaments? (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Fri, 16 Feb 2007 20:22:03 +0000 (GMT)
I have used a switching DC power supply on my linear for many years. The original one I had was pretty old and used discrete components throughout (yes, that old!) - it was completely rf quiet. Last
/archives//html/Amps/2007-02/msg00262.html (7,439 bytes)

26. Re: [Amps]8877 blower requirement...TXN ! &Acirc;Now..Airflow sensing ? (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Tue, 10 Apr 2007 15:56:10 +0100 (BST)
I think the fan is a rather good idea, particularly as it is then easy to also sense (indirectly) the blower speed. I shall use it forthwith! 73 Roger VE3ZI __________________________________________
/archives//html/Amps/2007-04/msg00053.html (7,114 bytes)

27. [Amps] Cinch-Jones Type 303 Connector (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Sat, 9 Jun 2007 01:18:50 +0100 (BST)
I know this is not the proper forum, but those that know seem to lurk here.. I am intending to use a Cinch-Jones type 303 connector for a low current 120V AC circuit within my amplifier. The specs sa
/archives//html/Amps/2007-06/msg00040.html (7,207 bytes)

28. Re: [Amps] 8877 Filament choke (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Fri, 16 Nov 2007 00:55:26 +0000 (GMT)
For what it's worth, my remote station amplifier is based on an old (~1970) CSI 1kW FM (100MHz) broadcast transmitter that used an 8877 in the final. It did not originally have a filament choke - and
/archives//html/Amps/2007-11/msg00217.html (7,148 bytes)

29. Re: [Amps] Relays (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Mon, 31 Mar 2008 16:27:21 +0100 (BST)
Add the IC765 to your list of Icom radios with a negative holdover on the relay release in the full QSK mode. This is when using the 'accessory' ptt output (transistor keying) - it is just about zero
/archives//html/Amps/2008-03/msg00387.html (8,026 bytes)

30. Re: [Amps] Fabrication & part placement (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Fri, 18 Apr 2008 12:57:00 +0100 (BST)
Just a thought. Some years ago I modified an MLA2500 to use a single 3CX800A7, and decided there was not enough space to mount the tube vertically as well as allowing an air supply below. (Re-phrase
/archives//html/Amps/2008-04/msg00237.html (8,071 bytes)

31. [Amps] Subject: Re: Chimney for GS-31B (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Fri, 2 May 2008 13:55:51 +0100 (BST)
For what it's worth, I have used some "High-Temp Silicone" manufactured by "By The Fire Hearth Products". It is intended for "sealing gas appliance venting, heating ducts, and general high temp seali
/archives//html/Amps/2008-05/msg00008.html (6,992 bytes)

32. [Amps] Old tubes and other components (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Mon, 9 Feb 2009 06:50:55 -0800 (PST)
A local amateur has a quantity of tubes and other components mostly dating back to the 50s and 60s. These include: 2 x NIB 833A tubes 2 x NIB 304-TL tubes 2 x 811 tubes 'part used' National Velvet Ve
/archives//html/Amps/2009-02/msg00233.html (6,973 bytes)

33. [Amps] Kilovac HC-4 Relays (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Tue, 17 Feb 2009 16:37:21 -0800 (PST)
I have a number of Kilovac HC-4 vacuum relays which have very nice specs, but are not rated for RF use. I understand that they use a different contact material from, for example the HC-1, and can be
/archives//html/Amps/2009-02/msg00539.html (6,840 bytes)

34. [Amps] Digital read out (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Thu, 26 Feb 2009 18:57:38 -0800 (PST)
"Some time ago I came across a operator that was using Potentiometers with roller inductors and variable caps to indicate their position via a meter or digital read out. Have looked the web over and
/archives//html/Amps/2009-02/msg00691.html (6,806 bytes)

35. [Amps] KiloVac HC4 Relays (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Sat, 7 Mar 2009 11:45:42 -0800 (PST)
Last month I posed a question about using these relays for RF switching even though they are not specifically rated for that purpose. The general consensus of the replies was that they would be OK al
/archives//html/Amps/2009-03/msg00234.html (7,759 bytes)

36. Re: [Amps] KiloVac HC4 Relays (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Sat, 7 Mar 2009 17:48:32 -0800 (PST)
I have received a private email strongly disagreeing with my conclusions on these relays :-) I still believe I am correct about the use of tungsten contacts in rf vacuum relays and that, based on man
/archives//html/Amps/2009-03/msg00236.html (6,982 bytes)

37. [Amps] Clips for oil-filled capacitors (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Thu, 19 Mar 2009 16:50:55 -0700 (PDT)
After looking at the nice pictures of YC156 amplifiers, my mind wandered to the large oil-filled capacitors. The capacitors themselves are easy enough to get, but does anyone know of a source for the
/archives//html/Amps/2009-03/msg00492.html (6,713 bytes)

38. Re: [Amps] Clips for oil-filled capacitors (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Sat, 21 Mar 2009 08:24:21 -0700 (PDT)
Many thanks for all the suggestions about these clips, and especially for the exceptionally generous offer to send me some from a junk box. The general concensus seems to be to make my own and that i
/archives//html/Amps/2009-03/msg00502.html (7,817 bytes)

39. Re: [Amps] High SWR, (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Wed, 22 Apr 2009 17:13:39 -0700 (PDT)
I know this has been said before, but just because your SWR meter says there is x Watts of power coming back down the line, it doesn't mean that it is being dissipated in your transmitter. All it mea
/archives//html/Amps/2009-04/msg00223.html (7,478 bytes)

40. Re: [Amps] filament choke questions (score: 1)
Author: Roger Parsons <ve3zi@yahoo.com>
Date: Thu, 8 Oct 2009 04:43:29 -0700 (PDT)
Whilst the explanation below makes perfect sense, I have 1kW and 500W ex commercial FM (100 MHz) broadcast transmitters made by CCI - the former uses an 8877 and the latter a 3CX800A7. Neither of the
/archives//html/Amps/2009-10/msg00135.html (9,440 bytes)

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