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Total 523 documents matching your query.

141. Re: [Amps] exciter overshoot (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Fri, 9 Jun 2006 16:48:07 +0200 (CEST)
Exciter overshoot has been mentioned a lot here in the past. I seem to remember that full power spikes are not uncommon because of the use of ALC loops for power setting, and some rigs are worse than
/archives//html/Amps/2006-06/msg00237.html (7,155 bytes)

142. Re: [Amps] glass tape scotch 27 (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Wed, 14 Jun 2006 16:37:17 +0200 (CEST)
Will asked: If you're building a one off (as so many hams do), you probably don't worry too much about scraping around for a roll of tape if finding something cheaper will take too long and may not d
/archives//html/Amps/2006-06/msg00285.html (7,205 bytes)

143. Re: [Amps] glass tape scotch 27 (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Wed, 14 Jun 2006 17:46:04 +0200 (CEST)
Wouldn't surprise me. For every 1c that a government part increases in first cost, the end cost goes up by 3c. Much of which is down to the procurement policies. The US is probably the worst in this
/archives//html/Amps/2006-06/msg00287.html (6,933 bytes)

144. Re: [Amps] VHF UHF Amp Book (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Mon, 19 Jun 2006 08:45:43 +0200 (CEST)
If you collect old radio books (as I do), it's worth having. A lot depends on which edition, too, but as a source book for up to date projects, I wouldn't touch it. There are one or two useful things
/archives//html/Amps/2006-06/msg00323.html (6,869 bytes)

145. Re: [Amps] SELL: Ameritron AL1200 Contestor's Amplifier (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Sun, 25 Jun 2006 07:19:56 +0200 (CEST)
This all leads me to wonder if someone, somewhere, has got a simulation program into which you can feed the tube characteristics and get out the parameters such as intermod, input impedance, grid dis
/archives//html/Amps/2006-06/msg00361.html (8,849 bytes)

146. Re: [Amps] IM distortion and such (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Mon, 26 Jun 2006 10:56:56 +0200 (CEST)
design outside what is actually published on a spec sheet that only covers a limited number of situations under any condition, even if the component manufacturer, field history, or direct testing sho
/archives//html/Amps/2006-06/msg00420.html (7,899 bytes)

147. Re: [Amps] IM distortion and such (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Mon, 26 Jun 2006 13:56:26 +0200 (CEST)
You have a better opinion of component manufacturers than I have!!!! I think the problem here is this thread, like many on this reflector, has had a major performance change.< You are quite right, of
/archives//html/Amps/2006-06/msg00424.html (7,927 bytes)

148. Re: [Amps] Friedrichshaven - a new toy (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Mon, 26 Jun 2006 16:56:04 +0200 (CEST)
U.S. dollars would be $3012.33.< Is there customs duty, sales taxes, etc., to pay over and above that? One supposes that US Type Approval doesn't come cheap, but I don't understand why, with the FCC
/archives//html/Amps/2006-06/msg00435.html (7,833 bytes)

149. Re: [Amps] AL-80B questions (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Mon, 26 Jun 2006 22:20:28 +0200 (CEST)
of time will often cause an arcing tube, or a "big bang". < Tom, you've been told more than enough times that the bang is caused by VHF parasitics................!!!!!!!!!! :)- 73 Peter G3RZP _______
/archives//html/Amps/2006-06/msg00465.html (7,505 bytes)

150. Re: [Amps] AL-80B questions (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Tue, 27 Jun 2006 02:45:08 +0200 (CEST)
OK, probably a stupid question. Are we sure that the tuning point with minimum input capacitance is actually tuned to 50MHz, and not 100MHz, with the stage acting as a power doubler? 73 Peter G3RZP _
/archives//html/Amps/2006-06/msg00473.html (7,757 bytes)

151. Re: [Amps] IM distortion and such (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Tue, 27 Jun 2006 16:14:28 +0200 (CEST)
never quite being finished with their designs.< So how do you tell the difference between the mahemetician, the physicist, the accountant and the engineer? You ask 'What's 2 plus 2?' The mathematicia
/archives//html/Amps/2006-06/msg00508.html (8,768 bytes)

152. Re: [Amps] IM distortion and such (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Wed, 28 Jun 2006 07:12:52 +0200 (CEST)
IM3 or IM5. (harmful IM3 is 2 * F1 - F2, or 2*F2-F1, IM5 is 3*F1-2*F2, 3*F2-2*F1 and so on through all odd-order products).< If it's a square law curve, for example, there are NO third order products
/archives//html/Amps/2006-06/msg00542.html (9,138 bytes)

153. Re: [Amps] IM distortion and such (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Wed, 28 Jun 2006 14:30:38 +0200 (CEST)
expensive Eimac offerings and the 811A offered by everyone. Also, if I remember correctly, it was specifically created as an amateur service tube as was the 3-1000Z. Interestingly enough, the 572B is
/archives//html/Amps/2006-06/msg00548.html (11,058 bytes)

154. Re: [Amps] Parasitic Resistors (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Wed, 28 Jun 2006 14:58:41 +0200 (CEST)
Doug asked: The answer almost depends on what religion you are................ I like the big Carborundum types, if you can get them. Others like nichrome wire, or metal film or carbon film or.......
/archives//html/Amps/2006-06/msg00550.html (7,250 bytes)

155. [Amps] Really silly question (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Wed, 28 Jun 2006 15:16:50 +0200 (CEST)
So I've had this problem appear on the amplifier...... Bear in mind I've had chance to see it, but not chance to dig in to find out what's happening, and it's a fault that has appeared after some 19
/archives//html/Amps/2006-06/msg00553.html (8,568 bytes)

156. Re: [Amps] *** SPAM *** RE: Parasitic Resistors (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Wed, 28 Jun 2006 15:19:32 +0200 (CEST)
this application.< It depends. Parasitic suppression is very dependent on a number of things, especially layout and lead lengths and tubes and components... I like a process of empiric eclecticism.
/archives//html/Amps/2006-06/msg00554.html (7,227 bytes)

157. Re: [Amps] IM distortion and such (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Thu, 29 Jun 2006 09:11:26 +0200 (CEST)
had high level "sweet spots" where the positive slope of IMD level as a function of input power actually reversed and formed a local minimum at a fairly high input power level.< Yes, Mike, it's a wel
/archives//html/Amps/2006-06/msg00617.html (8,622 bytes)

158. [Amps] (no subject) (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Thu, 29 Jun 2006 09:35:32 +0200 (CEST)
That's very true. I was told that the earliest RAF WW2 airborne VHF transceivers used a Class C grid leak biased PA with modulation on the driver stage. The distortion was considered 'acceptable'. No
/archives//html/Amps/2006-06/msg00618.html (6,993 bytes)

159. Re: [Amps] Ideal bandswitch brand for 3 kW out am? (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Fri, 30 Jun 2006 00:25:21 +0200 (CEST)
Frank asked: The 1p 6 way switch from a WW2 tuning unit (TU5B, TU6, TU7 etc) for the BC191/375 transmitter. Last time I looked, $3 or so from Fair Radio Sales. 6 ways - 160, 80, 40, 30 and 20, 17 and
/archives//html/Amps/2006-06/msg00642.html (7,525 bytes)

160. Re: [Amps] Ideal bandswitch brand for 3 kW out am? (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Fri, 30 Jun 2006 09:40:02 +0200 (CEST)
200 W.<< Limits are different elsewhere, so a full power amplifier is allowed. In any case, the original question came from Germany - if I remember correctly, they can have 700 watts or so.. 73 Pete
/archives//html/Amps/2006-06/msg00653.html (7,694 bytes)

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