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References: [ +from:dj7ww@t-online.de: 172 ]

Total 172 documents matching your query.

141. Re: [Amps] Swan Mark 1 on 160 meters (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Thu, 1 Jul 2021 12:06:07 +0200
Hi Jim, I guess the shorted 160m coil might have been resonant on 10m and the circulated current caused the heating of the toroid, not the coupling. 73 Peter If I knew, I would have stated that fack
/archives//html/Amps/2021-07/msg00002.html (12,261 bytes)

142. Re: [Amps] Swan Mark 1 on 160 meters (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Thu, 1 Jul 2021 18:50:09 +0200
Fair-Rite does not produce powdered iron cores. 73 Peter I clearly understand that, and I'm pointing out how you and other designers can figure out which materials are suitable for THOSE uses, which
/archives//html/Amps/2021-07/msg00011.html (8,517 bytes)

143. Re: [Amps] Vacuum Relay Question (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Tue, 27 Jul 2021 09:44:44 +0200
I prefer vacuum relays outside, they are immune to corrosion and not that expensive when ex military stock from Russia like B1B or B2B SPST types. 73 Peter I think that the point was that the expensi
/archives//html/Amps/2021-07/msg00079.html (9,680 bytes)

144. Re: [Amps] TL-922A on 17 & 12 (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Tue, 12 Oct 2021 19:07:33 +0200
It tells me that the pi net is not optimized for those bands and efficiency dropped for that reason and the input filters are not wide enough for those bands as well and drive power is less. There is
/archives//html/Amps/2021-10/msg00058.html (9,985 bytes)

145. Re: [Amps] 1:9 un-un for grid driven tetrode (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Sun, 24 Oct 2021 16:47:57 +0200
That 1:9 unun and 450 ohm resistor is obviously for use with a high power linear tetrode amplifier. Passive grid would not work with grid current. Tetrodes requiring a few hundred volts of drive are
/archives//html/Amps/2021-10/msg00084.html (8,653 bytes)

146. Re: [Amps] 1:9 un-un for grid driven tetrode (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Sun, 24 Oct 2021 18:53:04 +0200
The ham might have been asked by a broadcaster to build such amp. I was asked as well about a 30-50KW amp. Helped already in the past with the construction of the 10KW version (2x 3CX3000A7). https:/
/archives//html/Amps/2021-10/msg00088.html (8,130 bytes)

147. Re: [Amps] 1:9 un-un for grid driven tetrode (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Mon, 25 Oct 2021 19:35:15 +0200
Yes, a small grid current through a 50 ohm load will not do much bias shifting and impedance change. 73 Peter, DJ7WW The National NCL-2000, ca 1964-70 used a pair of 8122 tetrodes with an untuned res
/archives//html/Amps/2021-10/msg00095.html (11,889 bytes)

148. Re: [Amps] QRO Technologies HF2000 plate choke, cont. (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Sat, 13 Nov 2021 01:50:03 +0100
It went up into flames and smoke when I tried it on 18.15MHz in my L4B. 73 Peter, DJ7WW I'm sold on the RF choke from RF Parts https://www.rfparts.com/rfc3.html Replaced RF choke (Mess) of Alpha 89 w
/archives//html/Amps/2021-11/msg00017.html (9,466 bytes)

149. Re: [Amps] Alpha 76PA Conversion - Drive Issue (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Thu, 2 Dec 2021 19:45:59 +0100
Eimac specified a maximum of 2250V. 73 Peter 3cx800 tubes like 2600-2700 on the plates for maximum gain.   2000 volts is a bit anemic for 3cx800 tubes.   _____________________________________________
/archives//html/Amps/2021-12/msg00010.html (7,473 bytes)

150. Re: [Amps] Triode Amps (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Thu, 2 Dec 2021 22:15:59 +0100
Eimac specifies 890W for a single tube at 3.5KV plate voltage and 740W at 3kV. 73 Peter, DJ7WW The 3-500Z is an excellent tube, but 1500 W isn't reasonably available out of a pair, even at increased
/archives//html/Amps/2021-12/msg00015.html (8,599 bytes)

151. Re: [Amps] Alpha 76PA Conversion - Drive Issue (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Thu, 2 Dec 2021 22:19:23 +0100
Indeed, 2.5KV were specified in the preliminary data sheet from 1983. 73 Peter, DJ7WW Yes, and it seems that limit was adhered to by amateur amplifier manufacturers about as well as speed limits are
/archives//html/Amps/2021-12/msg00017.html (8,898 bytes)

152. Re: [Amps] FW: FW: Triode Amps / options / tetrodes (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Sat, 4 Dec 2021 09:10:24 +0100
I donīt think that the 7F171RA is much cleaner then the 4CX3000A which is a very similar tube also developed for low intermodulation. What I see on the qrz page is the IMD at 1KW output and driven wi
/archives//html/Amps/2021-12/msg00042.html (8,131 bytes)

153. Re: [Amps] FW: FW: Triode Amps / options / tetrodes (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Sat, 4 Dec 2021 14:17:34 +0100
You are probably mixing it up with the 3CPX5000A7 (YC156/179). The 3CX5000A7 requires 10V heater voltage at 17.5A. Blower requirement at 2KW anode dissipation is 29cfm with 0.1" pressure drop. 73 Pet
/archives//html/Amps/2021-12/msg00045.html (11,282 bytes)

154. Re: [Amps] Centrifugal Blowers (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Thu, 27 Jan 2022 23:32:32 +0100
For my as well. G2E085 is the EBM blower model for the 3CX1500A7. G2E120 for 3CX3000A7. Bought my first G2E085 in 1976 for a 4CX1000 amp, price went up by factor 10 since then. I think W8JI sells the
/archives//html/Amps/2022-01/msg00113.html (13,501 bytes)

155. Re: [Amps] Western Electric (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Wed, 23 Mar 2022 17:01:09 +0100
Single tube USD 699 at WE in Georgia, 879 Euro over here 73 Peter, DJ7WW Where do they sell these tubes? eBay? Retail? How much for a 300B? Thanks, 73, Jim W7RY ______________________________________
/archives//html/Amps/2022-03/msg00057.html (15,029 bytes)

156. Re: [Amps] Fw: Western Electric (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Wed, 23 Mar 2022 23:04:49 +0100
I would be sceptical about their knowledge as it took them 5 years to develop it. 73 Peter, DJ7WW Be sure to order early to get the 10% discount!    73s Bob W5RG gear and one's technical knowledge co
/archives//html/Amps/2022-03/msg00065.html (13,311 bytes)

157. Re: [Amps] Measuring filament voltage (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Wed, 22 Jun 2022 16:49:49 +0200
I just convert the AC voltage at the socket to DC with a bridge rectifier and calibrate the panelmeter for the specified voltage. 73 Peter, DJ7WW Well, that keeps things wonderfully simple.?????? 73,
/archives//html/Amps/2022-06/msg00097.html (13,426 bytes)

158. Re: [Amps] 10 kw CCS on 6M (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Mon, 12 Sep 2022 21:19:13 +0200
Yes, no difference, just bigger and more powerful. 73 Peter, DJ7WW Don Fox raises a question I've wondered about for years: how are these very high power amplifiers initially placed in service? Today
/archives//html/Amps/2022-09/msg00016.html (7,922 bytes)

159. Re: [Amps] Harris RF-110A AM-3924 (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Tue, 20 Sep 2022 17:26:00 +0200
The 500V are not the 1500B screen voltage, they are the plate voltage for the 8122 and feed the screen regulator which supplies about 300V for the 1500B screens and 225V for the 8122 screens. But nev
/archives//html/Amps/2022-09/msg00036.html (8,807 bytes)

160. Re: [Amps] 3cx800 filament transformer (score: 1)
Author: "Peter Voelpel" <dj7ww@t-online.de>
Date: Fri, 30 Sep 2022 22:25:48 +0200
Far too large, a 50VA transformer is sufficient 73 Peter, DJ7WW Hello George, I would think that a transformer core from a microwave oven rewound for the required voltage and current would be plausib
/archives//html/Amps/2022-09/msg00055.html (8,257 bytes)

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