If you don’t mind an oldie but goody,
I recommend the National NCL2000.
I’ve got two of them and consider them among the best amps ever made.
They easily put out about 1300 watts on a 240v line. The power supply was built
to maintain 1000 watts continuous duty. Tubes are a pair of RCA/Burle 8122
tetrodes still available new (albeit expensive).
However they show up as inexpensive surplus on ebay about once a week. The 8122
was/is used in thousands of broadcast and shipboard transmitters.
One can find good condx NCL2000’s for $600 to $800.
These days with the exorbitant rise of transmitting tube prices, availability
of the tubes is probably the number one consideration.
73,
Doug/WA1TUT
> On Mar 23, 2021, at 10:56 PM, Paul Baldock <paul@paulbaldock.com> wrote:
>
> How about an Alpha 87A $2400
> ________________________________
> From: Amps <amps-bounces@contesting.com> on behalf of Ron Ellis
> <KH6DV@hawaiiantel.net>
> Sent: Tuesday, March 23, 2021 6:21:14 PM
> To: amps@contesting.com <amps@contesting.com>
> Subject: [Amps] Wanted
>
> Does anyone on the list have a good used AL-82, 1200 or 1500 amp they are
> Willing to sell. These things are getting hard to find. Prefer the 82 as I
> love
> The glow of fire bottles but would consider any AL-1200 or 1500 if not too
> Expensive.
>
> Thanks
> Ron KH6DV
>
>
> Sent from Mail for Windows 10
>
> From: amps-request@contesting.com
> Sent: Tuesday, March 23, 2021 6:00 AM
> To: amps@contesting.com
> Subject: Amps Digest, Vol 219, Issue 11
>
> Send Amps mailing list submissions to
> amps@contesting.com
>
> To subscribe or unsubscribe via the World Wide Web, visit
> http://lists.contesting.com/mailman/listinfo/amps
> or, via email, send a message with subject or body 'help' to
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> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Amps digest..."
>
>
> Today's Topics:
>
> 1. Re: QRO HF2000 tank coil Q question (gudguyham)
> 2. Re: QRO HF2000 tank coil Q question (John Keating)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 23 Mar 2021 01:24:38 +0000 (UTC)
> From: gudguyham <gudguyham@aol.com>
> To: John Keating <john.keating@outlook.com>, Peter Voelpel
> <dj7ww@t-online.de>, "Amps@contesting.com" <Amps@contesting.com>
> Subject: Re: [Amps] QRO HF2000 tank coil Q question
> Message-ID: <2105074950.2623203.1616462678906@mail.yahoo.com>
> Content-Type: text/plain; charset=UTF-8
>
> Have you guys taken into consideration that the tank circuit in these amps
> only transform down to 200 ohms, not 50 ohms from the plate impedance? ?After
> the tank circuit it passes through a 4 to 1 balun which brings it down to 50
> ohms.
>
>
> Sent from the all new AOL app for iOS
>
>
> On Monday, March 22, 2021, 2:05 PM, John Keating <john.keating@outlook.com>
> wrote:
>
> Thanks Peter. I calculate a Q of 7 to 8 for the stock design mentioned in the
> previous email.
>
> There are still a fair number of these amps in use, I wondered if others had
> similar experience.
>
> I considered redesigning for higher Q but the modifications to the entire
> tank circuit would be extensive. Again, I wondered if anyone had done such a
> thing.
>
> 73, John
>
> -----Original Message-----
> From: Peter Voelpel [mailto:dj7ww@t-online.de]
> Sent: Monday, March 22, 2021 10:52 AM
> To: 'John Keating'; Amps@contesting.com
> Subject: RE: [Amps] QRO HF2000 tank coil Q question
>
> I used stacks of T225-2 for a mobile antenna loading coil on 40m.
> Measured Q was around 400.
> Toroid coils with taps, which no good idea anyway, will have much lower Q.
> As part of a pi network for 160m in the 2KW out class only T400 was not
> getting too hot, stacks of T300 still overheated in RTTY.
>
> 73
> Peter
>
> -----Original Message-----
> From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of John Keating
> Sent: Montag, 22. M?rz 2021 17:23
> To: Amps@contesting.com
> Subject: [Amps] QRO HF2000 tank coil Q question
>
> Wondering if anyone can provide the specs on the low band tank coil for a
> QRO HF2000.
>
> It appears to be a stack of two red-mix T225A-2 iron powder toroids, with a
> total of 25 turns, and taps for 40M at the 7th turn, and for 80M at the 13th
> turn.
>
> Also wondering if anyone else notices how hot it gets on 160m.
>
> 73, John
> AI6LY
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Tue, 23 Mar 2021 01:28:30 +0000
> From: John Keating <john.keating@outlook.com>
> To: gudguyham <gudguyham@aol.com>, Peter Voelpel <dj7ww@t-online.de>,
> "Amps@contesting.com" <Amps@contesting.com>
> Subject: Re: [Amps] QRO HF2000 tank coil Q question
> Message-ID:
>
> <BYAPR04MB39278776F13EA293352AC6488A649@BYAPR04MB3927.namprd04.prod.outlook.com>
>
> Content-Type: text/plain; charset="utf-8"
>
> yes I took that into consideration for the calculations.
>
> From: gudguyham [mailto:gudguyham@aol.com]
> Sent: Monday, March 22, 2021 18:25 PM
> To: John Keating; Peter Voelpel; Amps@contesting.com
> Subject: Re: [Amps] QRO HF2000 tank coil Q question
>
> Have you guys taken into consideration that the tank circuit in these amps
> only transform down to 200 ohms, not 50 ohms from the plate impedance? After
> the tank circuit it passes through a 4 to 1 balun which brings it down to 50
> ohms.
>
>
> Sent from the all new AOL app for
> iOS<https://apps.apple.com/us/app/aol-news-email-weather-video/id646100661>
>
> On Monday, March 22, 2021, 2:05 PM, John Keating <john.keating@outlook.com>
> wrote:
> Thanks Peter. I calculate a Q of 7 to 8 for the stock design mentioned in the
> previous email.
>
> There are still a fair number of these amps in use, I wondered if others had
> similar experience.
>
> I considered redesigning for higher Q but the modifications to the entire
> tank circuit would be extensive. Again, I wondered if anyone had done such a
> thing.
>
> 73, John
>
> -----Original Message-----
> From: Peter Voelpel [mailto:dj7ww@t-online.de<mailto:dj7ww@t-online.de>]
> Sent: Monday, March 22, 2021 10:52 AM
> To: 'John Keating'; Amps@contesting.com<mailto:Amps@contesting.com>
> Subject: RE: [Amps] QRO HF2000 tank coil Q question
>
> I used stacks of T225-2 for a mobile antenna loading coil on 40m.
> Measured Q was around 400.
> Toroid coils with taps, which no good idea anyway, will have much lower Q.
> As part of a pi network for 160m in the 2KW out class only T400 was not
> getting too hot, stacks of T300 still overheated in RTTY.
>
> 73
> Peter
>
> -----Original Message-----
> From: Amps
> [mailto:amps-bounces@contesting.com<mailto:amps-bounces@contesting.com>] On
> Behalf Of John Keating
> Sent: Montag, 22. M?rz 2021 17:23
> To: Amps@contesting.com<mailto:Amps@contesting.com>
> Subject: [Amps] QRO HF2000 tank coil Q question
>
> Wondering if anyone can provide the specs on the low band tank coil for a
> QRO HF2000.
>
> It appears to be a stack of two red-mix T225A-2 iron powder toroids, with a
> total of 25 turns, and taps for 40M at the 7th turn, and for 80M at the 13th
> turn.
>
> Also wondering if anyone else notices how hot it gets on 160m.
>
> 73, John
> AI6LY
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com<mailto:Amps@contesting.com>
> http://lists.contesting.com/mailman/listinfo/amps
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com<mailto:Amps@contesting.com>
> http://lists.contesting.com/mailman/listinfo/amps
>
> ------------------------------
>
> Subject: Digest Footer
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
> ------------------------------
>
> End of Amps Digest, Vol 219, Issue 11
> *************************************
>
> _______________________________________________
> Amps mailing list
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