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1. [Amps] RF Power transistors (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Sun, 5 Jan 2003 20:50:28 -0000
as second is For hf, the bipolars are usually better value - SD1407s come in cheap, for example, as do THA15s (sold with their SD... number these days but I forget it). There's a guy in Holland who a
/archives//html/Amps/2003-01/msg00044.html (8,074 bytes)

2. [Amps] RF Power transistors (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Mon, 6 Jan 2003 07:57:19 -0000
As far as I know, M/A Com have the 150s in production. I haven't yet tried their version myself, but I have used several of the 28V fets in production runs without any problems. There's certainly ple
/archives//html/Amps/2003-01/msg00050.html (7,870 bytes)

3. [Amps] Re: Chassis cleaning (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Tue, 14 Jan 2003 21:53:17 -0000
recoat - or of Isn't anodising non-conductive? That might not be optimum on an amplifier chassis. Steve
/archives//html/Amps/2003-01/msg00116.html (6,921 bytes)

4. [Amps] A bit OT - Inverter transformers (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Tue, 21 Jan 2003 10:27:09 +0000
A friend has asked if I can make a 12V to 1300V 300W inverter to replace the dynamotor powering one of his old army sets. I hate winding transformers, so can anyone point me towards a ready made tran
/archives//html/Amps/2003-01/msg00172.html (6,469 bytes)

5. [Amps] Thompson cap RF current ratings? (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Sun, 8 Dec 2002 11:38:55 -0000
true wheel..... How about putting it in series with a dummy load and run, say 100W rf - that's 1.4A rms. See how hot it gets. General question - does this work? Steve
/archives//html/Amps/2002-12/msg00138.html (7,827 bytes)

6. [Amps] RF103 info received! MOSFET Question (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Tue, 10 Dec 2002 07:56:30 -0000
You might find Semelab D1029 worth looking at. It's up over 300W cw at 225MHz, it was developed for the 220MHz Digital Audio transmitters in Europe. Depending on your pulse length, you might be able
/archives//html/Amps/2002-12/msg00159.html (8,287 bytes)

7. [Amps] NCL2000s (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Mon, 16 Dec 2002 11:22:45 +0000
Spotted on ebay uk - pair of NCL2000s with 4 x 8122 spare tubes. www.ebay.co.uk item 1945522506 Steve
/archives//html/Amps/2002-12/msg00206.html (6,145 bytes)

8. [Amps] Switch Help Needed (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Tue, 31 Dec 2002 22:50:39 -0000
Pardon the off-topic bandwidth, guys, but there are so many resident parts-savvy folks here that might have a source for me. I am in need of some switches that actuate when immersed in water. I am bu
/archives//html/Amps/2002-12/msg00319.html (6,719 bytes)

9. [Amps] Re: Amps digest, Vol 1 #357 - 15 msgs/INRUSH CURRENT PROTECTION (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Fri, 1 Nov 2002 07:55:07 -0000
It's also interesting to leave the resistor in there and look at the current when you load up the PSU output. Steve
/archives//html/Amps/2002-11/msg00001.html (6,810 bytes)

10. [Amps] pandoras parasites (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Thu, 7 Nov 2002 07:47:12 -0000
Does anyone have experience with stability of GS35b on hf? It's got useful gain to around 1GHz but being a planar triode, it should be better still on grid inductance. Steve
/archives//html/Amps/2002-11/msg00084.html (7,192 bytes)

11. [Amps] RMS-PEP & 2x8877 (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Thu, 7 Nov 2002 16:12:38 -0000
Yes - you do the calculation with the *rf* rms voltage and current at the peak of the modulation envelope. Steve
/archives//html/Amps/2002-11/msg00102.html (8,579 bytes)

12. [Amps] RMS-PEP & 2x8877 (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Thu, 7 Nov 2002 22:42:38 -0000
the cause Please don't take offence if I rewrite: If an rf voltage (or current) were to dissipate in a resistive load, then the RMS value of that voltage (or current) would be the same as the amount
/archives//html/Amps/2002-11/msg00111.html (8,843 bytes)

13. [Amps] Power ratings N/BNC/SO239? (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Sun, 10 Nov 2002 16:01:01 +0000
N - 4kW BNC - should be similar to N type as contacts are the same. No specific data for BNC but for TNC the 1:1 SWR is about the same as N type. There's an extra curve labelled 'limitation by electr
/archives//html/Amps/2002-11/msg00157.html (7,497 bytes)

14. [Amps] RMS Power (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Sun, 10 Nov 2002 23:17:33 -0000
go Isn't that just the mean, or average power. I can see why you take the mean, or average of the voltage or current squared to get the average power but I can't get my head round how the average of
/archives//html/Amps/2002-11/msg00162.html (7,571 bytes)

15. [Amps] EIMAC Confusion (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Wed, 13 Nov 2002 13:41:03 -0000
OUTPUT OP In this situation, isn't efficiency rf output divided by dc input? Max. device dissipation is just that, a maximum limit of (dc input minus rf output). Where tube specs. refer to anode diss
/archives//html/Amps/2002-11/msg00200.html (7,541 bytes)

16. [Amps] EIMAC Confusion (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Wed, 13 Nov 2002 14:33:58 +0000
Indeed - it might vary between manufacturers and tubes. The first data sheet that came to hand was Eimac 4CX1500A. This presents the info in two forms. In the 'typical operating' bits it gives specif
/archives//html/Amps/2002-11/msg00203.html (7,672 bytes)

17. [Amps] LP filter effects (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Sat, 16 Nov 2002 08:14:30 -0000
Assuming the power meter is between the LPF and antenna, it's difficult to see how the LPF could be increasing the harmonic level. Another possible cause is that your meter has poor directivity and h
/archives//html/Amps/2002-11/msg00268.html (8,093 bytes)

18. [Amps] LP filter effects (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Sun, 17 Nov 2002 07:40:43 -0000
to to since I think they don't - I failed to find measurable harmonics when I tried looking, and Peter Chadwick found the same. I think he tested at higher power than the 800W I had. Steve
/archives//html/Amps/2002-11/msg00281.html (8,672 bytes)

19. Fw: [Amps] LP filter effects (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Sun, 17 Nov 2002 08:38:06 -0000
87A of to filter have more. If we are looking at 100W of harmonic energy in 1500W output power, that's only 12dB down. I'd expect the amp to be a lot cleaner than that. Steve
/archives//html/Amps/2002-11/msg00282.html (8,630 bytes)

20. [Amps] 4cx350f/j's (score: 1)
Author: g8gsq@qsl.net (Steve Thompson)
Date: Sun, 17 Nov 2002 14:48:57 -0000
Is heat I think the 26.5V suited the military's 24V nominal preferred supplies. As best I recall, the heater power is the same as in the 6V version, so the warm up time is the same. They go very nice
/archives//html/Amps/2002-11/msg00286.html (7,861 bytes)


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