- 1. Re: [Amps] Adhesive forTeflon sheet (score: 1)
- Author: Steve Thompson <g8gsq72@gmail.com>
- Date: Mon, 21 Mar 2011 21:15:26 +0000
- Sodium based etchants such as Tetra Etch are widely used with PTFE based pcb laminates. Nasty stuff, potentially explosive. I've seen suggestions of polyolefin primer such as http://www.permabondllc
- /archives//html/Amps/2011-03/msg00159.html (7,287 bytes)
- 2. Re: [Amps] SB-200 power supply diodes (score: 1)
- Author: Steve Thompson <g8gsq72@gmail.com>
- Date: Sun, 27 Mar 2011 22:54:20 +0100
- http://www.duncanamps.com/psud2/index.html for a dedicated pspice programme which will give you a very good idea of what's what in a PSU - including allowing for transformer resistance which isn't so
- /archives//html/Amps/2011-03/msg00219.html (9,063 bytes)
- 3. Re: [Amps] what is a 4 wire 240VAC service? (score: 1)
- Author: Steve <g8gsq72@gmail.com>
- Date: Mon, 04 Apr 2011 10:50:36 +0100
- In the UK, between 2001 and 2006 a TOTAL of 35 people died as a result of using/misusing domestic electrical appliances and installations. Decreasing that rate was the reason given for introducing he
- /archives//html/Amps/2011-04/msg00075.html (8,708 bytes)
- 4. Re: [Amps] Alpha vs Henry (score: 1)
- Author: Steve Thompson <g8gsq72@gmail.com>
- Date: Sat, 09 Apr 2011 07:51:38 +0100
- Not necessarily the warmest - you have to allow for the emissivity of objects. I don't know a figure for air, but polished metal and glass can vary a lot - a dab of paint of white correction fluid pr
- /archives//html/Amps/2011-04/msg00309.html (8,222 bytes)
- 5. Re: [Amps] Airflow meter (score: 1)
- Author: Steve Thompson <g8gsq72@gmail.com>
- Date: Fri, 15 Apr 2011 22:00:50 +0100
- The last few cars I've had have switched from airflow measurement to Manifold Absolute Pressure (MAP) sensors. I guess that's an alternative to the U tube manometer. Steve ___________________________
- /archives//html/Amps/2011-04/msg00452.html (6,823 bytes)
- 6. Re: [Amps] Power handling of an SMA (score: 1)
- Author: Steve <g8gsq72@gmail.com>
- Date: Tue, 26 Apr 2011 17:03:32 +0100
- Suhner data shows approx. 500W based on dielectric strength, but there's a second 'low SWR' curve on the chart which extrapolates to around 1500W at 1.3GHz. The spec. also gives 10kW for 1us. The con
- /archives//html/Amps/2011-04/msg00544.html (7,282 bytes)
- 7. Re: [Amps] Power handling of an SMA (score: 1)
- Author: Steve Thompson <g8gsq72@gmail.com>
- Date: Tue, 26 Apr 2011 22:48:01 +0100
- I suspect a lot of issues with 259s arise from the variation in materials. I see lots with nylon and brown 'plastic' (bakelite or SRBP?) insulation which I wouldn't trust under stress or with age. Th
- /archives//html/Amps/2011-04/msg00552.html (8,188 bytes)
- 8. Re: [Amps] Power handling of an SMA (score: 1)
- Author: Steve Thompson <g8gsq72@gmail.com>
- Date: Wed, 27 Apr 2011 08:20:06 +0100
- I found big differences in N type socket construction where the centre contact is captive (mostly 4 hole or bulkhead sockets). With Amphenol, for example, the pin has a bit of knurling to lock it int
- /archives//html/Amps/2011-04/msg00554.html (9,186 bytes)
- 9. Re: [Amps] AN762 Bias Question (score: 1)
- Author: Steve Thompson <g8gsq72@gmail.com>
- Date: Mon, 02 May 2011 17:20:35 +0100
- I suspect the use of 'bias' in two different contexts might be muddying the waters. The 100mA per device is the standing or quiescent current the transistors should draw from the 12V supply in order
- /archives//html/Amps/2011-05/msg00001.html (7,515 bytes)
- 10. [Amps] Generator (score: 1)
- Author: Steve <g8gsq72@gmail.com>
- Date: Tue, 17 May 2011 16:39:25 +0100
- Any UK amp enthusiasts interested in a 15kVA trailer genny? Wired for 3 x 240V but can deliver 415V 3 phase if wanted. Please contact me directly for details. Thanks, Steve __________________________
- /archives//html/Amps/2011-05/msg00140.html (6,143 bytes)
- 11. Re: [Amps] srft3034 data sheet (score: 1)
- Author: Steve <g8gsq72@gmail.com>
- Date: Sun, 22 May 2011 18:23:22 +0100
- Looking in 1990 Motorola data, there's a JO3037 rated for 37W (400-512MHz, 12.5V). That's a TRW part number and J03037 (TRW used zero no O) is in a 1986 TRW book prior to the takeover. Given some sim
- /archives//html/Amps/2011-05/msg00195.html (7,054 bytes)
- 12. Re: [Amps] arrrrgggg!! (score: 1)
- Author: Steve Thompson <g8gsq72@gmail.com>
- Date: Mon, 23 May 2011 17:22:36 +0100
- I think Carey said he was using the YU1AW 'lazy builder' circuit. That's not the usual resonant stripline with capacitive coupling design. Visualising it on Smith chart is the easiest way for me to
- /archives//html/Amps/2011-05/msg00201.html (7,572 bytes)
- 13. Re: [Amps] T/R relay (score: 1)
- Author: Steve Thompson <g8gsq72@gmail.com>
- Date: Thu, 26 May 2011 22:45:24 +0100
- I've used similar types at VHF with bits of capacitance to tune out the inductance of the internals but found them too touchy at UHF. There's also the issue of skin effect and how plating behaves at
- /archives//html/Amps/2011-05/msg00236.html (7,420 bytes)
- 14. Re: [Amps] Memorial Day weekend amplifier fun/work (score: 1)
- Author: Steve Thompson <g8gsq72@gmail.com>
- Date: Tue, 31 May 2011 08:13:03 +0100
- It was a public holiday here too. At the other end of the technology spectrum, I did a bit of fiddling with coax transformers and got a BLF578 transistor running cw (continuous wave, not Morse code)
- /archives//html/Amps/2011-05/msg00279.html (7,816 bytes)
- 15. Re: [Amps] Should a blower run after amp shutdown? (score: 1)
- Author: Steve Thompson <g8gsq72@gmail.com>
- Date: Fri, 03 Jun 2011 07:53:14 +0100
- The anode might not get hotter when the blower is turned off, but the other parts of the tube will, as heat from the anode is conducted into them and they no longer have the cooling effect of the air
- /archives//html/Amps/2011-06/msg00012.html (7,922 bytes)
- 16. Re: [Amps] Using an oil capacitor (score: 1)
- Author: Steve Thompson <g8gsq72@gmail.com>
- Date: Mon, 20 Jun 2011 07:51:03 +0100
- It can be very hard to tell - if it was designed for low duty pulse discharge the designer could concentrate on size, weight and price without worrying much about getting heat out from the inside. I
- /archives//html/Amps/2011-06/msg00260.html (8,195 bytes)
- 17. Re: [Amps] Using switch mode power supply for heater power (score: 1)
- Author: Steve Thompson <g8gsq72@gmail.com>
- Date: Tue, 28 Jun 2011 21:58:35 +0100
- Hunt around for a PSU that does current limit rather than shut down. Some have the option to switch between the two. Alternatively, add an external current limit circuit that's switched out once the
- /archives//html/Amps/2011-06/msg00309.html (7,924 bytes)
- 18. [Amps] Resonance (score: 1)
- Author: Steve Thompson <g8gsq72@gmail.com>
- Date: Tue, 05 Jul 2011 19:04:03 +0100
- Before everyone goes throwing their best handbags at each other, don't forget that any definition of resonance has to work for weights on springs, pendulums, columns of air etc. etc. What that transl
- /archives//html/Amps/2011-07/msg00054.html (6,306 bytes)
- 19. Re: [Amps] GG tuned input with autotuner (score: 1)
- Author: Steve <g8gsq72@gmail.com>
- Date: Thu, 07 Jul 2011 16:46:44 +0100
- At high power, the current flowing through the tube is not a nice neat sinewave, it's spiky with lots of harmonic content. If the cathode circuit doesn't give the harmonics a path to go through, the
- /archives//html/Amps/2011-07/msg00063.html (7,774 bytes)
- 20. Re: [Amps] GS35b FWB issue] (score: 1)
- Author: Steve Thompson <g8gsq72@gmail.com>
- Date: Mon, 11 Jul 2011 18:44:21 +0100
- Fuses between the transformer secondary and the bridge :-) To kill diodes in that way, you've got to be looking at something approaching a short - it's hard to see how loose screws would cause that.
- /archives//html/Amps/2011-07/msg00110.html (6,823 bytes)
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