Is there a Amsat BB favorite between switching and linear [power

supplies]?

I won't speak to noise, which is the only potential issue with switching power supplies, but other than that, I am writing an article for QST that points out how the world of power and emergency power has changed drastically over the last decades. Entirely due to switching power supplies and regulators:

PROS: 1) A 90% reduction in size and weight 2) Laptop supplies that can supply 12v at 5 to 10 amps 3) Universal inputs 115V to 240V AC 4) * also run on 150 to 330 VDC 5) Hybrids and Electric Vehicles have Kilowatts of 150 to 330 VDC available 6) Home grid-tie solar has Kilowatts of high voltage DC available 7) 12VDC to 120VAC inverters are now sine and modified sine at 90%+ efficiency 8) * These internally run on 200 VDC or so. Easy to run great distances on small wire if you run them directly on HV DC derived from your Hybrid or Solar.

CONS: with today's litigious society and general ignorance (compared to the vacuum tube days when even cub-scouts built 2 tube radios with High Voltage), it is doubtful that QST will publish the article. They have rejected it before, but I keep whittling away at the details.

Bottom line, is that high efficiency high voltage DC is everywhere and because everything runs on switching power supplies that run internally on HV DC and regulators that accept a wide range of input, then HV DC could be the new universal power source.

Problem is, Hybrid and EV MFR's are not going to provide access to HV DC willingly due to safety an liability issues. Same for Solar installers.... Same for QST.

But you can get some of what I am writing about on this page: http://aprs.org/FD-Prius-Power.html http://aprs.org/alternative-energy.html

For example, buried in a Camry Hybrid is a nice compact stand-alone 14 volt 100 AMP DC/DC supply. Input can be 200 to 350 volts DC (which you can get from 120V or 240VAC with just some diodes).. Problem is, it is bolted to the $1000 salvage battery and the salvage guys won't sell it separately.

The Prius 100amp 14v supply is integrated into the huge drivetrain inverter and inseparable from that $3000 unit (salvage cost).

As we electrify transportation and anyone with good sun goes solar, HV DC will be something Hams will be getting used to again.

Bob, Wb4APR

At 10:54 AM 2/18/2011, Bob Bruninga wrote:

...

Is there a Amsat BB favorite between switching and linear [power

supplies]?

I won't speak to noise, which is the only potential issue with switching power supplies, but other than that, I am writing an article for QST that points out how the world of power and emergency power has changed drastically over the last decades. Entirely due to switching power supplies and regulators:

PROS:

1. A 90% reduction in size and weight
2. Laptop supplies that can supply 12v at 5 to 10 amps
3. Universal inputs 115V to 240V AC
4. • also run on 150 to 330 VDC
5. Hybrids and Electric Vehicles have Kilowatts of 150 to 330 VDC available
6. Home grid-tie solar has Kilowatts of high voltage DC available
7. 12VDC to 120VAC inverters are now sine and modified sine at 90%+

efficiency 8) * These internally run on 200 VDC or so. Easy to run great distances on small wire if you run them directly on HV DC derived from your Hybrid or Solar.

CONS: with today's litigious society and general ignorance (compared to the vacuum tube days when even cub-scouts built 2 tube radios with High Voltage), it is doubtful that QST will publish the article. They have rejected it before, but I keep whittling away at the details.

Bottom line, is that high efficiency high voltage DC is everywhere and because everything runs on switching power supplies that run internally on HV DC and regulators that accept a wide range of input, then HV DC could be the new universal power source.

Problem is, Hybrid and EV MFR's are not going to provide access to HV DC willingly due to safety an liability issues. Same for Solar installers.... Same for QST.

But you can get some of what I am writing about on this page: http://aprs.org/FD-Prius-Power.html http://aprs.org/alternative-energy.html

For example, buried in a Camry Hybrid is a nice compact stand-alone 14 volt 100 AMP DC/DC supply. Input can be 200 to 350 volts DC (which you can get from 120V or 240VAC with just some diodes).. Problem is, it is bolted to the $1000 salvage battery and the salvage guys won't sell it separately.

The Prius 100amp 14v supply is integrated into the huge drivetrain inverter and inseparable from that $3000 unit (salvage cost).

As we electrify transportation and anyone with good sun goes solar, HV DC will be something Hams will be getting used to again.

Bob, Wb4APR

---

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I am rebuilding my 4.2kV PS for the 2m-8877. Does that qualify? QST still publishes high-power tube amplifier designs in their handbook. What's 150-250v amongst friends? Of course HV DC can badly burn or Kill you.

I was 14 years old when working on my DX-35 with 850vdc on the 6146 plate.

I agree that many hams these days aren't not trained to handle high-voltage with all the 12vdc solid-state electronics available. But QRO sspa are running at 50vdc and higher. There are rules for safe work on HV...time to review them.

73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-1.4kw*, 432-100w, 1296-testing*, 3400-winter? DUBUS Magazine USA Rep dubususa@hotmail.com ====================================== *temp not in service

At 12:26 PM 2/18/2011, Vince Fiscus, KB7ADL wrote:

At 12:01 PM 2/18/2011 -0900, "Edward R. Cole" kl7uw@acsalaska.net wrote:

...

I am rebuilding my 4.2kV PS for the 2m-8877.

That'll get you into AO-51. ;-)

Not me! I'm not getting the blame for melting the AO-51 receiver.

...

I was 14 years old when working on my DX-35 with 850vdc on the 6146 plate.

I agree that many hams these days aren't not trained to handle high-voltage with all the 12vdc solid-state electronics available. But QRO sspa are running at 50vdc and higher. There are rules for safe work on HV...time to review them.

I know that's true. Even the large caps in high current 13v supplies. I thought I had things discharged and just to be sure before I started poking around with a screwdriver checking other things, I thought I would be sure the filter caps discharged, so I put the screwdriver across the terminals .....

You know arc welders run at low voltage,,,but lots of current. Discharging a large filter cap is a potential welding unit! Same goes for getting across the terminals of a large battery (a wrench or screwdriver laying across a car battery will cause a lot melting and possible overheat the battery enough to explode!

You should have seen the spark.

And a loud "bang" or "pop"? You ought to hear what 4kV sounds like when it arcs to ground!

Watch for burn and eye damage situations if working around high capacity/voltage systems.

Rule of HV: NEVER touch a HV circuit until it is verified that no voltage remains. Hooking/disconnecting HV probes to measure HV is always done with power-off/discharged. Connect the HV probe/meter and do not touch them when HV is applied. In commercial HV systems there is dead-man hook: a metal hook like a shepards crook with a cable to ground attached to a long insulated handle. You do not hold it to short HV circuits. YOU toss it onto the circuits and step quickly back. I was taught this at NASA where we had a walk in 100kV PS (think it was housed in a semi trailer). It ran the anode on 20kW s-band klystron amps.

ALWAYS inform someone when you are about to test HV (in case you need medical assistance). INSTRUCT them to NEVER touch you or go near the equipment if you get shocked/electrocuted. Show them how to shut down the Main Breaker on the house (but CALL 911 FIRST, because a lot of cordless phones quit when the power is off). DO NOT attempt CPR if you are not absolutely sure that power is off. In most electrocutions the heart goes into fibrillation and ordinary CPR will not revive a person. It will extend life if it can be done safely. Be sure to tell 911-operator that an electrical shock has occurred.

Most electrocutions above 240v are fatal. NO SECOND CHANCE! Sort of like falling off that 100-foot tower - you only do it once.

73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-1.4kw*, 432-100w, 1296-testing*, 3400-winter? DUBUS Magazine USA Rep dubususa@hotmail.com ====================================== *temp not in service