Astron Power Supply

[WA6MHZ]

I have FOUR Astron 35s running 24/7 here. Doesn't seem to use up that much extra electricity. Its the old REEFER that causes me to have $180/Mo electricity bill!

[WA9SVD]

Maybe, but efficiency is only one thing we hams should look at when buying a supply. Astron's linear supplies are popular partly due a long history of being reliable, easy to work on, reasonable price, but probably most importantly, RF quiet. Switchers have not had a good reputation with RF noise, but there are good ones to be found, you'll just have to pay more.

However, I am not looking at efficiency under load (where switchers shine over linears) but under no load. I have a 25A switcher here that I'll try, but I don't think it'll do well as it has a fan that runs continuously.

All of this is predicated on the assumption that the supply is in use more or less continuously (7/24/365 in my case) and most of the time is spent under no, or very low load. It's the "vampire" power (http://en.wikipedia.org/wiki/Standby_power) that my shack uses, and I am wondering how my power supply choice affects my usage.

Steve
KV6O

A BIG disadvantage (IMHO) with switch-mode power supplies, aside from possible RF interference, is proprietary components and circuits. Linear supplies such as the Astrons employ circuitry that's practically public domain, and they include a schematic when you purchase the supply. Not so with the switching supplies, so repairs are not a simple matter of pulling out a National Semiconductor Data Book and fixing a supply if that ever becomes the case.

[N0SYA]

That's why the perfect place to store your copy of the ARRL Handbook is on top of the Astron.

73,
Bill

There ya go. I put a linear psu for a laptop on it and a 18h gel cell to deaden the buzz - still buzzes. Gonna have to retrofit it with a foam block betwixt xformer and lid as described elsewhere.

[WA9SVD]

There ya go. I put a linear psu for a laptop on it and a 18h gel cell to deaden the buzz - still buzzes. Gonna have to retrofit it with a foam block betwixt xformer and lid as described elsewhere.

That's a bit unusual. unless I'm within 2' of my Astron RS-35A, the only wqy I can tell it's powered is by the lighted switch, even if it's powering my 100 Watt HF radio. (Then again, the QRM on some bands makes hearing ANYthing impossible.)
But again, it's better to have a supply that has a bit of extra capacity, rather then pushing a supply to it's edge (or beyond) on a regular basis. Even with a draw of about 24 Amperes (HF Radio at full power FSK, VHF multimode radio on receive, and a few assorted low current draw) I don't detect any significant noise or "hum" at 60 Hz, and nothing on HF, VHF, or UHF, nor is there any recognizable interference on AM broadcast frequencies. I aso know that I'm NOT pushing my power supply close to or beyond it's specifications, and perhaps that's why it's served 95% of the time, 24 / 7, for 20 years. It's only turned off when I'm gone for more than a weekend period of time.

[WA7PRC]

A BIG disadvantage (IMHO) with switch-mode power supplies, aside from possible RF interference, is proprietary components and circuits. Linear supplies such as the Astrons employ circuitry that's practically public domain, and they include a schematic when you purchase the supply. Not so with the switching supplies, so repairs are not a simple matter of pulling out a National Semiconductor Data Book and fixing a supply if that ever becomes the case.

My homebrew DC-DC switch-mode boost power supplies (11.5 to 13.8V @ 25A for my HF rig and 11.5 to 16V @ 4.5A for my laptop PC) use off-the-shelf parts, as does the MFJ-4416B. It is also based on the common '3524 PWM controller. There are many sources of similar parts, all off-the-shelf. There is NO mystery here.

As indicated by testing with a spectrum analyzer, mine are nearly dead quiet over MF-HF. While the MFJ unit doesn't specify how quiet it is, since it is meant to be used with ham gear, I expect it is also quiet. This area is also quite mature -- there's NO black magic.

What wasn't mentioned was dynamic regulation. In the past, that is another area in which switchers lagged linears. They've had good pulse response for quite some time now.

[WA9SVD]

My homebrew DC-DC switch-mode boost power supplies (11.5 to 13.8V @ 25A for my HF rig and 11.5 to 16V @ 4.5A for my laptop PC) use off-the-shelf parts, as does the MFJ-4416B. It is also based on the common '3524 PWM controller. There are many sources of similar parts, all off-the-shelf. There is NO mystery here.

As indicated by testing with a spectrum analyzer, mine are nearly dead quiet over MF-HF. While the MFJ unit doesn't specify how quiet it is, since it is meant to be used with ham gear, I expect it is also quiet. This area is also quite mature -- there's NO black magic.

What wasn't mentioned was dynamic regulation. In the past, that is another area in which switchers lagged linears. They've had good pulse response for quite some time now.

So you are assuming that every switching supply on the market uses the same controller chip, and "similar" components are always equivalent components? I can give you examples of "25 uFD capacitors" can fail rapidly in switching circuits if they don't have the proper characteristics.

Properly designed (and BUILT) switching supplies can be an option for Amateur use, but "switching supplies" in general can not, many are NOT designed to reduce or (preferably) try to eliminate RF interference to sensitive receivers. If your HB supplies produces no RF interference, that's commendable. But that's not the case to warrant a widespread approval of switching supplies; each design or model needs to be individually evaluated.

[KE3WD]

Meanwhile, time and technology marches on, leaving the old curmudgeons and their prejudices concerning newer technologies ever in the dust.

Or,

"If man were meant to fly he'd have wings..."

"You'd have as much chance of doing that as going to the Moon..."

"Single Sideband will never catch on, it sounds so nasty..."

Look, Switching Supplies are here to stay.

Likely will out and out totally replace linear supplies in the future. Lighter weight, much higher efficiencies, total elimination of the bulky, heavy, iron-core 60Hz transformer, which translates directly to less cost of manufacture, the handwriting's on the wall.

And, as technology marches inexorably forward, reports of EMI/RFI problems with Switching Supplies will also become a thing of the past.


73

[WA9SVD]

Meanwhile, time and technology marches on, leaving the old curmudgeons and their prejudices concerning newer technologies ever in the dust.

Or,

"If man were meant to fly he'd have wings..."

"You'd have as much chance of doing that as going to the Moon..."

"Single Sideband will never catch on, it sounds so nasty..."

Look, Switching Supplies are here to stay.

Likely will out and out totally replace linear supplies in the future. Lighter weight, much higher efficiencies, total elimination of the bulky, heavy, iron-core 60Hz transformer, which translates directly to less cost of manufacture, the handwriting's on the wall.

And, as technology marches inexorably forward, reports of EMI/RFI problems with Switching Supplies will also become a thing of the past.


73

As long as they are properly designed and implemented. There are good and bad designs, both linear and switching. There will be linear supplies of questionable design and quality, that don't even provide over voltage protection (an addition of approximately $1-2) and there are switching supplies that eliminate RFI suppression components to reduce cost.

Linear supplies such as Astrons have often been in continuous service for 25 years or more, (providing for individual stations as well as repeaters) and still going strong. The reliability and "perseverance" of switching mode supplies remains to be seen.

[K1ZJH]

And, as technology marches inexorably forward, reports of EMI/RFI problems with Switching Supplies will also become a thing of the past.


73

That part is doubtful, unless the supply is from a ham or commercial radio manufacturer.
The incidence of interference from incidental radiators is climbing, rather than abating.

Pete

[WA9SVD]

That part is doubtful, unless the supply is from a ham or commercial radio manufacturer.
The incidence of interference from incidental radiators is climbing, rather than abating.

Pete

Interesting comment. I Had a TI "TravelMate" laptop that had a "SMPS" AC Supply/charger (AKA switch mode power supply) that totally wiped out all ability to control the TV's in my parent's home. When the P/S was in use, no remote control. Unplug the remote, and remotes functioned properly. Over multiple tests, over several months, that was the pattern; the SMPS was the problem. And THAT was only a 15 Watt adapter.

SMPS Supplies may be a "technology" of the future, but they still can (and sometimes do) have drawbacks.