Power supply location

Marchboom

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I am putting together a cabinet to hold a 2 meter/70cm transceiver, a CB radio, and 2 handheld scanners. All will have antennas located in the attic. I plan to use a separate power supply and was wondering if it could be located within a foot or so from the radios or would the power supply cause interference with the radios.

Thanks
 

mmckenna

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That power supply -should- be fine if it's filtered well enough.

Make sure you are getting the 12 volt model. The photo you posted shows a 24 volt version.
Shouldn't be any issue having a well filtered switch mode power supply close to the radio.
 

prcguy

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That power supply has a good chance of interfering with the CB or any HF radio. I have several Meanwell power supplies and they put out lots of RFI in the HF range. One is a 15V 100A job to power an HF amplifier and I was able to reduce the RFI to a usable level by wrapping the AC and DC power cables through large ferries and adding a .03uf disc cap across hot and ground at the output side of the ferrite.
 

mmckenna

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You gotta ask yourself why the huge difference in price.
Good point. Referencing my post above, $32.00 versus $139/$165 probably comes at the cost of several things, including good filtering.

A quality switch mode power supply shouldn't be much of an issue.
I think for your application, you could save some money by not getting such a large supply. Stick with one of the ones above, Samlex, Astron, I've even had good luck with DuraComm, but for running a dual band radio, a CB and 2 scanners, you could probably do just fine with a 15 amp supply. The dual band radio is probably going to only pull 12-13 at the most when transmitting. The CB will only pull 2-3 amps at the most when transmitting. Unlikely you'd ever be talking on CB -and- amateur radio at the same time. Even then, a 15 amp supply would be fine, as they often have some headroom of a few amps. The scanner won't pull much, maybe one amp each if they were actively receiving and you had the volume cranked up all the way.
 

ka3aaa

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if your smaty you will want a well known manufactur thats been around like astrton for you supply. They a pricey but well worth the investment because the radios are only as good as the power supplies that power them, I have three of them in service for years now and they are still rock solid.
 

prcguy

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Astron has the best after warranty repair in the business, they will fix just about any power supply no matter what you did to it for about $20. I luv Astron. I got a couple of these recently and have been very happy, they are real small for their current rating and travel nice plus no RFI so far.

I'm just gonna throw this out there.

MEAN WELL LRS-350-12 $32
Samlex SEC-1235 $139
Astron SS-30 $165

You gotta ask yourself why the huge difference in price.
 

vagrant

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I have a Powerwerx. It provides me with RFI when operating on 6 meters whether connected to the RX radio or not. I still use it as it wasn't that bad, but I'm not usually working weak stations with it on 6. With the convenience of Powerpole plugs, I use it mainly for temporarily power and charging stuff. I did not notice an issue on other bands after noticing it on 6 meters. It could be that just mine is wonky.

Also, Astron...yes +1. I have an RS-35A that will probably still be working after I'm dead.

I got a couple of these recently and have been very happy, they are real small for their current rating and travel nice plus no RFI so far.
 

lebrunmn

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You've gotten some good advice and a few good product suggestions... As luck would have it, I have an opinion on this matter--don't we all?

If you like the form factor of the power supply you mentioned in your third post, you should like what I use:

87047

This PS sits just six inches from my dear-to-my heart Kenwoods--though the antenna is 25 feet away and outside--and there is no noise whatsoever. Also, this isn't made in China, but in the good ole USA. It's just $60 on Amazon.

Hope this helps. Good luck!
 

Marchboom

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Thanks so much for all the good responses.
Would keeping distance (4-5') from the radios and antenna cable eliminate the interference problem? Maybe enclosing the PS?
 

AK9R

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There are several ways that a power supply can cause interference to your radios.

The electronics may emit RF noise and you may be able to reduce that by shielding the box.

The 120 VAC power cable and the 12 VDC cable to your radio may carry RF noise from the power supply. You may be able reduce that by wrapping the cables through toroidal ferrite cores.

Any of these RF transmission paths may be picked up by your radio's antenna. Distance between the power supply and the antenna may help here. But, if your antenna cable or the connectors in that cable are "leaky", some RF may still be heard by your radio.

Noise may also get into your radio through the 12 VDC power line if the output of the power supply is not properly filtered. A switch-mode power supply generates an alternating current at a higher frequency than the line current and then rectifies and filters that AC. The quality of the filtering has a big impact on how "clean" the DC is that goes to your radio. Also, during times of heavy current draw, the power supply may appear to generate more noise on the DC supply to your radio.
 

bharvey2

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Meanwell makes a variety of inexpensive switching powers supplies aimed at the commercial and medical industries and come in a variety of form factors. As PRCGUY pointed out, filtering isn't always their strong suit. I've used them but prefer Lambda if I'm going with a switching supply. I have several that I used for both VHF/UHF and HF radios. If you go the Meanwell route, keep it a few feet away from your radios and filter the snot out of it as suggested above and you'll probably be okay.
 

AK9R

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Getting a bit off topic, but the Alinco has a very interesting feature. That noise offset knob shifts the frequency of the switcher a bit. Theoretically, you could use that knob to move the switching frequency away from your frequency of interest.
 

bharvey2

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Getting a bit off topic, but the Alinco has a very interesting feature. That noise offset knob shifts the frequency of the switcher a bit. Theoretically, you could use that knob to move the switching frequency away from your frequency of interest.

Well, that's novel. Turning a shortcoming into a feature?
 

Groeteschele

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Astron the best of power supplies I know. Also with heavy duty power cables it's good to have power supplies safely installed in closet with high temperature alarm installed in ceiling over them.
 
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