| Author |
Message |
    
Scoobydoo
Intermediate Member
Username: Scoobydoo
Post Number: 106
Registered: 8-2005
| | Posted on Friday, April 07, 2006 - 8:50 pm: | 
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Hi everyone, im researching a power supply for my GMRS repeater, It needs to be at least 15 amps continous and also needs to be able to be on 24/7 and stand up to long durations of use without overheating. I also need low ripple and noise. Tripplite power supplys sound like quality units but maybe there is something more suited to my application. Computer power supply maybe? Thanks for any and all help.  |
Jp1116
Intermediate Member
Username: Jp1116
Post Number: 105
Registered: 5-2002
| | Posted on Wednesday, April 12, 2006 - 7:56 am: |
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Astron is one of the most recommended power supplies for that application. They have them in rack mount versions too. My Pyramid tends to get hot and I think they put fans on the newer ones so that may no longer be a problem. The Astron seems to dissapate the heat better without a fan. |
Tech237
Moderator
Username: Tech237
Post Number: 273
Registered: 4-2004
| | Posted on Wednesday, April 12, 2006 - 8:01 pm: |
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24/7 at 15 amps. mmmm.Run a bank of batteries with a charger system and at least that way if the power fails the repeater is still alive. |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1166
Registered: 6-2004
| | Posted on Wednesday, April 12, 2006 - 9:51 pm: |
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Why would you need 15 amps? GMRS power is limited to 50 watts maximum, and less with a base antenna:
95.135 Transmitter power limits.
(a) No station may transmit with more than 50 watts output power.
(b) [Reserved.]
(c) A small control station at a point north of Line A or east of Line C must transmit with no more than 5 watts ERP.
(d) A fixed station must transmit with no more than 15 watts output power.
(e) A small base station must transmit with no more than 5 watts ERP. |
Tech237
Moderator
Username: Tech237
Post Number: 275
Registered: 4-2004
| | Posted on Thursday, April 13, 2006 - 1:42 pm: |
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455,
I'd assume that he is looking at over engineering based on the fact a supply running at less than it's rated outpu will run cooler and therefore less stress on the components than r\one running close to the limit.
At least thta would be the way I'd do it. |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1167
Registered: 6-2004
| | Posted on Thursday, April 13, 2006 - 8:09 pm: |
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So you would use a power supply with about 8x the current it would need 90% of the time? |
Tech237
Moderator
Username: Tech237
Post Number: 278
Registered: 4-2004
| | Posted on Friday, April 14, 2006 - 9:31 am: |
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455.
Yes and have done commercially many many times. In 30 years in the trade I have never had a radio site go down because of a power supply failure.
I did it not only for the reason I mention above but also as it gives leeway for a future unconsidered expansion.
Right now in my shack my radios run on 2 x 30A supplies each of which supplys only 6A on receive and around 10-12A when I transmit. The supplies are 8 years old and have never given me any trouble.
All I can add is that I, for one, cannot argue with a formula that has worked for so long. |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1170
Registered: 6-2004
| | Posted on Friday, April 14, 2006 - 8:50 pm: |
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I don't disagree regarding a commercial system, but I would choose a supply that was rated for continuous service and not intended for ICS.
But considering that a repeater is used for ICS, it's overkill. If I was that worried I'd do as you suggested earlier and use a bank of batteries and a charger. |
Tech237
Moderator
Username: Tech237
Post Number: 281
Registered: 4-2004
| | Posted on Saturday, April 15, 2006 - 9:38 am: |
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455,
NO argument there, or at leat run a battery backup system with maybe solar charging.
The thing is we all do things the way we feel works best for us and as such how I do things may not suit some one else and in these discussion we can argue it back and forth with the result being we all (yes I include me - never to old or knowledgable to learn) learn something we did not know before.
That is one of the reasons I love the BBS. |
Scoobydoo
Intermediate Member
Username: Scoobydoo
Post Number: 107
Registered: 8-2005
| | Posted on Tuesday, April 18, 2006 - 7:43 pm: |
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Yes, the system will be on automatic battery backup power. I did find some industrial switching power supplies, Samlex and Mean well. 20 amp unit is under 100 dollars, should work perfect. Hollowpoint445, on your question on why I needed one with at least 15 amp rating is because my repeater when keyed, draws 11 amps. 20 amps continous should be more than enough. Thanks for all the help. |
