Author Topic: DIY power supply for yaesu ft2900r 2m mobile ?  (Read 11236 times)

Offline Smurf Hunter

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DIY power supply for yaesu ft2900r 2m mobile ?
« on: May 14, 2014, 11:13:49 AM »
I'm looking at 2m mobile rigs for base station use.
The ft2900r can go up to 75watts.  While I may not run that hot I'd like my rig to support it.

Assuming I scrap up an AC/DC supply with enough amps is there any downside?

I have an old PC power supply that was an aftermarket purchase years ago.  It powered 6 drives and a bunch of peripherals in its day.  I will confirm the amp output when I get home.

I also have a collection of 12vdc wall warts.  Can I start out with a 10amp one to get started?

I may invest is a purpose built power supply later but want to understand the options.

Offline Carl

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Re: DIY power supply for yaesu ft2900r 2m mobile ?
« Reply #1 on: May 14, 2014, 12:24:03 PM »
While a PC power supply may work,there are drawbacks.
(1) PC power are normally 12 volts ,5 volts,and 3 volts with 12 volts being just that...12 volts...and NOT 13.6 to 13.8 +or- 15%, you will not get full power out of the radio,which is no big deal.
(2) RF can cause problems with switching power supplies (I said CAN , not will,as some supplies work fine)
(3) There are many HOW TO pages and videos on the modification to the power supply to get it to turn on and STAY ON.
(4) Not a big worry ,but when switching supplies fail...they can fail to ZERO volts (GOOD) or 300 volts and more(need I say BAD)

You might think to use a spare boat ,lawn-mower battery and a small wall wart or charger for temporary duty as batteries last LONGER when properly used ,rather than stored.

And YES..a 10 amp supply should keep you stable at up to 25 watts or so RF out on the radio

I own and use  Yaesu 1802,1900,2800,2900 8800,8900 mobile radios tied to solar,batteries,commercial power supplies and YES even converted PC power supplies and either have done it good ,or been lucky as ALL of the radios are still great after many years of service. Just always double check the voltage AND POLARITY before power to radio is applied, REVERSE POLARITY CAN DO DAMAGE EVEN WHILE THE RADIO IS NOT "ON" , Not yelling ,but that part is important.

Offline Smurf Hunter

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Re: DIY power supply for yaesu ft2900r 2m mobile ?
« Reply #2 on: May 14, 2014, 01:14:59 PM »
While a PC power supply may work,there are drawbacks.
(1) PC power are normally 12 volts ,5 volts,and 3 volts with 12 volts being just that...12 volts...and NOT 13.6 to 13.8 +or- 15%, you will not get full power out of the radio,which is no big deal.
(2) RF can cause problems with switching power supplies (I said CAN , not will,as some supplies work fine)
(3) There are many HOW TO pages and videos on the modification to the power supply to get it to turn on and STAY ON.
(4) Not a big worry ,but when switching supplies fail...they can fail to ZERO volts (GOOD) or 300 volts and more(need I say BAD)

You might think to use a spare boat ,lawn-mower battery and a small wall wart or charger for temporary duty as batteries last LONGER when properly used ,rather than stored.

And YES..a 10 amp supply should keep you stable at up to 25 watts or so RF out on the radio

I own and use  Yaesu 1802,1900,2800,2900 8800,8900 mobile radios tied to solar,batteries,commercial power supplies and YES even converted PC power supplies and either have done it good ,or been lucky as ALL of the radios are still great after many years of service. Just always double check the voltage AND POLARITY before power to radio is applied, REVERSE POLARITY CAN DO DAMAGE EVEN WHILE THE RADIO IS NOT "ON" , Not yelling ,but that part is important.

I did some reading since posting, and realize hacking an old ATX PSU may not be worth the trouble/risk.   
A new, quality brand name 15-20A supply is as expensive as the transceiver. While I'm not necessarily a cheapskate, I need to ease into new hobbies slowly - in the interest of "domestic tranquility".

Maybe a larger capacity 12VDC SLA/marine battery would suit me better in the near term.

I have a wallwart smart charger that I use to charge up a variety of 12VDC lead acid batteries.  I've been meaning to build up a more substantial battery bank being just charging cell phones and laptops. 

If I got a 20AH SLA battery, and left the AC smart charger attached, could I simultaneously attach the DC leads from a mobile transceiver to the battery terminals?
I realize without AC power recharging it, a modest 20AH would probably only last for a couple hours depending on the amount of power and transmissions.

Curious what my options are to get started.


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Offline Smurf Hunter

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Re: DIY power supply for yaesu ft2900r 2m mobile ?
« Reply #4 on: May 14, 2014, 02:52:10 PM »
Just get this and be done with it...

https://www.google.com/search?q=JETSTREAM+JTPS28&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&channel=sb

I had one, wish I still did.

GL,
TOG

I might - but here's an ironic/annoying attribute I've read about the JTPS28.  It's noisy, which isn't a huge deal, but one of the "features" of the FT-2900r is that it's fanless.  So seems kind of counter intuitive to add a noisy power supply to an otherwise silent rig.


Offline armymars

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Re: DIY power supply for yaesu ft2900r 2m mobile ?
« Reply #5 on: May 14, 2014, 03:24:36 PM »
  I own a FT 2900 and some times power it up with a scrap power supply from medical equipment that I striped from a scrap metal yard. It's 12 amps and built like a battleship. I payed 10 dollars for it. Copper is expensive, but not electronics at scrap metal yards because some electronics are considered hazardest waste. They're happy to see it go.
  I've also have bought surplus power supplies at Dayton for eight dollars each. They're switchers are light  and give me 20 amps. These are made for industrial equipment and quite robust. Mad Scientist had a pallet of these. I wish I had got more.   

Offline Alan Georges

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Re: DIY power supply for yaesu ft2900r 2m mobile ?
« Reply #6 on: May 14, 2014, 07:35:46 PM »
Maybe a larger capacity 12VDC SLA/marine battery would suit me better in the near term.

I have a wallwart smart charger that I use to charge up a variety of 12VDC lead acid batteries.  I've been meaning to build up a more substantial battery bank being just charging cell phones and laptops. 

If I got a 20AH SLA battery, and left the AC smart charger attached, could I simultaneously attach the DC leads from a mobile transceiver to the battery terminals?
I realize without AC power recharging it, a modest 20AH would probably only last for a couple hours depending on the amount of power and transmissions.

I'd go with a battery.  A 2900 draws 0.3A when squelched.  If you only draw down a 20AH battery by half to spare it, that's 33 continuous hours of listening.  Talking doesn't take that much more total energy, as long as you keep the power low and don't get long-winded.  If you're willing to draw a 50AH battery down to zero, it'll keep things listening for just under a week.

Also, with a battery you have a lot of options.  If the power's out and you drain the battery down, you can either bum some power off a friend with a generator, or just recharge it by running your car.

Earlier you wrote that you've already got a charger, which is great when the grid's up.  If the power's off though, you still may be able to find a friend with a generator.  It wouldn't be hard to top things off every couple of days.

Finally, as a radio power supply, a deep-cycle battery works really well.  It can dump amps to the radio if you need the full 75W transmit power, but it's equally happy when you dial things back.  Also, batteries are the quietest power supplies out there, both electrically and sound-wise.  No switching, no 60Hz hum, no fans, just quiet little electrochemical reactions.

About leaving the AC power recharging when running the radio, it might work but I wouldn't.  Even a little 7AH SLA brick would be enough for an evening of local talking, and you can plug things back in to recharge afterward.  Unplugged, you wouldn't have to worry about any noise the batt charger might be making.

Offline Carl

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Re: DIY power supply for yaesu ft2900r 2m mobile ?
« Reply #7 on: May 15, 2014, 12:49:12 PM »
The Jetstrean,and other power supplies that are "Noisy" are not really a problem with FM radios,more an issue with HF (shortwave). That said  I suggest you find a local HAM  club and get known(even if not yet a HAM) as often there are lots of extra power supplies about for $50 or less. I have a dozen or so,but shipping is high on  these rascals(are you close to Shreveport?) and I even have the power supply in a previous link (I got it for $50,from R&L electronics ...used list as a demo with no box)

  OH yes ,the battery, a 20 amp GEL cell,while OK is designed for C10 ( load of 1/100 off rated current) and might not last so long when discharged so heavily, If they are FREE ,or close..go for it. I suggest a 50 amp hour or greater(think car battery size) and also know that ALL batteries are RENTALS, they go bad in TIME weather you use them or not. Average is about 3 years to 5 years on wet cells and about the same for GEL cells. That is why I suggested the boat or lawn mower battery as you might already have one and using it would only help you keep it maintained.

  I use OPTIMA yellow top and blue top GEL cells in a wheel  equipped ice chest (flea market find) with the inverter on top for air circulation...but I am getting off track as they cost about $200 each and we were going ECONOMY. Sorry I get carried away sometimes...but I escape!

Offline Smurf Hunter

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Re: DIY power supply for yaesu ft2900r 2m mobile ?
« Reply #8 on: May 15, 2014, 01:19:39 PM »
The Jetstrean,and other power supplies that are "Noisy" are not really a problem with FM radios,more an issue with HF (shortwave). That said  I suggest you find a local HAM  club and get known(even if not yet a HAM) as often there are lots of extra power supplies about for $50 or less. I have a dozen or so,but shipping is high on  these rascals(are you close to Shreveport?) and I even have the power supply in a previous link (I got it for $50,from R&L electronics ...used list as a demo with no box)

  OH yes ,the battery, a 20 amp GEL cell,while OK is designed for C10 ( load of 1/100 off rated current) and might not last so long when discharged so heavily, If they are FREE ,or close..go for it. I suggest a 50 amp hour or greater(think car battery size) and also know that ALL batteries are RENTALS, they go bad in TIME weather you use them or not. Average is about 3 years to 5 years on wet cells and about the same for GEL cells. That is why I suggested the boat or lawn mower battery as you might already have one and using it would only help you keep it maintained.

  I use OPTIMA yellow top and blue top GEL cells in a wheel  equipped ice chest (flea market find) with the inverter on top for air circulation...but I am getting off track as they cost about $200 each and we were going ECONOMY. Sorry I get carried away sometimes...but I escape!

Any day now my "general" license will appear on the ULS.

There are 3-4 clubs within 10 miles of me.  I must admit, most seem a bit insular and even set in their ways - with 1995 looking websites, and the average age member  > 30 years older than me.
I know face-to-face these guys love to talk shop and will freely share what they know and believe.   I don't mean to sound snobby, but I'm not looking to hang out for hours on end, I've got a busy young family and far too many hobbies at this stage in my life.  That all said, I'm more than happy to join multiple clubs, especially to support those with repeaters I use.

I should probably just drop in on a local HAM fest and check it out. 

Would it be too creepy if I directly mention I'm looking for an "Elmer" to mentor me? 


Offline armymars

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Re: DIY power supply for yaesu ft2900r 2m mobile ?
« Reply #9 on: May 15, 2014, 03:14:28 PM »
  I doubt it would be creepy. There is always someone who likes to teach. The average age of hams now is 60 years old. So there's nothing you can do about that. If you want to get to know a club, most get together for breakfast once or twice a month. Next is how your treated on the repeater. This is a good start. Last visit there field day site and see what type of set up they're running. Are they die hard contester's or social get togeather's. Better yet an even mix. Look at how they set up their portable stations. Field Day is the third week end of June. From 1 PM Sat. to 1 PM Sunday. Set up will often start the day before. 73

Offline TiredOldGrunt

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Re: DIY power supply for yaesu ft2900r 2m mobile ?
« Reply #10 on: May 15, 2014, 04:16:35 PM »
I ran the above posted JS switcher on both HF and VHF, even looked at the output on my scope...

zero noise, buy with confidence.

GL,
TOG

Offline Smurf Hunter

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Re: DIY power supply for yaesu ft2900r 2m mobile ?
« Reply #11 on: May 15, 2014, 04:41:08 PM »
I ran the above posted JS switcher on both HF and VHF, even looked at the output on my scope...

zero noise, buy with confidence.

GL,
TOG

The weekend after next, the club where I took my exam is hosting an open house/swap meet.  I'll drop by and see if anyone is willing to part with a power supply for a good price.  If nothing comes I'll consider a new JTPS28. 

Offline backwoods_engineer

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Re: DIY power supply for yaesu ft2900r 2m mobile ?
« Reply #12 on: May 15, 2014, 07:28:23 PM »
Congrats on getting your license. SmurfHunter.

I think a gel cell, with an appropriate charger, could be a fine power supply to start out with, and it also gives a "preparedness" bonus by giving you the ability to communicate at home even without AC power.

The thing I'd start looking for next would be an inexpensive AC charger for your gel cell, and then after that, an inexpensive 15 - 50 Watt 12V solar panel and charger for it. 

Steven Harris rails against trickle chargers for good reason; just get the Schumacher 6A battery charger that he recommends on battery1234.com, put it on Gel-Cell mode, and put some more permanent connectors on the end of the wires.   I recommend you get a pre-bonded 30Amp PowerPole connector kit from PowerWerx.com, and a Red-Dee Power Distribution Block to be able to hook up your rig, battery, charger, and solar panel all together.  There's an 8-way Red-Dee, too.  You can crimp the connector pins with pliers for now, but the crimper they sell is excellent.

Yes, you'll have to replace your gel cell every few years, but having that short-term-grid-down redundancy is an awesome capability, and very much in the spirit of ham radio.  We were "preppers" before "prepping" was cool.

Offline backwoods_engineer

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Re: DIY power supply for yaesu ft2900r 2m mobile ?
« Reply #13 on: May 15, 2014, 07:31:41 PM »
By the way, your rig isn't much more than 50% efficient in transmit.  That means to make 75 Watts, you'll need at least 150 Watts.  At 13.6V (nice full battery), that means at least 11 Amps.  So, your 10A "wall wart" isn't going to cut it on full-power mode.  You could reduce TX power to low or medium, but why not just go with the gel-cell?

Also, not sure what the make/model of gel-cell you are talking about, but some of the smaller ones can't source 11 Amps.  You still might have to run in medium power TX mode.

Offline Carl

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Re: DIY power supply for yaesu ft2900r 2m mobile ?
« Reply #14 on: May 16, 2014, 08:44:55 AM »
Smurf Hunter...and others.

There are many ways to and end .
Older HAMs as an ELMER,will often have you taught 'OLD' ways of doing things.
One must be flexible to new things as innovation happens.Some long time HAMs
actually welcome new things ,others are just SET in there ways.

A fellow NEW HAM will often as not , have joined for the same reasons you did and
you can learn the mysteries together. I have elmered a few NEW HAMs and often others talk them into buying lots of junk because shiny stuff looks cool. But what works is more important.

A fellow HAM bought a $700 self tuning antenna ...cutting edge,and I asked him how that 8 foot antenna was better than a stainless CB 9 foot whip ($35) and an LDG automatic tuner ($139) When he got over his shock , he found no reasonable answer. Except when he hit a tree limb and destroyed his fancy new gizmo.

Get some balance,NEW and OLD have much to tell you and SOME of it worth learning.If you get time to read,there is a lot of info on the internet,here is one   http://www.k0bg.com/ that I like to read and learn from.

Would the ideas of an elmer at a distance be of any help? While I'd be happy to share my thoughts with you ,the critics would only turn it in to 'monkeys flingin' poop' in  no time.

If it is allowed ...KB5WMY at gmail dot com . I don't often raise my hand.

Offline Smurf Hunter

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Re: DIY power supply for yaesu ft2900r 2m mobile ?
« Reply #15 on: May 16, 2014, 11:05:23 AM »
Carl,

Your handful of posts have already been immensely helpful.  In my adult life I've gotten into many hobbies from ground zero, and have learned a lot of lessons.  I'm fairly pragmatic about researching gear and seriously evaluating my personal usage patterns. 

I'm not going to buy anything for bragging rights, nor will I buy something and keep it on the shelf so I can claim I'm "prepared".  I'd rather buy something modest, use the heck out of it, develop knowledge and opinions.  Then when it comes time to upgrade, I'll know what's up.

Frankly I don't have a lot of respect for people who whip out a credit card and say "give me the best" without having a clue why it's "the best".  It happens with outdoor gear, firearms, mechanics tools, etc.  I'm too polite to say anything face to face, but just a pet peeve of mine.

Every decision is a trade-off.

73


Offline Carl

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Re: DIY power supply for yaesu ft2900r 2m mobile ?
« Reply #16 on: May 16, 2014, 05:04:00 PM »
We are much of the same thoughts.Some things are best learned by mistake as the lesson is better learned.But I try to nudge others in the direction I have learned ,through my mistakes and many years of exploring the potential of HAM and before that CB (I built my first CB from a scrap TV chassis ,along with my first antenna) I was the youngest REACT ORGANIZER in Virginia ,back when REACT meant something...had over 500 radio operators in the DC area(FallsChurch VA...I was 13)
 
 There I go ,rambling again..sorry guys, I will try to keep in line.