They made a Mil-Spec version of the IC-781 that sold for over $10,000 almost 15 years ago. It seems like if you build it, someone will buy it and I'd guess it would cost at least that much or more. The one thing I did not think about when I posted this was line current. It sure would not run well on a standard 15 amp 110 volt North American wall outlet. Then again if this rig is within the budget, so is the electrician.
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1250W CW from a single power FET!!
- Thread starter eagle1911
- Start date
They made a Mil-Spec version of the IC-781 that sold for over $10,000 almost 15 years ago. It seems like if you build it, someone will buy it and I'd guess it would cost at least that much or more. The one thing I did not think about when I posted this was line current. It sure would not run well on a standard 15 amp 110 volt North American wall outlet. Then again if this rig is within the budget, so is the electrician.
B
BOOTY MONSTER
Guest
if you consider it would take twelve 2879s for the same power and the associated components this should be a lot cheaper . plus you wouldn't need a driver amp till you used 4 of them . but by then you'd be looking at 5000 watts of on spec rated power ...... from a "4 pill" . LOL
water/liquid cooling would be more efficient than air cooling . with the popularity of water cooling for computers driving the cost of the hardware down its not as expensive as it used to be . the only thing that would need to be custom made for these would be the liquid cooling block the fet and liquid tubes attach to . a nice chunk or copper with holes drilled through and hose nipples on the ends shouldn't be difficult to make .
Computer Water Cooling - FrozenCPU.com *
peltier cooling could be another option , as long as the area around it is properly insulated to prevent condensation .
Peltier Coolers (TEC) | Coldplates | Page 1 | Sort By: Product Title A-Z - FrozenCPU.com *
water/liquid cooling would be more efficient than air cooling . with the popularity of water cooling for computers driving the cost of the hardware down its not as expensive as it used to be . the only thing that would need to be custom made for these would be the liquid cooling block the fet and liquid tubes attach to . a nice chunk or copper with holes drilled through and hose nipples on the ends shouldn't be difficult to make .
Computer Water Cooling - FrozenCPU.com *
peltier cooling could be another option , as long as the area around it is properly insulated to prevent condensation .
Peltier Coolers (TEC) | Coldplates | Page 1 | Sort By: Product Title A-Z - FrozenCPU.com *
If I am not mistaken the ability of these type devices to handle high levels of SWR comes from being run on lower voltage. Typical Vcc is 50 volts but they will not handle high SWR at that level while running them at 40 volts or so will make them almost immune to high SWR however the power output will be considerably lower. I could be wrong mind you and am just basing this on my experience with the Motorola MRF-151G 300 watt MOSFET.
Given that these are 30-50V devices, I think that powering the amp would be the biggest challenge. It would take quite a beefy power source to run just one of these to full power, much less several. I do still think that these offer some real cost-effectiveness to a DIYer though.. $270ish for 1.25kW worth of active elements is very affordable.. most likely affordable enough to offset the cost of building/buying a power source.
B
BOOTY MONSTER
Guest
at 50 volts what would be the minimum amp rating for a power supply for this FET ?
would two of these work ?
http://www.iotaengineering.com/dls4820.htm
or one of these ?
http://www.trcelectronics.com/Meanwell/rsp-2400-48.shtml
http://www.trcelectronics.com/Meanwell/rsp-3000-48.shtml
would two of these work ?
http://www.iotaengineering.com/dls4820.htm
or one of these ?
http://www.trcelectronics.com/Meanwell/rsp-2400-48.shtml
http://www.trcelectronics.com/Meanwell/rsp-3000-48.shtml
Last edited by a moderator:
Not nearly the problem encountered when trying to run crazy assed power from a 16 pill Dave Made solidstate amp or the like from a 12-18 volt supply in the houise. The current required is much lower due to the higher voltage.
Given the efficiency and allowing for headroom I would go with the last one you listed.Basic rule would be to look at the power output from the amp versus power available from the power supply and then cut the supply rating in half and that will get you the VERY bare minimum that the supply should be used for. Throw in some for headroom and pick the supply that fits the bill.
Thats the truth.
Take for example Ameritron ALS1300, with power supply just barely capable of supplying the required current.
In any case, current limiting on power supply is required. Firstly and foremost, to protect the power supply, but if you rate a power supply with double capacity you need current limit threshold set to level of RF amp will pull at maximum RF power to protect RF device from damaging power levels.
Not all power supplies are created equal. Higher quality supplies will actually be capable of delivering the promised power continuously and safely.
Would it be proper to use two of these devices, in order to get FCC approved 'clean output'?
Or does it have fairly clean specs before filtering with just one device?
Or does it have fairly clean specs before filtering with just one device?
NXP just one-upped on freescale:
NXP puts the 'extreme' in extremely rugged LDMOS transistors
You can see them in the video, abusing the device under the most extreme conditions without damage.
Gone should be the days of blown devices due to broken coax or damaged antenna.
NXP puts the 'extreme' in extremely rugged LDMOS transistors
You can see them in the video, abusing the device under the most extreme conditions without damage.
Gone should be the days of blown devices due to broken coax or damaged antenna.
WOW!! 125:1.. that's amazing! I thought the 65:1 that the Freescale device withstands was impressive..
I actually just received an engineering sample of the MRF6VP11KH: MRF6VP11KH Product Summary Page It's not as rugged (10:1) but it looks to be useful nonetheless.. they're not offering samples of the 1.2kW device yet.
It's a 1kW peak dual MOSFET similar to the 1.2kW device described here. After the amp project I'm currently working on is finished I'm planning on using it in a 500W PEP SSB. Since the device is rated for 1kW peak, I figure that it should be nice and clean (not to mention long lived) at 500W.
I actually just received an engineering sample of the MRF6VP11KH: MRF6VP11KH Product Summary Page It's not as rugged (10:1) but it looks to be useful nonetheless.. they're not offering samples of the 1.2kW device yet.
It's a 1kW peak dual MOSFET similar to the 1.2kW device described here. After the amp project I'm currently working on is finished I'm planning on using it in a 500W PEP SSB. Since the device is rated for 1kW peak, I figure that it should be nice and clean (not to mention long lived) at 500W.
B
BOOTY MONSTER
Guest
That sounds about right.. Henry Radio out of LA sells these little BeO ceramic attenuators. My plan would be to integrate one into the input of the amp so that higher drive can be applied, with a max of roughly 1.5W being allowed through the attenuator for a specific input.
I am just curious why you need that much power to begin with?
Tim the Toolman Taylor-"More Power, ahh, ahh, ahh"