This MRFE6VP61K25H solid state device is catching on fast in amateur radio circles. HF Amps next. http://www.m2inc.com/pdf_manuals/2M-1K2.pdf 73 Bruce-K1FZ
> This MRFE6VP61K25H solid state device is catching on fast in amateur radio > circles. HF Amps next. > > http://www.m2inc.com/pdf_manuals/2M-1K2.pdf Here is the tough time with this, because I'm sure most people take device manufacturer's data at surface value. All of this stuff, to this point of time, is mostly vaporware. Here are the worries: 1.) While manufacturer's make wild claims about device VSWR tolerance, those specs are really just creative marketing fantasy. A 2:1 SWR would instantly blow the device up if peak voltage breakdown is exceeded, or over a short period of time if heat limits in the junction are exceeded. If you do not see SWR fault protection, and there are no current limits, you can bet devices will fail with some conditions of mismatch. Their popular U-tube video is at pulsed service with a power limited supply. I can do the same thing with MRF150's, and actually designed a medical device that ran 1000 watts of peak output power on two MRF150's, without SWR protection, on 27.120 MHz. The reason it lived is the power supply would barely supply 100 watts average power, and it was pulsed duty cycle with very low Q filters and matching. 2.) No SSB IMD spec's. 3.) All public data appears to be matched narrow-band class-C pulsed service.(Continue reading)
Hi Tom, The new Harris Flexiva 10 KW FM band (not pulse) stereo transmitter is not having a heat problem with air cooling, in a reasonably small package . It has individual modules that can be hot switched. Will have more info when we install it next few weeks. It's going up on a mountain with no automobile/ truck road, so transporting takes time. I only meant that it was catching on fast in general. A French design is also making a 2 meter amp. A pair of the devices, with an built in ALC, to keep the output below the non linear portion could could be one approach to a 1.5 KW Amp.. The Harris Salesman, Engineer, Ham, said there was already a W2 using a pair, but had a small water cooled system. 73 Bruce >> This MRFE6VP61K25H solid state device is catching on fast in amateur >> radio >> circles. HF Amps next. >> >> http://www.m2inc.com/pdf_manuals/2M-1K2.pdf > > > Here is the tough time with this, because I'm sure most people take device > manufacturer's data at surface value. All of this stuff, to this point of > time, is mostly vaporware.(Continue reading)
On 7/7/2012 1:18 PM, Bruce wrote: > Hi Tom, > > The new Harris Flexiva 10 KW FM band (not pulse) stereo transmitter is not > having a heat problem with air cooling, in a reasonably small package . It The problem with starting with a saturated amplifier and then backing off the power for linearity is that the dissipation actually goes UP when you reduce the output power. The maximum dissipation occurs at something like 1/3 of maximum power. Therefore, this FM transmitter is not really proof that a linear amplifier is practical. I have done a lot of work with Dick Brounley's laser drivers. He gets up to 750 watts (continuous duty) out of a pair of MRF150's at 81.36 MHz, just below the FM band. Dick's design is great for its intended application, but doesn't translate to a ham amplifier. Furthermore, it is water cooled. The biggest problem Dick has thermally is cooling the ferrites in the output transformers. He actually has to heat sink them with copper sleeves. RF lasers are lucky to have 10% efficiency in terms of converting RF to light. Therfore, they are all water cooled and this makes water cooling for Dick's amplifiers basically "free". Rick N6RK
Hi Bruce, > The new Harris Flexiva 10 KW FM band (not pulse) stereo transmitter is > not > having a heat problem with air cooling, in a reasonably small package . It > has individual modules that can be hot switched. I'm sure Harris did a great job. The modules can be swapped while the TX is on, even power supply modules, which is a nice feature. But hot or live swapping does not mean the modules are "hot switched", as in allowed to have no load while amplifying. Generally a module is designed to remove power first when pulled, and apply power last when plugged in, which is nothing at all like some ham transmitting with an arcing tuner, or without a feedline. You will also note Harris protects the modules, which is what everyone should do. VSWR ratings in data sheet are really useless marketing hype, because near full power in longer duty cycle modes, as little as a 2:1 VSWR can blow a device out. My point is about Ham gear use where people are thinking they do not need to watch SWR or other parameters. There is little worry in a commercial transmitter that runs the device at 600 watts or less per device with adequate protection for SWR and thermal issues, and most likely current limiting. We should not translate what Harris did into something with no thermal protection, no SWR protection, and twice the power on the device!! > The Harris Salesman, Engineer, Ham, said there was already a W2 using a > pair, but had a small water cooled system.(Continue reading)
BEKO in Germany uses them in their 2m amps for about two years. Last year I was operator at a contest station with 3x HLV-2000 into three antenna groups. They worked perfectly at 2KW out for the 24 hours. The HLV-1000 uses one of those transistors and is upgradeable with a second, the HLV-2000 uses two and the HLV-4000 uses four MRFE6VP61K25H. http://www.beko-elektronik.de/index.php?do=03,01,01,02,05&lang=en Wideband and HF seems to be more difficult. 73 Peter, DJ7WW -----Original Message----- From: topband-bounces <at> contesting.com [mailto:topband-bounces <at> contesting.com] On Behalf Of Bruce Sent: Samstag, 7. Juli 2012 20:47 To: topband <at> contesting.com Subject: Topband: New Linear amp This MRFE6VP61K25H solid state device is catching on fast in amateur radio circles. HF Amps next. http://www.m2inc.com/pdf_manuals/2M-1K2.pdf 73(Continue reading)
Uh, I thought the legal limit was 1.5 KW.... Sent from my iPhone On Jul 7, 2012, at 7:49 PM, "Peter Voelpel" <df3kv <at> t-online.de> wrote: > > BEKO in Germany uses them in their 2m amps for about two years. > > Last year I was operator at a contest station with 3x HLV-2000 into three > antenna groups. > They worked perfectly at 2KW out.... > > 73 > Peter, DJ7WW > >
On 7/7/2012 11:28 PM, Chortek, Robert L wrote:
> Uh, I thought the legal limit was 1.5 KW....
Only in the US. Limits vary by country with some as high as 5KW
others as low as 400W.
73,
... Joe, W4TV
On 7/7/2012 11:28 PM, Chortek, Robert L wrote:
> Uh, I thought the legal limit was 1.5 KW....
>
> Sent from my iPhone
>
> On Jul 7, 2012, at 7:49 PM, "Peter Voelpel" <df3kv <at> t-online.de> wrote:
>
>>
>> BEKO in Germany uses them in their 2m amps for about two years.
>>
>> Last year I was operator at a contest station with 3x HLV-2000 into three
>> antenna groups.
>> They worked perfectly at 2KW out....
>>
>> 73
>> Peter, DJ7WW
>>
>>
>
(Continue reading)
On Sat, 2012-07-07 at 23:45 -0400, Joe Subich, W4TV wrote: > On 7/7/2012 11:28 PM, Chortek, Robert L wrote: > > Uh, I thought the legal limit was 1.5 KW.... > > Only in the US. Limits vary by country with some as high as 5KW > others as low as 400W. > > 73, > > ... Joe, W4TV And by band. This is a top band list but other bands have already been introduced into the discussion. 73, Bill KU8H
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