Peter,
<18 kg for a 1000 watt unit including the SMPSU is great.
Keep that shack door shut as the amp otherwise gets blown off your desk ;-)
Cheers, Dick Knol
PA3DUV
----- Original Message -----
From: "Peter Frenning [OZ1PIF]" <oz1pif@privat.dk>
To: "PA3DUV" <pa3duv@planet.nl>; <g3rzp@g3rzp.wanadoo.co.uk>;
<amps@contesting.com>
Sent: Monday, November 21, 2005 10:42 AM
Subject: Re: [Amps] 2 kW amp project
> I'm building a 1KW 144MHz amp based on 4xMRF151G and a massive 50V/49A
> SMPSU (again surplus telecom). Total weight is less than 18Kg (all
> components at hand and factored in), 42x45x18cm excluding handles.
> So maybe it's only ~55W/Kg, but more importantly: It's legal max, easily
> portable, and robust enough to bring along for DXpeditions!
>
> Same thing with an analog PSU would have been a min. of 15Kgs heavier plus
> much more prone to transit damage (because of the very heavy transformer),
> this I think is the more pertinent fact.
> Of cause if we had easy access to HV SMPSUs a tube amp would be possible
> weighing even less....
>
> Vy 73 de OZ1PIF, Peter
>
> ********** OZ1PIF **************
> email: oz1pif(no-spam-filler)@privat.dk
> http://home24.inet.tele.dk/oz1pif/
> Ph. +45 4619 3239
> Snailmail:
> Peter Frenning
> Ternevej 23
> DK-4130 Viby Sj.
> Denmark
> ***********************************
>
> ----- Original Message -----
> From: "PA3DUV" <pa3duv@planet.nl>
> To: <g3rzp@g3rzp.wanadoo.co.uk>; <amps@contesting.com>
> Sent: Monday, November 21, 2005 10:24 AM
> Subject: Re: [Amps] 2 kW amp project
>
>
>> Peter,
>>
>> The weight of an Icom PW1 solid state power amplifier (1 kW out) is 25
>> kg@
>> 1000 watt output (40 watt/kg)
>> The weight of an Emtron DX2 twin GU74B tube amp is 27 kG @ 1500 watt
>> output.
>> (56 watt/kg)
>> The weight of an Emtron DX4 twin GU84B tube amp with 3 phase PSU is 76 kg
>> @
>> 6000 watt output. (79 watt/kg)
>>
>> The PW1 is equipped with a SMPS, the tube amps with tape wound
>> transformers
>> with a FWD
>>
>> The tube amp wins hands down when it comes to power/weight ratio.
>>
>> Cheers, Dick Knol
>> PA3DUV
>>
>>
>>
>>
>>
>> ----- Original Message -----
>> From: "Peter Chadwick" <g3rzp@g3rzp.wanadoo.co.uk>
>> To: <amps@contesting.com>
>> Sent: Monday, November 21, 2005 9:36 AM
>> Subject: Re: [Amps] 2 kW amp project
>>
>>
>>> The article in QEX was not a simple multi band device, although I
>>> suppose
>>> it could eventually get to that. It uses a lot of cheap FETs, and goes
>>> up
>>> to 7 MHz. Going up to 28MHz with cheap FETs may not be on. The output
>>> transformer is fearsome, with 1/2 inch copper tubes silver soldered to
>>> 1/8
>>> inch thick copper heatspreaders. Copper is vile stuff to work, too, when
>>> it comes to drilling and tapping. Incidentally, it behoves one to be
>>> careful when working with sheet copper, since any small cuts that you
>>> get
>>> from it frequently tend to get infected and take a long time to heal -
>>> although not as long as RF burns!
>>> The problem with Class E is that it isn't linear, although it modulates
>>> well for AM. This suggests that for SSB, either a Cartesian or Polar
>>> loop
>>> approach is required, which adds considerably to the complexity -
>>> possibly
>>> a Callum modulator could be used, but that's fairly critical on set up,
>>> too. Personally, I need some convincing that at the end of the day, for
>>> homebrew ham use, the big SS amp really wins out. From the viewpoint of
>>> interesting technical experimentation, there is a lot of fun to had from
>>> it, though. One major factor for a linear amplifier is still the
>>> heatsinking. Teaching grandmama to suck eggs here, but a larger
>>> allowable
>>> temperature rise means that the cooling is less critical.
>>> Accepting the switching regulator (and high voltage SMPS are available),
>>> I
>>> doubt the tube amp ends up much different in size and weight. There is
>>> the
>>> minor problem of making sure the SMPS is electrically quiet enough, of
>>> course. OK, you can switch it off on receive, but if it requires a surge
>>> limitation on input current, QSK would be a problem.
>>> The tube amp with the 75lb HV transformer isn't likely to get easily
>>> knocked off the table, though!
>>>
>>> 73
>>>
>>> Peter G3RZP
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> ========================================
>>> Message Received: Nov 21 2005, 12:48 AM
>>> From: "Bill Turner"
>>> To: "wc6w@juno.com" , Amps@contesting.com
>>> Cc:
>>> Subject: Re: [Amps] 2 kW amp project
>>>
>>> At 09:54 AM 11/20/2005, wc6w@juno.com wrote:
>>>
>>>>Hi Bill,
>>>> Item #1 is easy. Get a surplus 48V switching power supply from
>>>> the telecom world.
>>>>
>>>> My best suggestion for #2 is a dual pi-net. 50 ohms to 500-1000
>>>> ohms back to 25-100 ohms. This provides both matching & harmonic
>>>> suppression. Two switched coils, 3 (small) vac. variables, plus
>>>> some ceramic padders for 80 & 160. Physically about 6" x 7" x 12"
>>>> including motor drives for the caps & 10 position bandswitch.
>>>>
>>>>73 & Good morning,
>>>> Marv WC6W
>>>
>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>
>>> Sounds good. I almost wish I hadn't started the 8877 project but it's
>>> too far along to stop now. :-)
>>>
>>> Where does one find the surplus telecom supplies? Can you suggest a
>>> manufacturer of new ones?
>>>
>>> 73, Bill W6WRT
>>>
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>>
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