There was a YouTube video showing
the output of the amp, running ~ 1KW,
being shorted with a big screwdriver.
Lots of sparks, but no damage to the
device.
I think they can put some form of VSWR
protection right on the chip.
BTW, I own an SPE 1.3K-FA, great Amp.
73, Dick, W1KSZ
On Tue, Dec 6, 2016 at 7:26 AM, Catherine James <catherine.james@att.net>
wrote:
> Is that VSWR of 65:1 key-down transmit at 1,700 watts, without any
> pulsing? So if I accidentally transmit normal hand-sent slow CW into a bad
> antenna mismatch, no damage will occur?
>
> I've gotten really suspicious of those high SWR claims for solid-state
> power devices because they are always qualified heavily by duty cycle.
>
> --Cathy
>
> --------------------------------------------
> On Tue, 12/6/16, Ken Durand <N4zed@comcast.net> wrote:
>
> Subject: Re: [Amps] Stock up on tubes?
> To: "'Jim Thomson'" <jim.thom@telus.net>, amps@contesting.com
> Date: Tuesday, December 6, 2016, 4:14 AM
>
> Ampleon has added a new
> LDMOS power transistor to its family of extremely rugged
> power transistors designed specifically for use in high
> power amplifiers operating in the 10 to 500 MHz. Suiting use
> in a wide variety of broadcast and industrial applications,
> and capable of operating with a VSWR up to 65:1, the device
> is rated to deliver 1,700 Watt CW or 1,900 Watt pulsed.
>
>
> https://www.everythingrf.com/News/details/3046-1900-watt-
> ldmos-power-transistor-for-broadcast-industrial-and-medical-applications
>
> Ken
> N4zed
>
> -----Original Message-----
> From: Amps [mailto:amps-bounces@contesting.com]
> On Behalf Of Jim Thomson
> Sent: Monday,
> December 05, 2016 11:05 PM
> To: amps@contesting.com
> Subject: [Amps] Stock up on tubes?
>
> Date: Sun, 4 Dec 2016 22:48:45
> +0000
> From: Bill Turner <dezrat@outlook.com>
> To: Amps group <amps@contesting.com>
> Subject: Re: [Amps] Stock up on tubes?
>
>
> On Sun, 4 Dec
> 2016 15:43:53 -0600, Kim wrote:
>
> >When the SS devices are as easy to use
> *and* and cheap enough to meet
> >our
> current hollow state device's price point, vacuum tubes
> will go the
> >way of the dodo. We're
> progressing rapidly towards that, but it'll be a while,
> yet.
>
> REPLY:
>
> In terms of the device itself,
> that day is already here. The LDMOS devices from NXP are
> fully capable of replacing tubes in a legal limit amp and
> the price already beats tubes too. A pair of them that
> easily puts out 1500 watts is around $400. Compare that to
> an 8877.
>
> You can be sure
> designers are working hard to build the circuitry around
> them that will soon make tubes pretty much obsolete.
>
> FlexRadio already has a legal
> limit amp that is awaiting FCC approval using said devices
> and they expect approval before the end of the year.
>
> As with everything, time will
> tell.
>
> 73, Bill W6WRT
>
> ## Problem with SS is.....
> they typ only run 50% eff. To get 1.5 kw CCS output
> on
> RTTY / FM, data modes, you require 3
> kw dc input. 3000-1500 = 1500 W CCS
> dissipation..
> = 5115 BTUs.
>
> ## 1500 watts CCS
> dissipation is one helluva lot of heat to try and
> dump....which is not going to
> be quiet
> anytime soon. That would be a feat in itself...
> just check out dishtronic.
>
> ## Then you require a myriad of 2 kw CCS
> rated LP filters, and be able to relay switch em.
>
> ## Then you require the 2 kw
> CCS rated auto tuner...so the SS amp doesnt blow its
> brains out....
> ditto with the myriad of LP
> filters...and associated relays.
> Plan B
> is use enough devices so its rated for 2.5 kw out into a
> 1:1 SWR, so it will handle 1.5 kw
> into
> a 2:1 swr. Then use LP filters that will
> handle 1.5 kw CCS into high swr.
>
> ## Then you require the 50 –100
> vdc switching type power supply... but that is
> not an issue these days.
>
> ## Then cross your fingers that the end
> product doesnt have lousy IMD... like dishtronics –30 db
> pep ( IMD-3),
> which is no better than any
> sweep tube amp from the 70s.
>
> ## an auto tune tube amp is
> still the biggest bang for the buck..for
> now. Any manual tune tube amp
> is an even bigger bang for the buck....
> provided you dont require instant band change.
>
> Jim VE7RF
>
>
>
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