Leigh, with all the great rcvrs out there, I do not worry about my transmitted
signal. Whenever a ham has the urge to write or even worry about IMD, he
should instead go visit a shut-in or a nursing home and cheer people up. 73,
Charly
> From: jim.thom@telus.net
> To: amps@contesting.com
> Date: Mon, 16 Nov 2015 02:49:29 -0800
> Subject: [Amps] SPE 1.3K-FA and FTDX-5KMP
>
> Date: Sat, 14 Nov 2015 08:28:13 +1030
> From: "Leigh Turner" <invertech@frontierisp.net.au>
> To: <amps@contesting.com>
> Subject: Re: [Amps] SPE 1.3K-FA and FTDX-5KMP
>
>
> Charly, sadly there's an over-hyped obsession out there about Tx purity and
> associated IMD specs for ham rigs....
>
> Having said that many current SS amp offerings are poor performers in this
> regard when driven to their rated PEP output :-(
>
> Leigh
> VK5KLT
>
> ### Leigh, the yaesu FTDX-5000MP uses a PAIR of VRF-1511Gs. They are the
> 170 vdc rated version of the MRF-151G..... ( 50-60 vdc rated).
>
> ## Now comes along SPE..with its 2.0K...running a whopping 2 kw pep output
> from
> just SIX MRF-151Gs. Now if SPE can achieve 2000w pep from 6 x devices,
> then
> yaesu should be able to get 666 watts pep from 2 x devices. Can you
> imagine the
> FTDX-5K running 666 w pep out ? Well it would fare a little better than
> the SPE junk.
>
> ## at least yaesu, and also the SS in the ARRL handbook, both used
> VRF-151Gs.
> SPE didn’t even use the correct version of the 151G. The SS devices usually
> fare a
> lot better with higher voltages, with reduced imd being the result. If
> folks want to
> run high power on ssb, then at least take advantage in the latest and
> greatest in
> technology..and use the 170 vdc rated VRF-151G. doesn’t cost anymore
> than the MRF-151G. The VRF-151G has been out for several years now...
> its old news really. Perhaps SPE didn’t get the memo ?
>
> ## Like I mentioned b4, that SPE 6 x MRF-151G amp is a 600-750 watt pep
> output max amp on ssb, that’s it. 2000w pep out from it would be 4 steps
> below an imd garage truck. And no, the FCC etc, don’t regulate crap IMD
> on the ham bands. No specs, no regulations pertaining to IMD, be as wide
> as you want, as long as its within the ham bands etc.
>
> ## yaesu in class A..... driving any of the 3 x spe amps... to rated
> output =
> IMD garbage. But folks like charly say they only look at one spec... rated
> pep
> out on ssb.
>
> ## BTW, if you look through the online SPE manuals, they say not to use
> speech processing,
> since this increases the duty cycle on the ss amp..and it will cook. (it
> will also increase the average power in the
> imd products, so the imd will then sound even louder).
>
> ## No folks, SPE didn’t get it right. They are selling you a bill of
> goods. End of story.
>
> Jim VE7RF
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