### Charly, you still don’t fathom the concept of bad TX IMD...on SSB !
You can have the very best RCVR on the planet, and it will do you NO good at
all, if the bozo
above / below your freq....is transmitting wideband IMD garbage. If you have
a 2nd spare XCVR..... put in on your desk, with perhaps a 2-6 inch piece of
wire stuffed into the
SO-239 for a temp antenna. Switch in some RX attenuation on the 2nd XCVR.
Then TX on your main xcvr...with and without the SPE amp...and listen with
headphones on the
temp 2nd xcvr. Then tune up /down on the 2nd xcvr...listening for IMD
crap. Also try switching in any speech processing..and u will see that the
imd crap gets a helluva lot louder
still. These days, you wont make any friends with a lousy TX signal. SPE
is delusional if they think they are building state of the art amps.
Jim VE7RF
From: Charles H
Sent: Monday, November 16, 2015 4:00 PM
To: Jim Thomson ; amps@contesting.com
Subject: RE: [Amps] SPE 1.3K-FA and FTDX-5KMP
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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