[Elecraft] Ten Tec never sounded so good!

[Joe Subich, W4TV]

> For all those intent on boosting low power radios with a 
> cheap external PA, you can see measurements here: 
> http://www.w8ji.com/rm_hla-150_test.htm
> 
> The very best the RM Italy amp gets on *any band at any 
> power* is about like a FT1000MP on the very WORSE band for 
> the MP.

If you had not documented that the transistors were only rated 
for 70W PEP, I would have thought that one of the push-pull pair 
was open with those results.  I don't know what transistors 
are but those IM plots would suggest the bias is incorrect - 
which might be logical if RM Italia are using an undersized 
heatsink. 

> There is no convincing people that our 100 watt radios at 
> 100 watts are barely acceptable as is, and that all these 
> little tricks that give another 1-2 dB more power can 
> increase splatter 15 dB or more. Worse yet, those cheap 
> illegal amplifiers that make 10-watt radios into 100 watters 
> are going to be our undoing.

Very true ... we would be better off with 48V transistors 
with power levels below 200W PEP.  There are several devices 
capable of 3rd and 5th order IMD better than -40 dB at that 
power level. 

73, 

   ... Joe, W4TV 
 



> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Tom W8JI
> Sent: Thursday, April 15, 2010 7:11 AM
> To: Gary Gregory; lstavenhagen
> Cc: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] Ten Tec never sounded so good!
> 
> 
> << On SSB it isn't so much the folks on ESSB, although we 
> have a few of those
> here also unfortunately, but rather the poorly adjusted 1KW 
> plus amplifierrs
> and badly adjusted audio that causes me to screw up my nose 
> and do a quick
> QSY..(:-))>>
> 
> If we are every going to fix things we need to honestly 
> discuss the real problems.
> 
> I have been doing a survey of ops on 20 and 40 meters with 
> very bad signals, and nearly all the nasty signals were not 
> high power. Most, after I broke in for a friendly chat, we 
> running small amps and just mistuning or overdriving them. 
> A significant number had "peaked" their radios up and were 
> running a bit more output from a 100 watt radio. As a matter 
> of fact a contestor who brought his FT1000MP's to me had his 
> 100 watt radios screwed up to 130-140 watts, so this may be 
> a more common practice then we think. I lowered his radios 
> to 100 watts, and after a while when the radios came back 
> for another update they were back up to 130-140 watts again. 
> At that power level the radios had IM3 in the -20 dB PEP 
> range, and products out to the 17th order were still strong.
> 
> For all those intent on boosting low power radios with a 
> cheap external PA, you can see measurements here: 
> http://www.w8ji.com/rm_hla-150_test.htm
> 
> The very best the RM Italy amp gets on *any band at any 
> power* is about like a FT1000MP on the very WORSE band for 
> the MP.
> 
> There is no convincing people that our 100 watt radios at 
> 100 watts are barely acceptable as is, and that all these 
> little tricks that give another 1-2 dB more power can 
> increase splatter 15 dB or more. Worse yet, those cheap 
> illegal amplifiers that make 10-watt radios into 100 watters 
> are going to be our undoing.
> 
> 73 Tom 
> 
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