[TenTec] RF Speech Processor

Bob McGraw - K4TAX RMcGraw at Blomand.net
Fri Jun 14 09:25:44 EDT 2013

While DX operation demands certain artifacts of sound to be successful,  the 
issue remains that today's RF PA's operating on 13 volts have a significant 
amount of transmitted IMD products.  Increasing the average power with 
processing only adds to the IMD artifacts which does affect other users on 
the bands.   Is this good operating practice?   Certainly this is not the 
way I was taught but seems to be the result of inconsiderate operators with 
an "all for me" attitude and mentality.

Personally today I find many hams do have bad or poor sounding signals on 
the air while very few having great sounding signals.  The pollution on the 
bands is clearly increasing, largely due to stations affected with RFI 
issues, excessive processing and over driven stages from poor operator 

Just this morning on a 75 meter net with 85 stations checked in,  there were 
some 7 stations noted to have really bad sounding signals due to RF issues. 
Of these 7  being 8.2% of those that checked into the net, there were 2 
which were nearly unreadable although the signal strength was clearly above 
S 9.     These 7 stations were not using Tentec radios either.  Once they 
were advised of such and they reduced the speech processing level or reduced 
the mike gain the issue was mostly cleared although RF splatter was noted on 
voice peaks.

Folks, we need to not only press the radio designers and manufactures to 
produce radios with better IMD characteristics, but also we must strive to 
educate operators that "all knobs to the right" and efforts to make the watt 
meter move higher up scale will not make for a better signal.

Bob, K4TAX

----- Original Message ----- 
From: <dhhdeh at comcast.net>
To: <tentec at contesting.com>
Sent: Friday, June 14, 2013 7:57 AM
Subject: [TenTec] RF Speech Processor

> Gary is 100% correct if your objective is to work rare DX in a competitive 
> environment. This can be configured as he describes with great success 
> towards that end.
> Back in the 1970's one of my good friends and DX mentor who was, and is, a 
> top DX'er around here (#1DXCC, Worked All Counties X4, Worked All Oblasts, 
> high scores in the DX contests etc) ran a TR-7 with no on-board processor 
> into two VOMAX RF processors in series (very similar to the TT 234 and 
> today's digital 715) into a L4-B and then to a 4 element wide spaced 20m 
> monobander at 75 feet. A big gun DX'er he was.
> It wasn't pretty sounding but there was no pileup of that era that he 
> could not crack with more than three calls. None.
> I used to tell him that it sounded like "war" mode but it worked marvels 
> for his DXing objective back then.
> My experience with the 715 using it with my Omni V.9, Corsair II and now 
> my Omni VII is that it gives my signal the presence similar to having a 
> 600 watt amp in line. And if I really need that contact, I occasionally 
> use it in series with the rig's on-board SP with similar results to what 
> Gary describes, being careful of how much of each to use. No tower, beam 
> or linear here and with #348 for DXCC..... It works.
> 73 de N1LQ-Dave
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