[TenTec] OMNI VII vs. K3 ? Opinions invited.,

[Rick - NJ0IP / DJ0IP]

As always Sinisa, you are correct.
Nice to hear from you again!

The one place I have seen a difference is when trying to tune a linear.
While varying the power on any Ten-Tec, and tuning the amp, it simply varies
the output power of the amp.
I've had JA makes that seemed to jump around, like they would suddenly
reduce power.
Then I wasn't sure if the input power had dropped or if it was the settings
of the amp causing the change.

In any case I preferred the way the Ten-Tec tuned.

Now something to think about.
If I run 100w on the Ten-Tec and 40 watts are reflected, then as you say,
the amp or antenna receive 60w.
If my non TT rig reduces the power to 60w, due to high SWR, it is putting
out 60W but it is only driving the load with about 40w.
Or is my thinking wrong?

73
Rick

-----Original Message-----
From: tentec-bounces at contesting.com [mailto:tentec-bounces at contesting.com]
On Behalf Of shristov
Sent: Sunday, April 25, 2010 9:56 AM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] OMNI VII vs. K3 ? Opinions invited.,


Rick - NJ0IP / DJ0IP <Rick at DJ0IP.de> wrote:

> ... this full power into 3:1 SWR


Hi Rick,


"full power into 3:1 SWR" is just a myth.
Did you ever read such a claim made by TenTec?

There is nothing inside TenTec transceivers to make them to DELIVER full
power into a mismatched load.

TenTec transceiver do not DELIVER full power into a mismatched load.
They just fail to reduce the drive with high SWR because they mis such a
circuitry.
Consequently, the FORWARD power stays the same, at 100 W.

But we must remeber that:

  DELIVERED power = FORWARD power - REFLECTED power.

Power meters inside Orion, Omni VII, and virtually all the other rigs
display FORWARD, not DELIVERED power.

With SWR = 3, we have:
  FORWARD power = 100 W
  REFLECTED power = 25 W
  DELIVERED power = 75 W

Similarly, with SWR = 10, we would have:
  FORWARD power = 100 W
  REFLECTED power = 67 W
  DELIVERED power = 33 W

The only thing that can make PA deliver full power into a mismatched load
is, of couse, a tuner.
TenTec transceivers are no exception.


73,

Sinisa  YT1NT, VE3EA