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Re: [TenTec] Dirty Transmitters - Flex and Yaesu

To: tentec@contesting.com
Subject: Re: [TenTec] Dirty Transmitters - Flex and Yaesu
From: Jim Brown <k9yc@audiosystemsgroup.com>
Reply-to: k9yc@arrl.net, Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Wed, 9 Dec 2015 17:19:54 -0800
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
On Wed,12/9/2015 4:34 PM, terry foskey via TenTec wrote:
  Jim,I am in engineering, questioning why and developing designs, it's what I 
do. I have commercial and Amateur licenses. The rule you provide for Ham 
operations is true, however, the passage can be interpreted many ways and I 
stand my statement there is no specific rule being violated.

It is, but you're looking for a number. The rule is written so that the "number" is dictated by the state of the art. It allows the Rules to progress with developments in ham radio manufacturing. I serve on an international standards committee, and we have written Standards in exactly that way, and for that exact reason.

Elecraft has set the state of the art with an expensive rig, Kenwood has further defined it with a moderately priced rig. I would thus define what Kenwood has done as "the state of the art" for the masses.

  What we consider dirty today is light years better than the transmitters of 
old.

Which is why the Rules are written as they are.

Regarding performing real world operational tests, I have conducted enough 
operational tests on US combat aircraft and been involved with testing of US 
Navy vessels to know that labs and real world aren't the same.  Many factors 
come into play regarding the real effects described as coming from dirty 
transmitters, such as quality of receiver front ends,

Nope. The quality of receiver front ends is part of the SYSTEM, but not part of the transmitter. We're talking TRANSMITTERS.
  mode of operation (your bandwidth FCC quote comes into play), etc.

I suggest that you borrow a K3 with a P3 and start looking at real signals on the air. On SSB band, you'll see signals splattering above and below what should be a 2.8 kHz wide bandwidth (I'm not talking ESSB, I talking about sidebands above the cutoff of the SSB TX filter and BELOW the suppressed carrier frequency of an USB signal). On the CW bands, you'll see signals that are more than 50 dB down at +/- 300 Hz, and you see signals that are only 25 dB down at 1 kHz! The former are mostly K3s (and a few Flex rigs with their new firmware).

The mode can simply enhance or lessen the effects.

No, the distortions present in the equipment and the limitations of the rigs involved is what changes what you observe.

  My demonstration is my desire to satisfy my personal curiosity -  I want to 
witness the issue or non-issue being described in the lab and I will be using 
two of the worst listed corporate violators based on forum Opinions ie Flex and 
Yaesu.

Your information on Flex is a bit old. Their 5000 series was a dog for trash, and the version of the 6500 that ARRL tested a year or two ago was pretty dirty, but the word I've heard is that firmware released soon after cleaned it up a lot. I've been trying to borrow on to measure to confirm that.

Regarding your choice to upgrade, I am sure Elecraft appreciates your monetary 
and verbal support.  Remember to upgrade again once the bar is raised higher.

Yep. They just raised the bar with the newly designed synthesizer developed for their upgraded K3S, and made the synth board available as an upgrade for K3 owners. I upgraded my three K3s almost immediately. Tests by Rob Sherwood and ARRL Labs show quite significant improvement of phase noise on both RX and TX, as well as significantly reduced TX bandwidth.

Perhaps TenTec will satisfy your need to upgrade with an Omni VII plus or an 
Orion III.

Those synth boards sell for about $240, and get me 90% of the way from a 2007 rig to the brand new 2015 version. Compare that with the cost of going from an Orion I to an Orion II. With a company philosophy like that, it will take a lot to cause me to change horses. :) AND -- Elecraft is a stable US company, whose two principals are EEs and active hams who read their own email reflector every day to keep in touch with their customers.

73, Jim K9YC

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