Kim,
Why do we even talk about 3rd order IMD?
Does anybody even know?
The answer is obvious: the rules define specs for that, so that's what we talk
about.
The 3rd order IMD is measured with a two tone signal.
Why 2 tones?
The only mode using two tones is RTTY.
Voice has thousands of tones and harmonics come in other flavors than 3rd
harmonic.
We have , 2nd, 4th, 5th, 6th, 7th, and so on.
By good radios, the next higher harmonic is a few dB lower than the ones lower
than it.
But there are radios currently on the market where the 7th harmonic suddenly
shoots back up nearly as high as the 3rd harmonic.
And that's just with 2 tones.
Add in the human voice and you will have a boatload of bogus signals up and
down the band.
The reason people are not aware of this is because the ARRL doesn't test it and
Rob does, but he doesn't publish a list.
In order to understand the picture here, you have to go back nearly 10 years in
time and just look at ALL of the presentations Rob has made since then. In
each presentation he shows this kind of information for 3 or 4 transceivers and
from one year to the next, the model of the transceivers he is showing changes.
Nowhere can you find the information of all of them, without going through
lots of presentations (which I have taken the time to do).
IT IS SHOCKING!
BTW, Rob has now gone to testing IMD using white noise, which better resembles
the human voice than a 2-tone test.
If you are interested in this topic, you need to just go look at his material.
Most of it is posted on my web site, here:
http://www.dj0ip.de/transceivers/sherwood/
The best single presentation on transmitter IMD is a subset of his 2011 BARC
presentation.
On slides 24 thru 43 he explains a lot of this in detail, AND you can even
download the audio files (tape recording of Rob) for the 3 subsets of that
presentation. One of them is exclusively on transmitter technology. It is
58MB in size. It's here:
http://www.dj0ip.de/transceivers/sherwood/barc-new-in-2011/
73
Rick, DJ0IP
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Kimberly Elmore
Sent: Monday, July 01, 2013 7:15 PM
To: Discussion of Ten-Tec Equipment
Subject: [TenTec] Tx IMD and Purity
Rick, you make an excellent point! Are you speaking of only IMD performance? If
so, how good is good enough? Speaking only of 3rd order (O3) IMD, my old
TS-930S has O3 IMD of -35 dB while my Orion II has a worse value of -28 dB. The
best available may be the FT-2000D running class A, with O3 IMD below -41 dB
(the QST article noted that this was as low as the ARRL could measure). At -30
dB, the transmitted power of the O3 IMD with 100 W PEP is 0.1 W PEP. If I add a
(perfect) amp with ~12 dB of gain, I'll see 1.5 W PEP of transmitted O3 IMD. If
we were to set a target for transmit IMD numbers, what do you think it should
be? Is there something the manufacturers can do to meet these goals aside from
running everything class A? Should everything run off of a 28 V or 56 V supply
or...?
I'm sincere in my question because I don't know enough about PA design to know
if the manufacturers are cutting corners that make otherwise efficient
transmitters dirtier than they need to be.
73,
Kim N5OP
________________________________
From: Rick - DJ0IP / NJ0IP <Rick@DJ0IP.de>
To: 'Discussion of Ten-Tec Equipment' <tentec@contesting.com>
Sent: Monday, July 1, 2013 10:50 AM
Subject: Re: [TenTec] Orion II has ended production
But it affects all of us.
So it's our misery too.
BTW, though Ten-Tec doesn't produce any really bad ones, their signals are far
from being good.
The TX IMD of the Kenwood TS-590 is not particularly good . . . yet it is
better than my Eagle.
:-(
(so I work CW - hi).
73
Rick, DJ0IP
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of k6jek
Sent: Monday, July 01, 2013 5:46 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Orion II has ended production
Perhaps the lack of emphasis on transmit cleanliness is that it's somebody
else's misery
On Jul 1, 2013, at 8:34 AM, Rick - DJ0IP / NJ0IP wrote:
> Well if we are pointing out Rob Sherwood points, let's not forget that ONE
> BIG POINT he makes is, there is no further need to continue work on the
> receiver technology now, until we fix the dirty transmitters on the band.
>
> Why is it nobody ever wants to talk about this? Everyone talks receiver,
> receivers, receivers....
>
> A good receiver is one that does not crunch in the presence of a strong
> station on a neighboring channel.
> But if that station is a strong signal using many of today's rigs, driving an
> amp, he's not just on the neighboring channel.
> He's splattering across your frequency and there are no receiver features for
> removing that.
>
> 73
> Rick, DJ0IP
>
> -----Original Message-----
> From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Ted
> Bryant
> Sent: Monday, July 01, 2013 5:12 PM
> To: 'Discussion of Ten-Tec Equipment'
> Subject: Re: [TenTec] Orion II has ended production
>
> Amen, Bob.
>
> In addition to the audio issues in current radios, Sherwood has demonstrated
> how AGC performance can seriously affect the ability to copy stations in the
> presence of noise, especially pulse-type noise. AGC performance is yet
> another factor rarely mentioned and certainly not reflected in "the charts".
>
> A couple more interesting (and often overlooked) points that Sherwood makes:
> 1 - receiver requirements are more demanding for cw contesting/DXing
> than ssb
> 2 - a receiver with about 80db dynamic range is entirely adequate for
> most contesting/DXing situations
>
> 73, Ted W4NZ
>
>
> -----Original Message-----
> From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Bob
> McGraw - K4TAX
> Sent: Monday, July 01, 2013 10:08 AM
> To: Discussion of Ten-Tec Equipment
> Subject: Re: [TenTec] Orion II has ended production
>
> Rick brings forward a point which is one objection that I find with the use
> of the Sherwood Engineering report, i.e. "the charts".
>
> ***** Let me make it clear, Rob's test data and tests are very
> accurate, very useful and very valid. *****
>
> The fallacy is hams seem to believe solely in the ranking position on the
> report and they fail to acknowledge that radios are ranked according to ONE
> FACTOR only. They seem to neglect other factors which I find to equally
> or in some cases more important.
>
> To Ricks point, if a radio for example, is rated in the top 10 in the "chart"
> and it has poor audio as some do, then does this make it a great radio? My
> take, if it has a great receiver performance but has bad audio,
> it is a lousy radio. I agree totally with Rob's assessment presented at
> Dayton in that a radio must be easy to use and enjoyable to use. Failing
> these two points, it is not a "good" radio regardless of the numbers or the
> ranking position on the "charts".
>
> I've found that the Sherwood Engineering report can be downloaded to an EXCEL
> file where upon one can sort or parse the values based on 1 or 2 or 3
> different values or parameters. Still even with this, it does nothing to
> reveal the audio performance, TX performance or "use-ability" of a brand or
> model. To evaluate a product without having one side by side with another,
> the reports including the Sherwood Engineering report, the product review by
> ARRL Lab and by RSGB serve as outstanding sources. I suggest taking these
> reports and building ones own EXCEL spreadsheet to attain model by model
> paper comparison. Yet this still does nothing for the "usability" factor.
>
> In looking at the current "chart" publication (22 June 2013) , I find
> that 7 of the top 10 lines are USA made products. I think that
> certainly speaks well of US designed and manufactured products. This
> of course is based on ONE FACTOR only. :-)
>
>
> 73
> Bob, K4TAX
>
>
> ----- Original Message -----
> From: "Rick - DJ0IP / NJ0IP" <Rick@DJ0IP.de>
> To: "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
> Sent: Monday, July 01, 2013 3:08 AM
> Subject: Re: [TenTec] Orion II has ended production
>
>
>> Joe, don't just "take a look", use your ears and "listen" to the K3.
>>
>> I did, and I compared it to an Eagle, side by side for about a month.
>> I sold the K3. Crappy audio.
>> And NO, the firmware update did not fix it. It just improved it.
>> It's still bad audio.
>>
>> 73
>> Rick, DJ0IP
>>
>>
>> -----Original Message-----
>> From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Joe
>> W2KJ
>> Sent: Sunday, June 30, 2013 3:23 AM
>> To: Discussion of Ten-Tec Equipment
>> Subject: Re: [TenTec] Orion II has ended production
>>
>> Take a look at the Elecraft K3...it's receiver(s) are at the top of
>> the charts.
>>
>> I have a K3 and really enjoy using it...best receiver I have used in
>> 51 years of hamming...oh, and the QSK ain't bad either (grin).
>>
>> I sold my Orion a while back after being disappointed that Ten Tec
>> didn't really follow up on firmware updates for many months after
>> bugs were discovered and reported.
>>
>> With John Henry back in the company hopefully that won't be the case
>> anymore.
>>
>> Interested in what Ten Tec will follow the Orion family with.
>>
>> 73, Joe W2KJ
>>
>>
>>> That's my biggest concern that firmware development will cease...
>>>
>>>
>>>
>>> I hope until Ten-Tec has a replacement for it’s flagship it will
>>> continue to develop firmware releases for the Orion. I also hope
>>> the sub receiver upgrade will continue to be available for a
>>> while...been saving my pennies for that addition to my Orion II.
>>>
>>>
>>>
>>> It’s ashamed really...there is not another product in the market
>>> positioned where the Orion II sits. One has to spend a considerable
>>> amount of money above the cost of the Orion II to purchase a desktop
>>> transceiver (non-PC based) with the feature set the Orion II possesses.
>>> With Icom it’s the 7800 at $13000.00 or with Yaesu it’s the 5000 at
>>> I don’t know how much. (they dropped the 2000) Now Kenwood has the
>>> 990 but it’s too new to be fully sorted out and it’s a few K$ more than the
>>> OII....
>>>
>>>
>>>
>>> There are many radios out there...but few with dual receivers and
>>> dual tuning knobs which has become a must have in a DX radio for
>>> me.... Don’t do point and click radio’s either....
>>>
>>>
>>>
>>> Just a personal thing...
>>>
>>>
>>>
>>> Guess that makes the Elecraft K3 the winner....at lease one can
>>> start basic and grow it to the level of the radios mentioned above....
>>>
>>>
>>>
>>>
>>> Cecil Acuff
>>> Gulfport MS
>>> K5DL
>>>
>>>
>>> From: Kim Elmore
>>> Sent: June 29, 2013 4:06 PM
>>> To: Bob Gibson; Discussion of Ten-Tec Equipment
>>> CC: Discussion of Ten-Tec Equipment
>>> Subject: Re: [TenTec] Orion II has ended production
>>>
>>>
>>> All radios cease production at some point, so this was inevitable.
>>> It doesn't make our radios worthless or perform any worse.
>>>
>>> What's not clear is how much additional firmware development there
>>> will be in the future. I hope TenTec doesn't cease all development,
>>> but their resources are limited and we can't expect firmware
>>> development to continue indefinitely. Someday, firmware support will have
>>> to end.
>>>
>>> Kim N5OP
>>>
>>> "People that make music together cannot be enemies, at least as long
>>> as the music lasts." -- Paul Hindemith
>>>
>>> On Jun 29, 2013, at 15:54, Bob Gibson <w5rg@yahoo.com> wrote:
>>>
>>>> I wish I had known this two weeks ago when I bought a new one!!
>>>>
>>>> Bob Gibson W5RG
>>>>
>>>>
>>>> ________________________________
>>>> From: PC Anderson <xtraham58@hotmail.com>
>>>> To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
>>>> Sent: Saturday, June 29, 2013 2:30 PM
>>>> Subject: Re: [TenTec] Orion II has ended production
>>>>
>>>>
>>>> Looks like my comments were blocked.
>>>> Andy W3LI
>>>>
>>>>>
>>>>>
>>>>> Thanks for the heads up Ron.
>>>>>
>>>>> Guess I'm shaking my head at why they couldn't "Eaglize" the Orion
>>>>> RF design and update the controller/display/etc and end up with an
>>>>> Orion III.
>>>>> I love the Orion form factor.
>>>>>
>>>>> 73,
>>>>> Barry N1EU
>>>>>
>>>>> On Sat, Jun 29, 2013 at 6:14 PM, Ron Castro <ronc@sonic.net> wrote:
>>>>>
>>>>>> I just got this in the TenTec newsletter:
>>>>>>
>>>>>> "On a rather sad note, about the time you read this message, we
>>>>>> will have sold out of the last 566 Orion II transceiver.
>>>>>> Unfortunately, due to the availability of some very critical
>>>>>> parts plus skyrocketing prices for difficult components, the
>>>>>> staff at TEN-TEC decided to discontinue this product. This does
>>>>>> not mean we will not trade or sell used and demo Orion's and Orion II
>>>>>> models.
>>>>>> We will continue service and support this product as we have done
>>>>>> in the past with all TEN-TEC products. Is a new Orion III on the
>>>>>> horizon? There are plans for several new TEN-TEC products lined
>>>>>> up for the future but at this time no concise decision has been
>>>>>> made for another Orion transceiver."
>>>>>>
>>>>>> All good things come to an end...
>>>>>>
>>>>>> Ron Castro
>>>>>> N6IE
>>>>>> www.N6IE.com
>>>>>>
>>>>>> Member:
>>>>>> ARRL
>>>>>> Redwood Empire DX Assn.
>>>>>> Northern California Contest Club
>>>>>> Northern California DX Foundation
>
>
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