[Amps] IM Distortion

Wed Jun 28 08:16:06 EDT 2006

Does the new graphite tubes change any of the dynamic of the
discussion? i.e. 3-500Zg. It would appear the supposed extra
100 watts of plate dissipation should enable you to "Pump up
the Volume". Something that post dates the Eimac sheets  ...

ed K0KL

-----Original Message-----
From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com]On
Behalf Of amps-request at contesting.com
Sent: Tuesday, June 27, 2006 4:07 PM
To: amps at contesting.com
Subject: Amps Digest, Vol 42, Issue 75

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Today's Topics:

   1. Re: IM distortion and such (Will Matney)
   2. Re: IM distortion and such (Will Matney)
   3. Re: IM distortion and such (R L Measures)
   4. Re: IM distortion and such (R L Measures)
   5. Re: IM distortion and such (R L Measures)
   6. WTB: Johnson SK-650 or Johnson 124-109-1 socket (wc6w at juno.com)
   7. Re: IM distortion and such (Will Matney)

----------------------------------------------------------------------

Message: 1
Date: Tue, 27 Jun 2006 14:44:18 -0400
From: "Will Matney" <craxd1 at verizon.net>
Subject: Re: [Amps] IM distortion and such
To: amps at contesting.com
Message-ID: <200606271444180130.07AE73EF at outgoing.verizon.net>
Content-Type: text/plain; charset=us-ascii

Tom,

No, your not showing everything I said. It does in fact mention "Two-Tone DC
Plate Current 280 mA" It lists it in the same place with two different
currents that would cause the same result (with single tone). That would be
the only reason to place both under the same title. Though this is for class
B, I said in a later e-mail that I know IMD would be better under class AB
or B. Actually the IMD shown drops 5 dB by dropping the plate voltage and
the plate current a small amount under another reference in the spec sheet
before this.

For some odd reason, during the last 3-4 days, my mails to this list are not
posting as soon as I send them. It is like they are being delayed by a few
hours sometimes before they are posted. Some of these reference mail I have
sent but hasn't been posted yet.

Again Quote;

RF Linear Amplifier
Grounded-Grid, Class B

Maximum Ratings

Typical operation (Minimum distortion products at 1 KW PEP input)**
DC Plate Voltage 2500V
Zero Signal DC Plate Current* 130 mA
Single-Tone DC Plate Current 400 mA
Single-Tone DC Grid Current 120 mA
Two-Tone DC Plate Current 280 mA
Two-Tone DC Grid Current 70 mA
Peak Envelope Useful Output Power 600W
Resonant Load Impedance 3450 Ohms
Intermodulation Distortion Products -33 dB

*Approximate Value
** Measured Data From A Single Tube

End Quote

Better IMD was obtained by lowering the plate voltage under "(Minimum
Distortion Products)" at -38 dB, 500W, and at 2000 Vdc.

Best,

Will

*********** REPLY SEPARATOR  ***********

On 6/27/06 at 2:22 PM Tom W8JI wrote:

>> Tom,
>>
>> It says it on page two of the Eimac 3-500Z spec sheet. See
>> the one the link was provided for earlier.
>
>Single tone carrier level has absolutely nothing to do with
>operation in a different set of conditions such as two-tone
>modulation at a different anode voltage, bias, and power
>level. You are reading more into the data sheet than it is
>saying.
>
>For a given set of tuning conditions (load line) a person
>can make the single tone level any level he wants by varying
>drive and the two-tone test will remain the same as long as
>the two-tone power level isn't changed. Single tone and
>two-tone are two totally different conditions, and as the
>data sheets say other operation is permissible.
>
>Two other random people besides myself have now posted that
>the did the equivalent of a transfer function (which is what
>really measures linearity) and both posted the best
>linearity when the steady-state loadline was established at
>about 550mA. Actual performance under one set of conditions
>cannot be determined by extracting data from a test under
>totally different conditions.
>
>73 Tom
>
>
>_______________________________________________
>Amps mailing list
>Amps at contesting.com
>http://lists.contesting.com/mailman/listinfo/amps

------------------------------

Message: 2
Date: Tue, 27 Jun 2006 16:37:30 -0400
From: "Will Matney" <craxd1 at verizon.net>
Subject: Re: [Amps] IM distortion and such
To: r at somis.org, amps at contesting.com
Message-ID: <200606271637300990.08161EA1 at outgoing.verizon.net>
Content-Type: text/plain; charset=us-ascii

It's in the PDF file that was posted by someone earlier. There was nothing
in it though about class AB RF amp operation.

http://www.mif.pg.gda.pl/homepages/frank/sheets/088/3/3-500Z.pdf

Best,

Will

*********** REPLY SEPARATOR  ***********

On 6/27/06 at 1:31 PM R L Measures wrote:

>On Jun 27, 2006, at 6:51 AM, Will Matney wrote:
>
>> Rich,
>>
>> It was the same thing as they printed it I was refering, or to me
>> it was as I wrote it. It was Eimacs maximum rating at 1 KW input, G-
>> G, class B RF amp showing it's minimum distortion, or the way they
>> have it listed.
>
>I have seen no info from Eimac on Class B for the 3-500Z.
>>
>> Best,
>>
>> Will
>>
>> *********** REPLY SEPARATOR  ***********
>>
>> On 6/27/06 at 6:19 AM R L Measures wrote:
>>
>>> On Jun 27, 2006, at 2:46 AM, Tom W8JI wrote:
>>>
>>>>> They can be used on up in current, say for pulse circuits
>>>>> and RF heating. The 400 mA is the maximum plate current at
>>>>> single tone for minimum distortion. That's for 600 watts
>>>>> PEP useful power each. That's listed in the tables on page
>>>>> 2 or 3 under a class B RF amp.
>>>>
>>>> Will,
>>>>
>>>> Where did you get the idea 400mA is a "minimum distortion"
>>>> condition?
>>>
>>> Good point, Tom.  Will should have said something like:  for minimal
>>> distortion, the max rated anode-I is 400mA.
>>>>
>>>> 73 Tom
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Amps mailing list
>>>> Amps at contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>>
>>>
>>> R L MEASURES, AG6K. 805-386-3734
>>> r at somis.org
>>
>>
>>
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>
>R L MEASURES, AG6K. 805-386-3734
>r at somis.org

------------------------------

Message: 3
Date: Tue, 27 Jun 2006 13:11:23 -0700
From: R L Measures <r at somis.org>
Subject: Re: [Amps] IM distortion and such
To: "Tom W8JI" <w8ji at w8ji.com>
Cc: amps at contesting.com
Message-ID: <5C0B4587-16AC-471C-8C86-370583FA370B at somis.org>
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed

On Jun 27, 2006, at 11:22 AM, Tom W8JI wrote:

>> Tom,
>>
>> It says it on page two of the Eimac 3-500Z spec sheet. See
>> the one the link was provided for earlier.
>
> Single tone carrier level has absolutely nothing to do with
> operation in a different set of conditions such as two-tone
> modulation at a different anode voltage, bias, and power
> level. You are reading more into the data sheet than it is
> saying.

As I see it, no matter what kind of modulation one is trying to
amplify, at the point when an incremental increase in input no longer
increases output (which call the transfer function) by the same
factor as was observed at lesser currents, the cathode is running out
steam and the tube is beginning to lose linearity.  Even though there
is a 3a line on the 3-500Z/ 8002 characteristic curves, does this
mean that all will be well in linear service at 3 peak anode
amperes?  If this were the case, at 4kV, single 3-500 linear
amplifiers could produce 2500w PEP.

OTOH, Tom may be right in saying that tuning up at 550mA produces
good linearity in an AL-80 or SB-1000, but from the impure matter I
hear from these two amps on the air that are driven with 100w, I have
doubts.
>
> For a given set of tuning conditions (load line) a person
> can make the single tone level any level he wants by varying
> drive and the two-tone test will remain the same as long as
> the two-tone power level isn't changed. Single tone and
> two-tone are two totally different conditions, and as the
> data sheets say other operation is permissible.

But there can be no help if the cathode is running out of emission.
>
> Two other random people

What are their callsigns, e-mail addresses, and telephone numbers?

> besides myself have now posted that
> the did the equivalent of a transfer function (which is what
> really measures linearity) and both posted the best
> linearity when the steady-state loadline was established at
> about 550mA.

I don't see how because 550mA corresponds to c. 1650mA peak, which is
well into the non-linear region.

> Actual performance under one set of conditions
> cannot be determined by extracting data from a test under
> totally different conditions.

Peak emission capability is negotiable?

cheerz, Tom
>
> 73 Tom
>
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>

R L MEASURES, AG6K. 805-386-3734
r at somis.org

------------------------------

Message: 4
Date: Tue, 27 Jun 2006 13:28:13 -0700
From: R L Measures <r at somis.org>
Subject: Re: [Amps] IM distortion and such
To: "Joe Subich, W4TV" <w4tv at subich.com>
Cc: amps at contesting.com
Message-ID: <184482BA-C1F0-4E39-802D-D4B4BB8ED09E at somis.org>
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed

On Jun 27, 2006, at 9:39 AM, Joe Subich, W4TV wrote:

>
> No, Will should have said "for minimum distortion at 1 KW PEP
> input and class B service at 2500 Volts, the maximum plate
> current at single tone ..."
>
> There is no indication that 1KW PEP class B produces more or
> less distortion that say 1500 W PEP in class AB2 at 3000 V
> on the plate.  You cannot arbitrarily apply one set of conditions
> to a completely different set of circumstances.
>
Class B has zero ZSAG.  Class AB2's ZSAG is typically 20% of  I-anode
max.  For Producing IMD, Class B is the queen bee.
> 73,
>
>    ... Joe, W4TV
>
>
>> -----Original Message-----
>> From: amps-bounces at contesting.com
>> [mailto:amps-bounces at contesting.com] On Behalf Of R L Measures
>> Sent: Tuesday, June 27, 2006 9:20 AM
>> To: Tom W8JI
>> Cc: craxd1 at verizon.net; amps at contesting.com
>> Subject: Re: [Amps] IM distortion and such
>>
>>
>>
>> On Jun 27, 2006, at 2:46 AM, Tom W8JI wrote:
>>
>>>> They can be used on up in current, say for pulse circuits
>>>> and RF heating. The 400 mA is the maximum plate current at
>>>> single tone for minimum distortion. That's for 600 watts
>>>> PEP useful power each. That's listed in the tables on page
>>>> 2 or 3 under a class B RF amp.
>>>
>>> Will,
>>>
>>> Where did you get the idea 400mA is a "minimum distortion"
>>> condition?
>>
>> Good point, Tom.  Will should have said something like:  for minimal
>> distortion, the max rated anode-I is 400mA.
>>>
>>> 73 Tom
>>>
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> Amps mailing list
>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>
>> R L MEASURES, AG6K. 805-386-3734
>> r at somis.org
>>
>>
>>
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
>
>

R L MEASURES, AG6K. 805-386-3734
r at somis.org

------------------------------

Message: 5
Date: Tue, 27 Jun 2006 13:31:08 -0700
From: R L Measures <r at somis.org>
Subject: Re: [Amps] IM distortion and such
To: craxd1 at verizon.net
Cc: amps at contesting.com
Message-ID: <8E7B071D-D953-4B2A-A6E5-016EED4448A8 at somis.org>
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed

On Jun 27, 2006, at 6:51 AM, Will Matney wrote:

> Rich,
>
> It was the same thing as they printed it I was refering, or to me
> it was as I wrote it. It was Eimacs maximum rating at 1 KW input, G-
> G, class B RF amp showing it's minimum distortion, or the way they
> have it listed.

I have seen no info from Eimac on Class B for the 3-500Z.
>
> Best,
>
> Will
>
> *********** REPLY SEPARATOR  ***********
>
> On 6/27/06 at 6:19 AM R L Measures wrote:
>
>> On Jun 27, 2006, at 2:46 AM, Tom W8JI wrote:
>>
>>>> They can be used on up in current, say for pulse circuits
>>>> and RF heating. The 400 mA is the maximum plate current at
>>>> single tone for minimum distortion. That's for 600 watts
>>>> PEP useful power each. That's listed in the tables on page
>>>> 2 or 3 under a class B RF amp.
>>>
>>> Will,
>>>
>>> Where did you get the idea 400mA is a "minimum distortion"
>>> condition?
>>
>> Good point, Tom.  Will should have said something like:  for minimal
>> distortion, the max rated anode-I is 400mA.
>>>
>>> 73 Tom
>>>
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> Amps mailing list
>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>
>> R L MEASURES, AG6K. 805-386-3734
>> r at somis.org
>
>
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>

R L MEASURES, AG6K. 805-386-3734
r at somis.org

------------------------------

Message: 6
Date: Tue, 27 Jun 2006 20:59:41 GMT
From: "wc6w at juno.com" <wc6w at juno.com>
Subject: [Amps] WTB: Johnson SK-650 or Johnson 124-109-1 socket
To: amps at contesting.com
Message-ID: <20060627.140039.10883.295404 at webmail28.lax.untd.com>
Content-Type: text/plain

QST

Anyone on the group happen to have an extra Eimac SK-650 socket handy?
 Or a Johnson 124-109-1

This is the all white plastic version, no metal frame or mounting ears,
which accetps the 4CX250 family.

I just need one.

73 & Good afternoon,
   Marv WC6W

*

________________________________________________________________________
Try Juno Platinum for Free! Then, only $9.95/month!
Unlimited Internet Access with 1GB of Email Storage.
Visit http://www.juno.com/value to sign up today!

------------------------------

Message: 7
Date: Tue, 27 Jun 2006 16:58:08 -0400
From: "Will Matney" <craxd1 at verizon.net>
Subject: Re: [Amps] IM distortion and such
To: r at somis.org, amps at contesting.com
Message-ID: <200606271658080950.08290331 at outgoing.verizon.net>
Content-Type: text/plain; charset=us-ascii

Ok,

I went and pulled my Eimac book down. I hadn't earlier where it was at as I
couldn't hardly reach it from my wheelchair.
I guess I need shorter book shelves : ) Anyhow, this one does have the Class
AB2 listed as below from page 2. Strangely, this one does not mention class
B like the pdf did.

Quote;

Radio frequency Linear Amplifier
Cathode driven
Class AB2

Maximum Ratings:

DC plate voltage 4000 Vdc
DC plate current 0.4 ampere
Plate dissapation 500 watts
Grid dissapation 20 watts

Typical operation (Frequencies to 110 MHz)
Class AB2, peak envelope or modulation crest conditions

>>(Here I'm going to show the maximum plate voltage they show of 3500 Vdc)

Plate voltage 3500 Vdc
Cathode voltage +15 (+10 at 3000 and 0 at 2500)
Zero signal plate current 53 mA
Single-tone plate current, CW 3/4 400 mA
Two-tone plate current 262 mA
Single-tone grid current  108 mA
Two-tone grid current 58 mA
Single-tone power input 1400 W
Useful output power, CW or PEP 890 W
Resonant load impedance 5000 ohms
Intermodulation distortion products;
3rd order -40 dB
5th order -45 dB

Single-tone current for 3500 Vdc operation may reach this value during short
periods of circuit adjustment only.

IMD products are referenced against one tone of a two equal tone signal.

Currents listed corrospond to SSB, or "two-tone" average current at peak of
signal envelope.

End Quote.

Best,

Will

*********** REPLY SEPARATOR  ***********

On 6/27/06 at 1:31 PM R L Measures wrote:

>On Jun 27, 2006, at 6:51 AM, Will Matney wrote:
>
>> Rich,
>>
>> It was the same thing as they printed it I was refering, or to me
>> it was as I wrote it. It was Eimacs maximum rating at 1 KW input, G-
>> G, class B RF amp showing it's minimum distortion, or the way they
>> have it listed.
>
>I have seen no info from Eimac on Class B for the 3-500Z.
>>
>> Best,
>>
>> Will
>>
>> *********** REPLY SEPARATOR  ***********
>>
>> On 6/27/06 at 6:19 AM R L Measures wrote:
>>
>>> On Jun 27, 2006, at 2:46 AM, Tom W8JI wrote:
>>>
>>>>> They can be used on up in current, say for pulse circuits
>>>>> and RF heating. The 400 mA is the maximum plate current at
>>>>> single tone for minimum distortion. That's for 600 watts
>>>>> PEP useful power each. That's listed in the tables on page
>>>>> 2 or 3 under a class B RF amp.
>>>>
>>>> Will,
>>>>
>>>> Where did you get the idea 400mA is a "minimum distortion"
>>>> condition?
>>>
>>> Good point, Tom.  Will should have said something like:  for minimal
>>> distortion, the max rated anode-I is 400mA.
>>>>
>>>> 73 Tom
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Amps mailing list
>>>> Amps at contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>>
>>>
>>> R L MEASURES, AG6K. 805-386-3734
>>> r at somis.org
>>
>>
>>
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>
>R L MEASURES, AG6K. 805-386-3734
>r at somis.org

------------------------------

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End of Amps Digest, Vol 42, Issue 75
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