[Amps] Amps Digest, Vol 101, Issue 24
W8HW
w8hw at att.net
Wed May 18 08:51:42 PDT 2011
PA Efficiency is often miss-understood. In general it is Power out / all
power in, as defined by the FCC. Lets take a closer look at this.
The problem is that most people do remember the DC input to plate, but
forget or miss-understand that Power in also includes drive power and Screen
(if used). It is all power in, which makes since because that is what
efficiency is (all power out dived by all power consumed) by a device, in
this case the final amplifier. The difference is heat (thus lost power)
regardless if it is because of plate, screen, grid or tank circuit or
other. The FCC does not include filament power. Not only did we have to do
that in broadcasting, but in the "old days", that was how the FCC defined it
for ham radio, a fact that is often forgotten. It is easy to forget. Hope
this helps.
73, Bruce, W8HW, w8hw at att.net
I buy or service broke radios
----- Original Message -----
From: <amps-request at contesting.com>
To: <amps at contesting.com>
Sent: Wednesday, May 18, 2011 11:16 AM
Subject: Amps Digest, Vol 101, Issue 24
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> Today's Topics:
>
> 1. PA efficiency (Carey Lockhart, KC5GTT)
> 2. Re: PA efficiency (Dr. David Kirkby)
> 3. Re: PA efficiency (Jeff Blaine)
> 4. Re: 4CX1000 value? (hs0zed at csloxinfo.com)
> 5. Re: PA efficiency (Carey Lockhart, KC5GTT)
> 6. Re: PA efficiency (Carl)
> 7. Re: PA efficiency (David Kirkby)
> 8. Transistor Amp (fa014040 at skynet.be)
> 9. Re: 3 phase transformer (Tomm V Aldridge)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 17 May 2011 23:27:52 -0500
> From: "Carey Lockhart, KC5GTT" <kc5gtt at gmail.com>
> Subject: [Amps] PA efficiency
> To: <amps at contesting.com>
> Message-ID: <76F5880D4C414DF4B3833031C2BFFB47 at careychbqjio7i>
> Content-Type: text/plain; charset="iso-8859-1"
>
> hello all,
>
> what is the proper formula to get the PA efficiency of a amplifier?
>
> Carey
>
> ------------------------------
>
> Message: 2
> Date: Wed, 18 May 2011 05:36:40 +0100
> From: "Dr. David Kirkby" <david.kirkby at onetel.net>
> Subject: Re: [Amps] PA efficiency
> To: amps at contesting.com
> Message-ID: <4DD34CD8.6020504 at onetel.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> On 05/18/11 05:27 AM, Carey Lockhart, KC5GTT wrote:
>> hello all,
>>
>> what is the proper formula to get the PA efficiency of a amplifier?
>>
>> Carey
>
> 1) Calculate the input power = V * I
>
> where V is anode/collector/drain voltage (depending on whether its tube or
> semiconductor
>
> I is the anode/collector/drain current (depending on whether it's tube or
> semiconductor)
>
> 2) Measure the output power P.
>
> 3) Efficiency (in percentage) = 100*P/(V*I)
>
>
> Note, few power meters are going to be accurate to better than +/- 10%
> (including the Bird, despite its spec of 5% of FSD), so don't expect an
> accurate
> result unless you use a precision power meter with a calibrated coupler or
> attenuator.
>
> Dave
>
>
> ------------------------------
>
> Message: 3
> Date: Wed, 18 May 2011 00:33:06 -0500
> From: "Jeff Blaine" <keepwalking188 at yahoo.com>
> Subject: Re: [Amps] PA efficiency
> To: "Dr. David Kirkby" <david.kirkby at onetel.net>,
> <amps at contesting.com>
> Message-ID: <7E9486F568B74345824C7AB7D8BD636F at 8710w>
> Content-Type: text/plain; charset="iso-8859-1"
>
> David,
>
> In the case of the GG, do you not need to deduct the drive power from the
> Po? Otherwise, the efficiency is overstated and the Pd is
> understated. I could be wrong?
>
> 73, Jeff AC?C
> www.ac0c.com
>
> -----Original Message-----
> From: Dr. David Kirkby
> Sent: Tuesday, May 17, 2011 11:36 PM
> To: amps at contesting.com
> Subject: Re: [Amps] PA efficiency
>
> On 05/18/11 05:27 AM, Carey Lockhart, KC5GTT wrote:
>> hello all,
>>
>> what is the proper formula to get the PA efficiency of a amplifier?
>>
>> Carey
>
> 1) Calculate the input power = V * I
>
> where V is anode/collector/drain voltage (depending on whether its tube or
> semiconductor
>
> I is the anode/collector/drain current (depending on whether it's tube or
> semiconductor)
>
> 2) Measure the output power P.
>
> 3) Efficiency (in percentage) = 100*P/(V*I)
>
>
> Note, few power meters are going to be accurate to better than +/- 10%
> (including the Bird, despite its spec of 5% of FSD), so don't expect an
> accurate
> result unless you use a precision power meter with a calibrated coupler or
> attenuator.
>
> Dave
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
>
> ------------------------------
>
> Message: 4
> Date: Wed, 18 May 2011 18:27:05 +0700
> From: hs0zed at csloxinfo.com
> Subject: Re: [Amps] 4CX1000 value?
> To: "Roger (sub1)" <sub1 at rogerhalstead.com>
> Cc: amps at contesting.com
> Message-ID: <1305718025.4dd3ad09764c6 at webmail.csloxinfo.com>
> Content-Type: text/plain; charset=TIS-620
>
> Okay guys, think I have it now, and all understood about the different
> tube
> types, just sort of made me wonder for a minute.
>
> The long and short of this story, I'm offered a 30S-1 as a gift but must
> buy the
> sealed in the bag factory fresh(ish) Eimac tube to go with it. Paying a
> fair
> market price is therefore more than okay, I'm not looking to go cheap on
> this
> and indeed a little over the top will not be a problem, even make me feel
> a
> little better. Now I've seen the likely value at a couple of places I can
> make
> an informed offer. Thanks to all.
>
> Thread drift is okay by me, I suffer from wife drift! Far more troubling,
> damned
> expensive too, ha ha!
>
> Cheers
> Martin, HS0ZED
>
>
> Quoting "Roger (sub1)" <sub1 at rogerhalstead.com>:
>
>> On 5/16/2011 8:11 PM, Carl wrote:
>> > Especially when Roger gets involved..............
>> Hey! A little thread drift now and then is a healthy thing...<:-))
>>
>> 73
>>
>> Roger (K8RI)
>> >
>> > Carl
>> >
>> >
>> > ----- Original Message ----- From: "Alek Petkovic" <vk6apk at bigpond.com>
>> > To: "Roger (sub1)" <sub1 at rogerhalstead.com>; "Carl"
>> > <km1h at jeremy.mv.com>
>> > Cc: <amps at contesting.com>
>> > Sent: Monday, May 16, 2011 5:46 PM
>> > Subject: Re: [Amps] 4CX1000 value?
>> >
>> >
>> >> There is also the 8432 which is identical in every regard to the
>> >> 9295A except that the contact ring is smaller and so the SK184 needs
>> >> to be modified slightly to accommodate this.
>> >>
>> >> That also has nothing to do with the 4CX1000 but since when has the
>> >> subject line had any relationship with the contents of the postings
>> >> on this list. ha ha.
>> >>
>> >> 73, Alek.
>> >>
>> >>
>> >> At 02:20 AM 17/05/2011, Roger (sub1) wrote:
>> >>> On 5/16/2011 9:36 AM, Carl wrote:
>> >>>> That is also a PL-172A and found in the Hallicrafters HT-33A/B.
>> >>> Well...kinda, sorta, almost. They are electrically identical. The
>> >>> PL-172 is listed as a PL-172/8295A but the 8295A is not listed as a
>> >>> 8295A/PL-172. The 8295A is also physically about a 3/8" to 1/2"
>> >>> taller (all in the insulator) and is a ceramic to metal seal while
>> >>> the PL-172 is a glass to metal seal and noted for being leaky. The
>> >>> 8295As bring at least double the price of the PL-172s. OTOH the
>> >>> price for either vary all over the place. A couple weeks back an
>> >>> 8295A that was one of the "condition unknown, but I think it's good"
>> >>> went for around $250 (give or take a tad).
>> >>>
>> >>>
>> >>> 73
>> >>>
>> >>> Roger (K8RI)
>> >>>
>> >>>>
>> >>>> No relationship to the 4CX1000 which was in thousands of Collins
>> >>>> 30S1's.
>> >>>>
>> >>>> Carl
>> >>>> KM1H
>> >>>>
>> >>>>
>> >>>> ----- Original Message ----- From: <hs0zed at csloxinfo.com>
>> >>>> To: "Roger (sub1)" <sub1 at rogerhalstead.com>
>> >>>> Cc: <amps at contesting.com>
>> >>>> Sent: Monday, May 16, 2011 4:19 AM
>> >>>> Subject: Re: [Amps] 4CX1000 value?
>> >>>>
>> >>>>
>> >>>> Oh, $2400! That sounds a lot, Is the 8295A a special replacement
>> >>>> for the
>> >>>> 4CX1000? I'd like to get a fair estimate as I have been offered a
>> >>>> new sealed in
>> >>>> the bag Eimac one and want to offer a fair price.
>> >>>>
>> >>>> If new ones are now $410 but 2 years ago they were $2400 I guess
>> >>>> they must be
>> >>>> making them again.
>> >>>>
>> >>>> Cheers
>> >>>> Martin, HS0ZED
>> >>>>
>> >>>>
>> >>>> Quoting "Roger (sub1)" <sub1 at rogerhalstead.com>:
>> >>>>
>> >>>>> On 5/16/2011 3:13 AM, Alek Petkovic wrote:
>> >>>>> > They are $410.00 at http://www.vacuumtubes.net/prices.htm so I
>> >>>>> guess
>> >>>>> > $250 upwards would be a good price.
>> >>>>>
>> >>>>> Those prices are for a tested tube with a guarantee. Tested and
>> >>>>> guaranteed 8295A's were going for $2400 USD two years ago, while
>> >>>>> not DOA
>> >>>>> were running $200-$300. It just depends on how bad some one wants
>> >>>>> it.
>> >>>>>
>> >>>>> > 73, Alek and Sam.
>> >>>>> > VK6APK and VK6/SM3DYU
>> >>>>> >
>> >>>>> >
>> >>>>> >
>> >>>>> > At 01:58 PM 16/05/2011, hs0zed at csloxinfo.com wrote:
>> >>>>> >> What would be the likely value for a new sealed zero hours
>> >>>>> 4CX1000 >> tube?
>> >>>>> >>
>> >>>>> How old? that is also a factor.
>> >>>>>
>> >>>>> 73
>> >>>>>
>> >>>>> Roger (K8RI)
>> >>>>>
>> >>>>> >> Thanks
>> >>>>> >> Martin, HS0ZED
>> >>>>> >>
>> >>>>> >>
>> >>>>> >>
>> >>>>> >> _______________________________________________
>> >>>>> >> Amps mailing list
>> >>>>> >> Amps at contesting.com
>> >>>>> >> http://lists.contesting.com/mailman/listinfo/amps
>> >>>>> >
>> >>>>> > http://www.qrz.com/db/vk6apk
>> >>>>> > http://www.qrz.com/db/vk6ap
>> >>>>> >
>> >>>>> >
>> >>>>> > _______________________________________________
>> >>>>> > Amps mailing list
>> >>>>> > Amps at contesting.com
>> >>>>> > http://lists.contesting.com/mailman/listinfo/amps
>> >>>>> >
>> >>>>>
>> >>>>>
>> >>>>> _______________________________________________
>> >>>>> Amps mailing list
>> >>>>> Amps at contesting.com
>> >>>>> http://lists.contesting.com/mailman/listinfo/amps
>> >>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>>
>> --------------------------------------------------------------------------------
>>
>> >>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>>> _______________________________________________
>> >>>>> Amps mailing list
>> >>>>> Amps at contesting.com
>> >>>>> http://lists.contesting.com/mailman/listinfo/amps
>> >>>>
>> >>>>
>> >>>>
>> --------------------------------------------------------------------------------
>>
>> >>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>> -----
>> >>>> No virus found in this message.
>> >>>> Checked by AVG - www.avg.com
>> >>>> Version: 10.0.1375 / Virus Database: 1500/3641 - Release Date:
>> >>>> 05/16/11
>> >>>
>> >>>
>> >>>
>> >>>
>> >>> _______________________________________________
>> >>> Amps mailing list
>> >>> Amps at contesting.com
>> >>> http://lists.contesting.com/mailman/listinfo/amps
>> >>
>> >>
>> >> http://www.qrz.com/db/vk6apk
>> >> http://www.qrz.com/db/vk6ap
>> >>
>> >>
>> >>
>> >>
>> >> -----
>> >> No virus found in this message.
>> >> Checked by AVG - www.avg.com
>> >> Version: 10.0.1375 / Virus Database: 1500/3641 - Release Date:
>> >> 05/16/11
>> >>
>> >
>> >
>>
>>
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>
>
>
>
>
>
> ------------------------------
>
> Message: 5
> Date: Wed, 18 May 2011 07:20:26 -0500
> From: "Carey Lockhart, KC5GTT" <kc5gtt at gmail.com>
> Subject: Re: [Amps] PA efficiency
> To: <amps at contesting.com>
> Message-ID: <250F7563B33A48C2A40C4955F99B58E5 at careychbqjio7i>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> i was affraid of that. 58.3%. my gs31 2 meter amplifier i use for a
> standby
> isnt much more efficent than my gs-35 that just croaked. i have been using
> these yu1aw designs. have yet to get the rated operating paramters listed.
> i
> dont even have a clue where to start. i am wondering if there is a more
> proven design better suited to my skill level. any suggestions?
>
> Carey, kc5gtt
>
> ----- Original Message -----
> From: "Richard Solomon" <dickw1ksz at gmail.com>
> To: "Carey Lockhart, KC5GTT" <kc5gtt at gmail.com>
> Sent: Tuesday, May 17, 2011 11:56 PM
> Subject: Re: [Amps] PA efficiency
>
>
>> Pout/Pin
>>
>> Pin = Vp X Ip
>>
>> 73, Dick, W1KSZ
>>
>> On Tue, May 17, 2011 at 9:27 PM, Carey Lockhart, KC5GTT
>> <kc5gtt at gmail.com> wrote:
>>> hello all,
>>>
>>> what is the proper formula to get the PA efficiency of a amplifier?
>>>
>>> Carey
>>> _______________________________________________
>>> Amps mailing list
>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>
>
>
> ------------------------------
>
> Message: 6
> Date: Wed, 18 May 2011 10:07:09 -0400
> From: "Carl" <km1h at jeremy.mv.com>
> Subject: Re: [Amps] PA efficiency
> To: "Jeff Blaine" <keepwalking188 at yahoo.com>, <amps at contesting.com>
> Message-ID: <17866DD8CA79471BB4EAE623CBE078F9 at computer1>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> Of course you do Jeff but you also need to know how much power is passing
> thru.
> With tubes that include the required drive power on the spec sheet its
> easy
> to do. With Ruskie tubes you may need to take a WAG if the data isnt
> published.
>
> Carl
> KM1H
>
>
>
> ----- Original Message -----
> From: "Jeff Blaine" <keepwalking188 at yahoo.com>
> To: "Dr. David Kirkby" <david.kirkby at onetel.net>; <amps at contesting.com>
> Sent: Wednesday, May 18, 2011 1:33 AM
> Subject: Re: [Amps] PA efficiency
>
>
> David,
>
> In the case of the GG, do you not need to deduct the drive power from the
> Po? Otherwise, the efficiency is overstated and the Pd is
> understated. I could be wrong?
>
> 73, Jeff AC?C
> www.ac0c.com
>
> -----Original Message-----
> From: Dr. David Kirkby
> Sent: Tuesday, May 17, 2011 11:36 PM
> To: amps at contesting.com
> Subject: Re: [Amps] PA efficiency
>
> On 05/18/11 05:27 AM, Carey Lockhart, KC5GTT wrote:
>> hello all,
>>
>> what is the proper formula to get the PA efficiency of a amplifier?
>>
>> Carey
>
> 1) Calculate the input power = V * I
>
> where V is anode/collector/drain voltage (depending on whether its tube or
> semiconductor
>
> I is the anode/collector/drain current (depending on whether it's tube or
> semiconductor)
>
> 2) Measure the output power P.
>
> 3) Efficiency (in percentage) = 100*P/(V*I)
>
>
> Note, few power meters are going to be accurate to better than +/- 10%
> (including the Bird, despite its spec of 5% of FSD), so don't expect an
> accurate
> result unless you use a precision power meter with a calibrated coupler or
> attenuator.
>
> Dave
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1375 / Virus Database: 1509/3643 - Release Date: 05/17/11
>
>
>
>
> ------------------------------
>
> Message: 7
> Date: Wed, 18 May 2011 13:56:36 +0100
> From: David Kirkby <drkirkby at gmail.com>
> Subject: Re: [Amps] PA efficiency
> To: "Carey Lockhart, KC5GTT" <kc5gtt at gmail.com>
> Cc: amps at contesting.com
> Message-ID: <BANLkTik7gt5eZmp_R9Pp3DiTQveq8FrCbg at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> On 18 May 2011 13:20, Carey Lockhart, KC5GTT <kc5gtt at gmail.com> wrote:
>> i was affraid of that. 58.3%. my gs31 2 meter amplifier i use for a
>> standby
>> isnt much more efficent than my gs-35 that just croaked. i have been
>> using
>> these yu1aw designs. have yet to get the rated operating paramters
>> listed. i
>> dont even have a clue where to start. i am wondering if there is a more
>> proven design better suited to my skill level. any suggestions?
>>
>> Carey, kc5gtt
>
> It's totally pointless stating the efficiency to 3 significant figures
> (58.3%). Whilst if you use a DVM you can read DC voltages and currents
> to well under 1%, you wont be able to measure the RF power to anything
> like that accuracy. So your efficiency is probably somewhere between
> 48% and 68%. So worrying about the odd 1 percent is totally pointless
> unless you use professional, laboratory quality test equipment to
> measure the RF power.
>
> In fact, I doubt your high voltage probe is sufficiently to measure
> the voltage to better than 1%.
>
> Dave
>
>
> ------------------------------
>
> Message: 8
> Date: Mon, 16 May 2011 17:57:22 +0200
> From: <fa014040 at skynet.be>
> Subject: [Amps] Transistor Amp
> To: <Amps at contesting.com>
> Message-ID:
> <!&!AAAAAAAAAAAYAAAAAAAAAKwWy4VBYWFBuopElaHJZzbCgAAAEAAAACmZC5rleSdOjmPWe7IkTUkBAAAAAA==@skynet.be>
>
> Content-Type: text/plain; charset="us-ascii"
>
> Hello All,
> I am looking around for a transistored Amp between 1/2 to 1 KW
> Preferece goes to home made.
> Thanks for a shout.
> Jos
> ON4KJ
>
>
>
> ------------------------------
>
> Message: 9
> Date: Sun, 15 May 2011 23:10:49 -0700
> From: Tomm V Aldridge <taldridge at gmail.com>
> Subject: Re: [Amps] 3 phase transformer
> To: Ronald Brown <rg52brown at yahoo.com>
> Cc: amps at contesting.com
> Message-ID: <BANLkTimUBG9h0Tu7FrABacMNzvt_On6M-g at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Take care with core saturation as the cross section of the center leg is
> equal to those of the outer legs in a three phase xfmr which is not the
> case
> with a single phase xfmr where the center leg area is 2 times that of the
> outer legs as the flux is split evenly between the outer legs. Running
> the
> center primary at the three phase voltage divided by sqrt 3, 120 on a 208V
> transformer, will allow you to take the secondaries in all three legs in
> series or parallel as long as you observe the phasing. Paralleling is
> always iffy a any flux or turns imbalance will show up as a shorted turn
> and
> generate excessive heating n the windings.
>
> Tomm - KD7QAE
>
> On Sun, May 15, 2011 at 9:49 PM, Ronald Brown <rg52brown at yahoo.com> wrote:
>
>> I have a 3 phase plate transformer I want to use on single phase. It has
>> 3
>> separate sections and the secondaries can be separated. Can I just
>> parallel
>> them up ? I realize core limitations will play into this but is there
>> any
>> problem with just paralleling up all three sections?
>>
>> ron - K0idx
>>
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>
>
> ------------------------------
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
> End of Amps Digest, Vol 101, Issue 24
> *************************************
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