Unfortunately my Bird 43 has no peak reading option. It did have the option
once upon a time but I got tired of it eating 9v batteries and removed it.
I have also "discovered" that the screen voltage stability has a pretty
large effect on power output. Just as the plate voltage can sag under load, so
can the screen voltage, resulting in lower than expected plate current. G3SEK
figured all this out years ago when he designed his screen regulator board. I
guess I am a slow learner!
The current screen voltage setup shows about 5% more screen voltage with a
string of dots compared to full carrier. Hence, the question about string of
dots power reading vs. full carrier power reading. Even the string of dots
voltage is lower than the design goal so a new G2 power supply is definitely
warranted.
73,
K5GW
In a message dated 3/29/2005 10:10:04 A.M. Central Standard Time,
r@somis.org writes:
On Mar 28, 2005, at 5:53 PM, Gary Schafer wrote:
> If it is a peak reading bird it should show the same as with carrier.
... provided that the anode PS is regulated and one takes a reading
before the coax melts.
>
> 73
> Gary K4FMX
>
> TexasRF@aol.com wrote:
>>
>> And, along a similar vein: If a string of 50% duty cycle dots at say
>> 50
>> words per minute are transmitted, what should the Bird meter show for
>> power
>> output compared to full carrier?
>>
>> 73,
>> Gerald K5GW
>>
>> In a message dated 3/28/2005 3:14:31 P.M. Central Standard Time,
>> Dennis12Amplify@aol.com writes:
>>
>> For the EXPERTS.....,
>>
>> I have a question which I believe will combign the two most
>> interesting and
>> informative threads we have had going here on the reflector for
>> quite some
>> time.
>>
>> Why is it that a Bird 43 with a calibrated peak reading kit only
>> reads
>> THREE times the power for a peak reading of a 100% modulated AM
>> waveform,
>> instead
>> of FOUR times the power as the textbooks all say it should?
>>
>> Is it because the 43 is responding to a Half wave rectified signal
>> but
>> 'calibrated' to read as though it was responding to something else?
>>
>> I believe I have an answer, and it is directly related to both
>> threads, but
>> I was hoping for some open discussion of the subject to see where
>> it goes,
>> and if it goes in the direction of my solution or not...
>>
>> Hint: It is a mathematical relationship between the average response
>> of the
>> 43's analog meter movement and the FCC's definition of power output.
>>
>> Regards,
>>
>> Dennis O.
>>
>>
>>
>> It is surely the best thread we have seen on this reflector in a
>> long long
>> time. Very comprehensive, informative and lots of fun to follow.
>>
>> Thanks to all,
>> Alek. VK6APK
>>
>> At 08:33 PM 27/03/2005, David Kirkby wrote:
>>
>>> John and Mary Powell wrote in a different thread:
>>>
>>>
>>>> Is there a body of opinion out there that considers the above
>>>> subject
>>>
>>> has gone on far too long, or got out of hand. To me it appears as
>>> if
>>> academic intransigence has got in the way of the Reflector dealing
>>> with
>>> it's core business. I noted an earlier plea for an end to of
>>> this uninteresting topic, which evolved from a simple enquiry as
>>> to
>>> accuracy of the Bird 43 Wattmeter.
>>>>
>>>> Cheers
>>>
>>>> John Powell. ZL1BHQ
>>>
>>
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>>
>>
>>
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>>
>
>
>
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>
>
Rich Measures, 805.386.3734, AG6K, www.somis.org
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