The word in the regs is "necessary ", not "desired". Bob
Sent from my iPhone
On Oct 30, 2014, at 2:00 PM, Glen Zook <gzook@yahoo.com> wrote:
The problem is that "desired communications" is not defined!
If the operator desires to have a 40 dB over S-9 (with S-9 defined as a 50
microvolt signal level) at every location, then that operator can run more
power, and still obey the rules, than an operator who just desires that their
signal can barely be detected above the noise level.
Glen, K9STH
Website: http://k9sth.net
On Thursday, October 30, 2014 11:00 AM, Drax Felton <draxfelton@gmail.com>
wrote:
And this one too...
At all times, transmitter power must be the minimum necessary to carry out the
desired communications.
> On Oct 30, 2014, at 10:16 AM, Robert Logan via Amps <amps@contesting.com>
> wrote:
>
> Thought I might mention the legal limit for AM is 375 watts carrier. Bob.
> NZ5A
>
> Sent from my iPhone
>
> On Oct 30, 2014, at 9:04 AM, Kimberly Elmore <cw_de_n5op@sbcglobal.net> wrote:
>
> Any amp will be inefficient when used as a linear amplifier for AM because as
> drive is reduced, efficiency is reduced. They will all generate a lot of heat
> in this application. However, the AL-1200 should hold up well to the
> lock-and-talk culture. In AM, PEP is 4X the carrier, Overall, you want the
> carrier to be at 1/4 of the amp's rated PEP output.
>
> Assuming the driver generates 100 W output, tune the amp for max or 1500 W
> output (whichever comes first) with the amp in SSB mode. You want SSB mode
> because you want the best linearity. Whether or not you use SSB or CW makes
> little difference in the efficiency for your application but makes a big
> difference in linearity.
>
> Usually, when the driving rig is in AM mode, the carrier is reduced to 1/4 of
> the max PEP SSB output. In such cases, you should see no more than 375 W
> carrier power (375 x 4 = 1500).
>
> If you are trying to drive it with an older plate-modulated tube rig, you ill
> have to be careful if you reduce the power output because the modulation
> transformer is designed with a particular output impedance in mind. If you
> reduce the drive to the PA, the impedance changes and you will have to set
> the proper audio level using a scope or modulation monitor.Start with audio
> gain at zero, bringing it up slowly. Otherwise, you risk arcing in and
> destruction of the modulation transformer.
>
> Kim N5OP
>
>
> On Thursday, October 30, 2014 8:05 AM, Gary Smith <Gary@ka1j.com> wrote:
>
>
>
> One thing for sure, run it at the CW
> setting, use the lower KV setting and you
> will run far cooler for a given KW out.
>
> 73,
> Gary
> KA1J
>
>
>> I want to run my AL-1200 on AM for a short stint (2 hours operating
>> time, 50% overall duty cycle). I have tested it at about 225 watts
>> carrier output, and with moderately high duty cycle transmissions (known
>> in the AM crowd as 'Old Buzzarding'), it gets quite hot.
>>
>> What is the max recommended AM carrier power for long-winded transmissions?
>>
>> Also, I'm assuming it should be tuned up for proper operation at double
>> the carrier power.
>>
>> I searched the list finding no real answers.
>>
>> Thanks,
>>
>> Tony, K1KP
>
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