[Amps] 1 db compression point procedure ?

Joe Subich, W4TV lists at subich.com
Thu Jul 1 05:57:43 PDT 2010


 > A linear transmitting amp for hams is not dealing with the additive
 > effects of hundreds of signals.

  .... or the very high peak to average ratios of multi-carrier digital
signals.

73,

    ... Joe, W4TV

On 7/1/2010 8:25 AM, Carl wrote:
> Celluar amps operate over a multi channel bandwidth with many signals as do
> CATV line amps and your typical rice box transceiver receiver section.
>
> A linear transmitting amp for hams is not dealing with the additive effects
> of hundreds of signals.
>
> Carl
> KM1H
>
> ----- Original Message -----
> From: "Saandy Eban"<alexeban at gmail.com>
> To: "Colin Lamb"<k7fm at teleport.com>
> Cc:<Amps at contesting.com>
> Sent: Thursday, July 01, 2010 3:05 AM
> Subject: Re: [Amps] 1 db compression point procedure ?
>
>
>> ...Point is, the 1dB compression point can be 5-10 dB below our usual
>> operating conditions.
>> it has more to do with low level amplifiers than with high power ones.
>> low level amplifiers have to cope with myriads of signals coming from the
>> antenna and they are supposed to generate  as few intermodulation products
>> as possible!
>> high power amplifiers have to cope only with their own internal
>> nonlinearities, so they depend more on the drive levels and correct
>> operating points. to analyze these products, the 2 tone test is more
>> representative.
>> i can tell you that in order to operate close to the 1dB compression
>> point cellular amplifiers operate at about 10% of their rated maximum
>> power.
>> not very effective from our point of view.
>> Alex 4Z5KS
>>
>> On Wed, Jun 30, 2010 at 11:23 PM, Colin Lamb<k7fm at teleport.com>  wrote:
>>
>>> How to know when you have reached the 1 db compression point!
>>>
>>> Find a qso with both stations having strong signals.  QSY about 20 kHz
>>> away
>>> and put your station on the air with a test and whistling often into the
>>> mike.  Then listen on your frequency.  Keep turning up the mike gain.
>>>
>>> When the ham that was 20 kHz away comes onto your frequency and hurls
>>> insults at you, then you know you have reached the 1 db gain compression
>>> point.
>>>
>>> 73,  Colin  K7FM
>>> _______________________________________________
>>> Amps mailing list
>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>
>>
>>
>> --
>> Saandy
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>> http://lists.contesting.com/mailman/listinfo/amps
>
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