It's common to use a pi-L only on the lower bands and a simple pi on the higher
ones. This
may be in order to use a smaller-sized output capacitor. Or perhaps additional
harmonic
suppression is necessary on the lower bands to meet FCC (etc.) regulations.
On 1/26/2011 4:35 AM, Ulf (SM0NOR) wrote:
> Yes, you are right.... I was confused because I thought it said "pi-l" in
> the specs
> sheet. But it doesn't.
>
> Still my question applies to the bigger amplifiers. For example the
> specifications of
> AL-1500 says "pi-l" but if you check the schematics, the third coil, after
> C2, called
> L4 is only tapped once!
>
>
> 73's
>
> Ulf (SM0NOR) ulf@sm0nor.com
>
>
>
> On 26 jan 2011, at 13.16, Dave M wrote:
>
>>
>> I hate the layout of the supplied schematic , but it is a standard Pi
>> network not PiL
>> the second coil is strictly for the higher freqs
>>
>>
>> ......................................................................................................
>>
>>
>>
73 VE3DV , Dave
>>
>>
>>
>>
>>
>>> From: ulf@sm0nor.com Date: Wed, 26 Jan 2011 13:04:07 +0100 To:
>>> amps@contesting.com
>>> Subject: [Amps] Pi/L in Ameriton amps?
>>>
>>> I'm helping a friend of mine who bought a damaged 811H. Transformer and
>>> tubes where
>>> gone. New transformer is on the way from Ameritron and tubes we found
>>> locally. I
>>> think we will have it up and running on no time! Now my question: is it a
>>> pi/l tank
>>> in this amp? The manual says so but the second coil has only two tappings.
>>> Does it
>>> mean that the high bands goes through the same inductance and the low bands
>>> go
>>> through the whole coil? What does it do for the intermediate resistance? I
>>> noticed
>>> all Ameritron amps are the same.
--
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|