[Amps] New SB-200 owner

[jeremy-ca]

Ive found absolutely no benefit to a Pi-L in a monoband 6M amp Peter. Ive 
also not tested or experienced a commercial amp that includes 6M, or even a 
xcvr in some cases, that cannot benefit from a good LPF at both the input 
and output.

As I mentioned at some point in this thread I use a BPF at the input of my 
6M station amp and at higher VHF/UHF amps also for that matter. Being on top 
of the highest elevation for many miles I'm subjected to RF pollution from 
nearby commercial sites. The filters make a marked improvement to reception.

Carl
KM1H




----- Original Message ----- 
From: "Peter Chadwick" <g3rzp at g3rzp.wanadoo.co.uk>
To: <amps at contesting.com>
Sent: Thursday, September 27, 2007 12:16 AM
Subject: Re: [Amps] New SB-200 owner


> Roger said:
>>More than likely I'd move on to the ARRL Handbook and build a PI-L network
> for the desired Q at the operating frequency which in this case is 50 to 
> 54
> MHz.<
>
> Is there any advantage in using a pi-L, rather than a straight pi and 
> suitable low pass or bandpass filtering to get the harmonics down? 
> Especially since we're talking of a single band amplifier that needs to 
> have the second harmonic at least 70dB down, and I doubt a pi-L will do 
> that on its own
> Does the pi-L give a greater impedance matching range for any given Q 
> variation or something? Although I'd have thought that on 6, you'd be 
> looking at pretty low SWR anyway.
>
> 73
> Peter G3RZP
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