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Re: [CQ-Contest] A bandpass filter design

To: cq-contest@contesting.com
Subject: Re: [CQ-Contest] A bandpass filter design
From: Rudy Bakalov via CQ-Contest <cq-contest@contesting.com>
Reply-to: Rudy Bakalov <r_bakalov@yahoo.com>
Date: Sat, 29 Apr 2017 18:19:34 -0400
List-post: <cq-contest@contesting.com">mailto:cq-contest@contesting.com>
I own Pavel's filters and can testify that they work amazingly well in SO2R and 
M/S setups, especially as part of a triplexer based system. No cross-band 
interference at all at full legal power. Even the highly sensitive Icom 7300 
does not suffer from any overloads.

I have also operated at two major M/M stations that use stubs.  The difference 
is night and day in favor of the filters. If I were to do it again, I will 
chose Pavel's filters again (I am actually buying more triplexers and HP BPFs).

Rudy N2WQ

Sent using a tiny keyboard.  Please excuse brevity, typos, or inappropriate 
autocorrect.


> On Apr 28, 2017, at 4:36 PM, Pavel <un7lg@shaw.ca> wrote:
> 
> Peter,
> 
>> It has better numbers as 4O3A, DG0SA, VA6AM.
> 
> It is hard to compare my filters with your design despite the fact that they
> are very close by circuits. 
> I think we had a different specifications for the design.
> 
> - I designed BPFs not for a maximum band isolation. BPFs were optimized to
> be used with Triplexer.
> - I achieved better than -85dB band isolation together with triplexer (this
> is more than sufficient number) with good Return Loss and low Insertion Loss
> - the minimum in-band ripples and the best Return Loss was a goal ( NOT a
> maximum band isolation) for the design to get Triplexer and BPF's Impedances
> very close to 50ohm
> - my filters desinged and built for up to 4000 PEP watt output power
> 
> You never published Return Loss achived for the design  to compare filters
> by all numbers and not only by band isolations
> 
> P.S. 
> I cannot compare my BPFs and triplexer with coax stub's sytem as I do not
> think that building triplexer using a coax stubs could be a good idea. 
> 
> 
> Pavel
> VA6AM
> 
>> My Projects: https://va6am.com/ 
>> 
> 
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