My problem is that I am going back to only doing 2m during contests and I
"need" two filters (144 - 146 and 146 - 148) to separate the FM side which is
planned for 350 watts and the fun side which is planned for 1200 watts - sort
of SO2R on a single band.
Don, NL7CO
-----Original Message-----
From: Roger Rehr W3SZ <w3sz73@gmail.com>
To: vhfcontesting <vhfcontesting@contesting.com>
Sent: Mon, Jan 23, 2017 2:53 pm
Subject: Re: [VHFcontesting] Inline 2m Bandpass Filter
After the EME contest a few months ago I ended up sweeping my system to
try to identify points of weakness. I saw exactly what David points
out. The striking result is shown at:
http://www.nitehawk.com/w3sz/OverlayDCIandKA0RYT144-500.gif
A cavity-input preamp sweep is shown in blue with the DCI filter
superimposed in violet. (Sorry, I am an old-school guy and not good on
color names. I know the names of the colors eight that came in the
original Crayola crayon box, and that's about it. So if you don't think
the colors in the graph are blue and violet, you might be right. But to
me they are blue and violet).
So if you have a 432 ingress problem you can't use the DCI to solve it.
73,
Roger W3SZ
On 1/22/2017 9:39 PM, David Carlson wrote:
> What application do you want the filter for? I have a DCI 146-4H that was
> recently tested on a network analyzer. This filter starts to roll off around
> 144 MHz and has slightly higher insertion loss, and slightly lower return
> loss at 144.2 than I would like. It also passes 432 MHz, so would be of
> little use in keeping a 432 signal out of your 2m preamp or front end. The
> sweep shown on the DCI website only goes to 166 MHz.
> 73,Dave AA9D
>
> On Sunday, January 22, 2017 6:21 PM, Tom <k8tb@bosscher.org> wrote:
>
>
> Sean,
>
> Look at OCI. I believe this was the guy who started DCI, then sold it,
> then started up his own company.
>
> http://www.ocicom.com/index.php/amateur-radio/products/2-meter-bandpass-filter
>
> Tom K8TB
>
>
>
> On 1/22/2017 2:37 PM, Sean Waite wrote:
>> Hi all,
>> Does anyone know of a decent 2m bandpass filter that can be left inline on
>> transmit with 100W? I see them for 6m and below, but not 2m.
>>
>> I've found this: http://www.antennas-amplifiers.com/2m-100W-Bandpass-Filter
>> but
>> was hoping for something a smidgen cheaper. If there isn't one, I guess
>> I'll go that route.
>>
>> Thanks!
>> Sean WA1TE
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>>
>>
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