Hi All...a number of you have no clue waht I am talking about...first
each station I have has a transmit (100 watt) bandpass filter that
helps to reduce out of band noise created by one rig on another band
...then there is a 80 db bandpass filter after the amp (very high
power bandpass filter)....so there is something on the order of 130 db
rejection of OUT of band interference.To further reduce INBAND would
require a Crystal filter (read low power no transmit thru) or some
other very high Q very narrow filter thast only has 5-10 khz of
operating bandwidth...no such device is sold currently on the ham
market....at one time Sherwood engineering would custom make a xtal
filter that is installed in a trancsevicer that has in and out rcvr
terminals on the back of the radio... in WRTC comp[etition in Brazil a
few years ago 4O3A introduced a switchable xtal filter device that
would switch xtals in 5 khz increments...allowing him to transmit and
rcv within 5 khz of the run radio effectively...I am attempting to get
my rcvrs so that we too can hear close to the run stationand at a
lower level than we currently do. Currently my station has antenna
separation that is over 500 ft apart from run station to mult
station...I am working at extending that number so that INBAND
interference will go down by the square of the distance...this will
improve INBAND interference also...I have enough OUTof BNAD rejection
from the combination of BAndpass filters...so to implement what I need
will require a modification to the Orions in my station to allow the
insertion of a xtal filter in the rcvr path....
de Rick NQ4I
On Mon, Feb 27, 2012 at 5:37 PM, Ron Castro <ronc@sonic.net> wrote:
> We set up something like that every FD using an Orion II. We found that the
> OII was perfectly clean and we could operate on the same band at the other
> transceiver with no interference FROM the OII, but the ICom blew S-5
> wide-band noise that I could see on a spectrum analyzer. You can't get that
> out once it's generated.
>
> Those bandpass filters multi multi's use won't work either since they cover
> the whole band.
>
> Our solution was to set up the antennas side-to-side about 200' apart and use
> a Mark V at the other station. Worked perfect!
>
> Ron Castro
> N6IE
> www.N6IE.com
> Member:
> REDXA NCCC
> NCDXF ARRL
>
>
> -----Original Message-----
> From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com] On
> Behalf Of Mike Bryce
> Sent: Monday, February 27, 2012 1:40 PM
> To: nq4i@contesting.com; Discussion of Ten-Tec Equipment
> Cc: Discussion of Ten-Tec Equipment
> Subject: Re: [TenTec] adding xtal filter to the Orion
>
> It would seem to me the simplest thing to do is to get one or two of the band
> filters commonly used by multi-station contesters.
>
> Our radio club uses them for FD
>
> Off hand I don't know the exact technical name for them
>
> Mike wb8vge
>
> Sent from my iPhone
>
> On Feb 27, 2012, at 4:11 PM, nq4i@contesting.com wrote:
>
>> Hi Kim. It is a rcvr problem not transmitter. When 2 stations are on
>> the same band there is an inherent noise generated in either rcvr that
>> can be supressed. Currently the Orion transmitter is one of the
>> cleanest transmitters on the market. My aim is to allow a second rcvr
>> to hear at a lower level than the current s4 level. I am not a design
>> engr but am relating what I know and what io hear. It maybe that to
>> achieve that would require transmitter filtering. But some improvement
>> can be had by addressing the rcvr. Rick Sent on the Sprint® Now
>> Network from my BlackBerry®
>>
>> -----
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