It depends on whether the preamp is generating the intermod or the
IC-9100 is generating the intermod. If the intermod is due to mixing
in the IC-9100's internal preamp, put the notch filter between the
LNA and IC-9100 so it does not impact the system noise figure.
73,
... Joe, W4TV
On 5/11/2014 2:14 PM, Drax Felton wrote:
The notch will only be in the receive path since the setup has a mast
mounted rx/tx relay too that protects the LNA.
-----Original Message-----
From: John Lemay [mailto:john@carltonhouse.eclipse.co.uk]
Sent: Sunday, May 11, 2014 2:12 PM
To: 'Drax Felton'
Subject: RE: [TowerTalk] 2m intermod filter placement
Drax
The right answer will depend on your individual circumstances. However, it's
far easier to try it after the preamp, ie next to the rig. If it works,
that's just fine. If it doesn't work then you need to try it before the
preamp. Doing that will undoubtedly place some loss before the preamp and
affect your overall noise figure, which is a good reason for this to be the
second choice.
Is the notch filter designed to withstand your EME transmit power ?
John G4ZTR
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Drax
Felton
Sent: 11 May 2014 19:00
To: towertalk@contesting.com
Subject: [TowerTalk] 2m intermod filter placement
I recently put up a phased set of four 2m meter antenna for EME to find out
that the front end of my IC-9100 is being blasted by pager intermod.
I got a notch filter for the frequencies involved from PAR Electronics.
Question is now: Where inline is the best place to put the filter?
Before or after the mast mounted pre-amp? Or down at the radio end?
KB3X
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|