TenTec
[Top] [All Lists]

[TenTec] Orion and Inrad 762

To: tentec@contesting.com, orion@contesting.com
Subject: [TenTec] Orion and Inrad 762
From: Bill Tippett <btippett@alum.mit.edu>
Reply-to: tentec@contesting.com
Date: Tue, 31 Aug 2004 11:08:28 -0400
List-post: <mailto:tentec@contesting.com>
Do we have any idea how good the Inrad 762 might be at very close spacings? Let's take another look at the Inrad plot below. I've marked points below which show a total bandwidth of about 1300 Hz at -30 dB attenuation on the skirts. Assuming the #762 is correctly centered, this means signals at a spacing of 650 Hz or more should be attenuated by at least 30 dB, which means that their IMD products will be attenuated by at least 90 dB. If we further assume interference is coming primarily from one side, we can use PBT to shift 250 Hz which should effectively yield ~90 dB IMD rejection at 400 Hz spacings on one side of the passband (of course the other side of the passband would also shift 250 Hz also reducing the 90 dB IMD rejection to signals at 900 Hz spacings and above...still better than any other receiver I know of). My estimates have not been verified by actual measurements yet but I am hoping Sherwood or someone will be able to confirm them in the near future and will post any results here.

http://users.vnet.net/btippett/inrad_.htm (see new plot at very bottom)

73, Bill W4ZV

_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec

<Prev in Thread] Current Thread [Next in Thread>
  • [TenTec] Orion and Inrad 762, Bill Tippett <=