We had the benefit of a fairly simple, flat environment, both at the (now closed) Fountain Valley location and the main OATS in Irvine. It was possible to put a bicon in an area where almost every ambient could be canceled, but tedious in the extreme, because the location was peculiar to each ambient.
Using a delay line and variable gain/attenuation, and careful siting of the ambient antenna, seems to me appropriate for _most_ OATS except those in hilly country - and those generally are there because of the low ambients. by the way, this is NOT a new idea; indeed, I believe there have been Papers in the IEEE EMC Proceedings on this kind of a a setup. The stumbling block seems to have been FCC reluctance to approve a non-standard setup. But if SA were taken with an ambient canceler going, it seems to me that would effectively demonstrate equivalence. Cortland Cortland ====================== Original Message Follows ==================== >> Date: 07-May-99 10:05:24 MsgID: 1068-8273 ToID: 72146,373 From: "Brent DeWitt" >INTERNET:[email protected] Subj: Phase cancellation Chrg: $0.00 Imp: Norm Sens: Std Receipt: No Parts: 1 I have also played with phase cancellation, and found one very serious limitation, multipath. Unless you are out in a situation where the ambients look pretty much like point sources, you will be limited in the depth of the null that you can create, since you can only cancel one phase front with one "reference" antenna. Since many folks build sites in the hills, mountains or gullies to try to avoid ambients, this puts the site in a worst case location for using phase cancellation. Maybe in Topeka......... Best regards, Brent DeWitt ====================== End of Original Message ===================== --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
