[NLRS] Feedhorns for 902 and 1296

[John (JK) Kalenowsky, K9JK]

Wouldn't that be to think outside of the "horn"? (Sorry...couldn't resist 
;-) --JK

----- Original Message ----- 
From: <Scanner.Kleindl at VerizonWireless.com>
To: <acepilot at bloomer.net>; "NLRS List" <nlrs at mailman.qth.net>
Sent: Wednesday, October 11, 2006 12:05
Subject: RE: [NLRS] Feedhorns for 902 and 1296




Well one should think outside of the box by using a 2 ele dipole a director 
with a reflector in front of dish. This setup is used in the commercial 
world. A 8 foot dish is around 24 and a 10 foot is 26 dBi at 900 Mhz and for 
1296 8ft=28 & 10ft is 30. Dave NØKP

-----Original Message-----
From: nlrs-bounces at mailman.qth.net [mailto:nlrs-bounces at mailman.qth.net] On 
Behalf Of Scott
Sent: Wednesday, October 11, 2006 6:08 AM
To: NLRS List
Subject: [NLRS] Feedhorns for 902 and 1296



If I did the calculations correctly, according to the 1988 ARRL Antenna 
Book, for 902 I would need a (circular) feedhorn of about 9.8" in diameter 
and 42-63" in length (6.9" by 28-42" in length for 1296).  That is following 
the advice to make the feedhorn 2 to 3 guide wavelengths long.  My question: 
Is it necessary to have this much length or would 1 guide wavelength be OK? 
What are the effects of a shortened length?
Something to do with dish illumination perhaps?  The dish is either 8'
or 10' in diameter.

--
Scott N0EDV
http://corbenflyer.tripod.com/
Building RV-4
Gotta Fly or Gonna Die
_______________________________________________
NLRS mailing list
NLRS at mailman.qth.net
http://mailman.qth.net/mailman/listinfo/nlrs


The information contained in this message and any attachment may be
proprietary, confidential, and privileged or subject to the work
product doctrine and thus protected from disclosure.  If the reader
of this message is not the intended recipient, or an employee or
agent responsible for delivering this message to the intended
recipient, you are hereby notified that any dissemination,
distribution or copying of this communication is strictly prohibited.
If you have received this communication in error, please notify me
immediately by replying to this message and deleting it and all
copies and backups thereof.  Thank you.

_______________________________________________
NLRS mailing list
NLRS at mailman.qth.net
http://mailman.qth.net/mailman/listinfo/nlrs