[NLRS] 900 MHz filters

[tosca005 at umn.edu]

I came across some more filters on eBay for the 900 MHz band. Unlike the 
large "can" filters I found before, these are quite compact, approximately 
4" x 3" x 1" in size. They are designed to have a 15 MHz bandwidth with a 
1.5 dB insertion loss +/- 0.4 dB typical or 2.3 +/- 1.0 dB maximum over the 
passband. At an additional 5 MHz outside the passband, they are about 10 dB 
down (minimum 9 dB), and at 25 MHz outside the passband, they are about 
60-70 dB down (minimum 48 dB). I bought two of them, and each of them came 
with its own test results.

The original passband is 890-905 MHz, so the -10 dB points are at about 885 
and 910 MHz; the -60 dB points are at about 860 and 935 MHz.

The seller has retuned one for better elimination of the noise below 900 
MHz by moving the passband up to roughly 900-915 MHz. The curve shape looks 
pretty similar otherwise. He does NOT offer to retune them prior to sale, 
but I didn't press him to see if he would do it for an additional price. He 
said that they were not that difficult to retune if you have the proper 
equipment.

He's selling them for $20 from his eBay store (no bidding involved). He has 
"more than 10 available". The listing is at:

http://cgi.ebay.com/890-905-Railroad-Band-RF-Filters-903-NOS_W0QQitemZ120313289461QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item1c033b1af5

Sorry, but that is supposed to be all one line, so you may have to paste 
that fractured URL into Notepad and then un-break the lines.

I have no financial interest in this. I bought some stuff from the guy and 
he was extremely helpful, and I know that there has been interest among the 
list members for 902 MHz filters before, so those are my only reasons for 
passing along this information.

73 de W0JT