With frequency spacings that close (only 25 kHz away), you won't have any
problems as far as desense goes, but you WILL need to run multiple-stage
isolators to prevent IM. Concidentally, the 3rd harmonc of 147.39 is
442.17, but that shouldn't be a problem since that's near your UHF Tx
frequencies (it would definately be a problem if it were your Rx frequency).
--- Jeff
--------------------------------------------
Jeff DePolo WN3A - [EMAIL PROTECTED]
Broadcast and Communications Consultant
> -----Original Message-----
> From: johnmichaelwelton [mailto:[EMAIL PROTECTED]
> Sent: Monday, February 28, 2005 9:22 AM
> To: [email protected]
> Subject: [Repeater-Builder] Colocating second UHF rptr
>
>
>
>
> I have a site on top of the local hospital with 3 2in galvanized
> mounts attached to the roof separated by ~5ft each. On the first two
> I have a DB404 on 442.150/R [abt 50 watts out of the duplexer] and
> the middle mount is a DB224 on 147.390/R [also abt 50 watts out of
> the duplexer]. I'd like to put a second UHF rptr at the site on the
> open third mount and dedicate to VOIP application [I have a dedicated
> LAN on emergency power and T3 lines to campus]. I'm considering
> putting up a DB411 and using either 442.125 or 442.175 as potential
> freqs (both are available here) thinking that the respective
> duplexers will help notch out the adjacent tx signal some and will
> still have ~5Mhz split between TX and RX. The only other options I
> have is a roof vent that could support maybe an X50 or something
> equivalent that is very small and this is on the main roof one floor
> below and abt 100 ft away from the main 442.150 antenna (I have 1/2
> in LDF4 to run there).
>
> Any comments if the 10ft or so between the two UHF antennas will work?
>
> John/N4SJW
> Charleston, SC
>
>
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Anti-Virus.
> Version: 7.0.300 / Virus Database: 266.5.1 - Release Date: 2/27/2005
>
>
--
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.300 / Virus Database: 266.5.1 - Release Date: 2/27/2005
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/Repeater-Builder/
<*> To unsubscribe from this group, send an email to:
[EMAIL PROTECTED]
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
