RadioReference on Facebook   RadioReference on Twitter   RadioReference Blog
 

Go Back   The RadioReference.com Forums > Commercial, Professional Radio and Personal Radio > Motorola Forum


Motorola Forum - For general discussion of Motorola land mobile radio equipment and their trunking technologies.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1 (permalink)  
Old 01-04-2018, 10:13 PM
Member
   
Join Date: Feb 2010
Location: Tampa, FL
Posts: 463
Default XPR5550 high power, need low power tx

I have a bunch of high power UHF 5550 control stations (in guard shacks) that are close to my customer's UHF Capacity Plus site. Each control station has a large outdoor antenna. I am showing -20dBm on my repeater inputs on the RX multicoupler outputs from the controls stations. Not good. Cant reduce multicoupler gain due to reducing the portable radio coverage. So, any decent way to reduce the high power radio's tx? I would like to go into Tuner and drag the power slider down, but am guessing that is not an acceptable solution......? If I can't find a software solution, then it will be small antennas buried in the guard shacks. Thank you, TT
Reply With Quote
Sponsored links
  #2 (permalink)  
Old 01-04-2018, 10:20 PM
MSS-Dave's Avatar
Member
   
Join Date: Jan 2010
Location: Generally Central Florida
Posts: 331
Default

Quote:
Originally Posted by TampaTyron View Post
I have a bunch of high power UHF 5550 control stations (in guard shacks) that are close to my customer's UHF Capacity Plus site. Each control station has a large outdoor antenna. I am showing -20dBm on my repeater inputs on the RX multicoupler outputs from the controls stations. Not good. Cant reduce multicoupler gain due to reducing the portable radio coverage. So, any decent way to reduce the high power radio's tx? I would like to go into Tuner and drag the power slider down, but am guessing that is not an acceptable solution......? If I can't find a software solution, then it will be small antennas buried in the guard shacks. Thank you, TT
You should be able to reduce your transmitter output to about 20 watts, I don't think you can go lower than that. The next thing you could do is make an inline attenuator either with a bunch of RG58 or put in a 20 watt 6 DB attenuator in the antenna line if you can get the power turned down. The way I read your question your control stations are fairly close to the system so you can take a fairly large hit on your receive sensitivity. What RSSI do you see on your control stations as it is right now?

Sent from my SAMSUNG-SGH-I337 using Tapatalk
Reply With Quote
  #3 (permalink)  
Old 01-05-2018, 8:18 AM
Member
   
Join Date: Jun 2013
Location: Texas
Posts: 3,057
Default

You can turn a high power unit down as far as 9W when it comes to the XPR5550. To verify, the CPS will state the power range under the Device Information.

What I typically do, put ducks on the radios and run them at low power but ideally that works best if you can get the radios down to 5W.
Reply With Quote
  #4 (permalink)  
Old 01-05-2018, 2:55 PM
MSS-Dave's Avatar
Member
   
Join Date: Jan 2010
Location: Generally Central Florida
Posts: 331
Thumbs up

Quote:
Originally Posted by MCore25 View Post
You can turn a high power unit down as far as 9W when it comes to the XPR5550. To verify, the CPS will state the power range under the Device Information.

What I typically do, put ducks on the radios and run them at low power but ideally that works best if you can get the radios down to 5W.
Thanks for this info. I haven't been into 5550 at all so I figured they might be like the bricks in XPR8400 that won't go below 20.
Reply With Quote
  #5 (permalink)  
Old 01-05-2018, 4:02 PM
Member
   
Join Date: Aug 2006
Location: Boyton Beach, FL
Posts: 222
Default

Looking at a code plug for an XPR-5550 with the HHCH.

The Device Page indicates - Power range Watts 20.0 - 48.0

An under General Settings you have the Low TX & High Tx settings that can then be toggled via a button.

Lower then 20 Watts you will need to put it on the bench and tune it down manually.

==============
Attached Images
 
Reply With Quote
Sponsored links
  #6 (permalink)  
Old 01-05-2018, 6:17 PM
Member
   
Join Date: Jun 2013
Location: Texas
Posts: 3,057
Default

Quote:
Originally Posted by Firebuff880 View Post
Looking at a code plug for an XPR-5550 with the HHCH.



The Device Page indicates - Power range Watts 20.0 - 48.0



An under General Settings you have the Low TX & High Tx settings that can then be toggled via a button.



Lower then 20 Watts you will need to put it on the bench and tune it down manually.



==============


I may have pulled a XPR5550e codeplug. People have not been labeling which of the two at the office lately…


Sent from my iPhone using Tapatalk
Reply With Quote
  #7 (permalink)  
Old 01-06-2018, 12:46 AM
Member
   
Join Date: Oct 2017
Posts: 128
Default

I hear coax and a dummy load still make for a good radiating source if you're close enough! ������

Last edited by masstech; 01-06-2018 at 12:46 AM.. Reason: ��
Reply With Quote
  #8 (permalink)  
Old 01-06-2018, 1:19 AM
Member
   
Join Date: Feb 2010
Location: Tampa, FL
Posts: 463
Default

I may put one of those right angle mini-u male to bnc female adapters on it. Then put a bnc portable whip on it.... see if I can smoke it at 20 watts (but with TDMA). TT
Reply With Quote
  #9 (permalink)  
Old 01-06-2018, 4:39 PM
Member
   
Join Date: Aug 2006
Location: Boyton Beach, FL
Posts: 222
Default

Quote:
Originally Posted by TampaTyron View Post
I may put one of those right angle mini-u male to bnc female adapters on it. Then put a bnc portable whip on it.... see if I can smoke it at 20 watts (but with TDMA). TT
https://www.tessco.com/products/disp...o.do?sku=57417

https://www.tessco.com/products/disp...o.do?sku=17174

Have had no issues with this combination.
Reply With Quote
  #10 (permalink)  
Old 01-06-2018, 7:24 PM
Member
  Amateur Radio Operator
Amateur Radio
 
Join Date: Mar 2003
Location: PALM BEACH, FLORIDA
Posts: 2,843
Default

I would never use an antenna 1 inch from a radio that was transmitting 20 watts into it. Maybe with 10 feet of coax to get some distance from the radio.
__________________
FORMERLY MOONBOOTS
Reply With Quote
  #11 (permalink)  
Old 01-06-2018, 7:48 PM
Member
   
Join Date: Aug 2006
Location: Boyton Beach, FL
Posts: 222
Default

Quote:
Originally Posted by N4KVE View Post
I would never use an antenna 1 inch from a radio that was transmitting 20 watts into it. Maybe with 10 feet of coax to get some distance from the radio.
5550 e

High Power Output:
VHF: 25-45 W
UHF Band 1: 25-40 W
UHF Band 2: 1-40 W
800: 10-35 W
900: 10-30 W

Low Power Output:
VHF: 1-25 W
UHF Band 1: 1-25 W
Reply With Quote
  #12 (permalink)  
Old 01-06-2018, 10:37 PM
Member
  Amateur Radio Operator
Amateur Radio
 
Join Date: Mar 2003
Location: PALM BEACH, FLORIDA
Posts: 2,843
Default

What that means is the hi power output radio [45 watts] can not go below 25 watts on low power. But the low power output radio [25 watts] can go as low as 1 watt on the low power setting.
__________________
FORMERLY MOONBOOTS
Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -5. The time now is 3:49 AM.


Powered by vBulletin® Version 3.8.2
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
All information here is Copyright 2012 by RadioReference.com LLC and Lindsay C. Blanton III.Ad Management by RedTyger
Copyright 2015 by RadioReference.com LLC Privacy Policy  |  Terms and Conditions