good way to ground cb antenna.... - Page 2 - Ranger-Forums - The Ultimate Ford Ranger Resource


General Technical & Electrical General technical and electrical discussion for the Ford Ranger that does not fit in any other sub-forum.

Reply
 
LinkBack Thread Tools Search this Thread
  #26  
Old 01-25-2006
n3elz's Avatar
RF Veteran
 
Join Date: Jun 2004
Location: Kennett Square, PA
Posts: 10,620
Quote:
Originally Posted by fletch12518
but i do need a single coax right?
Roger roger...50 ohm coax. Some co-phase harnesses actually use 75 ohm coax for the y-splitter.
Reply With Quote
  #27  
Old 01-26-2006
Member
Thread Starter
 
Join Date: Oct 2005
Location: Havre De Grace,Md
Posts: 3,262
got her working now! thank goodness!!
Reply With Quote
  #28  
Old 01-26-2006
FireRanger's Avatar  
Join Date: May 2004
Location: CT
Posts: 0
If I can find a jumper, I will experiment this afternoon. How much dB loss does this cause?
Reply With Quote
  #29  
Old 01-26-2006
n3elz's Avatar
RF Veteran
 
Join Date: Jun 2004
Location: Kennett Square, PA
Posts: 10,620
It's not so much the loss, Matt, as the "foldback" it causes in your transmitter. Most modern rigs detect mismatch and reduce output power accordingly. Most impedance mismatches (particularly when purely "resistive") cause their loss in two ways then:

1) Reflected power is wasted, disappated in the final of your rig.
2) The reflected power is used by the rig to determine final drive and most rigs reduce final drive in direct proportion to detected reflective power.

Even a 3:1 SWR actually represents rather small power loss in terms of how much is wasted in reflection -- but the rig will see it and to "save the finals" will reduce the drive.
Reply With Quote
  #30  
Old 01-26-2006
FireRanger's Avatar  
Join Date: May 2004
Location: CT
Posts: 0
Does it cause any measurable loss on RX?
Reply With Quote
  #31  
Old 01-26-2006
n3elz's Avatar
RF Veteran
 
Join Date: Jun 2004
Location: Kennett Square, PA
Posts: 10,620
Not so much. I remember a discussion about this and that was supposed to be one of the weird things: it was hard to measure the receiving loss. It should because some of the power from the antenna on receive is reflecting back from the receiver -- but I really can't say how much. Almost all discussions I've seen focus on transmit.

If you read that article I linked, you see that in some cases a transmission line might IMPROVE the match by being deliberately cut off-length. Often, when we mount antenna's close to reflective surfaces (like cabs in our truck) we make the antenna "reactive". It's actually possible to cut the feedline to make it reactive in the opposite direction (like, if the antenna has capacitive reactance, make the feedline inductively reactive) to acheive a better match.
Reply With Quote
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
CB Install: Replaced AM/FM w/ CB Antenna (done) 56k No way! dave11o11 Project Logs 25 12-13-2009 06:59 PM
Positive Ground vs Negitive Ground malydeen General Technical & Electrical 5 05-08-2008 11:23 AM
4 way to 7 way wiring harness Question ? ghettogord General Ford Ranger Discussion 1 03-10-2008 10:31 PM
two-way, three-way, four? shadow905 Audio & Video Tech 13 09-20-2006 06:56 PM
I want a good, ground shaking set up.... PVEdge03 Audio & Video Tech 7 08-10-2005 02:55 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 Off
Pingbacks are Off
Refbacks are Off



All times are GMT -6. The time now is 10:00 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.