If it wasn't for my SWR questions yall'd be bored.

[Metal Head]

Question 1:
Using my new MFJ-259B with a 9' piece of coax from it to my ant. I have a SWR of 1.1 w/ X=0 on 27.205mhz. When I put the FMJ in front of my amp the reading goes much higher. Am I reading the box and should I not do it this way.

Question 2:
I'm useing RG-8/U which is rated at 50 ohms. Why is my "R=" value reading 59 on 27.205mhz?

This has definetly been a learning experience for me. For years I used to throw something together, check it with my dosey and let it go. Could it be I'm just worring to much? :? :?

 

[AMPOWER]

Get a 5w dummy load from MFJ and start troubble shooting the problem..
-coax to the dummyload...
-6' jumper to the amp to dummyload on the ANT side of the amp...

AM POWER

 

[Switch Kit]

Hey Metal dude , welcome to the Wonderful World of CB Radios /Antenna's (-: Wow !! and here I thought I was the only one over the years that could drive myself crazy with all of this SWR mumbo jumbo !!(along with the work and a few headachs on the side) It was all so much easier for me before I decided to become a perfectionist with it all .....IM sure it will all even out for you one way or the other. It always helps me sometimes to simply remember what used to work for me before I decided to get so damned technical . Good Luck to you.

 

[Metal Head]

Hey Metal dude , welcome to the Wonderful World of CB Radios /Antenna's (-: Wow !! and here I thought I was the only one over the years that could drive myself crazy with all of this SWR mumbo jumbo !!(along with the work and a few headachs on the side) It was all so much easier for me before I decided to become a perfectionist with it all .....IM sure it will all even out for you one way or the other. It always helps me sometimes to simply remember what used to work for me before I decided to get so damned technical . Good Luck to you.

You sized me up exactly.

 

[Captain Kilowatt]

Re: It it wasn't for my SWR questions yall'd be bored.

Question 1:
Using my new MFJ-259B with a 9' piece of coax from it to my ant. I have a SWR of 1.1 w/ X=0 on 27.205mhz. When I put the FMJ in front of my amp the reading goes much higher. Am I reading the box and should I not do it this way.

Question 2:
I'm useing RG-8/U which is rated at 50 ohms. Why is my "R=" value reading 59 on 27.205mhz?

This has definetly been a learning experience for me. For years I used to throw something together, check it with my dosey and let it go. Could it be I'm just worring to much? :? :?

Q# 1 :With the MFJ-259 in front of the amp you are seeing the input impedance as presented by the antenna as well as any effect the amp may have on the system overall.You should connect it just before the antenna to truly see the antenna impedance.

Q# 2 : The impedance of your cable may be 50 ohms but the analyzer sees the overall impedance presented by the antenna and anything else in line which could be almost anything depending on how well the antenna system is tuned.

 

[Metal Head]

Re: It it wasn't for my SWR questions yall'd be bored.

Q# 1 :With the MFJ-259 in front of the amp you are seeing the input impedance as presented by the antenna as well as any effect the amp may have on the system overall.You should connect it just before the antenna to truly see the antenna impedance.

Q# 2 : The impedance of your cable may be 50 ohms but the analyzer sees the overall impedance presented by the antenna and anything else in line which could be almost anything depending on how well the antenna system is tuned.

I did that to start with and got the 1.1 SWR. Are you saying I can't measure the SWR before the amp. at all with the MFJ?

As far as the antenna being tuned, it's a 102" whip with a spring..no tuning there.

 

[AMPOWER]

To better measure the input tuning of your amp...
You are going to need a Bird meter a 5w slug or even a 25w slug and a single / dual line section,,,
"the MFJ only puts out a 1/8w signal out of the anylizer..."

AM POWER

 

[Captain Kilowatt]

The analyzer will measure the SWR at whatever point it is inserted into the line.Your antenna is providing an SWR of 1.1:1 from what you said and that is good.The amp being inline is affecting the SWR of the overall system and that is why you are seeing something differant when you put the MFJ-259 before the amp.the addition of relays inside the amp can affect the SWR as measured at the input of the amp.Ideally they won't affect it much but we do not live in an ideal world.Also as AMPOWER said the input impedance to the amp may change a bit with a differant driving power of a few watts instead of the mere fraction of a watt the analyzer provides.