High SWR on Diamond X-200

[thursdasy]

Hey everyone, new ham here. Last weekend I installed a Diamond X-200 on a cold water pipe running on the side of my house. Seemingly it has been working great but today when I plugged in an old Diawa SWR & power meter I noticed my SWR was five when transmitting. The frequency I'm testing on is 146.000.

Should I have the range switch on the meter set to 15W? I'm testing on low power on a Kenwood TM-V71. When I set the range switch to 150w my SWR is close to one. Not sure if I'm using the SWR meter properly I inherited this from my grandfather so I don't have any instructions.

My coax is 50 feet and everything should be 50 omhs

EDIT:

So I removed the antenna from the mounting brackets and the SDR went to where it should be. Can I not mount the antena directly to a cold water pipe? So currently my mast is mounted via a V-bolt to a cold water pipe.

 

[popnokick]

The pic of the meter in your post shows an SWR of 2 (Reflected) and a forward (output) power of 5 watts (with the Range switch set at 15 full scale). So you have a 2 to 1 SWR - not sure if that is before/ after you removed the antenna from the brackets. What you should be looking for is a minimum reading on the "Reflected" needle and a maximum reading on the "Forward" scale/needle.

Mounting to a pipe should be fine for that dual-band base Diamond antenna. Something else is probably wrong (other than the mount). Any chance you could send us a pic of the mounted antenna?

Did you run all the basic checks on the coax with a multimeter? Disconnect antenna, check the radio end by using the ohmmeter leads across the center and outer conductors and be sure it is "open" (no shorts). Put an alligator clip across the center and outer conductors at the antenna end, then go back down to the radio end of the coax and ensure you a seeing continuity/shorted.

Finally.... how are the antenna, coax, and radio grounded?

 

[thursdasy]

Hello, the reading on the SWR is when it was mounted to the cold water pipe. When I removed the antenna from the mounting brackets the SWR meter barely moved. Can you explain how to determine SWR with this meter? I understand we want as little reflected power as possible, just not clear on how you determined the 2:1 SWR.

I attached two photos of the mounted antenna.

I haven't tested the coax though when the antena want not mounted the SWR meter showed different results.

Other than the antenna being mounted to a cold water pipe it isn't grounded with anything else.

 

[popnokick]

The pic explains everything now. Unfortunately, the mounting has a couple of major problems:
1 - The metal mounting pipe... and the siding (aluminum?) of the building is absorbing your radiated signal
2 - The antenna appears to be missing two or more of the counterpoise/ground element rods

First and most importantly, you've got to get the antenna away from the pipe and away from the side of the building. That will best be done by getting it on or above the roofline. That type of antenna is omnidirectional, and needs free space around it in all directions. That means getting it up high and above the roof. Does the pipe you're currently mounted to extend above the roof? If so, move the antenna to the rooftop and attach the mount to the portion of the pipe that is above the roof. Don't forget to reattach the other groundplane/counterpoise element. Run the coax back down the same pipe that you are already using. Getting the antenna onto the roof is going to make a HUGE difference in your SWR, and both the receive and transmit range of the antenna.

Also, I was incorrect about your SWR. It is closer to 5 to 1, and is read from the intersection of the needles and the red lines marked SWR. However, what I wrote about minimizing the Reflected needle reading is still correct. The reflected power should be near zero as possible.

 

[thursdasy]

Thanks for the advice. I need an additional ladder to get all the way on the roof. Once I do I can mount the antenna on the roof which should hopefully solve this problem. And yes the pipe extends above the roof so I can easily mount it. =)

Thanks for the help!

 

[popnokick]

Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 6_1_4 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10B350 Safari/8536.25)

Perfect! I think you'll be very happy with the result of moving the antenna to the portion of the pipe that's above the roof, putting the entire antenna "in the clear" and unobstructed. Work safely making the change.

 

[mmckenna]

Comment removed.... Looks like you figured it out.

 

[majoco]

..and your cross-pointer VSWR meter show a VSWR of 5 - read the red scale underneath where the pointers cross.

 

[thursdasy]

I mounted the antenna on another pole and now the SWR meter is reading 1. Thanks everyone for the help.

 

[popnokick]

Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 6_1_4 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10B350 Safari/8536.25)

You've got it now. Let us know how it's working (TX/RX) as compared to where it was.

 

[thursdasy]

My forward is now three with a reflected needle at zero. I had to increase the coax length from 50 to 100 feet.

 

[Rt169Radio]

My forward is now three with a reflected needle at zero. I had to increase the coax length from 50 to 100 feet.

What kind of coax are you using?

 

[thursdasy]

What kind of coax are you using?

I have two 50 Foot (CABLE XPERTS CXP1318FC50 | 50 FT 9913Flex type cable with PL 259s) cables. I didn't want to throw out my existing 50 foot cable so I purchased a coupler and an additional 50 foot cable.

 

[Rt169Radio]

I have two 50 Foot (CABLE XPERTS CXP1318FC50 | 50 FT 9913Flex type cable with PL 259s) cables. I didn't want to throw out my existing 50 foot cable so I purchased a coupler and an additional 50 foot cable.

How is your coax loss with that kind of run?

 

[LtDoc]

Figure the loss for 100 feet of that cable. The coupler will contribute very little to the total. I think the additional height and the fact that the antenna isn't next to things, as it was, will more that negate any additional losses due to the feed line.
- 'Doc

 

[Cataddict]

Thursday:

The 9913 cable you have should be fine. It's should be about the same as LMR-400 Ultraflex, which is decent stuff. So for a 100 ft run on 146.00 that's about 1.8 dB total loss.

I still can't tell from your photo if you have all three radials installed on the X200. I don't know specifically how the X200 will behave with only one radial. They are all there for a purpose.

Just FYI, I have a X200 that I use because I needed an antenna with that form factor and I've been happy with it. It's only 10' above my roof, and your roof looks higher. So you should expect pretty good performance.