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Another Newbie With Antenna Issues


Question

Posted

Let me preface this by saying I am an absolute newbie! Last radio was a Realistic Mini 23 CB radio in the late 70s.

I purchased a Midland MXT 575 and their MXTA26 antenna to mount on the spare tire rack of my Wrangler. The spare was putting pressure on the antenna so I ordered a ground plane kit from Nagoya and roof mounted it. Checked the SWR and it was 3.78.

Unhappy with that, and the fact I couldn't drive in and out of my carport, I purchased a mount that pivots. I didn't have the correct connections on the cable at this point so I mounted without the ground plane kit. SWR? 19.99! Dang! I shut it down and waited for another cable.

New cable and ground plane kit installed today and SWR is still 19.99! I though maybe an antenna issue, so I replaced with Midland's Ghost Antenna. No reading whatsoever on the meter now. I am thinking it must be the meter. Any of y'all have sound theories? Any ideas are greatly appreciated.

Thanks

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Posted
41 minutes ago, WSFX665 said:

Let me preface this by saying I am an absolute newbie! Last radio was a Realistic Mini 23 CB radio in the late 70s.

I purchased a Midland MXT 575 and their MXTA26 antenna to mount on the spare tire rack of my Wrangler. The spare was putting pressure on the antenna so I ordered a ground plane kit from Nagoya and roof mounted it. Checked the SWR and it was 3.78.

Unhappy with that, and the fact I couldn't drive in and out of my carport, I purchased a mount that pivots. I didn't have the correct connections on the cable at this point so I mounted without the ground plane kit. SWR? 19.99! Dang! I shut it down and waited for another cable.

New cable and ground plane kit installed today and SWR is still 19.99! I though maybe an antenna issue, so I replaced with Midland's Ghost Antenna. No reading whatsoever on the meter now. I am thinking it must be the meter. Any of y'all have sound theories? Any ideas are greatly appreciated.

Thanks

20241220_123559.jpg

20241220_124236.jpg

It might be the meter, but I bet it’s either the cable or the mount. 

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Posted (edited)
7 minutes ago, SteveShannon said:

It might be the meter, but I bet it’s either the cable or the mount. 

Thank you, Steve

How do you check the cable?

Edited by WSFX665
Added a Thank you
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Posted

If you have a multimeter, disconnect from the radio and antenna/mount and check continuity on the outer connectors end to end, the center pin end to end, and do the center to outer.  First 2 should have continuity, 3rd should not.

Same story connected to the mount...center pin on the mount to center on the cable, outer threaded to connector on cable.

I tried one of those Nagoya ground planes and didn't see good results, but that 19.99 is saying a broken connection or short to me too

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Posted
12 minutes ago, WSFX665 said:

Thank you, Steve

How do you check the cable?

The easiest way is to swap it out to another. 
Otherwise check for continuity from one end to the other on both the shield and the center conductor. But, the shield and center conductor must not be shorted to each other. 

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Posted
2 minutes ago, wayoverthere said:

If you have a multimeter, disconnect from the radio and antenna/mount and check continuity on the outer connectors end to end, the center pin end to end, and do the center to outer.  First 2 should have continuity, 3rd should not.

Same story connected to the mount...center pin on the mount to center on the cable, outer threaded to connector on cable.

I tried one of those Nagoya ground planes and didn't see good results, but that 19.99 is saying a broken connection or short to me too

Ok, Thanks!

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Posted
17 minutes ago, SteveShannon said:

The easiest way is to swap it out to another. 
Otherwise check for continuity from one end to the other on both the shield and the center conductor. But, the shield and center conductor must not be shorted to each other. 

Ok, that test passed.

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Posted
28 minutes ago, AdmiralCochrane said:

What range does your multimeter read?  Some of my coworkers tell me that a circuit is open, then I find they are using meters that only read up to 6k ohms and the circuit was a 10K ... wasn't open, but their meter couldn't tell

I misread your question. It looks like it reads up 2k. The actual reading is 6 or 7

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Posted
19 minutes ago, WSFX665 said:

I misread your question. It looks like it reads up 2k. The actual reading is 6 or 7

Could you show us a picture of your multimeter.
For an open circuit it should read something like OL.  Of course if you’ve got a probe in each hand it’s measuring the conductivity of your body and all bets are off. 😄

For a continuous conductor it should read in some tenths of an ohm. 
End to end - shield:
IMG_4491.thumb.jpeg.ed56800b6e3c3782e4b79952052f9714.jpeg


End to end - center:

IMG_4492.thumb.jpeg.5671da0e9866e0037dd6d4e50540b319.jpeg

 

center to shield - open circuit (my probe slipped while I was trying to hold it one handed to take the picture but you get the idea). It shows that it’s an open circuit (OL) and it is on the Megohm range:

IMG_4494.thumb.jpeg.d649a5b39dbf8ac54ef96bf2bb2f5c6a.jpeg

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Posted
8 minutes ago, SteveShannon said:

Could you show us a picture of your multimeter.
For an open circuit it should read something like OL.  Of course if you’ve got a probe in each hand it’s measuring the conductivity of your body and all bets are off. 😄

For a continuous conductor it should read in some tenths of an ohm. 

I was using the green scale at the top. Is this correct?

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Posted
1 minute ago, WSFX665 said:

I was using the green scale at the top. Is this correct?

20241220_200150.jpg

Yes, and your meter has two different ohms ranges - you’re in the x10 range which would appear to be open even if it’s not. I would test the circuits that should be closed using the x10 range and test the circuits that should be open using the x1k range.

So now the SWR meter is blank or just doesn’t change?

Also, I went back to the top. You thought you had a bad cable so you ordered another and it shows the same SWR of 19.99?  I am sorry, but I doubt that two separate cables are bad. That leaves something else, the mount, the ground plane kit, or the antenna and I suspect the mount since you’ve tried it with and without the ground plane and with two different antennas. Or it’s the SWR meter. Honestly I’m just guessing but if I were there I would eliminate one thing after another. 

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Posted
5 minutes ago, WSFX665 said:

Only thing on the screen is the info when you power it on. Nothing changes when mic is keyed

So, just the power up screen?  Maybe it is the meter. Try taking it all the way back to where you started. Do you have a local friend with a radio?

I'm going to bed. Maybe someone else can think of something to try. 

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Posted
4 hours ago, SteveShannon said:

So, just the power up screen?  Maybe it is the meter. Try taking it all the way back to where you started. Do you have a local friend with a radio?

I was thinking the same...back to the ground plane and no mount, and see if the swr goes back to the high 3's.  if so, it would seem like the mount is the issue, in some way.  if not, that would point to something is awry with the meter.

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Posted
10 hours ago, SteveShannon said:

Could you show us a picture of your multimeter.
For an open circuit it should read something like OL.  Of course if you’ve got a probe in each hand it’s measuring the conductivity of your body and all bets are off. 😄

For a continuous conductor it should read in some tenths of an ohm. 
End to end - shield:
IMG_4491.thumb.jpeg.ed56800b6e3c3782e4b79952052f9714.jpeg


End to end - center:

IMG_4492.thumb.jpeg.5671da0e9866e0037dd6d4e50540b319.jpeg

 

center to shield - open circuit (my probe slipped while I was trying to hold it one handed to take the picture but you get the idea). It shows that it’s an open circuit (OL) and it is on the Megohm range:

IMG_4494.thumb.jpeg.d649a5b39dbf8ac54ef96bf2bb2f5c6a.jpeg

Well, that’s embarrassing.  The black lead was in the current reading A socket rather than the Com socket.  Obviously it must be low impedance (perhaps just a fuse) between the two sockets, but it’s not right. Mea culpa, mea culpa, mea maxima culpa!

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Posted (edited)
20 minutes ago, SteveShannon said:

Well, that’s embarrassing.  The black lead was in the current reading A socket rather than the Com socket.  Obviously it must be low impedance (perhaps just a fuse) between the two sockets, but it’s not right. Mea culpa, mea culpa, mea maxima culpa!

It happens.😀 
Edit: I’m laughing with you of course and not at you because (1) I missed it myself and focused on the screen with “OL” and (2) I’ve done that before.

Edited by WRUU653
Clarification
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Posted

First you had an SWR of 3.78.   After making changes you got the 19:1 reading.  Now, you said that the meter no longer reads anything when the mic is keyed.   Is it possible that the radio is no longer transmitting after that high SWR that it experienced?   I realize that the radio should protect itself from extreme SWRs but maybe this time it did not??

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Posted
10 minutes ago, WSAM454 said:

First you had an SWR of 3.78.   After making changes you got the 19:1 reading.  Now, you said that the meter no longer reads anything when the mic is keyed.   Is it possible that the radio is no longer transmitting after that high SWR that it experienced?   I realize that the radio should protect itself from extreme SWRs but maybe this time it did not??

It's transmitting at least as far as the HT in the house. I just remembered that I have the Mag Mount antenna that came with the radio! Headed out to test the meter on that that now. 

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Posted

Ok, so I dug the mag mount antenna out and tested that as well as retesting the others. Here's what I got this morning:

Mag Mount: SWR 1.19, 45 Watts

Ghost: SWR 1.36, 50 Watts

MXTA26: SWR 1.10, 46 Watts

So apparently it was the meter or operator error 😜. Needless to say I am both pleased with this morning's results and a bit embarrassed by my panic.

I certainly appreciate you guys helping me sort this out, as well as your patience!

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Posted
16 minutes ago, WSFX665 said:

Ok, so I dug the mag mount antenna out and tested that as well as retesting the others. Here's what I got this morning:

Mag Mount: SWR 1.19, 45 Watts

Ghost: SWR 1.36, 50 Watts

MXTA26: SWR 1.10, 46 Watts

So apparently it was the meter or operator error 😜. Needless to say I am both pleased with this morning's results and a bit embarrassed by my panic.

I certainly appreciate you guys helping me sort this out, as well as your patience!

Meter was connected backwards? The radio was on the antenna side of the meter, and antenna on the radio side?

 

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