ULTRA high SWR reading

[spike1202]

I just got a new President "Bill" 40 ch CB hooked up to a side mount 4' Firestik NGP I've had for a while. It's mounted on a aluminum ladder rack on a aluminum topper not grounded to the truck. The coax cable, antenna and mount came as a set from Firestik. I verified continuity of cable and it's connection to only the brass ant mount stud with the nylon insulator between the ring terminal and the mounting surface. I adjusted the antenna SWR trimming screw to its mid point, connected SWR meter; antenna to ANT side, radio to XMIT side. Set CB to channel 1, set SWR meter to REF, keyed mike and adjusted meter to SET position. I moved the meter to REF, keyed the mike and the meter pegs out. Same for channel 40 and 20. Verified my connections and tried a new SWR meter with same results. Switched out radio for a older Anytone SMART radio (in 40 ch CB export mode) and had the same "pegging the meter" result. Verified continuity of SWR meter jumper coax (both center conductor and shielding). Both radios seem to receive OK (unknown range). Risked a brief radio check on ch 19 and got a response but I've never seen a SWR meters peg like this. What am I doing wrong?? Can anybody offer a suggestion???

Thx in advance,

Matt

 

[jonwienke]

No RF ground. A ladder rack on a fiberglass topper is not a usable ground plane.

 

[prcguy]

I would check for something shorted or the mount put together wrong that is shorting out the coax. Check with an ohmmeter across the antenna connector, it should show open. Then check for continuiy from the center pin of the coax connector to the spring, that should show a short or a few ohms at the most.

The no ground firestick should work ok the way you have it mounted and the match might not be great but it should not peg off the meter. Do the measurements and get back to us.

 

[jassing]

No RF ground. A ladder rack on a fiberglass topper is not a usable ground plane.

He's using an NGP antenna...

Are you looping any extra coax? Are you using a quality SWR meter?

 

[K4EET]

@spike1202, until you get that SWR needle to stop pinning out full-scale, minimize your transmissions to the absolute bare minimum. I am not familiar with that antenna so I don't know if there is any mechanism to tune it for minimum SWR or not. If it is not designed to be trimmed, for now I would just do your SWR measurements at mid-band (Channel 19 at 27.185 MHz). And no more radio-checks until you get that meter to stop pinning itself! LOL!

For a quick "sanity check" if you have a friend with a mag-mount CB antenna that is known to exhibit a low SWR on Channel 19 (let's say that it should be below 1.8 to 1), you could place it in the ABSOLUTE CENTER (or as close as you can get) of your truck's HOOD (you want a lot of metal for a ground plane under most mag-mount antennas). If the SWR meter is still pinned, you might be doing something wrong in setting the meter on your new rig. If the SWR reads a nominal SWR value of say 2:1 or lower, then there is something wrong with your Firestik NGP antenna system.

Finally, and probably most important to say around here to new subscribers, Welcome to Radio Reference!

 

[mmckenna]

Set CB to channel 1, set SWR meter to REF, keyed mike and adjusted meter to SET position. I moved the meter to REF, keyed the mike and the meter pegs out.

Is this a typo?

Usually you'd set the meter to a "Set" or "FWD" position. That shows power going out of your radio towards the antenna. You would use that switch position, and set the needle to full scale deflection, or the "set" point. You should then set the meter to "REF", "Reflect", SWR, or whatever to read reflected power.

Maybe it would help if you told us what SWR meter you were using...

 

[spike1202]

He's using an NGP antenna...

Are you looping any extra coax? Are you using a quality SWR meter?

No sir, I left the excess lose and spread out on the rear cab floor. Though not high end I used a Workman SWR 2-T meter I've had for awhile and a new Astatic PDC1 meter.

 

[spike1202]

Is this a typo?

Usually you'd set the meter to a "Set" or "FWD" position. That shows power going out of your radio towards the antenna. You would use that switch position, and set the needle to full scale deflection, or the "set" point. You should then set the meter to "REF", "Reflect", SWR, or whatever to read reflected power.

Maybe it would help if you told us what SWR meter you were using...

Yes sir, I fat fingered it. I used the "FWD & "REF" switch positions and the "SET" area on the right end of the scale.

 

[mmckenna]

Yes sir, I fat fingered it. I used the "FWD & "REF" switch positions and the "SET" area on the right end of the scale.

OK, cool, that's what I figured...

A couple of things you can try:
Make sure your cables are all good. Disconnect everything. Using a continuity tester or multimeter, check all your cables end to end. Make sure the center conductor is showing continuity all the way through. Do the same with the outer shield. If there isn't continuity from end to end, stop and fix.

Next, make sure there are no short circuits between the center pin and the outer shield on the cable to your antenna and the short jumper from the radio to the SWR meter. If there is, stop and fix.

Next, with everything disconnected, check for continuity between the center pin of the antenna mount and the mounting bracket. There should not be continuity. If there is, stop and fix. Often it's the insulating washer that goes between the antenna mount and the bracket.

If all that checks out to your satisfaction….

Put everything back together. Make sure your truck is well away from anything metallic, garage doors, lamp posts, fences, etc. Middle of a big parking lot is ideal. Nearby metal can reflect your signal and throw the reading offReconnect the antenna to the mount. Connect the coaxial cable to the antenna mount. Connect the other end of the coax to the 'ANT' jack on the Astaic SWR meter. Connect the short jumper from the CB to the XMIT jack on the Astaic SWR meter.

Put the meter switches in the 10W/FWD position and the other switch in the PWR position. Key up the radio and make sure the meter is moving. It's probably going to put out somewhere between 2 and 4 watts. If it does, then your radio is transmitting (I think we've already established this, but making sure….)
Next, leave the left hand switch in the 10W/FWD position and the ANT switch on the right into the SWR position. Key up the radio and adjust the knob so the needle lands on the SET maker, full scale.
Dekey the radio, and move the left hand switch to 100W/REF position and key the radio.

If your SWR is still reading high, then you've got some challenges. Try the Workman meter. Hook it up like above. Put the switch in FWD, key the radio, adjust the knob for full scale deflection to the SET mark. Dekey the radio. Move the switch to the REF position, key the radio and read the SWR.

If it's still reading high and all the other tests checked out, then it's likely the antenna is bad. Even though I think you said you had a successful radio check, it could still be damaged.

Having two SWR meters go bad is not outside the realm of reality, but it's unlikely. If you have a friend with one you can try, that wouldn't hurt.

Sometimes ruling out faulty test gear is a big part of the job. You are ahead of the game with the two SWR meters. If you've ruled out the cable and mount, and both meters show the SWR is still too high, then it really sort of points at the antenna. Even though it's a "No Ground Plane" antenna, having it mounted over a metal rack/topper/truck can interact with the antenna. Moving it to the center of the rack might be something to try.

 

[spike1202]

@spike1202, until you get that SWR needle to stop pinning out full-scale, minimize your transmissions to the absolute bare minimum. I am not familiar with that antenna so I don't know if there is any mechanism to tune it for minimum SWR or not. If it is not designed to be trimmed, for now I would just do your SWR measurements at mid-band (Channel 19 at 27.185 MHz). And no more radio-checks until you get that meter to stop pinning itself! LOL!

For a quick "sanity check" if you have a friend with a mag-mount CB antenna that is known to exhibit a low SWR on Channel 19 (let's say that it should be below 1.8 to 1), you could place it in the ABSOLUTE CENTER (or as close as you can get) of your truck's HOOD (you want a lot of metal for a ground plane under most mag-mount antennas). If the SWR meter is still pinned, you might be doing something wrong in setting the meter on your new rig. If the SWR reads a nominal SWR value of say 2:1 or lower, then there is something wrong with your Firestik NGP antenna system.

Finally, and probably most important to say around here to new subscribers, Welcome to Radio Reference!

Roger that! I shouldn't have transmitted as all with that SWR reading and I won't again until I get this issue sorted out. The antenna has a trimming screw on the top I set at its mid point before I started. I ran around the antenna & mount with my multi meter at your suggestion and may have found the problem. I found continuity between the lower mounting stud, the aluminum mounting plate I made for the ladder rack - and the upper "insulated" mounting stud where the antenna coax connects. I attached a picture of the area. I have a 5 year old Wilson Little Wil magnetic antenna I hooked up and mounted as you suggested but it pegged the swr meter as well. To be fair I'd have to take its base a part to verify its condition with the multi meter and I have not as yet done that. I starting to believe a new NGP antenna is the next step. I really appreciate your help and any further guidance is more than welcome!

Thx again,

Matt This is the antenna, it's a Firestik LG4M2-B 4 ft. Side Mount Antenna with Ngp Kit with a Firestik Antenna SS3H Heavy Duty Stainless Steel Spring.

 

[spike1202]

OK, cool, that's what I figured...

A couple of things you can try:
Make sure your cables are all good. Disconnect everything. Using a continuity tester or multimeter, check all your cables end to end. Make sure the center conductor is showing continuity all the way through. Do the same with the outer shield. If there isn't continuity from end to end, stop and fix.

Next, make sure there are no short circuits between the center pin and the outer shield on the cable to your antenna and the short jumper from the radio to the SWR meter. If there is, stop and fix.

Next, with everything disconnected, check for continuity between the center pin of the antenna mount and the mounting bracket. There should not be continuity. If there is, stop and fix. Often it's the insulating washer that goes between the antenna mount and the bracket.

If all that checks out to your satisfaction….

Put everything back together. Make sure your truck is well away from anything metallic, garage doors, lamp posts, fences, etc. Middle of a big parking lot is ideal. Nearby metal can reflect your signal and throw the reading offReconnect the antenna to the mount. Connect the coaxial cable to the antenna mount. Connect the other end of the coax to the 'ANT' jack on the Astaic SWR meter. Connect the short jumper from the CB to the XMIT jack on the Astaic SWR meter.

Put the meter switches in the 10W/FWD position and the other switch in the PWR position. Key up the radio and make sure the meter is moving. It's probably going to put out somewhere between 2 and 4 watts. If it does, then your radio is transmitting (I think we've already established this, but making sure….)
Next, leave the left hand switch in the 10W/FWD position and the ANT switch on the right into the SWR position. Key up the radio and adjust the knob so the needle lands on the SET maker, full scale.
Dekey the radio, and move the left hand switch to 100W/REF position and key the radio.

If your SWR is still reading high, then you've got some challenges. Try the Workman meter. Hook it up like above. Put the switch in FWD, key the radio, adjust the knob for full scale deflection to the SET mark. Dekey the radio. Move the switch to the REF position, key the radio and read the SWR.

If it's still reading high and all the other tests checked out, then it's likely the antenna is bad. Even though I think you said you had a successful radio check, it could still be damaged.

Having two SWR meters go bad is not outside the realm of reality, but it's unlikely. If you have a friend with one you can try, that wouldn't hurt.

Sometimes ruling out faulty test gear is a big part of the job. You are ahead of the game with the two SWR meters. If you've ruled out the cable and mount, and both meters show the SWR is still too high, then it really sort of points at the antenna. Even though it's a "No Ground Plane" antenna, having it mounted over a metal rack/topper/truck can interact with the antenna. Moving it to the center of the rack might be something to try.

Thanks for the suggestions! I've started running through the set up with the multi meter and may have found the issue. On the antenna base mounting point I found continuity between the lower mounting stud, the aluminum mounting plate I made for the ladder rack - and the upper "insulated" mounting stud where the antenna coax connects. I attached a picture of the area. I continue to run through the cabling and connections to see what else I may find. I'll post what I find.

Thanks again for your help!

Matt

 

[mmckenna]

Thanks for the suggestions! I've started running through the set up with the multi meter and may have found the issue. On the antenna base mounting point I found continuity between the lower mounting stud, the aluminum mounting plate I made for the ladder rack - and the upper "insulated" mounting stud where the antenna coax connects. I attached a picture of the area. I continue to run through the cabling and connections to see what else I may find. I'll post what I find.

Thanks again for your help!

Matt

Well, there ya' go! It's often the insulating washers on these sorts of mounts that are the issue. If they don't go together just right, the short to the mount and will throw a high SWR like you saw. Should be an easy fix now. Once you get it resolved, try your antenna again, I think you'll find it'll be pretty close.

Also a guy named Matt.

 

[Ravenkeeper]

I just got a new President "Bill" 40 ch CB hooked up to a side mount 4' Firestik NGP I've had for a while. It's mounted on a aluminum ladder rack on a aluminum topper not grounded to the truck. The coax cable, antenna and mount came as a set from Firestik. I verified continuity of cable and it's connection to only the brass ant mount stud with the nylon insulator between the ring terminal and the mounting surface. I adjusted the antenna SWR trimming screw to its mid point, connected SWR meter; antenna to ANT side, radio to XMIT side. Set CB to channel 1, set SWR meter to REF, keyed mike and adjusted meter to SET position. I moved the meter to REF, keyed the mike and the meter pegs out. Same for channel 40 and 20. Verified my connections and tried a new SWR meter with same results. Switched out radio for a older Anytone SMART radio (in 40 ch CB export mode) and had the same "pegging the meter" result. Verified continuity of SWR meter jumper coax (both center conductor and shielding). Both radios seem to receive OK (unknown range). Risked a brief radio check on ch 19 and got a response but I've never seen a SWR meters peg like this. What am I doing wrong?? Can anybody offer a suggestion???

Thx in advance,

Matt

Installing No Ground Plane Kits -- ©1997 FIRESTIK® ANTENNA

 

[GrayJeep]

On the topic of high SWR (but probably not this setup), my favorite mag mount CB antenna checked out with low SWR a week ago but when I went to talk to a buddy when convoying my radio was only transmitting a buzz (RF oscillation). Checking further it only does that when the antenna isn't connected. I found infinite SWR.

I discovered that the crimped center conductor in the coax connector wasn't making contact anymore. So I soldered it. Looking at the other CB antennas I own I found the same crimped center connection - so I soldered them too.