CB Gods hate me .... Ebay LMR 400 is no good?

[AJAT]

the money I have spent is unbelievable... and you really don't want to be boarded.. but ok, I bought RF bonding for my pick up so I got a few 12 foot rolls of 1 1/4" braided strap... I bought 50 terminal ends... I bought the crimpers for 00 thru 8 AWG terminals and a roll of 4 awg ground straps.... I bought a trans hump cb mount $50 ( it didn't fit) I bought a multi angle floor mount piece $50 but that wouldn't fit either... VERY hard to get the radio in the truck... I bought a junk yard pull out tray for my pick up that I mounted my CB to and is working nicely.... I bought several fittings and cables.... the LMR400 was $109 the RG8 was $89 after taxes... the Tram3500 was under a 100 bucks when I got it....and can be bought for 50 now... I bought 3 top fence rails $30 each and two 1 1/4 EMT 10 footers plus stainless steel bolts and washes.... almost $300... I bought a lightning arrestor 90 bucks.... I found out I have to cut the LMR400 so it will come down the side of my mast STRAIGHT into a large waterproof box ( the plastic hinged box was $50) I was going to go past the box and up from under to make a drip loop.. but I was schooled that lightning will not do curves or bends thanks Bill..... so I spent $300 at DX engineering on LMR400 ends and a crimper and a stripper then another set of jaws for the crimper so I can do my RG8 then RG8 ends and a RG8 stripper.... then I guess i'm going to have to solder the center pin... so I bought solder and a soldering iron..... I also bought a relay for my mobile so I can go from the battery to the CB with 10AWG and when I shut off the key in the truck the CB will shut off.... I am trying to get a Mic holder for the truck.. got a magnet one but it doesn't fit my mic so I got another that sticks to the dash but it sticks out too far... there is no place to mount my base station on my work bench so I got a computer monitor arm bracket so I can mount it to the side of the bench and swing it to were I can see it and use it and still have my whole work bench... I bought 4 Stainless steel house to mast clamps ... I bought a couple of SWR meters... didn't seem to work ( real junk so I got the Rig Expert... ( WOW NICE UNIT) .. I've bought ground rods and grounding cable grounding clamps... I have a guy coming in to dig an 8 foot hole for my ground rod... I live on a rocky area... spent years learning you just can't dig on my property... all rocks the size of a watermelon you can't get them out with a post hole digger.... dummy loads.. all the bolts and star washers for doing the RF bonding on the truck... I have a 100 bucks into bolts washers drill bits ext... clear paint ....blue paint U bolts... I could honestly go on all day.. and it's more than a grand... I have a addiction / passion for CB handhelds... I now have over 30 of them and have been buying tools and testing gear for them so when I get my base station up I will be doing range testing and power testing on them and see what I can do... I thought it would be nice to take the dog for a walk and go out 1 mile and try to talk to the base.. then 2 miles and then 3 and then 4..... I will set up a video recorder on my base station.... going to be fun if I ever get the base up and running.... but if I had known three months ago when I retired.. I wouldn't have done it! ..for all I know my Cobra may not work! ... on the truck.... I did RF Bonding 6 places on bed to the frame... 4 places cab to frame... RF Bonding from CAB TO BED ...fenders doors ...hood... then I put 10 ground straps on it.... it all takes time and MONEY .. I could keep going but as I said I thought I would bore you ( sorry)

Radio hobbies can be very expensive. Nice job on the RF bonding. Most people don’t go that far.

 

[AJAT]

if this thing isn't done by late December, you may see all my gear stacked on the side of the road with a free sign... no wait.. all the trouble i've had... I think I'll burn it!

Don’t give up. But is you do burn it maybe it will keep the mosquitos away. LOL

 

[niceguy71]

Radio hobbies can be very expensive. Nice job on the RF bonding. Most people don’t go that far.

I had no idea how expensive the hobby is... pricing a new Antron 99 tonight.... it's going to be about $200 after taxes with ground plane kit..... every day is a set back... hopefully that will be it! ...from here on in it should only nickel and dime me to death..... thank you, for the compliment, on the RF bonding..... I have been told by some it makes all the difference in the world... and other's a trusted friend ( Bill ) laughed and said it won't do a thing, it's a complete myth...... me personally I have watched a few guys do the bonding on youTube one guy I learned a lot from BBI doing the bonding was amazing...others do the bonding they then talk all across the country on skip........ I have had a pick up truck in the 80's with the same CB I have now, 15 watts, I was lucky to get 3 miles... I tried about 10 different antenna's including a fiberglass 102" whip nothing would make it work ( a magnet mount K40 actually did pretty good) .... so I thought maybe the bonding was the problem.... so this time ( 2023) I did the bonding... we will see I just did it this weekend and I just checked the SWR... it actually got worse after the bonding ( probably just a coincidence and where I was parked) so far I have not been able to contact anyone so I would say it made no difference at all.

 

[522]

I know its been mentioned more than once... please check the continuity on your LMR 400
You have shown lots of pictures with your Rig Expert Meter.. how about a pic with a regular old digital multimeter.
This has got to be something simple and overlooked.

 

[niceguy71]

I know its been mentioned more than once... please check the continuity on your LMR 400
You have shown lots of pictures with your Rig Expert Meter.. how about a pic with a regular old digital multimeter.
This has got to be something simple and overlooked.

I posted that I checked for continuity from pin to pin and screw threads to screw threads... both had correct continuity I also checked both ends from pin to screw threads and got no continuity. I also did the dummy load and the SWR was 1.1 so I guess the LMR is good.... I did the same tests on the RG8 all did the same thing

 

[merlin]

Any reason you can't just stay with the RG-8 ? That is a good coax.
What you gain going to LMR-400 you will never notice on 11 meters.
Sounds a bit like the connectors on the LMR-400 are different in some manner.

 

[KI4ZNG]

I have to agree with Merlin. Some thing is up with the LMR-400 coax. I would use the RG-8.

 

[niceguy71]

Any reason you can't just stay with the RG-8 ? That is a good coax.
What you gain going to LMR-400 you will never notice on 11 meters.
Sounds a bit like the connectors on the LMR-400 are different in some manner.

this is baffling to me also... if I ran the RG8 to my CB and hooked it up I would be all done! but the whole issue started testing my antenna before I put it 32 feet in the air... I can't take it down by myself so I want everything to be right... I just leaned it against my fence to see if it would work... but I didn't want to hurt the coax cable end so I U-bolted it to the fence pole ... but I didn't even realize the antenna was lower than the fence.. everyone here caught my mistake ( thank you everyone)... so I put it on a pole a few feet above the fence and I get SWR of 13 on the LMR 400 and 1 point something on the RG8... everyone told me to test the lmr 400 and on a dummy load it seems good same with an ohm meter.... so they tell me the LMR 400 is ok and the 100 foot length and the higher resistance of the RG8 is masking the problem with the antenna!...... something is wrong.... lot of other stuff going on... but I am thinking it may be too close to the fence to test.... I am going to do a few more tests later this weekend and get to the bottom of it...

 

[niceguy71]

Any reason you can't just stay with the RG-8 ? That is a good coax.
What you gain going to LMR-400 you will never notice on 11 meters.
Sounds a bit like the connectors on the LMR-400 are different in some manner.

by the way I have not seen you in a while Merlin... nice to see you back

 

[smittie]

Antenna systems is one of the Dark Arts that requires sacrifices at midnight.

 

[Ubbe]

Look at the LMR400 connector and compare to the RG8 one if the center pin somehow doesn't make any connection. Either the center pin are not long enough or the connector doesn't screw on all the way, something makes it stop halfway.

If you have an analyzer that can show SWR along the length of the coax it probably show that the only fault are at a distance where the end connector and antenna are. Sometimes the weight of the coax pulls on the connector and the center pin gets retracted into the coax. It's always good to have a loop of coax right below the antenna and then the coax below it are secured properly while the loop are allowed to flex and move around a bit.

/Ubbe

 

[rescue161]

How long is the RG8 and how long is the LMR400? If they are different electrical wavelengths, then that is probably the source of the disconnect and the antenna would more than likely be the failure point.

 

[RFI-EMI-GUY]

The mounting instructions at the bottom say that the antenna must be 18 feet from any other metal object. It is mounted very close to the fence and earth.

As far as the RG8, yes either it is a wavelength issue or the RG8 cable is very lossey and masking the high VSWR.

The antenna could be damaged, mounted incorrectly (as it is) .

 

[prcguy]

The mounting instructions at the bottom say that the antenna must be 18 feet from any other metal object. It is mounted very close to the fence and earth.

As far as the RG8, yes either it is a wavelength issue or the RG8 cable is very lossey and masking the high VSWR.

The antenna could be damaged, mounted incorrectly (as it is) .

View attachment 147912

Mounting the antenna too close to large metal object like the fence can make the SWR a little worse but not like what's going on here. If the antenna had a 1.2:1 match on ch 20 when 18ft in the air it might go higher just 5ft above the fence but probably not more than 2:1.

 

[AJAT]

I forget, did you ever use the short jumper to check the antenna SWR ?

 

[devicelab]

I forget, did you ever use the short jumper to check the antenna SWR ?

This is the easiest test point. A simple 3-10ft piece of ANY coax would work here. Take the coax out of the equation.

 

[niceguy71]

How long is the RG8 and how long is the LMR400? If they are different electrical wavelengths, then that is probably the source of the disconnect and the antenna would more than likely be the failure point.

the LMR 400 is 40 feet long.... the RG8 is 100 feet.... the lmr 400 was laid flat out on the ground... the RG8 was coiled up in my hand

 

[jwt873]

Sometimes the weight of the coax pulls on the connector and the center pin gets retracted into the coax. It's always good to have a loop of coax right below the antenna and then the coax below it are secured properly while the loop are allowed to flex and move around a bit.

/Ubbe

This makes some sense.. I've been thinking connectors all the way through this thread. Unlike RG8, LMR-400 can be a little more tricky to attach to a PL-259 connector. The outer foil can be a problem.

If you're letting the cable just hang on its own weight when checking the SWR, then as Ubbe says, you could have the center conductor, or even the shield pulling away and not making contact. When checking SWR to a dummy load, I'm guessing it's just sitting on the ground. If so, then the cable isn't supporting any weight and there is no strain on the connector.

Try checking the SWR to a dummy load again. This time grab the cable and wiggle the connectors on both sides as you do it. See if it causes any change.

 

[niceguy71]

This makes some sense.. I've been thinking connectors all the way through this thread. Unlike RG8, LMR-400 can be a little more tricky to attach to a PL-259 connector. The outer foil can be a problem.

If you're letting the cable just hang on its own weight when checking the SWR, then as Ubbe says, you could have the center conductor, or even the shield pulling away and not making contact. When checking SWR to a dummy load, I'm guessing it's just sitting on the ground. If so, then the cable isn't supporting any weight and there is no strain on the connector.

Try checking the SWR to a dummy load again. This time grab the cable and wiggle the connectors on both sides as you do it. See if it causes any change.

I'll give it a shot... the ends have a heavy heat shrink on then that are molded on... hard to believe it could loosen up.... Times microwave makes good stuff.. but i'll check it out

 

[G7RUX]

I bought a 2 pack of two foot jumpers pl259's very cheap ones 14 bucks ... I took one out to the antenna and hooked it up to the Rig Expert.... I always seem to have trouble getting a great connection to my used Rig Expert but it always works... today it kept giving me all zeros??? so I got the other 2 foot cable and kept playing with it, it would go from Zero's to an SWR of 7 and finally I got it an swr of 2.1 to 3.4 ... so I guess that means my antenna is no good???? when I had it hooked up at the end I shook the antenna and Rig Expert and the 2 foot jumper and it always stayed about the same....... I then took my SWR Rig Expert to my pick up truck.... it's parked next to a building but this is just a test of the LMR 400... I hooked it up to my Tram 3500 and got an SWR of 1.6 to 1.7 ( it was way better out in an empty field) I then put the LMR400 between the Tram 3500 and the Rig Expert with a barrel connector and got an SWR of 1.4 to 1.7 .... so it looks like the LMR 400 is ok as everyone said. and I guess I'll buy an Antron 99 and a ground plane kit... I'll deal with that another time... running out of CB money... never expected to spend thousands and not have my base station up yet!!!! but it was SOOOOO close if not for the old Shakespeare not working it would be done.

Hmm.
How does the connector on the SWR analyser look? They can quite easily be damaged and would cause all sorts of odd readings.