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The Coax Connection: Interview about bad coax with Ray Nelson, N1MPD (#97)
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- เผยแพร่เมื่อ 12 ส.ค. 2024
- My second interview with coax expert Ray Nelson, N1MPD, covers how coax can go bad, primarily due to water entry. We talk about the proper method of waterproofing coax connections, and how to spot the poor quality coax that masquerades as the good stuff. MPDdigital is at www.mpddigital.us. Subscribe: / davidcasler . Ask Dave Playlist: goo.gl/inaQeB. Tip Jar: ke0og.net/tip-jar
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Hi Dave, I have installed hundreds of UHF antennas for AES radios in the alarm industry. I used Scotch 130C over the connectors and coax, then covered that with Scotch 33+ to protect the 130C from the Arizona sun. I never had any issues. This video is an excellent tutorial for everyone installing antennas.
That explains a lot. I've had problems with wiring, connectors and coax cables on various lab equipment over the years. Thank you.
Thank you both. Very useful information.
its ben about 15 20 years now but i went to unhook my Coax and drop it into a 1quart Jar during a lightning storm here n the south at the bottom of the Appalachian Mountain's and noticed a drop or 2 of water but didn't think much of it at the time But when i went to hook my stuff back up i Noticed that my 1quart jar had about 3 inches of water in the bottom & Then I Realized what was going on & had to Replace all my coax & Re seal every thing ! ! A lot of work for something that could have ben prevented n the first place ! I Also Got Took on Some of that Trash Coax You all Was Talking about..Luckily i discovered it Pretty fast when i hooked up a new radio & antenna and it only had roughly half or less of the receive i was expecting so i started the troubleshooting process an sure enough steel Shield & cca Center ! It Was Sold As Very High Quality all solid copper center & Copper Shield But it was not so i Messaged the seller and told them it was a pile of junk & i expected a full Refund !
Excellent knowledge base from a new ham licensee, will help make wise coax decisions. Thanks Dave
Just watched a bunch of your connector and cable videos. Very informative! Nice conversations with Ray.
Thank you again. My second viewing of this video. Gave me some more items to check on when trouble shooting. Glen, N0QFT
Great video, Thank you.
Thanks. This format is great.
Thanks. I need to do some more live interviews.
Great interview!
Thanks so much for such an important - and easily ignored - component
A very useful discussion with much useful information. thank you both gentelemen...73 Cristian, VK1FCLU
Good stuff Dave, you're a real asset to the Radio Hobby. I appreciated hearing about the poor materials used in the cheap coax and how it effect longevity. You get what you pay for as they say and if you go cheap, take all the sealing, handling and affixing precautions and recognize early deterioration. 73 -frank de KF2FI
Thank you
Exceptional interview, Dave. Makes me happy to hear that the MPD Digital cable purchases and my waterproofing techniques were both great ideas. All of my cabling is sealed using the materials that Ray described.
Sounds good!
Great video.
Wow - this is one of the best videos out there on any ham radio topic - thanks, Dave! It covers a item we do not usually pay much attention to but that has major impact on our operations. As always, you’ve done the rest of us a GREAT service, Dave!
i know Im asking randomly but does anyone know a way to get back into an instagram account??
I was dumb forgot my login password. I appreciate any tips you can offer me!
@Jordan Toby Instablaster =)
@Fabian Winston I really appreciate your reply. I found the site thru google and I'm waiting for the hacking stuff now.
I see it takes a while so I will get back to you later with my results.
@Fabian Winston It did the trick and I finally got access to my account again. Im so happy:D
Thanks so much you saved my account!
@Jordan Toby Glad I could help xD
Thank you. A good review. N0QFT
Dave , I dont always look at all my notifications but this one cough my eye, ....Having been in the radio business since the late 70s and being aware of coax problems, I found this video to be one of the most informative that I have seen in a long time. I have run across some of these coax adds on Ebay and amazon just this year , ever since I have become active in the Amateur Radio community again , having been inactive for some 20 years. Very good video thanks for the great info, WB5MG
You're welcome!
THANK YOU FOR THE INFORMATION, I have seen the old type phone drop wire that ran from the tower to the office for a remote, that when the tower was hit by lightning, there was No wire inside the (wire) there was only the rubber outside with no wire inside it! The tower took a lightning hit! The fiberglass antenna looked like a umbrella! The RG213 had the connector blown off where connected to the radio!
In the air force we called the self sealing silicon tape F-4 tape. It's what held an F-4 phantom flying. Lol
Thanks OG
Just watched this video again as a review. Thanks, again. N0QFT
Great video Dave and Ray.
Thank you
Crazy! I bought some LMR-600 ultra-flex on eBay (I'm Canadian, local options are overpriced) - It shipped from the USA. I installed N connectors at both ends, it appears legit to me, and tests amazingly good with a VNA, but now you've got me wondering! It performs really well for my use, at least, whether it's fake or not.
Needed to see/hear this...great stuff! Not only for Ham radio but comes in handy w/audio application’s as well...thnx K6ISJ
1) Nitto and 3M self-amalgamating tape is the only brands I use.
2) Quality 3M and Nitto commercial grade tar tape is totally UV resistant.
3) Water migration happens quite quickly - Seal your connections fully and properly.
4) Try to include drip-points and don't have connectors where they can sit in water or collect moisture.
The drip points especially are very important and often neglected
GOOD STUFF
Really good for new hams to know. The counterfeit cables extend into household power wiring, Category 5 & 6 cables, and CCTV cables. Nasty business when you buy cable from a national stocking distributor and find out their purchasing department was duped into buying huge lots of junk.
Great interview. You can tell Ray that one viewer placed an order thru amazon for 100 ft of LMR 400 cable and the self seal tape. When ordering thru amazon, it's a bit tricky to make sure it says MPDdigital and has 5 star reviews. The other vendor reviews complain about the quality of the pl-259s. I am doing antenna upgrades before winter. Gonna construct a full wave loop for 40 meters fed with a balun design 2.5 to 1 balun, and use it on 40 meters, 20 meters, 15 meters, and 10 meters. Always look forward to your informative videos David. 73 from the Ozarks.
I'm glad you gave Ray your business. I've heard that several others have too.
Thank You, Thank You, Thank You. I learned a lot. Now I just have to figure out how to use NanoVNA.
If I didn’t know any better I’d say y’all can pass for brothers.
I bought 2 pieces of LMR 400 from Ray EXCELLENT quality KN6JVS
I had an antenna that was up for ten years. water got in the coax . I had a high s w r I had yellow Belden that was about at the age limit. but it lasted another ten year with out getting water in it. it was purchased from a C B radio shop . where I bought it from. I had an army big stip and I used some thing that looked like a hard party when I took the antenna.
Great information on coax. Time to spend some money on 3m goods.
I had the same thing happen to my coax over many years. ..water wicked in over 40' of the coax...high swr and no propagations. ...good video Dave.
Jim...KB8YBG
Yes, I've got some collects with green copper in it too. I've been moving cables around a lot while testing antennas recently, so I need to go back and waterproof everything. Thanks for sharing your story.
AK5FM; Great video thank you.
You're welcome
I have a box of those connectors with the ring in it. noting comes with that kind of connection on the back of the radio. I wish I did because as for as i know they are far much that the pl-259 that is on the back at radio's
Hi Dave,
Great video. Very informative about Ebay coax sellers. 73 WB3BJU
1st video was great...... This one should be just as good.......
Another great video with lots of first hand, valuable experience from the best industry expert. David, the information you set forward to the ham radio commubnity is invaluable, thank you.
Your feedback on the following please: I have recently soldered a series of Messi & Paoloni 0.4inch / 10mm Broad Pro cables to their LP259 connectors; all high quality stuff (probably as good as it gets here in Europe). Is there a way to check the performance of my end product somewhow?
I am not sure if the soldering I did is good enough, either in terms of cold soldering (I think I did a good job in avoiding that) and in terms of enough solder going into the center conductor. What equipment do I deploy to test my cables, and are there reference standards in measured values? In terms of continuity I tested my cables and all is good.
Many thanks in advance, Stefanos, SV1QZW
That's a good video!
Thank you
Exceptionally informative and great information. This not only plagues coax from China on eBay but there is also a problem with descrete electrical parts from China being sold that are defective and made with questionable methods and materials. The last LMR 400 I got from Dx engineering was excellent, and I do only try to buy from only reputable dealers, I’ve bookmarked mdpdigital and Usacoax too, thanks and 73, Tom
K2bew My boss years ago got a good deal on variacs. The toggle switches died on every unit within a few years. Either the switches latched on or off. Unless you checked the voltage with a meter, the on/off status was unknown!
When I opened up the switches there was a small copper part where there should have been a brass part. When the softer copper deformed the switch failed!
K2bew to
That trash cable extends all the way into the USB charging cords (dead giveaway is that you have a "fast charging" aka 5v 2.1A charger on one end but you run a battery analyzer app on the phone and you're not getting anywhere near 10W into the battery with the battery starting at roughly 50%), and 3.5mm stereo aux cables too (giveaway here is lots of hum and/or low volume on the other end of the cable).
Cut the cable open, and sure enough, it's CCA wire not pure copper. And the ends are crimped not soldered (because of course they are, sure NASA trusts crimp joints and so do I, but that assumes competent manufacturing, something you roll the dice on when you buy from some unknown overseas brand on Amazon or AliBaba or Ebay or what have you).
I bought some of that "It Depends Stuff" and I like it. It's marked as Andrew CNT-400 made in USA. Looking it up revealed it was made in China, and a spec sheet. The shielding is braided Tinned Copper, aluminum foil tape, foam dielectric, then Copper plated Aluminum for the inner conductor. He said it's fine up 500 watts. My financial advisor says it's going to be a long time before I can call CQ with 500 watts. So what I got was a good bargain. My meters like it too.
Great topic for discussion too. I replaced some RG8X with the CNT-400 and found some of that green powder inside the connector and braid that had browned 8 inches back from the connector. It had been painted with liquid electrical tape with 3 coats as instructed. This time I am using spray on rubber coating made by the same manufacturer . Perhaps it will seep in first and protect it better this time. Edit: I am looking forward to getting more this year at Oklahoma City Ham Holiday July 27-28 Sat-Sun.
Thanks for the information. Sounds like you've had good luck with that cable.
Ever heard of Cabinet 213 Dave? Bought a patchlead and I have not heard of this yet..
Got 70 ft. Coax bad swr so I did ends. Did check for condition. Checks fine. But coax feels real oily but radio has good recieve. It it bad
Trying to setup a MFJ-2104 using 50ft of 213 coax and not having any joy. Using the mfj analyzer, it seems to be showing that the cable has an issue as it tests as 47.5 ft (velocity factor of .66) when in fact it's 50.1 ft. I put the dummy load on the cable as suggested by your guest and it tests with a low SWR across all applicable bands. So not sure if the cable is at fault or the hub of the antenna. Still testing and will post later what I find. Thanks for the great interview. Will buy all my future cable from USACoax!
It doesn't sound like your cable is at fault. The length discrepancy is likely within the error limits of the meter--test equipment at amateur price levels is not lab-grade. The snow is melting here, so I'll soon be able to do my review of the Octopus.
@@davecasler I took the Octopus hub to my elmer and either the balun wasn't working correctly or the solder bars for both banks of terminals was shorted as a quick continuity test showed. We didn't open the hub as that would have required de-soldering the hub. I have exchanged the hub with MFJ, which they did very quickly, and all is good with the world.
I have to put up an antenna can you get water proofing tape at your local electric shop. ?
Would liquid electrical tape work well for water proofing? Say 3 coats letting it dry between coats. That's what I did and it seems to be working, but it's only been about 3 years.
I use liquid electrical tape it seems better than the adhesive type tape, it is way more expensive but oh well and if the can is not sealed well it will dry out.
the word was putty. white putty. but it kept the water. boy I bought some rug 8 from amazon. I'm going to run a windom . will it be all right.?
Found this about two days late, anyone have experience with Aletix AX-400DB , it’s of course claiming to be equal to LMR-400 and yes I plan to put 500 watts in it below 30Mhz
I looked it up on the Internet and couldn't find anything. I'd stick with coax from vendors you know.
Custom RG-213 Cable build
Length120 FT Connector 1No Connector Connector 2No Connector Custom Heat ShrinkNo
Who makes the coax? belden? jefa?thanks
also whats rg8a/u? mil spec should be M17/74-RG213
only no. 97. this is a really old vieso , and I'm sure you won't see my ? because it it one of the earlier ones. you are probably on three or four hundred. .
Denso tape Or Vaseline both are non acid
Eye opening. Thankyou.
More chinese junk flooding the market. One of our sons lived in China and still has a Nutrition supplement business there -- his business does well because Chinese there trust taking supplements from an American better than from the Chinese. I love the Chinese people, unfortunately, as it happening in the US - - business cares less and less for truth and providing value and only about how to make immediate profits and to heck with their patrons.
ITS PAPASMURF!
I've got a length of coax, the air die electric type. or spiral die electric flexible type coax. I KNOW it's had water in it. Can I restore it with clr, calcium lime rust?
I've not heard of anybody restoring coax. But then again, I haven't heard of air dielectric collects in years. Are you certain that what you have is intended for use as RF transmission line?
David Casler it's like 9913. I got from the wireman.
9913 is good coax. The original 9913 specs are for Air Dielectric cable. This means there is a fine wrap of plastic tubing around the center conductor that is like an open pipe with only air used as insulation. It is fine coax, But once water gets in it you are pretty much done.
MPD Digital I'm replacing it with ca600. Not sure if it's the fake lmr600. But it's so big. It's voltage specs can't be bad or far off spec.
Are we sure that Ray is human? It sure looks like that at least his right ear is more Spock or Dwarf like than human.
Jokes aside this interview brings 'caveat emptor' (let the buyer beware) to the forefront.
I'm sorry but mpe digital makes the worse coax ever ...they use crimped ends and ther not worth shit !!! Use times microwave or alpha Delta. Alpha max ultra
Excellent. I was surprised coax don't last forever. I'm like the cowboy with the $200.saddle and the $10. horse. I spend money on some things and skimp on important things. de k9pdq