LMR-400 for Ham Radio/cb radio

[Slowmover]

Being that CB is an HF band, RG 213 is still the better choice due to the coax being all copper center conductor and copper shield which was designed to carry the larger wave length of HF up to 30 mHz. Solid copper is an excellent conductor for power transmission and ground.

LMR is copper clad and was intended for the shorter wavelength VHF frequencies and beyond where the losses increase significantly at 100ft lengths and more over HF.

The "spec" readers tend to favor LMR because dB losses and velocity factors look better but at HF frequencies, it's hardly an issue.

If the best spec's is what you want, go with 1/2 inch Heliax. I doubt you'll notice a difference but you'll sleep better at night knowing you have the best coax in town.

That recommendation appreciated.

You’ve got a number of good ones made both here and elsewhere (reasoning laid out). Thanks.

.

 

[Jay Mojave]

I have had to replace my Times Microwave LMR-400 3 times just this year. I will NEVER buy that crap again. It was the real deal not some knockoff but it will not handle any power. I ran an 8 pill thru it (1500 bird watts) and it melted like grilled cheese. Stick with RG-213/U and you will never have that problem. I learned my lesson.

Hello U75: Wow this is the first time I have heard LMR400 melted, I am curious as what antenna your using. My neighbor several miles away has put 6KW thu LMR400 on a Interceptor 10K Antenna with good results. Please pass the aluminum foil hats.

Jay in the Great Mojave Desert

 

[Unit 75]

Hey Jay. I was using a Shockwave 5/8 groundplane for the first melt and my 5 element beam for the second melt. Poorboy, here in Alabama, has melted his LMR400 as well. We have had many on air discussions locally and only those that had LMR400 from years ago are still happy. The new stuff is not up to par. 1500 bird watts on 27Mhz should not do this to good quality coax. Y'all got your opinions but when it comes right down to it...the proof is in the pudding. Just saying I will never run Times Microwave LMR-400 EVER again. (purchased from a very reputable cable supplier in Georgia NOT cheap China knock-off or a LMR equivalent but actual TIMES MICROWAVE ) Looking to buy a 1000 foot spool of RG-213/U right now as I have the shockwave and 2 beams to feed. Cheers!

 

[Tokin]

Hey Jay. I was using a Shockwave 5/8 groundplane for the first melt and my 5 element beam for the second melt. Poorboy, here in Alabama, has melted his LMR400 as well. We have had many on air discussions locally and only those that had LMR400 from years ago are still happy. The new stuff is not up to par. 1500 bird watts on 27Mhz should not do this to good quality coax. Y'all got your opinions but when it comes right down to it...the proof is in the pudding. Just saying I will never run Times Microwave LMR-400 EVER again. (purchased from a very reputable cable supplier in Georgia NOT cheap China knock-off or a LMR equivalent but actual TIMES MICROWAVE ) Looking to buy a 1000 foot spool of RG-213/U right now as I have the shockwave and 2 beams to feed. Cheers!

Try these folks for your spool. Id call for a quote. Theyre wholesalers so you should get a better deal on a spool. Freight shipping sucks but Allied has regional /area offices all over so they may ship to a satelite office for pick up.
They have Coleman cable made in Waukegan Illinois USA. Im happy with mine. This is RG213/M17-74 military spec but these folks have ANY cable type you may want or need.
https://www.awcwire.com/productspec.aspx?id=m17/74-rg213-coaxial-cable

 

[DainBramage]

Try these folks for your spool. Id call for a quote...
https://www.awcwire.com/productspec.aspx?id=m17/74-rg213-coaxial-cable

They don't have a loss chart that I could see, but, this looks a LOT like the DXE 213U, which is 1/3 the cost with free shipping (over $100).

also couldn't find a minimum bend radius or repeated flex cycle info.

I finally dug thru the website and found the loss chart, it's the same chart as all RG 213 cable.
the only difference with this cable from DXE 213U seems to be the outer cover.

 

[Tokin]

They don't have a loss chart that I could see, but, this looks a LOT like the DXE 213U, which is 1/3 the cost with free shipping (over $100).

also couldn't find a minimum bend radius or repeated flex cycle info.

I finally dug thru the website and found the loss chart, it's the same chart as all RG 213 cable.
the only difference with this cable from DXE 213U seems to be the outer cover.

Thats why i buy military spec cable. Mil spec should always be the same no matter the manufacturer. The only difference between commercial and mil spec is mil spec is made to military specifications not the manufacturers thus ensuring uniformity. Loss, wattage and voltage specs will be the same as commercial just a variance in materials/quality of being used.

 

[Tokin]

Being that CB is an HF band, RG 213 is still the better choice due to the coax being all copper center conductor and copper shield which was designed to carry the larger wave length of HF up to 30 mHz. Solid copper is an excellent conductor for power transmission and ground.

LMR is copper clad and was intended for the shorter wavelength VHF frequencies and beyond where the losses increase significantly at 100ft lengths and more over HF.

The "spec" readers tend to favor LMR because dB losses and velocity factors look better but at HF frequencies, it's hardly an issue.

If the best spec's is what you want, go with 1/2 inch Heliax. I doubt you'll notice a difference but you'll sleep better at night knowing you have the best coax in town.

Pretty sure all 1/2" heliax has a copper clad aluminum center conductor. Andrew is copper clad as is Eupen

 

[fourstringburn]

That recommendation appreciated.

You’ve got a number of good ones made both here and elsewhere (reasoning laid out). Thanks.

.

Thanks for that. I try to say things in easy terms where even I understand it better.

I read your posts and like your truck pics. It's good to see how others do their mobile radio installs which gives us ideas now and for the future.

 

[fourstringburn]

Pretty sure all 1/2" heliax has a copper clad aluminum center conductor. Andrew is copper clad as is Eupen
View attachment 40090

Didn't know that, that cable is too rich for me so I never looked into it. The connectors are pricey too.
At least the shield is copper corrugated.

That stuff is also rated for the minimal losses up in the gHz range so it is an overkill for HF. It's also rated for extreme high power so the guys running those Henry 8K amps need it. Of course since they are Hams, they never turn them up past legal limit 

Take a look inside the center wire. It looks like aluminum surrounded by hollow copper.

 

[Tokin]

Im selling my 1/2" for $1/foot

 

[543_Dallas]

LMR 400 used to say made in USA. The new stuff I ordered from DX Engineering doesn't. Seems like they've started importing their cable. It probably comes out of the same factory as the knock off brands.

While looking at specs I also noticed the rg213 will handle twice the voltage that LMR400 will. 5000 for rg213 volts vs 2500 volts for LMR400. I have put more than 1500 bird through the off brand jefatech LL400 and it didn't fail.

I have a feeling that harmonics could be to blame for the lmr400 failing where the 213 does not. Standing waves from the harmonics would cause a high voltage condition at every half wavelength.

 

[TIN_CAN]

Rg213 is good enough for 27mhz. There are other companies that make LMR 400 equivalents at a much lower price. I've been using various flavors of Jefatech coax for years. No way I'd spend money on genuine lmr 400 for cb or HF.

I agree with the Jafatech as decent coax been running 100' of the flex 400 for a few years no issues and pretty cheap to boot.

 

[543_Dallas]

I agree with the Jafatech as decent coax been running 100' of the flex 400 for a few years no issues and pretty cheap to boot.

I remember their LL400 being 50 to 60 cents a foot a few years ago. Their rg213 was actually more expensive at one time.

 

[Captain Kilowatt]

Pretty sure all 1/2" heliax has a copper clad aluminum center conductor. Andrew is copper clad as is Eupen

Indeed. All 1/2 inch heliax has a copper clad centre. There is NO difference in performance between solid copper or copper clad at HF. The RF simply does NOT penetrate deep enough to make any difference. All I use is Andrew LDF-4-50 except for short pigtails but I managed to get several hundred feet of used as well as new cable and connectors when I was in the broadcast business. Running el-cheapo cable would actually have cost me more.

 

[Dave Bedwell]

What about the RG 400 out there