[TowerTalk] LMR 400 Response from DAVIS RF

[Stephen Davis]

Wayne, hi, you are correct that there are many LMR 400 knock offs and almost all are made in China, thus the lower price.  We do not sell anything MI China due to the fact that tolerances acceptable by us and astute USA product buyers are not acceptable on a lot of various China made products.  Albeit, even Commscope (Andrew Heliax is part of Commscope)  have cables made in China, as does Times, but in both of those cases those mfrs are quite on top of quality control.

9913:  Yes, been a lot of problems with it.   Not to be confused with 9913F7, a totally different build, no problems.  9913F7 is very flexible, equal to LMR 400 UF  (Ultra flex) in all ways (equal low loss, & flex)  but it will last longer than 400 UF due to a completely different type of polymer outer jacket.  I recommend 9913F7 vs. LMR 400 UF, and slightly less expensive but longer life.

Back to LMR 400:   We have produced  a cable that is equal to LMR 400 and it is made in USA.  It is our DRF 400.  Contact me if you would like more info.

Jim,  thank you for mentioning the merits of Bury-Flex Tm, which has been an extremely popular product now sold by almost all the dealers  (HRO, AES, Universal, etc).
For HF to UHF use, it has the same low loss as LMR 400  and is more flexible than LMR 400 (Bury-Flex Tm has a 19 strand center conductor for flexibility whereas LMR 400 is a solid center conductor, yet Bury- Flex Tm has excellent low loss specs due to an excellent gas injected dielectric). I am the designer of Bury-Flex Tm which is also used by Lockheed Martin, NASA, and many others. 

  Wayne might not need Bury Flex Tm unless he needs more flexibility than LMR 400.  Otherwise our DRF 400 (LMR 400 equal) would suffice.

Bottom line:  Personally I would never buy any knockoff made in China.  Yes, you can save some bucks, but you wish you hadn't if/when it starts to go sour and/or in the middle of a contest or trying to work that rare DX.

73, Steve  K1PEK
Senior RF Cable Design Engr. & Founder
DAVIS RF Co.
      


> 
> Message: 5
> Date: Sun, 16 Mar 2014 00:46:55 -0400
> From: Wayne Kline <w3ea at hotmail.com>
> To: "towertalk at contesting.com" <towertalk at contesting.com>
> Subject: [TowerTalk] LMR 400
> Message-ID: <BAY177-W1E17547874D1654F9D8DB8F720 at phx.gbl>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> Hi Fellow TT'ers  
> 
> Spring is just around the corner... and that's Tower antenna work time :)
> 
> I hope to be joining the ranks of 6 meter newbies .   The 6 meter beam HB G0KSC OWA  .
> 
> The Feedline  88 ft to the grounding bar fitting... I never used the popular LRM400 . The only venture outside of GR213 or RG  214.
> 
> Was 9913 and that was feeding  the VHF and UHF DX cluster antennas for awhile .. How do you spell Garden hose !!!
> 
> Searching the WEB WOW there are some deal for 500' and 1000 ft rolls of this stuff , I assume it's off shore made ?
> 
> Other then saying it's  not made in this here US of A  ... any  negative feedback as compared  to Times ? brand ( US made I se on Google search .
> 
> 
> Wayne W3EA 
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> ------------------------------
> 
> Message: 6
> Date: Sat, 15 Mar 2014 22:46:47 -0700
> From: Jim Brown <jim at audiosystemsgroup.com>
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] LMR 400
> Message-ID: <53253AC7.5020103 at audiosystemsgroup.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> On 3/15/2014 9:46 PM, Wayne Kline wrote:
>> Other then saying it's  not made in this here US of A  ... any  negative feedback as compared  to Times ? brand ( US made I se on Google search .
> 
> Times is one of several high quality cable manufacturers, the others 
> being Belden, and Commscope. Building high quality coax requires 
> experience, skill, and serious quality control. Davis RF sells a very 
> nice coax called Bury Flex that they have made to their spec, and it's 
> highly regards.  I'd think pretty hard about straying beyond those products.
> 
> For more on this, study k9yc.com/Coax-Stubs.pdf
> 
> Finally, for only 88 ft at 50 MHz, you don't need to go nuts. At 50 MHz, 
> it's all copper loss, so you want a big center conductor and a beefy 
> copper braid. Look for good quality stuff from a quality vendor, and buy 
> a coax these properties. See the table in the link above.
> 
> 73, Jim K9YC
> 
> 
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