Earl,
Check out jefa tech. Great coax good prices.
73 Martin n4uu
On Feb 18, 2015 4:38 PM, "Earl Morse" <kz8e@wt.net> wrote:
> Coaxial cable here is bought in quantities of 500'. Scraps less than 100'
> get hauled off to the hamfest.
>
> Looking at price per foot of 3 popular types of 1/2" coax we have:
>
> LMR400 $1.18/ft or $589.99/500 ft roll
> RG213 $0.83/ft or $412.99/500 ft roll
> 9913 $1.12/ft or $559.99/500 ft roll
>
>
> Loss/100 ft of these @ 30MHz is:
>
> LMR400 0.7 dB
> RG213 1.2 dB
> 9913 0.7 dB
>
> At this frequency the loss in a 500' run (@30 MHz) would be:
>
> LMR400 3.5 dB
> RG213 6.0 dB
> 9913 3.5 dB
>
> Crunching these numbers, 2.5 dB can be gained from spending either an
> extra $177 for the LMR400 or $147 for the 9913 over the RG213. This is
> just for 30 MHz and a 500 foot run. Losses would be lower at lower
> frequencies and higher at higher frequencies especially when the dielectric
> loss properties of the cable kick in. Your run may be shorter, hopefully
> not longer. It starts to add up and an amplifier starts to look like a
> good deal where you can get 10 dB on all bands for the same price.
>
> These cables can all use the same cheap (but not too cheap) PL259
> connector. You might get a chunk of free 50 ohm 7/8" Heliax and spend $150
> for connectors.
>
> There are tons of other cables available. They all have different
> properties. They all have advantages and disadvantages. Your application
> may need direct burial or need to be very flexible. You may be phasing
> something and require something that needs a specific phase velocity. I
> have seen guys use aluminum jacketed 75 ohm CATV hard line where connectors
> are soldered to it with a pigtail and the shield is clamped to the aluminum
> jacket with a hose clamp then the whole thing gets a milk jug or bleach
> bottle shoved over the top of it. Hey, the cable is free.
>
> As with everything in life. Check the fine print. Figure out your
> cost/Bel. Take into account the frequency you are using and what exactly
> it is you want to do.
>
> If price/Bel is no object, then get your bank book out, give me a call,
> and I will build you a dream station. Heck, if we are talking contract I
> will even come over and operate it for you.
>
> Oh yeah, someday you will probably have to replace all that coax, probably
> around 10-15 years when the rest of the station starts breaking down. (I'm
> at 12 years now and over due especially after a well meaning neighbor hit
> the coax bundle going to the tower with a mower.) Then start saving up
> again for the rebuild as soon as you complete the station. (Are they ever
> really completed?)
>
> Earl
> N8SS
>
>
>
>
>
> >----------------------------
> >
> >Message: 1
> >Date: Tue, 17 Feb 2015 18:37:51 -0800
> >From: Jim Brown <jim@audiosystemsgroup.com>
> >To: towertalk@contesting.com
> >Subject: Re: [TowerTalk] Mosley Antenna Question
> >Message-ID: <54E3FAFF.8020406@audiosystemsgroup.com>
> >Content-Type: text/plain; charset=windows-1252; format=flowed
> >
> >On Tue,2/17/2015 1:30 PM, Ed Sawyer wrote:
> > I can tell you one reason to spec RG213 over LMR400 to feed your Mosley
> > tribander, or any other tribander for that matter.
> >
> >There are some misconceptions here that are the result of advertising.
> >Loss below about 500 MHz is entirely due to the resistance of the
> >conductors at the frequency of interest. The dielectric does not
> >contribute to loss below that frequency unless it's wet, and if it's
> >been wet, the braid is probably degraded, increasing copper loss. :)
> >
> >If you really want low loss, use hard line. I'm feeding my SteppIR with
> >350 ft of 7/8-in. :)
> >
> >73, Jim K9YC
> >
> >
> >------------------------------
>
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>
>
>
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