Seeking Coax recommendations

[W4EWH]

I've decided to redo my antennas: I had an 80/40 dipole hanging over my swimming pool, and I think all it did was heat the water, plus the guy rope broke and so I'm looking to change.

I'm going to try an Inverted-V, but I'll need to buy new coaxial cable to put it in, and I'm looking for the best price/performance ratio.

I want:

• RG-8 or equivalent
• for the low bands only
• It must be durable: I'd like to get at least five years out of it
• I'll consider direct-burial-rated coax if the price isn't too different, but it's not "gotta have"

Belden 8237 is about $1/foot: is it worth the money, or will lesser-known brands work as well?

All opinions welcome.

73, Bill W1AC

[WU2D]

Everybody has a favorite - Frank GFZ likes RG-214 and you can probably get it in a direct burial version. LMR-400 is overkill but it also would be a good choice.

LMR400DB 50 
Times Microwave  0.405  Low loss Coax, Direct Burial  1.09 per ft
50-200 ft .95 

These are double shielded cables with very low loss.

You are right, they all seem to be in the dollar per ft price range.

Mike WU2D

[W9GT]

RG 214 is good and the foam dielectic versions of RG8 are great if you don't plan on bending the stuff over a short radius and keeping it there....such as a choke balun on a PVC form or something like that.  The center conductor compresses the dielectric and moves toward the shield causing an impedance bump...or worse yet, a possible short over time.  The LMR 400 and similar versions of super RG8 are really nice...and have better loss characteristics than standard RG8 or RG214.  I use both, and really like the LMR 400 stuff.  I have some other coax that is similar, but made by a different manufacturer.  Sometimes, you can get some good deals on 100 ft rolls at hamfests.  I got some at Dayton that was a roll end and almost a hundred feet for only a few bucks.  Overall...the foam dielectric and double shielding really are nice for VHF-UHF use, but probably are uneccessary or of limited value at HF.   

I really like Heliax or hardline for long runs and you can even get the 75 ohm CATV stuff for free, but it is not very practical for feeding dipoles.  You need some flexible line. 
Just my 2 cents....


73,  JAck, W9GT

[W1IA]

The rg8X was pretty good stuff for medium power applications
It has less weight for dipoles without center support.
otherwise the LMR-400 can be had for 174.00 for a 500 ft roll on epay...very low-loss and a velocity factor of 0.86

Brent W1IA

[W3SLK]

Check out the surplus joints. I remember getting 200' of RG-214 (MIL-SPEC) for $25 new! I still have a few feet of it left. If its good enough for our troops, its good enough for me.

[John K5PRO]

About 14 years ago I picked up a spool of Times Microwave Impervion IP-8 from Surplus Sales of Nebraska. It was the direct burial version of RG8, having a jelly like material just inside the braid. It is supposed to prevent water ingress if it gets nicked, or gophers take a lil' nibble. I buried it directly like they suggested. Been running it for my dipole with up to 1100 watts peak, SSB. Haven't put the hammer on it with high power AM though.

[WA1GFZ]

Any of you guys ever use that 1/2 inch network cable. I think it has a #14 center conductor and is 50 ohms. I have a spool of it with 50 ohm loads on each end. When Andersen Labs cleaned house I bid $10 on it and won. It looks like it has Teflon insulation a light orange color. Not real flexable with a solid conductor but would be good to run out to a junction or phasing box. The best cable I've ever seen is this stuff a good 9/16 to 5/8 thick double shielded teflon. I had a short run I used on my LPDA. I think it has #12 stranded conductor. I modified an Andrews connector to mate to it. It in a lot thicker than RG393 at $5 a foot.

[N6WDR]

Any of you guys ever use that 1/2 inch network cable

I use a brand name of Mohawk network cable, and I have had no problems with it.  I called the manufactor and they claim it is the equivelant to RG213.

This stuff I have is double sheilded and comes in the wonderfull color of yellow, but I can't complain, I had a 500ft spool given to me.

Richard

[Steve - WB3HUZ]

I used some of that cable to feed a 75 meter dipole about 10 years ago. It worked fine. I did notice that the jacket began to deteriorate though. I don't think that stuff was made to be used out doors.

Any of you guys ever use that 1/2 inch network cable

I use a brand name of Mohawk network cable, and I have had no problems with it.  I called the manufactor and they claim it is the equivelant to RG213.

This stuff I have is double sheilded and comes in the wonderfull color of yellow, but I can't complain, I had a 500ft spool given to me.

Richard

[WD8BIL]

I don't think so either Steve.
I have some of the 58/u equivalent feeding my 40 meter Vee and the Blue jacket shows signs of UV assault.
This stuff was taken out of the MCI switching center in Cleveland 15 years ago. It does, however, still work pretty well. Centr conductor is teflon insulated.

[Steve - WB3HUZ]

Yea, it's nice stuff. The jacket was easily punctured too. I think it's stuff left over or removed from Thicknet installations - 10Mbs Ethernet over coax. It was the high speed shiznitz before Ethernet over Cat5 really got going.

[WA1GFZ]

The stuff I have looks just like RG393

[W1RKW]

A couple of years ago I bought about 500ft of  RG8 (Belden 8237) from a place I think was called Vetco Electronics in Washington state.  It basically amounted to $.20/ft. It was the best deal I could find on the net.  I don't know if they still have it but it might be worth a shot. Don't have their webaddress bookmarked and a quick search didn't turn them up but I remember they were elusive when doing a Google search.  I lucked out after digging deep into several Google search pages.

[Pete, WA2CWA]

I've been using Belden's 9913F7 coax for the last several years with great success.
http://www.therfc.com/9913f.htm
Got it at The RF Connection.
Also use it for the 6 and 2 meter antennas.

[W4EWH]

Check out the surplus joints. I remember getting 200' of RG-214 (MIL-SPEC) for $25 new! I still have a few feet of it left. If its good enough for our troops, its good enough for me.

Thanks, I'll check around.

Bill
P.S. When I was stationed at Danang, I visited the Tropo station on Monkey mountain, and I asked the tech there if he had any problem with fading. He pointed to the power dial, which was marked off in Kilowatts. Good enough for the military, good enough for a New England Legal Limit ...

[W4EWH]

I've been using Belden's 9913F7 coax for the last several years with great success.
http://www.therfc.com/9913f.htm
Got it at The RF Connection.

That's good news: I'll give them a call tomorrow and check on current prices.

Bill

[W4EWH]

Here's a follow-up question:

I'm going to run the coax I install about eight feet up, on "traveler" wires, to keep it out of the snow and away from my snowblower. However, in the past I've found that garden-variety cable ties break after a short time, probably from UV, but I'm not sure.

Please tell me what you're using to tie cable to towers, etc., and how I can prolong the life of the ties.

TIA.

Bill

[W4EWH]

... the LMR-400 can be had for 174.00 for a 500 ft roll on epay...very low-loss and a velocity factor of 0.86

Brent,

I see some generic brands on Ebay, but nothing from Times Microwave: have you used the generics? How did it work out?

If you bought coax made by Times Microwave, please tell me the name of the vendor. TIA.

73, Bill

[W4EWH]

Yet another question:

What happens if I use 75 ohm coax on a dipole? Of course there's a mismatch, but I'd like to know if anyone has experience with it and if I can shorten the antenna to raise the impendance without it becoming too reactive.

73, Bill

[Steve - WB3HUZ]

There may be no mismatch. The feedpoint impedance of a dipole can range from 40-80 Ohms depending on the height above ground and the ground conductivity. Whatever the mismatch may be, it not enough to worry about.

[W4EWH]

There may be no mismatch. The feedpoint impedance of a dipole can range from 40-80 Ohms depending on the height above ground and the ground conductivity. Whatever the mismatch may be, it not enough to worry about.

Thanks, that's good to know. Since I'm a perfectionist, I'll ask if the usual pi-network output, e.g., on a Valiant, could handle the mismatch.

Also, do inverted-V antennas tend to have a higher impedance than straight dipoles?

73

[KA1ZGC]

Since I'm a perfectionist, I'll ask if the usual pi-network output, e.g., on a Valiant, could handle the mismatch.

Yes.

If you can dip and load the final to the correct values, there is no "mismatch". With a pi-network output, there's no need to have everything at exactly 50 ohms; since the output network is simply transforming your final's output impedance into the load impedance, whatever that impedance may be.

I run 200-250 watts into 120 feet of RG-11 without any trouble. If I care about VSWR (and I usually don't), I take a walk to the other end of the feedline and retune at the antenna (walking's good for you). Same deal there, the tuner simply transforms the input impedance to the output impedance.

The absolute values are meaningless, only the relative values matter. If your rig can tune to the load without the tank coil getting hot or a cap arcing, that's all the perfection you need. Making everything meet certain exact values won't make it perform any better than that.

--Thom
Keep Away One Zorched Ground Conductor