Seeking coax reccomendations for an Ed Fong 2m/70cm antenna

[dtx-120]

Will be needing about 20' from a Ed Fong antenna mounted on a second story balcony to an indoor HT (4/5 watts). Would like to eventually use the same cable to run 25 watts using a mobile as a base. I'm familiar with the RG-58 used on my Diamond MR77 mobile mag mount antenna, but considering an RG-8 coax due to it being a bit less lossy and without a signigant increase in thickness. Approximately 6 feet of the cable will remain outside. Any and all suggestions are appreciated.

/dtx

 

[KB4MSZ]

At only 20' it isn't really going to make much difference.

 

[questnz]

Check this Coax Calculator

 

[nanZor]

Ed-Fong antennas - well made classics.

At 25 watts so close to the rig, even with the EF's, I recommend using Type-43 ferrite rings or snap ons near the back of the transceiver to thread the coax around.

This may be especially important for a handheld's front-end that isn't truly meant for anything more than a rubber duck. The common-mode of the coax braid may pick up a lot of junk, transfer it to the antenna, and back down into the ht.

Even with the excellent EF's, you can run into this problem. Just a heads up.

 

[dtx-120]

Ed-Fong antennas - well made classics.

At 25 watts so close to the rig, even with the EF's, I recommend using Type-43 ferrite rings or snap ons near the back of the transceiver to thread the coax around.

This may be especially important for a handheld's front-end that isn't truly meant for anything more than a rubber duck. The common-mode of the coax braid may pick up a lot of junk, transfer it to the antenna, and back down into the ht.

Even with the excellent EF's, you can run into this problem. Just a heads up.

Good to know thanks.

 

[KB4MSZ]

Why not kill two birds with one stone. Install 7/8" hardline. You would have just about no loss at all and the outdoor 6' section could double as a mast.

 

[dtx-120]

Why not kill two birds with one stone. Install 7/8" hardline. You would have just about no loss at all and the outdoor 6' section could double as a mast.

Interesting but would that be prone to flexing from the wind?

 

[mmckenna]

I'm familiar with the RG-58 used on my Diamond MR77 mobile mag mount antenna, but considering an RG-8 coax due to it being a bit less lossy and without a signigant increase in thickness. Approximately 6 feet of the cable will remain outside. Any and all suggestions are appreciated.

The RG-8x isn't really that much better than RG-58.
Feed line losses vary depending on frequency and cable length. Higher Frequency = More loss. Lower frequency = less loss.
also,
Longer cable = more loss Less cable = less loss.

20 feet isn't really enough to make much of a noticeable difference, unless you were switching from some cheap Chinese crap cable to the above mentioned combo mounting mast/feed line 7/8 heliax.

RG-58 would be just fine if that's what you have available.
If you need to buy a new cable, Times Microwave LMR-240 is some nice stuff. Still small enough to route through walls easily, still fairly flexible, but a bit lower loss than the others.

The drawback with heavier cable is that connecting it directly to your radio is going to put a lot of strain on the antenna connector. You really do want something fairly flexible and light to do that. For a 20 foot run, no point in doing transitions from one to the other.

The Antenna Farm will do custom cable assemblies for you.
https://www.theantennafarm.com/catalog/coaxial-cable-342/custom-made-cable-assemblies-344/

 

[jaspence]

I have been using an Ed Fong dual band antenna for about 6 years. The first 4 years it had a good grade RG-58 cable which I replaced about 2 years ago. The total coax length is about 35 feet, and it works very well. Be sure to seal the connectors and you should get very good service from it.

 

[dtx-120]

The RG-8x isn't really that much better than RG-58.
Feed line losses vary depending on frequency and cable length. Higher Frequency = More loss. Lower frequency = less loss.
also,
Longer cable = more loss Less cable = less loss.

20 feet isn't really enough to make much of a noticeable difference, unless you were switching from some cheap Chinese crap cable to the above mentioned combo mounting mast/feed line 7/8 heliax.

RG-58 would be just fine if that's what you have available.
If you need to buy a new cable, Times Microwave LMR-240 is some nice stuff. Still small enough to route through walls easily, still fairly flexible, but a bit lower loss than the others.

The drawback with heavier cable is that connecting it directly to your radio is going to put a lot of strain on the antenna connector. You really do want something fairly flexible and light to do that. For a 20 foot run, no point in doing transitions from one to the other.

The Antenna Farm will do custom cable assemblies for you.
https://www.theantennafarm.com/catalog/coaxial-cable-342/custom-made-cable-assemblies-344/

I was planning on using antenna farm. I'll take a look at using the LMR-240. Thanks!

 

[dtx-120]

I have been using an Ed Fong dual band antenna for about 6 years. The first 4 years it had a good grade RG-58 cable which I replaced about 2 years ago. The total coax length is about 35 feet, and it works very well. Be sure to seal the connectors and you should get very good service from it.

Thanks. What would you reccomend to weatherproof the connection with?

 

[mmckenna]

Thanks. What would you reccomend to weatherproof the connection with?

First, when you order the cable from Antenna Farm, spring for the extra cost heat shrink tubing on the connectors. This won't necessarily do much to help waterproof the connection, but it helps and it really helps act as a strain relief.

For waterproofing the connection….
Connect the coax and test it to make sure it's all working.
Wrap a layer of electrical tape around the entire connection, start at the bottom, a few inches down the coaxial cable. Wrap up towards the antenna, overlapping each wrap 1/2 way. When you get to the top, reverse direction and run the overlapping tape back down to where you started.

Then, use a layer of butyl rubber tape over the connection, start at the bottom and wrap up, overlapping each time. Use your fingers to mold the tape in well around the connection and smooth it out.

Then follow up with a final layer of electrical tape, starting below the end of the butyl tape, overlap 1/2 way each wrap up to the top, then reverse direction back down to the bottom.

That's the industry standard way of doing it, and it works well. It's a pain to take apart if you need to move the antenna or replace the cable.
But, doing it right the first time will save your cable. Any water getting inside, even condensation, will start corroding the copper and make a mess.

 

[dtx-120]

There's 4 different types of LMR 240 cable and under "flexible" there's 3 different sub types. Any suggestions?

https://www.theantennafarm.com/cata...semblies-344/rg-8x-lmr-240-coaxial-cable-381/

https://www.theantennafarm.com/cata...l-cable-381/flexible-low-loss-rg8x-cable-383/

 

[mmckenna]

This one:
https://www.theantennafarm.com/catalog/times-microwave-lmr-240-1458

Standard Times-Microwave LMR-240. There are cheaper versions from other manufacturers, but for a 20 foot run, is saving a few bucks really worth it? Seriously, it's your money, it's up to you, and you really might not be able to tell the difference.

As for the 4 different types...
You don't need Direct Bury, that's got a water displacing gel filler that's designed to allow you to put the cable directly in the ground and cover it up with dirt. Not necessary. Plus if the water displacing gel leaks out (shouldn't, but could) it's a pain to deal with.

You don't need Fire Retardant. At least I hope not….

The super flexible stuff likely isn't needed, either. It's a bit more flexible than the standard stuff, but it comes at a cost. Unless you plan on tying it in knots, probably not worth it.

 

[WA8ZTZ]

Agree with mmckenna on the weatherproofing tape.
Keep tension on the tape as you wrap, then let up on
the tension for the last couple of turns.
My choice for tape is Scotch 33... costs more but well worth it.
The cheap hardware store stuff turns into a gooey mess.
Another good method of weatherproofing is electrical duct seal
intended for outdoor application.

 

[dtx-120]

This one:
https://www.theantennafarm.com/catalog/times-microwave-lmr-240-1458

Standard Times-Microwave LMR-240. There are cheaper versions from other manufacturers, but for a 20 foot run, is saving a few bucks really worth it? Seriously, it's your money, it's up to you, and you really might not be able to tell the difference.

As for the 4 different types...
You don't need Direct Bury, that's got a water displacing gel filler that's designed to allow you to put the cable directly in the ground and cover it up with dirt. Not necessary. Plus if the water displacing gel leaks out (shouldn't, but could) it's a pain to deal with.

You don't need Fire Retardant. At least I hope not….

The super flexible stuff likely isn't needed, either. It's a bit more flexible than the standard stuff, but it comes at a cost. Unless you plan on tying it in knots, probably not worth it.

Thanks for all the info. I ended up going with an Ed Fong rollup antenna. I'm going to mount it on a 13 ft fiberglass windsock pole from JackKite and will bungee it to the balcony railing for easy removal and portability. That will get the base antenna approximately 25 ft off the ground and and with about three to four feet of it extending over the roof line. Roll-up is 5 feet + 3 feet of BNC cable and 6 feet BNC extension cable.

This setup (along with a PVC ground stake) can be easily stowed on a bike pannieer rack to take on bike trips or set up while bank fishing. I figure lemme get at least a 25 watt mobile rig as a base before I go whole hog with a semi-permanent balcony solution and long cable runs.

$40 for antenna + $47 for the mast and mount (shipping included in both prices). I can also use this rig on field day activities as well. Easy breezy!

Best to you!

/73

 

[Ubbe]

https://www.amazon.com/Proxicast-Pro-Grade-Weatherproof-Self-Fusing-Electrical/dp/B00K5GW67O


/Ubbe

 

[dtx-120]

Agree with mmckenna on the weatherproofing tape.
Keep tension on the tape as you wrap, then let up on
the tension for the last couple of turns.
My choice for tape is Scotch 33... costs more but well worth it.
The cheap hardware store stuff turns into a gooey mess.
Another good method of weatherproofing is electrical duct seal
intended for outdoor application.

Thank you

 

[W5lz]

This is a duplicate reply....
With a 20 foot feed line length there will be negligible loss with any commonly used coax. Any loss from the feed line will be a VERY small fraction of a dB(dBi or dBd). Use whatever you got...

 

[graywoulf]

I'm using 50 feet of "The Wireman" LMR 400 ( They call it Super 8 ) with my Fong DBJ-1 antenna and getting great results. I'm hitting a repeater that is 104 miles from me at full scale.