33 replies to this topic

[gman1971]

FSJ4-50B is the same diameter as LMR400... and it won't suck after it gets exposed for a few months. Been there done that.. I used to have spools of the USA made LMR400, all gone now.

 

G.

 

 

Thanks for the suggestions. Heliax maybe a little to much for me right now. Don't think I need a 7/8 cable. 

 

Can anyone provide a link to a good coax cable to purchase? Not sure where to go on getting coax cable. Like website.

[Danny]

FSJ4-50B is the same diameter as LMR400... and it won't suck after it gets exposed for a few months. Been there done that.. I used to have spools of the USA made LMR400, all gone now.

 

G.

 

Do you suggest the FSJ4-50B over the LMR400? 

 

Where can I go to look at pricing and to purchase? Thanks!

[gman1971]

Yes, absolutely.

 

I did the same thing when I replaced my 25 foot LMR400 UHF-UHF feedline with FSJ4-50B N-Male N-Male, same length. The heliax I got was factory made. I got mine from eBay as a NIB New Old Stock, I paid 35 bucks for 25 foot with 2 preinstalled trimetal N-male connectors, which are like 29 bucks a pop.

 

To give you quantitative figures: The antenna feedline connector at the base now reads a near perfect 50.03 Ohms impedance, and the return loss is -38dBm... as expected range now is measured in tens of miles, too, as opposed to the LMR400 which had an impedance of 43 Ohm and a -28 dBm return loss, while not bad, range was at best 10 miles.

 

There are people here who can also make these cables. I just wanted a factory cable with the datasheet and sweep chart to ensure I wasn't getting a dud.

 

The keyword on eBay to find a N to N heliax is "PNMNM" if you type that you'll get every cable on eBay that has N-male (NM) to N-male (NM)  There are a ton of listings, just look for FSJ4-50B.

 

G.

 

Do you suggest the FSJ4-50B over the LMR400? 

 

Where can I go to look at pricing and to purchase? Thanks!

[Danny]

Yes, absolutely.

 

I did the same thing when I replaced my 25 foot LMR400 UHF-UHF feedline with FSJ4-50B N-Male N-Male, same length. The heliax I got was factory made. I got mine from eBay as a NIB New Old Stock, I paid 35 bucks for 25 foot with 2 preinstalled trimetal N-male connectors, which are like 29 bucks a pop.

 

To give you quantitative figures: The antenna feedline connector at the base now reads a near perfect 50.03 Ohms impedance, and the return loss is -38dBm... as expected range now is measured in tens of miles, too, as opposed to the LMR400 which had an impedance of 43 Ohm and a -28 dBm return loss, while not bad, range was at best 10 miles.

 

There are people here who can also make these cables. I just wanted a factory cable with the datasheet and sweep chart to ensure I wasn't getting a dud.

 

The keyword on eBay to find a N to N heliax is "PNMNM" if you type that you'll get every cable on eBay that has N-male (NM) to N-male (NM)  There are a ton of listings, just look for FSJ4-50B.

 

G.

 

Thanks. I will look on Ebay for this cable. 

 

I did a keyword search for PNMNM but didn't find FSJ4-50B in any of the 55 results that returned. So I will keep searching each day to see if one appears.

 

Is this the cable you use for your base antenna? Is yours a 1/2 or 7/8?

[gman1971]

Yes, FSJ4-50B 25 feet. PNMNM . Its about the same thickness of LMR400 and its fairly flexible compared to the LDF4 heliax, which is basically like wrestling with an anaconda...

 

Attached is a picture of LMR400, left most, FSJ4-50B heliax, center, and LDF4-50A heliax (mini anaconda)

 

G.

 

EDIT: What length do you need?

 

Thanks. I will look on Ebay for this cable. 

 

I did a keyword search for PNMNM but didn't find FSJ4-50B in any of the 55 results that returned. So I will keep searching each day to see if one appears.

 

Is this the cable you use for your base antenna? Is yours a 1/2 or 7/8?

Attached Files

•  heliax_vs_lmr400.jpg   73.23KB   3 downloads

[Danny]

Yes, FSJ4-50B 25 feet. PNMNM . Its about the same thickness of LMR400 and its fairly flexible compared to the LDF4 heliax, which is basically like wrestling with an anaconda...

 

Attached is a picture of LMR400, left most, FSJ4-50B heliax, center, and LDF4-50A heliax (mini anaconda)

 

G.

 

EDIT: What length do you need?

 

Probably 75' or even 100' to be on the safe side

[gman1971]

Well, 75' to 100' is a large difference, remember that crimping heliax is not easy without the right tools... I know this b/c I botched it before... with the tool is a lot easier. 

 

Use a string to find out the exact length, then find the next cable in size.

 

For a 100' run I think its probably better to ask here, pretty certain others can sell you a 100' FSJ4-50B with crimped N connectors on both ends, and even a sweep of such cable.

 

G.

[kb2ztx]

If your going for 100' Id probably move to the LDF and not the FSJ.

[Danny]

Looking closer 75' would meet the needs. I'll keep looking for FSJ4 cable on Ebay. I'm not finding much right now but I'll keep looking. 

[gman1971]

What he said, for a 100 foot run its certainly worth considering LDF (aka. Anaconda coaxial)

 

If your going for 100' Id probably move to the LDF and not the FSJ.

[JohnE]

https://forums.mygmr...-losses/?p=2165

[gman1971]

I was prey to the cable loss BS scam, apparently the low loss cable myth seems to be targeted towards beginners just to sell them low performance LMR400, misleading them into believing that a .3 dB loss is going to render your radio useless. Not so.

 

FYI, I currently have a 2.3 dB insertion loss between my preselector and the 3 TX/RX bandpass cavities combined on my house base setup, even with a 2.3 dB I can easily reach 20 miles on 25W base to mobile... again, don't fall for the cable loss BS. A 1 dB loss is not going to hurt anything. Go with Heliax, and not b/c of the lower loss, but for the lower noise, which means better signal to noise ratio, since with LMR400 chances are the noise floor will increase by a few dB, which will certainly hurt things a lot more than losing a 0.3 dB of your signal. Again, don't use UHF chrome connectors, use N trimetal. Impedance mismatch and PIM will also ruin your range too... and will be an absolute witch hunt to find them.

 

 

G.

 

 

 

https://forums.mygmr...-losses/?p=2165

[Danny]

Thanks all for this information. I will keep searching on Ebay until I find a cable that appears. 

[1URFE57]

Bough all my radio and cable needs from them...DX Engineering and HRO-Ham Radio Outlet.