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RG400 cable, Non aviation source

Freemasm

Freemasm

Well Known Member
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Not sure what Forum category this belongs in.

I try not to cheap-out but $14.60/ft for Coax is kinda insane, especially for something that isn't exclusive to aviation.

The antenna for the 2@ coms, xponder, 2@ GPS are run with RG400 from Stein. Got to make the long run to the wingtip for the nav.

Question = Anybody ever use commercially sourced (including Amazon) RG400 for such?

Your helpful feedback would be appreciated
 
i used COTS rg-58 cable for my archer antennae. both get reception out to 80 miles. is use 400 for gps, but simple 58 for comm and nav. never had an issues. I was carefull to use the 58 with a stranded core. unsure if this is aviation specific, but important imo for strain relief in vibration environments. think i got it from spruce. i think i used 400 for the transponder and adsb on my 10, but if it were $15/ft i doubt i would have.
 
Last edited:
Freemasm said:
Not sure what Forum category this belongs in.

I try not to cheap-out but $14.60/ft for Coax is kinda insane, especially for something that isn't exclusive to aviation.

The antenna for the 2@ coms, xponder, 2@ GPS are run with RG400 from Stein. Got to make the long run to the wingtip for the nav.

Question = Anybody ever use commercially sourced (including Amazon) RG400 for such?

Your helpful feedback would be appreciated
Click to expand...
I may be missing something here, but Stein is showing $6.95/ ft for RG 400 50ohm.
www.steinair.com

RG-400 Coax Cable, 50 OHM - Steinair Inc.

RG-400 Coax Cable for ADS-B, COM, GPS, NAV communication on Aircraft.
www.steinair.com www.steinair.com
 
I’ve got a spool. How much do you need? Let’s make a deal.
I also have a spool of thermocouple wire. Way more of both than I’ll ever need.
 
Freemasm said:
Not sure what Forum category this belongs in.

I try not to cheap-out but $14.60/ft for Coax is kinda insane, especially for something that isn't exclusive to aviation.

The antenna for the 2@ coms, xponder, 2@ GPS are run with RG400 from Stein. Got to make the long run to the wingtip for the nav.

Question = Anybody ever use commercially sourced (including Amazon) RG400 for such?

Your helpful feedback would be appreciated
Click to expand...
About $2/ft here.
 
Examples range from $1.38 @ Amazon to $14.60 @ ACS to $18.39. I'm aware of the dice roll when purchasing from Amazon (or EBay): but, at 1/10 the price and only the Nav antenna the temptation is strong.

Screenshot 2026-07-06 122723.jpg
Screenshot 2026-07-06 122609.jpg
 
I found the following review on Amazon to be helpful:

Being unmarked and at a price of about 1/3 that of Mil-spec RG-400, I was skeptical but decided to give this a try for a non-critical application -- and I was pleasantly surprised. I measured the 40 foot length with a professional grade vector network analyzer (VNA) and compared it to a length of Mil-spec cable I'd previously purchased from a reliable source.

Velocity factor and characteristic impedance (Z0) of the two cables were virtually identical. Also, the Z0 of this cable was at least as constant along the 40 foot length as that of the Mil-spec cable, indicating that the physical construction is uniform with no anomalies. The shields appear to be as tightly wound as those of the Mil-spec cable.

The only difference I could detect was a slightly higher loss. I measured the loss only between 3 and 200 MHz which was the range where I'll be using it. The loss of this cable was about 6% greater at 3 MHz, and 1 to 2 percent greater at 10 - 200 MHz. These could indicate that the silver plating on this cable isn't as thick, or might be some other material. This small difference in loss itself would be insignificant in just about any application, but if due to a plating difference it might mean that the cable would deteriorate in a shorter period than the Mil-spec counterpart, if exposed to the environment for a long time.

At least as far as I'm able to determine, this cable will be useful for a lot of applications calling for RG-400/U, at greatly reduced expense.
 
I've got some of the amazon rg400 that I've been meaning to test along with some real (new) rg400 from stein and some old (flooded) rg400 from the 182 and a VNA that i barely know how to use. I've got some cheapo BNC crimp connectors on the way. I've also got some 40 year old RG58 to compare it to.

Assuming I get time to I'll post results later in the week after the connectors show up.
 
fl-mike said:
I’ve got a spool. How much do you need? Let’s make a deal.
I also have a spool of thermocouple wire. Way more of both than I’ll ever need.
Click to expand...
I am also in the market and would take 75 to100' if you have it and we can agree on the price.
 
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