Rgu59U or RG400

[Lyndon]

My transponder antenna and G3X antenna. Experimental aircraft. 

$20 vs $250.

Happy to pay the extra if needed.

Thoughts 

Thanks Lyndon 

[Blueadventures]

400 is the way to go in my opinion, better inner cable quality.

[Lyndon]

Thanks 

[Blueadventures]

What length are you chasing, I may be able to spare some.

[Lyndon]

A fair bit. Around 16 feet. 

Thanks for the offer but I just bought it.

Thanks Lyndon 

[Kyle Communications]

RG59 is 75 ohm coax NOT 50 ohm.

RG400 is what you need to be using. Its a double shielded teflon coax at 50 ohms. Less loss that RG58 which is 50 ohm coax. 

[Lyndon]

Now don't shoot me.

$13 a foot for the 400.

The Chinese stuff is like $1 foot. It's just TV Ariel cable right ????

The $8 NMC connectors vs the $1 Chinese ones ??? 

Lyndon 

[FlyBoy1960]

YEEP..  Get the chinese stuff, no problems.  I would also recommend you use a really cheap Kmart oil in the engine, or better yet get used oil because you know if you filter it it will be almost as good as new.

 

Go budget all the way and on the day you need to use your radio for an emergency, no one will hear you, but that's okay.

 

⛔

[Lyndon]

That's a no I take it 

 

 

Now don't shoot me.

$13 a foot for the 400.

The Chinese stuff is like $1 foot. It's just TV Ariel cable right ????

The $8 NMC connectors vs the $1 Chinese ones ??? 

Lyndon 

[skippydiesel]

Despite the advocates of spend big = quality, bleating on about future dangers etc, I advocate doing the best research analyses you can ie cost : benefit.

 

With an experimental aircraft, you have great freedom and with it responsibility, to do the right thing (whatever that means for a given project).

 

E.G. You can easily make a flexible transponder antenna for the cost of connector, some multi strand copper wire, solder and shrink tube, at a guess $5 all up.

 

IF your Chinese coax will do the job, to an airworth (transmit & receive) standard - go for it. Spending x 10 will not make the system more efficient or have any implications on safety.😈

[coljones]

On 02/12/2025 at 10:36 PM, Kyle Communications said:

RG59 is 75 ohm coax NOT 50 ohm.

RG400 is what you need to be using. Its a double shielded teflon coax at 50 ohms. Less loss that RG58 which is 50 ohm coax. 

At 126.7 what is the loss per metre of the best cable and the Chinese alternate

[Kyle Communications]

I just used AI but the figures are correct.

3dB loss is half so if your putting out 10 watts of power out of the radio then you are losing 5watts in transmit and half of the strength of the recived signal

So it depends of course how long a run of coax you use. The shorter the better and every dB counts

The cost difference is not a lot between both types. I know which one I will always use.

 

Mark

 

 

 

At 126 MHz (the aviation band), RG400 coaxial cable has an estimated signal loss (attenuation) of approximately 14.3 to 14.5 dB per 100 meters (roughly 4.4 to 4.5 dB per 100 feet).

 

At 126 MHz (common for aviation communications), standard RG58 coaxial cable typically exhibits a signal loss (attenuation) of approximately 17.5 to 19.5 dB per 100 meters (roughly 5.3 to 6.0 dB per 100 feet). 

[coljones]

30 minutes ago, Kyle Communications said:

I just used AI but the figures are correct.

3dB loss is half so if your putting out 10 watts of power out of the radio then you are losing 5watts in transmit and half of the strength of the recived signal

So it depends of course how long a run of coax you use. The shorter the better and every dB counts

The cost difference is not a lot between both types. I know which one I will always use.

 

Mark

 

 

 

At 126 MHz (the aviation band), RG400 coaxial cable has an estimated signal loss (attenuation) of approximately 14.3 to 14.5 dB per 100 meters (roughly 4.4 to 4.5 dB per 100 feet).

 

At 126 MHz (common for aviation communications), standard RG58 coaxial cable typically exhibits a signal loss (attenuation) of approximately 17.5 to 19.5 dB per 100 meters (roughly 5.3 to 6.0 dB per 100 feet). 

So about 0.2db/ metre

[Kyle Communications]