Can I replace a 6ft piece of RG-58U between my VHF radio and the mast? With an 8 ft p

[GTom]

Originally Posted by betwys1

If losing 10% to 20% of your signal power through a single UHF connector is not noticeable (which it probably isn't unless you instrument the transmission path) then fine! Go ahead! <g>

Probably not even 10%:

https://www.iz2uuf.net/wp/index.php/...-n-on-430-mhz/

[Bycrick]

This last article refers to N vs UHF connectors. At least one of several articles previously cited showed that the biggest "problem" with UHF connectors was in the female-to-female barrel connector, not in the make connectors on the cable.

Since several companies make in line surge protectors with either N or UHF connections with the same specifications, it would seem that barrel connections just differ in quality. So one needs to use good quality connectors and adapters.

[betwys1]

Originally Posted by GTom

Probably not even 10%:

https://www.iz2uuf.net/wp/index.php/...-n-on-430-mhz/

Actually, you are right!
I was sloppy in converting 0.1 to 0.2 dB loss to % loss ~ I converted 0.1 BELS to 20% down [actually -20.567%] sigh.....

0.1 dB to 0.2 dB is actually -2.28% to -4.50%

However, if a ham cannot find a different attenuation as between UHF and N connectors on 430 MHz he is certainly doing something wrong.

When the ham quoted above faced up to the multiple critical responses he received, he tested again, a little more carefully.

~~~~~~~~~~~~~~~~~~~~~~~~~~
[HIS WORDS] Down to real world
Now we have established that our PL converter adds some millimeters of transmission line with a characteristic impedance of 46Ω. We verified that this causes VSWR to raise to 1.18 and we measured that the transmission loss is 0.17dB.
~~~~~~~~~~~~~~~~~~~~~~~~~~

so I mentioned 0.1 to 0.2 dB and this ham [finally] measures 0.17 dB?

But still, -0.17dB is only -3.84% loss.
If we are discussing the merits of a uhf/uhf 'barrel' that would possibly amount to two connector losses -0.17dB X 2 = 0.34dB = 7.54%

Finally!

[Bycrick]

Actually, I’d imagine that a poorly made barrel connector could have more than twice the loss of two connectors. Especially if one used a "long" barrel connector to pass through a deck or bulkhead.

But back to the real world. The power margin of VHF FM transmission is huge. In the absence of noise, or other signals, 5 watts will almost always get you to the horizon. Lots of boaters use 50’+ of RG-58 cable which results in at least a 50% loss, but the radio is perfectly useful.

At some point, trying to minimize loss another few tenths of a decibel becomes just a numbers game. I just looked at several VHF coaxial surge protectors. They all specified an insertion loss of "less than 0.3db." They’re physically equivalent to a barrel connector, so I doubt that a well-made barrel would be any worse.

[betwys1]

Originally Posted by Bycrick

Actually, I’d imagine that a poorly made barrel connector could have more than twice the loss of two connectors. Especially if one used a "long" barrel connector to pass through a deck or bulkhead.

But back to the real world. The power margin of VHF FM transmission is huge. In the absence of noise, or other signals, 5 watts will almost always get you to the horizon. Lots of boaters use 50’+ of RG-58 cable which results in at least a 50% loss, but the radio is perfectly useful.

At some point, trying to minimize loss another few tenths of a decibel becomes just a numbers game. I just looked at several VHF coaxial surge protectors. They all specified an insertion loss of "less than 0.3db." They’re physically equivalent to a barrel connector, so I doubt that a well-made barrel would be any worse.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I'm with Bycrick, by and large..... losing only 50% of your power means you are using about 100 ft of RG-8X NOT the more common RG58U cable which costs you about three quarters of your transmitter power. Check these tables for the gruesome facts
https://www.w4rp.com/ref/coax.html