1. The Good, the Bad and the Ugly
RF Connectors
The Good, the Bad and the Ugly

3. Coaxial cable as we know it was patented by AT&T in 1931
Coaxial cable was first conceived in the 1880’s and used in transoceanic cables at that time
Coaxial cable as we know it was patented by AT&T in 1931
Designed for wide bandwidth baseband television camera signals
Came into wide use during and after WWII.

4. Designed in 1930’s by E. Clark Quackenbush – worked for Amphenol
PL-259 – “Plug” #259 – military nomenclature
Designed in 1930’s by E. Clark Quackenbush – worked for Amphenol
Intended for use from 0.6 MHz to 300 MHz
Not a “constant impedance” connector
Impedance of a mated PL-259/SO-238 pair is 33 to 36 ohms, depending on manufacturer

5. PL-259 / SO-239

6. The length of the impedance mismatch in a SO-239 is 0.77”
The length of the impedance mismatch in a PL-259 is 0.25”
The length of the impedance mismatch in a SO-239 is 0.77”
Thus, a mated PL-259 / SO-239 has an impedance mismatch length of 1.03”
At 75 meters, this length is insignificant
At 2 meters, represents 1/80th of a wavelength and mismatch is measurable
At 70 cm, represents 1/25th of a wavelength and mismatch is significant

7. Type N

8. Type N

9. BNC (Bayonet Neill–Concelman) and SMA (Subminiature Version A) Connectors

12. Direct connection of test cables using superb SMAs.
Item
Description
Baseline:
Direct connection of test cables using superb SMAs.
SMA:
Same as baseline plus two more SMA barrels.
BNC:
Two SMA to BNC Converters plus one BNC Barrel in between.
TNC:
Two SMA to TNC Converters plus one TNC Barrel in between. N:
Two SMA to N Converters plus one N Barrel in between.
UHF 1″ Cl:
This is a 1″ Amphenol Model PL-258 Barrel with clear dieletric.
UHF 1″ Wt:
El cheapo 1″ SO-239 Barrel with White dielectric.
UHF 2″ Cl:
A 2″ SO-239 Barrel with Clear dielectric.
UHF 3″ Cl:
The combination of the Amphenol 1″ and the 2″ using a Male-Male joiner. It is really about 3.5″ long.
UHF T Wt:
A UHF T adapter with two SO-239 and one PL259 and White dieletric. The PL259 port was left open.
UHF Ft Cl:
A 12.5″ long SO-239 Barrel. This is the thing used to stick through walls.
PL/SO:
One SMA to N, then N to SO-239 Converter directly mated to one PL259 to TNC converter then TNC is adapted to SMA. This is the onlynon-barrel UHF configuration and presents the smallest and shortest impedance bump to the RF signal of all the UHF connections under test.