Old Ground Plane Antenna

[Recon]

Maybe someone has an idea if the antenna is or is not a CB antenna.
I was given a (possibly) twenty-year old (no coil) base antenna. I have no idea if it is a quarter-wave, half-wave of five-eight wave.
Total assembled length / height of center mast from the coax connector / SO 239 to the top is 17' 2-1/2".
Three radials. The length of each radial is 57-1/2". The diameter of each radial is 5/8". Yes, 5/8"! I have never seen 5/8" diameter radials.
They could probably support the weight of a small eagle.

 

[Crawdad]

Hard to be certain from here, but might be a 1/2wl for 10m based on the dimension of the vertical element. Bit short to be a 11m 1/2wave. Just a guess.

 

[Dr. Frankenstein]

An antenna analyzer will give you your answer ..... very quickly.

73

 

[groundwire]

Its a 1/2 wavelength cb antenna. 468 ÷ 27.185 = 17.215 (17' 2 1/2"). Simple!

 

[DoctorAudio]

Radio Shack had a half wave base antenna with those dimensions called the "Archer Super Maxim 1/2 wave", part number 21-902.

 

[Recon]

Radio Shack had a half wave base antenna with those dimensions called the "Archer Super Maxim 1/2 wave", part number 21-902.

Thank you sir! I'm guessing it must be a 70's era antenna.
I cannot install / use the three small radials on the top because the 10-32 mild steel screw had broken off.

 

[Recon]

Radio Shack had a half wave base antenna with those dimensions called the "Archer Super Maxim 1/2 wave", part number 21-902.

1975!
From what I have found, the radials should be 52" long. The radials I have are 55" long. Maybe the original radials were replaced. Would the longer radials have an adverse effect on the performance of the antenna?

 

[DoctorAudio]

You can make up for no capacitance hat by making the vertical radiator a couple inches longer.
The slightly longer radials shouldn't harm the performance any as it's just there to be a counterpoise for the half wave radiator which is why the designers weren't concerned about not making them 9 foot. Additionally, 3 inches of each radial will be inside the ground radial clamp effectively making them 52" electrically.

 

[Recon]

You can make up for no capacitance hat by making the vertical radiator a couple inches longer.
The slightly longer radials shouldn't harm the performance any as it's just there to be a counterpoise for the half wave radiator which is why the designers weren't concerned about not making them 9 foot. Additionally, 3 inches of each radial will be inside the ground radial clamp effectively making them 52" electrically.

55" includes the area in the clamp.