Antennas with springs

[JustinWHT]

Back In the mid-70s I had more antennas on my crewcab truck than a Russian gunboat (I was told) for low-band, VHF, and UHF systems.

The Larsen and Decibel Antennas VHF base loaded whips without springs had significant sway compared to the Antenna Specialist spring antenna. Driving slowly on bumpy terrain, the Larsen and dB had as much as -6 dB fade when the whip whipped around, and the ASP spring was stable

One of my Larsen whips broke at the base from metal fatigue. The OEM 18" VHF whips last about a year.

The NMO mount - a Motorola shop told me it stood for New MOtorola mount (early '70s) - was much better than the 3/8" hole collet mounts that could rip out.

 

[k6cpo]

I've had a spring loaded Larson 19 inch antenna on my truck for a bunch of years without any difficulties. But my truck isn't an off road vehicle and the worst roads it gets driven on are usually graded dirt.

 

[JustinWHT]

I've had a spring loaded Larson 19 inch antenna on my truck for a bunch of years without any difficulties. But my truck isn't an off road vehicle and the worst roads it gets driven on are usually graded dirt.

It's the 18" OEM antennas with pigtail on NMO center button that break. Your spring must be dampning the flex.

 

[tweiss3]

I've had a NMO150/450/758 on a car for 4 years now, it smacks parking decks and has survived car washes it's entire life, no sign of snapping.

 

[JustinWHT]

It was the 18" VHF whip antenna that was included in the radio packaging.

 

[tweiss3]

This one? Larsen NMOQW144 VHF 144-152 MHz Mobile Two Way Radio Antenna 21" NMO Mount Type

 

[ladn]

I modified my NMO 2/70 to add a spring at the base because the solid rod was too stiff in low overhangs. Now it just bends over.
I also found that off-road it doesn't whip around as much,

 

[JustinWHT]

This one? Larsen NMOQW144 VHF 144-152 MHz Mobile Two Way Radio Antenna 21" NMO Mount Type

Yes

 

[mmckenna]

This one? Larsen NMOQW144 VHF 144-152 MHz Mobile Two Way Radio Antenna 21" NMO Mount Type

I've replaced all those at work. If the whip doesn't get damaged, the seal eventually fails and water gets in resulting in corrosion. I keep a stock of Larsen NMOQ's and swap them out when found in the wild.

The EM Wave 1/4 wave antennas are more flexible, and I've been slowly switching to those. Stico is always an option.

 

[tweiss3]

I've replaced all those at work. If the whip doesn't get damaged, the seal eventually fails and water gets in resulting in corrosion. I keep a stock of Larsen NMOQ's and swap them out when found in the wild.

The EM Wave 1/4 wave antennas are more flexible, and I've been slowly switching to those. Stico is always an option.

I wanted a half wave for UHF, so I just installed a PCTEL and the spring is super stiff compared to the Larsen NMO2/7SH. How is the EM Wave poly flex base compared to others?

 

[mmckenna]

I wanted a half wave for UHF, so I just installed a PCTEL and the spring is super stiff compared to the Larsen NMO2/7SH. How is the EM Wave poly flex base compared to others?

I have their elastomer spring model 1/4 wave, and it's pretty stiff. I have not tried one of their open spring models yet.