PO v. NMO Mounts (1 Viewer)

[PKP80]

Simple Question, What's the difference?

The Mount pictured below is an NMO (correct me if I'm wrong).

 

[450 DUDE]

Ya that be the NMO.
I pefer the NMO its nice an beefy .
The other style is like a 3/8 bolt thread, like most CB's
Im not sure if its called po?

ken

 

[e9999]

is this cable particularly skinny?

 

[rusty_tlc]

is this cable particularly skinny?

I think you are looking at the ground strap.
Edit; Or not. A better picrure from the pasternack site Description: NMO Antenna Mount to SMA Female, RG58C/U, 10 feet
That gives you a better idea of scale.

 

[rusty_tlc]

Another NMO/SMA style from Pasternack.

 

[rusty_tlc]

I believe the style used with CB is the Pl 259,
Edit found a better picture on Pasternacks site.

 

[rusty_tlc]

This is the mating part for the PL 259
it is the SO239

 

[450 DUDE]

The ultra thin coax is called RG316 teflon cable.
Similar to the above.
The diamond mount I am using comes with 6' of this thin coax (nice stuff).
You just need an adaptor at the radio in most cases.

ken

 

[rusty_tlc]

The ultra thin coax is called RG316 teflon cable.
Similar to the above.
The diamond mount I am using comes with 6' of this thin coax (nice stuff).
You just need an adaptor at the radio in most cases.

ken

It works with a standard SMA connectors right?
We use similar stuff for test fixtures, RG409/U.

 

[PKP80]

Thanks guys

 

[Cruiserdrew]

Just to correct one thing above...

The NMO mounts were developed for drilling a hole in the roof, and then mounting the antenna there.

The PL239 (male) and SO239(female) connectors are 5/8 of an inch. I know, I just drilled a hole for that mount.

Similar CB mounts are actually a 1/2 inch hole, but the base of the antenna is 3/8 inch.

I think in our applications, where a lip or similar mount is involved, NMO or SO239 is a wash. Use what you like. If I were mounting through the roof, I'd go NMO for sure.

 

[Pskhaat]

The SO/PL239 thingies were originally designed as I understand for power connectors and somehow made their way into antennas. They do not maintain proper impedance as NMO does and are not weather-proof and have degraded performance above 150MHz. There is a reason BNC and other connectors exist. NMO is also a stronger mechanism.

 

[Cruiserdrew]

Are NMO mounts weather tight? I did not know that.

 

[rusty_tlc]

The SO/PL239 thingies were originally designed as I understand for power connectors and somehow made their way into antennas. They do not maintain proper impedance as NMO does and are not weather-proof and have degraded performance above 150MHz. There is a reason BNC and other connectors exist. NMO is also a stronger mechanism.

If they (SO239/PL259) were designed for power it was a crappy design since the center conductor makes contact before the shell. Typically power connectors are designed to make the ground connection before the power connection. Unless they were running power through the shell. Do you have any reference for that statement?

BNC's are crap for anything in the MHz range, IMHO.

 

[Pskhaat]

I'm quite certain all the Elmers I know say it at one time was a power connector, AC|DC I'm unaware. This is a quote I found from Wikipedia http://en.wikipedia.org/wiki/UHF_connector

World War II threaded connector design, from an era when UHF referred to frequencies over 30 MHz. Originally intended for use as a video connector in RADAR applications, it was later used for RF applications.

And this from radio-electronics.com which leaves it ambiguous. Radio meaning RADAR and video systems? Radio meaning RF transmission?

The UHF connector is a coaxial RF connector that is used in low cost applications for frequencies often in the HF and the bottom end of the VHF spectrum. Although it does not offer a particularly high level of performance, this RF connector is nevertheless satisfactory for many applications where cost may be an issue.

The UHF RF connector was designed in the 1930s by E. Clark Quackenbush, a design engineer working for the Amphenol company. This RF connector design was aimed to cover frequencies in the range 0.6 to 300 MHz and it was aimed at use within the radio industry. In view of the fact that the frequency of operation for the connector extended to 300MHz - the bottom of the UHF band of frequencies, it was given the name of UHF connector.

 

[rusty_tlc]

I'm quite certain all the Elmers I know say it at one time was a power connector, AC|DC I'm unaware. This is a quote I found from Wikipedia http://en.wikipedia.org/wiki/UHF_connector



And this from radio-electronics.com which leaves it ambiguous. Radio meaning RADAR and video systems? Radio meaning RF transmission?

"This RF connector design was aimed to cover frequencies in the range 0.6 to 300 MHz..."
That says it all.

 

[Pskhaat]

Rustly_TLC, both anecdotally and from all (questionable?) online references there is disparity between the origins. Wikipedia states this connector was used elsewhere first and is consistent with my stated rumors. Conversely the other article states the other. The truth? No idea, just wanted to present two competing references. I guess the final point is that UHF is not the best mounting method in comparison to something like NMO.

 

[rusty_tlc]

Rustly_TLC, both anecdotally and from all (questionable?) online references there is disparity between the origins. Wikipedia states this connector was used elsewhere first and is consistent with my stated rumors. Conversely the other article states the other. The truth? No idea, just wanted to present two competing references. I guess the final point is that UHF is not the best mounting method in comparison to something like NMO.

Sorry, I didn't mean to come across argumentative.

 

[Pskhaat]

Oh, no I didn't take it like that at all nor do I hope I was coming across the same.

 

[alia176]

This is the one I use: http://www.rfparts.com/diamond/k400snmo.html
comes with 13.5' of RG316 cable vs 6' for K400CNMO. Also, the end that goes into the radio comes with a SNMO (good for HT's I guess) and a SMA to PL259 connector. So, it plugs into the back of the HAM/CB radios easily. My application is for a 2M radio.

When the antenna is removed from the mount, a screw on NMO cover is used to keep everything clean. I also use a NMO mount for a cb radio antenna as well.

Cheers.