UHF or Type N ??

[HHD1]

Should we all be using type N connectors for GMRS?  Why does it seem that UHF connectors are the standard?  

 

I ask because I got a question wrong on my HamStudy.  I assumed that UHF connectors were correct for frequencies above 400 mHz since they are used all the time in GMRS.

What's the difference?

[Lscott]

2 hours ago, HHD1 said:

Should we all be using type N connectors for GMRS?  Why does it seem that UHF connectors are the standard?  

 

I ask because I got a question wrong on my HamStudy.  I assumed that UHF connectors were correct for frequencies above 400 mHz since they are used all the time in GMRS.

What's the difference?

The difference is the connector impedance. Anything in the RF path that deviates  from the nominal coax value of 50 ohms results in an elevated SWR, reflected power, back to the source.

The typical UHF connector can exhibit a range of impedance values, typically below 50 ohms, depending on the dialectic used between the shell and center pin. The worse ones use a brown colored material, similar to Bakelite. The better types use a white material, either Delron or Teflon. The best types use a a mostly air filled spoked wheel design.

The later type design yields an impedance close to the nominal coax value of 50 ohms. If you buy coax switches, SWR meters etc. and they only offer UHF connectors look for this type.

The “N” connector is designed for 50 ohms. The internal configuration looks like the BNC connector, but has a weather proof external shell. This is the preferred type for UHF work. There are in fact some Amateur and commercial gear, radios, that comes with factory installed “N” connectors. You typically see the UHF  type because that’s what most people have cables, antennas etc. terminated to use, not because they are ideal.

Will you have issues using them? That depends on how many you have in line and the design type. 

[OffRoaderX]

3 minutes ago, HHD1 said:

Should we all be using type N connectors for GMRS?

PL259 connectors work just fine for the purposes of GMRS, irregardless of what some people will try to tell us.. 

• Are N type connectors better? YES
• Will normal people using GMRS as intended notice any difference? NO

 

[marcspaz]

I'm with Randy on this one.  SO239 / PL259 connectors are perfectly fine.  I have been using them on the lower end of UHF for 40+ years.  I like N connectors more because there is less of a chance of having a bad ground connection, they are weather tight(ish), and have the proper design to more efficiently carry the RF signal... but dang... are they expensive.

 

Also, you will notice that damn near every GMRS radio, as well as commercial and amateur radios that operate at the 400MHz-500MHz range, come with a UHF connector or mini-UHF connector, straight from the factory.   This is because "we" will never see the difference in performance while doing what we do.

[SteveShannon]

47 minutes ago, HHD1 said:

Should we all be using type N connectors for GMRS?  Why does it seem that UHF connectors are the standard?  

 

I ask because I got a question wrong on my HamStudy.  I assumed that UHF connectors were correct for frequencies above 400 mHz since they are used all the time in GMRS.

What's the difference?

One of the things that I liked best about HamStudy was the ability to follow-up on questions to get the context, history, and reasoning behind one answer is more correct than the others.
When so called UHF connectors (PL259 + SO239) were first introduced, much lower frequencies were considered UHF.  Since then much higher frequencies are being used and the terminology has been more clearly defined.  UHF now means 300 MHz to 3000 MHz.  Amphenol, widely considered a very high quality manufacturer, considers 300 MHz as the upper frequency for “UHF connectors” unless the extended range versions are selected. 
But as in everything related to engineering, good enough is good enough.  Most of the UHF connectors used on better quality antennas are capable of handling 467 MHz frequencies just fine.  

[gortex2]

Some of this just goes to same old same old and folks are cheap. Hams especially dont like change. If the radio doens't have a PL259 its junk, same with antenna and everything in between. I remember hams coming into our shop back in the day becasue they bought motorola gear that came with a Mini UHF and instead of cutting the antenna cable off and crimping a Mini U on they wanted adapters. Then 2 months later they are back with broken adapters or issues. Motorola used Minu UHF on all bands from Lowband 33.00mhz all the way up to the 900 Mhz XTL. Even APX had the Mini UHF. Now with the multiband APX they are migrating to the QMA.

So while I agree N is btter alot of gear still uses the "uhf"" style connectors. I run N on everything after the radio just because (polyphaser, RF lines, antenna's) but now the industry is moving from DIN to 4.3-10 connectors to help with PIM. This is fnny as the 4.3-10 is very similar to a N but can handle PIM better as well as power. But as other said in the end the SO239 is cheap so you will see it forever. 

 

[SteveShannon]

27 minutes ago, tcp2525 said:

Absolutely! The loss between the two is astronomical. Using the PL259/SO239 combination is like a firefighter using a 1/2" hose to put out a car fire. Might as well use a dummy load on the back of your radio if you use PL259.

This is simply untrue for good PL259 and SO239 connectors from reputable companies. While they aren’t as good as N connectors in certain ways, especially for the higher end of UHF, at GMRS frequencies the attenuation is not nearly as dire as you assert.

[Radioguy7268]

The term "UHF connector" was given to the PL259 /SO239 style connectors back in the 1950's, when anything above 50 MHz was considered to be High Frequency. 

Do they work? Yeah. Are they any good? No, not really. 

It's just become a standard connector that many/most manufacturers have settled on, and it's probably not going away anytime soon. Personally, my method of building antenna lines is to use no more than 1 UHF connector in any configuration, and never once the coax leaves a building.  Other than that, it's Type N all the way.

 

[WRYZ926]

Another thing that I did not see mentioned yet is manufacturing costs. It is cheaper for manufacturers that produce HF, VHF, and UHF radios to only have to stock one type of connector. And as mentioned, SO239 connectors are cheaper and are still acceptable for UHF use. Manufacturers that only produce VHF and UHF radios will choose SO239 connectors since they work and cost less than N Type connectors.

The Icom IC-9700 has two separate antenna connections, one for VHF and one for UHF. And both are SO239. It boils down to cost savings for the manufacturer. The same goes for coax cables, its cheaper to use PL259 connectors.

Unless one is chasing long distance contacts on VHF and UHF with the least amount of signal loss then SO239/PL239 connectors work just fine.

[WRUE951]

I typically use the Type N Crimp-On with prober tools.  But Offroader is correct.  It takes some expensive test gear to detect the electrical differences between UHF and Type N and you wont notice any performance hits..   

[nokones]

And the "N" connector is easy to install and sorta hard to screw it up.

[Lscott]

On 11/25/2025 at 11:51 AM, WRUE951 said:

I typically use the Type N Crimp-On with prober tools.  But Offroader is correct.  It takes some expensive test gear to detect the electrical differences between UHF and Type N and you wont notice any performance hits..   

Not necessarily. It depends on the type and number. Besides just the connector people also use barrel connectors of various lengths for feed through walls and cable splicing. The longer the SO-239 double ended barrel connector the worse the results. Then there are the 90 degrees types when trying to route cables around sharp corners that would exceed the minimum bend radius for the cable.

 Many years ago I did some calculations for a simple barrel type connector and various frequencies and dialectic material. I used the basic loss-less transmission line equations to calculate the impedance miss-match for those who might be a bit curious. Remember this is just a simple "paper" calculation exorcise. See attached file.

RFU-537.pdf

UHF Connectors Rev-4.pdf

Edited December 1, 2025 by Lscott
Updated sample calculations with a 467MHz frequency, fixed some spelling and grammar errors.

[dugcyn]

let me ask a stupid question. lol

is the NMO mount considered a N connector regarding this discussion. just wondering because i am running 259 to 259 on my truck and get a bit of statice. now the radio is 259 no choice there but would I get considerable diference running NMO at my antenna? have not tried simply because I would also have to change mount that can rotate to allow me in garage.

[WRYZ926]

21 minutes ago, dugcyn said:

let me ask a stupid question. lol

is the NMO mount considered a N connector regarding this discussion. just wondering because i am running 259 to 259 on my truck and get a bit of statice. now the radio is 259 no choice there but would I get considerable diference running NMO at my antenna? have not tried simply because I would also have to change mount that can rotate to allow me in garage.

No it is not. A NMO connector is its own type and different from PL259/SO239 and N Type.

NMO mounts are weather resistant and preferred for mobile antennas. A NMO mount will be better as far as weather resistance. You probably have something in/on the vehicle that is causing the static and you need to figure that out and fix it in order to get rid of the static.

[WRUE951]

On 11/25/2025 at 4:10 PM, Lscott said:

Not necessarily. It depends on the type and number. Besides just the connector people also use barrel connectors of various lengths for feed through walls and cable splicing. The longer the SO-239 double ended barrel connector the worse the results. Then there are the 90 degrees types when trying to route cables around sharp corners that would exceed the minimum bend radius for the cable.

 Many years ago I did some calculations for a simple barrel type connector and various frequencies and dialectic material. I used the basic loss-less transmission line equations to calculate the impedance miss-match for those who might be a bit curious. Remember this is just a simple "paper" calculation exorcise. See attached file.

UHF Connectors Rev-3.pdf 42.52 kB · 3 downloads RFU-537.pdf 89.65 kB · 2 downloads

Back in my RF days I read several white papers on connectors specifically N-Type vs. UHF.. At the frequencies we use for GMRS there is no difference electrically and there is no notable difference until frequencies start pushing 10GHz.   There is definitely loses through straight splices and longer connectors although very minimal at GMRS frequencies..  I think there should be more concern with use of splices being another point of failure  at GMRS frequencies then the electrical differences.  

[WRUE951]

6 hours ago, tcp2525 said:

Absolutely! The loss between the two is astronomical. Using the PL259/SO239 combination is like a firefighter using a 1/2" hose to put out a car fire. Might as well use a dummy load on the back of your radio if you use PL259.

astronomical???   LMAO. 

[marcspaz]

At 450MHz, there is no practical difference. I have measured insertion losses of 0.1dB with a 2 foot patch cable with 2 UHF connectors on it, and I have measured insertion losses of 0.1dB on a 1 foot cable with two N connectors. Given that most people can't even tell the difference when there's a 1 or 2 dB loss by adding 40 or 50 ft of LMR 400 to the circuit, I can't believe that anybody's going to notice a 0.01 DB loss difference from a connector.

[Lscott]

1 hour ago, marcspaz said:

At 450MHz, there is no practical difference. I have measured insertion losses of 0.1dB with a 2 foot patch cable with 2 UHF connectors on it, and I have measured insertion losses of 0.1dB on a 1 foot cable with two N connectors. Given that most people can't even tell the difference when there's a 1 or 2 dB loss by adding 40 or 50 ft of LMR 400 to the circuit, I can't believe that anybody's going to notice a 0.01 DB loss difference from a connector.

People seem to be forever confusing impedance miss match with connector losses. They are totally different and not necessarily related. I see the same confusion in this thread.  

The problem with impedance miss match arises from the power being reflected from the point of miss match. If the source is also not matched to the line it also generates reflected power. The end result is multiple reflections, each one resulting in power loss due to the line attenuation. The term usually used is called miss match losses.

https://en.wikipedia.org/wiki/Mismatch_loss

When discussing losses associated with coax connectors we must be careful about which terminology is used.

For most applications for Hams, and use on GMRS, the miss match losses can mask out any of the connectors insertion, through, losses.

[tcp2525]

6 hours ago, Lscott said:

People seem to be forever confusing impedance miss match with connector losses. They are totally different and not necessarily related. I see the same confusion in this thread.  

The problem with impedance miss match arises from the power being reflected from the point of miss match. If the source is also not matched to the line it also generates reflected power. The end result is multiple reflections, each one resulting in power loss due to the line attenuation. The term usually used is called miss match losses.

https://en.wikipedia.org/wiki/Mismatch_loss

When discussing losses associated with coax connectors we must be careful about which terminology is used.

For most applications for Hams, and use on GMRS, the miss match losses can mask out any of the connectors insertion, through, losses.

Yep, and the N-connector avoids the primary source of the miss match, which is why always choosing the wrong connector for the job is a disaster. Just look at the mechanical construction of the N-connector and it is self-explanatory why it's the only choice for UHF frequencies. Sadly, the radio manufacturer's do their customers a great disservice by installing the dreaded SO239 connector. And frankly, even the N-connector is still a compromise as we should all be using DIN-connectors for GMRS.

[tcp2525]

On 11/24/2025 at 10:37 AM, HHD1 said:

Should we all be using type N connectors for GMRS?  Why does it seem that UHF connectors are the standard?  

 

I ask because I got a question wrong on my HamStudy.  I assumed that UHF connectors were correct for frequencies above 400 mHz since they are used all the time in GMRS.

What's the difference?

Absolutely! The loss between the two is astronomical. Using the PL259/SO239 combination is like a firefighter using a 1/2" hose to put out a car fire. Might as well use a dummy load on the back of your radio if you use PL259.