BNC or MINI UHF

metro121 · Post by **metro121** » Thu Aug 15, 2002 12:52 pm

I recently sold a 110 watt uhf Spectra to a long time friend of mine. He has been a ham for a long time and was actually the one who started me in radio when he fixed my first CB.

Anyway, this was his first Spectra after getting back into Ham and he was veryimpressed with the radio. He did make some moinor changes and the most impressive was changing the mini UHF connector to a BNC.

He noticed a big difference in TX power not to mention it was a lot easier to fasten and unfasten the antenna. It also made a more secure fitting.

I tried changing an 800 Trunked Spectra to a BNC connector . When I checked the RSSI in the one system I could never get from my house, I was shocked to now see I was getting some reception with an RSSI of 42.

I have sinced then changed out 10 of my radios to BNC. I have a few more to do in our patrol cars but the time spent is well worth.

nmfire10 · Post by **nmfire10** » Thu Aug 15, 2002 1:11 pm

Is it possible the solder connection on the board for the mini-UHF was just bad?

ScannerDan · Post by **ScannerDan** » Thu Aug 15, 2002 2:51 pm

How hard is it to make the change from the mini-uhf to BNC ?

Dan...

wa2zdy · Post by **wa2zdy** » Thu Aug 15, 2002 3:12 pm

And when those BNCs loosen up (as they inevitably will), you'll be changing them - again. BNC isn't used for a good reason. It's not physically secure among other things.

But good luck,

perthcom · Post by **perthcom** » Thu Aug 15, 2002 4:44 pm

I wish they were TNC connectors... constant impedance and won't loosen up... just smaller threads than N connectors

again just my 2cents

metro121 · Post by **metro121** » Thu Aug 15, 2002 5:04 pm

The loose connections were at the connector them selves. I just clipped off the connector and resoldered a BNC onto the existing cable in the radio.

If you use a good BNC connector , you should not have a problem with them comming loose. I have noticed that the mini UHF connectors do not hold a good center contact .

I agree that the TNC would probly be even a better connector but I happen to find some excellent coax for super high frquency ranges
with factory BNC connections on one end. The cables were used in cellular and microwave RF applications. This was enough to satisfy my concern with my use.

Yes you are right , there is a reason why Motorola does not use the TNC or BNC. You should be able to figure it out.

For those who may think I am making up snake oil stories, I challenge you to try it your self. If you are in the SOCAL area, I would be more than happey to demonstrate the differance. Bring your radio and I will bring mine, That way, you can't claim that I used a bad radio.

I'm not trying to sell anything here . I am just posting a very interesting find. After all , that is what this board is all about.

Monty · Post by **Monty** » Thu Aug 15, 2002 5:28 pm

HI:

I have alot of stories about our favorite Mini-Pl connector

Both Male & Female

I think Motorola makes millions of dollars on thier failure.

With the [ Jack ] portion of the Connector, not only is it
made [ Chaep ] many of the other mfgs of Male Plugs
manytimes will not eben fully mate with the jack.

If you ever take one apart, you will see a wedge shape
surface that should mate with the pin. Over time, the
Surface becomes dull, pitted, and in general, will fail
to make contact.

With a 100 Watt Radio, this can / is fatel, and is very
costly to repair.

Comes now the Male end.....One test we give to a new
tech, is to give him the proper tools to prepare, and install
a Mini Plug on RG-58A/u You would be amazed at how
poor most of them are, this too can be a direct cause
of a Power Amp Failure.

Although I would have liked to see a Screw On Style similar
to a Mini Type C, production costs would be to high compared
to the .10 Mini Jack.

I too have used / converted most of the ones I use to BNC
as well, and I have not had any problems....I even have
direct BNC replacement for the SO-239 Style, and they are
made by King.

But if the Connector is BRAND NEW, the ideal method is to
use a Pig-Tail Adaptor, this way one can keep the integraty
of the connector intact, and use what ever connector you
chose.

If one uses a BNC with a screw on shell, a little 242 locktite
will solve the problem.

Monty

nmfire10 · Post by **nmfire10** » Thu Aug 15, 2002 5:44 pm

Just take the coax right from the antenna, into the radio and solder it to the board. No jacks or terminals. Problem solved

Tron · Post by **Tron** » Thu Aug 15, 2002 6:53 pm

Sounds good until water migrates down the cable and into the radio. At least with a connector, there is a barrier of sorts.

Tron

nmfire10 · Post by **nmfire10** » Thu Aug 15, 2002 7:06 pm

Ah, put some silcone on there and your all set.

larryepage · Post by **larryepage** » Fri Aug 16, 2002 10:24 am

I also seriously considered replacing the mini-UHF connector on a 45 watt dash mount Spectra with a BNC connector. Even found a bulkhead mount connector that would drop right into place. After doing a little research, however, I decided to leave things as they are...

==> While it's true that because the BNC is a constant impedance connector there would be a little more power out and more sensitivity coming in to the radio, it's also true that ...

==> The BNC connector was designed for a specific purpose...to be easy and quick to make connections to test equipment. To accomplish that, it is less than a perfectly secure physical connection. And over time, as the surfaces oxidize or otherwise degrade, your connection will be less secure.

This can become a real problem, because unlike almost all other connectors, the ground connection is the one most likely to become intermittent with a BNC connector. This can lead to real performance problems, and (in the extreme) real safety problems.

So it is best to use BNCs where they were intended... test equipment connections (and now HT antennas). In both cases, the likelihood is that the connectors are placed and removed fairly frequently. This helps keep them clean and secure, and even more important, it forces at least some level of occasional visual inspection.

A much better choice (if you are going to make a change) would be a TNC connector. The TNC provides all the constant impedance benefits of a BNC but with the addition of a secure, screw-on ground.

By the way, if you are in need of a trivia fix, you may fin that the way these connectors got their names is somewhat interesting...

Seems that there were two engineers working at Bell Labs in the late 1940s and very early 1950s to develop improved connector types. Their names were Neill and Counselman (my spelling may not be exact).

So...the N connector is really the 'Neill' connector.
The C connector is really the 'Counselman' connector.

BNC = Bayonet Neill-Counselman
TNC = Threaded Neill-Counselman

techie · Post by **techie** » Fri Aug 16, 2002 3:44 pm

larryepage wrote:

By the way, if you are in need of a trivia fix, you may fin that the way these connectors got their names is somewhat interesting...

Seems that there were two engineers working at Bell Labs in the late 1940s and very early 1950s to develop improved connector types. Their names were Neill and Counselman (my spelling may not be exact).

So...the N connector is really the 'Neill' connector.
The C connector is really the 'Counselman' connector.

BNC = Bayonet Neill-Counselman
TNC = Threaded Neill-Counselman

That story is one of several rumors that have been floating around for a while.. no idea which one, if any are true or not..

One of the other rumors tags them as "Bayonet Naval Connector" and "Threaded Naval Connector"

A third rumor indicates that the code letters were arbitrary, and don't stand for anything at all.

motor59 · Post by **motor59** » Mon Aug 19, 2002 7:22 pm

I've also heard it defined as the British Naval Connector...
Based on my limited experience with things electrical and British (77MGB with Lucas (Prince of Darkness) wiring), I prefer your definition...

Will · Post by **Will** » Mon Aug 19, 2002 10:09 pm

The reason Motorola went with the Mini UHF connector, as told to me by one of the engineers in the Texas group, 1987. It is due to the fact that they needed a better connector on the 900 mhz radios than the old UHF so239, (good only to 300mhz) and most installers and technicians could NOT install the TNC or N or even BNC connectors properly. Accualy the specs on the mini UHF are prety good. BUT the TNC is way better and the BNC is a lot like the TNC in impeadance charictoristics, but NOT for any power. Most mobile cell phone units used the TNC and a lot of problems were due to improper connector installation.

My vote: TNC to 50 watts, N to 110 watts.

jim · Post by **jim** » Tue Aug 20, 2002 4:14 am

Lucas is the reason that the British drink warm beer!
They build the refreigerators.

USPSS · Post by **USPSS** » Tue Aug 20, 2002 10:10 am

MA-COM/GE/ERICSSON/TYCO, Orion radios use a TNC connector and I have never heard of a problem, and there are thousands in service in CA

srefurd · Post by **srefurd** » Tue Aug 20, 2002 8:45 pm

Not an expert or anything but Amphenol lists Neill and Concealman (SP) in the descriptions of the connectors on their web site. You'd think if anyone knows they would.

metro121 · Post by **metro121** » Wed Aug 21, 2002 3:50 pm

BNC BAN
NEXTELL
COMMUNICATIONS

Post by **HumHead** » Wed Aug 21, 2002 3:59 pm

Boy, I'm glad the topic isn't "F" connectors.......

bnn121 · Post by **bnn121** » Wed Aug 21, 2002 4:38 pm

Here in Pittsburgh, all of the Astro Spectra VHF and UHF high powered W3 and W9 head models come with a female UHF instead of the mini-uhf standard. Guess the FEDS wanted a SP on the radio and got it.

Jonathan KC8RYW · Post by **Jonathan KC8RYW** » Wed Aug 21, 2002 5:37 pm

HumHead wrote:Boy, I'm glad the topic isn't "F" connectors.......

Ahh... F connectors.

Nice connectors, if you use the Augat compression ones. Waterproof, no impedance changes, up to 1GHZ, what could be nicer?

I just wish they made some for 50 ohm coax.

Plus, you can use those CATV grounding blocks, so a charge doesn't zap the reciever.

Just stay far away from the F connectors Radio Shack sells, okay?

I wonder how the "F" connector found it's name?

metro121 · Post by **metro121** » Thu Aug 22, 2002 1:43 am

I think we should F all the connectors

Jonathan KC8RYW · Post by **Jonathan KC8RYW** » Thu Aug 22, 2002 2:46 pm

metro121 wrote:I think we should F all the connectors

You mean convert all of the connectors to "F?" Wouldn't that be costly and time consuming? I know the F connector is nice, but is it THAT nice?

OH, I see what you meant now. Never mind.

n5tbu · Post by **n5tbu** » Thu Aug 22, 2002 5:04 pm

Alot of people don't know this,but the only difference between a bnc,tnc,n connector is the nut!
for test equipment purposes we use an n with the nut grinded off,it fits alll equipment with an n or bnc/tnc,hope this helped a few techs?

BNC or MINI UHF

BNC or MINI UHF

Mini UHF/BNC/TNC

Re: Mini UHF/BNC/TNC