Batboard

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.

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

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

Dan...

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,

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

again just my 2cents

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.

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

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

Tron

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

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

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.

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...

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.

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

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

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.

BNC BAN
NEXTELL
COMMUNICATIONS

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

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.

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?

I think we should F all the connectors

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.

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?