# Tag Info

17

The "UHF" PL259/SO239 connector, which was originally designed at World War II times as a shielded banana plug is actually not a very good connector to be used on UHF frequencies, due to its non-continuous impedance and other properties. The common name is a bit misleading, since it's old - at the time of the design, UHF referred to frequencies above 30 MHz, ...

15

This is the one I use for my Baofeng UV-5R.

10

Here is a Diagram from page 11 of The (Chinese) Radio Documentation Project's Baofeng UV-5R Manual PDF:

9

I can't tell for sure without better pictures, but that looks like, not an RF connector per se, but a 3/8"-24 stud. This is very common for CB antennas. The reason I say it is not an RF connector is because it only makes one electrical contact. This means it can only be used for “monopole” antennas, not for feed lines or other types of antennas. To confirm,...

9

It depends on the frequency range the termination is rated for, and the power handling required. High power and high frequency is very difficult. At HF, any old non-inductive 50 Ω resistor will do. For higher power, we'd put many resistors in series and parallel, perhaps on a heat sink or in a can of oil. At VHF and UHF I've made very good terminations ...

9

For shortwave listening, it doesn't really matter – all these connectors are suitable for 30 MHz, and for reception you don't need to work with significant power. PL-259 2m-band If you, however, plan to work in the 2m band (2m being the wavelength, so frequency is, $f=\frac c\lambda=\frac{3\cdot10^8\,\frac{\text m}{\text s}}{2\,\text{m}}=150\,\text{MHz}$), ...

8

Gold has several really unique properties that allow for it's frequent use: Gold is the least likely metal to oxidize. From this table, it can be shown that Gold's electro-potential value is -1.1, meaning it should not oxidize at all, even in water. Wikipedia states this is the primary reason that some electrical contacts are gold plated. It is an extremely ...

8

UHF connectors are cheap and easy to install. In all other respects, they are inferior to more modern designs like BNC or N connectors. The major uses of UHF connectors are amateur and CB equipment in the US. BNC and N connectors are constant impedance and weatherproof. The BNC connector handles as much power as a UHF connector (500V peak) and is easier to ...

8

The Baofeng UV-5R and any other variations in the UV-5R family of radios have an SMA male connector on the radio mating to an SMA female antenna or SMA female adapter. In the picture I'm holding the anntenna along with the radio so that you can see for yourself which sex connector is on the radio and which is on the antenna.

8

Firstly, there's a hole for a locking pin in the connectors. The pin prevents the connectors from sliding apart. If there's a pin in there, you'll need to push it out with a punch. If there isn't a pin, it's possible the connector was assembled with cyanoacrylate glue. Since the roll pin can sometimes fall out, Anderson recommends glue in applications where ...

7

It is known as an SF style SMA connector. It is also commonly known as a Motorola SMA connector since they seem to be one of the few large scale users of this style connector You can find some adapters for this style of connector such as this RFB-1142-4 BNC adapter: http://www.hitechwireless.com/rf-industries-rfb-1142-4-bnc-f-sma-f-adapter/

7

It looks like a female TNC connector.

6

Silver has the highest conductivity of ordinary metals. It's also soft, which means the mating connectors squish together making a larger contact area, and thus lower contact resistance. Low, consistent contact resistance is important in RF connectors, because any significant change in contact resistance will change the impedance of the connector, resulting ...

6

I'm not sure what you mean by "M" type, but here are some points to address your question. Pros: Well understood, and very old, design that most know how to work with; Numerous vendors continue to manufacture various connector topologies with the 'UHF Connector' specifications. Note the PL-259 & SO-239 are but two examples of many compatible part ...

6

Connector use varies based on frequency band and also based slightly on power. The most common that I see, I have bolded, and while they are sorted by band, a VHF/UHF connector can be used on HF - it may not be common, but it's OK. On the other hand, an HF connector will be unacceptable at VHF/UHF, and only GHz/microwave connectors will be acceptable at ...

6

Yes, that is a standard Female SMA connector. Heads-up to be careful when purchasing SMA antennas as there are several combinations. Most higher-end HTs have a standard Female SMA connector on the radio, and a standard Male SMA on the antenna. Many of the newer Chinese-made HTs invert that, with the standard Male SMA on the radio, and a standard Female ...

5

For Question 1: As others have said, this does look like a PL-259/SO-239, commonly called a UHF Connector. Question 2: You can get wall mount adapters for these connections too, I'm not sure I can post links here, but search for "SO-239 wall plate". In the event you can't find this specific one, you could potentially use others, like the one in your ...

5

Gold makes good contacts because it is very nonreactive, and thus won't corrode or tarnish over time. Copper is a better conductor than gold, but copper will form a layer of oxide or other tarnish through normal exposure to the elements that will eventually increase the contact resistance of two mating copper contacts, rendering the connection faulty. See ...

5

Gold plated contacts provide reliable switching when the wetting current is low, because there is no oxide to breach for electrical contact to occur. Ex: a pushbutton switch used to signal a microcontroller digital input has a pullup resistor sized to flow 50 uA when the switch is closed. A switch without gold plating might not be reliable.

5

That is a standard female SMA connector.

5

PL-259 I'd really stay the hell away from PL-259. Undefined wave impedance, different manufacturer conventions, adapter stock of either decades of unknown storage (potentially in some moldy military box) or cheapest-supplier production are the main sources… It's a good thing that connector is becoming less common. It's something that you really don't want to ...

4

(I'm a retired USN Electronics Tech.) This is what they taught us about why the Navy chooses silver over other options. The oxides (aka tarnish) that forms on silver in air is nearly as conductive as the unoxidized silver. That is not the case with gold, nickel, tin, and so on. Thus when silver in a connection oxidizes you lose little conductivity and there ...

4

Currently, the best electrical conductivity is reached by materials such as nanotubes or graphene. They also have excellent mechanical properties. Unfortunately, there is still no technology of mass production, and thus we must rely on metals. The best metal for this purpose is silver (Ag). It has the highest conductivity, even better than copper and much ...

4

A complete replacement will be the most reliable solution. Barring that, replacement of one end if the resulting size is acceptable. I would rate a manual repair dead last. Soldered joints are rigid and even if the repair holds, it will place stress on adjacent sections of coax. These connectors and in fact, complete cables with MCX on one end and a ...

4

Note that the following may not apply to adapters, which may have lower power limits. This thread on eham contains a few suggestions. The third poster states that the design rating is 7 amps on the center pin, or 5 amps accounting for skin effect at different frequencies. This corresponds to 1250 watts for a 50 ohm feedline with a matched load. There is a ...

4

No, the UV-5R will not accept a female connector. The threads on the outside are for the nut that mounts the connector to the case.

4

From http://rallynotes.com/2017/03/12v-anderson-powerpoles/: This is a good image for orientation reference.

4

Is it ok to get a bunch of RG-58 sized connectors so that thinner types of coax will fit as well? Not if you want to do it right. Proper termination of coax requires a smooth transition from the coax shield to the connector. Mechanical compatibility is an issue as well if you don't want your cables constantly breaking. I've never seen a solder-on SMA ...

4

I avoid UHF connectors as much as possible. My shack is all Type N outdoors (weatherproof) and all BNC indoors. UHF connectors work fine for HF and even above that. But I hate connectors where you have to wiggle and retighten, then they still leak. Just a poor design. I've never seen UHF connectors on current professional broadcast gear. UHF connectors ...

4

So, what your measurement indicates is two things: yep, the thing is somehow connected. The deep dips in the return loss are points when the characteristic impedance of the connector+cable+connector+termination look like the source impedance of the VNA yep, it's a terrible non-constant complex impedance seen from the perspective of the VNA that's everything ...

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