North Florida Amateur Radio Society
W4IZ Jacksonville FL
nofars.net
Editor: Billy Williams, N4UF
n4uf
By Ross Goodall, WD4NJV
In amateur radio we come across many different RF Connectors. A coaxial RF connector is an electrical connector that is designed to work with certain frequencies and maintain proper shielding. Some connectors are better quality than others. It is important that the impedance be maintained.
Mechanically, these connectors will have a fastening mechanism such as threaded, cinch or bayonet. Much research had been done since 2000 because of the demand for inexpensive high data rate applications. 1
My first experience working with a connector was with Citizens Band transceiver using a PL259 UHF connector. Next followed using cable television connectors, computer connectors and amateur Radio connectors.
Common RF connectors:
BNC (bayonet Neill-Concelman) up to 4 GHz *
F Type Used in domestic TV and domestic satellite LNBs *
Motorola connector connects AM/FM antennas to automotive radios
Musa connector used in broadcast video
UHF connector PL-259 and SO-239 (Japanese firms such as Kenwood may refer to this as M type) up to 400 MHz and Mini UHF up to 2 GHz *
SMA 3.5 and 2.92 up to 18 GHz *
TNC up to 12 GHz
N up to 12 GHz used with hardline
EIA RF used in high power broadcast transmission using rigid hard line *
RCA type Radio Corp of America cinch connector used for audio and video. * 1
*Indicates most commonly used
There are numerous RF connectors and adapters that can easily be identified by going online and to the various RF connector vendors such as Bracke Manufacturing, 2 and Mouser 3.
At the Hamfests there will be numerous vendors with a wide selection at generally reasonable prices. Sometimes you may want to purchase a ready-made up cable and connector. Be certain to buy a cable that is a little longer than is needed. A right angle connector will help take the strain off a cable is some applications.
Hint: It is good to have a box of assorted connectors on hand. If you are working with someone and they ask you for a particular connector that you are not familiar with, just hand them the entire box with the assorted connectors allowing them to find the connector that they need. You instantly appear to become a knowledgeable and helpful expert.
In working at the repeater site it is advisable to have a wide assortment of connectors and adapters available because you can avoid any surprises of not being prepared. By having a wide assortment on hand it will save a trip back to the shop or the store and get the job done.
I had a retail management career and the corporate powers would order cables to connect sales floor computers to communicate with the office computer and use outside vendors for the installation.
Our store had a pharmacy computer that was diagonally across the store and required over a 500 ft run above a suspended ceiling. The cable was run but the much needed pharmacy computer would not communicate the office computer.
Corporate said the cable had been run and the vendor said the job was complete. Well several months later I was in an upstairs stock room (that did not have a suspended ceiling) and found an unconnected cable and at that point realized that not enough cable had been ordered to reach the office computer. Also the cable had terminated in the wrong gender.
It goes to underscore you only get what you inspect when dealing with outside vendors that do not communicate with local employees.
Hint: If you run a long cable above a suspended ceiling, try using a sling shot. Tie a weight to a string and then tie the string to the cable. The weight is shot pulling the string and ultimately the cable. It will take several "hops" to go across a longer distance.
The ARRL handbook gives cable stripping measurements for many connectors. Remember to use enough heat and let the solder flow, but not too much to melt any plastic insulation material on the connector. Check with a volt-ohm meter and if possible use a cable checker for locating continuity problems.
A connector sealant such as RTV Sealant will help keep moisture out of connectors when placed outside especially in humid and salt air applications. Since this stuff is very messy and sticky, a pair of disposable gloves will help keep your hands clean.
Additional hint: Don't forget to slide the outer connector shield cover piece and reducing adapter (if used) on the cable first, so the parts of the connector can be assembled correctly after the solder has cooled inside the core piece. This will avoid having to unsolder the connector to correct this forgotten step. Almost everyone has done this when we are in a hurry.
References:
1 Brackemfg.com
2 Mouser.com
3 Bing images, RF connect
nofars.net is independently funded. Opinions expressed are those of article authors and do not necessarily represent official viewpoints.
Copyright 2022 by Billy Williams & article authors
Non-commercial use permitted with source credit
nofars.net
Editor: Billy Williams, N4UF
n4uf