We talk about about choosing the best cable to use with your radio antenna. We introduce you to the types of cables available, when to choose one type over another, and tell you who we think makes the best cables and cable accessories on the market. Listen now!
As always, you can leave a comment here, and if we read it on a future episode, you could be eligible for a free t-shirt or some swag!
TWRS-165 - How to Choose an Antenna Cable for Your Radio
Show Notes:
Good show. I’ve wondered about stacking cables, using two different sizes connected together, to go from inside of a building to an outside antenna. Thank you for touching on that. What are some signs that the cable insulation is starting to breakdown due to weather exposure and age? I have seen some cables with cracked insulation and wondered how that will degrade the radio performance. Thank you for your podcast. I always look forward to new episodes.
Sean
It’s very common to change types and diameters where there’s a need. Thin and short sections around rotators, or through holes, but the issue is always the connector loss. The best connectors have some, cheap ones have less. You just do the maths. Add up loss end to end with lots of versions, and use the most appropriate. Sometimes the expensive low loss cable plus connectors is no better than one length of less good and probably cheaper cable.
On commercial masts really thick cable goes up the tower, but thinner stuff connects to antennas and equipment at both ends.
Those charts for comparing different cable thinesses and capabilities is so important. Your statement about buy once cry once is my motto.
I enjoyed the show. Last two didn’t keep my attention for the entire show (but hey, I at least started listening).
I wanted to comment on a couple of things. For one I am very much of the school of thought (traditional two-way radio guy) that LMR-type coax should not be used in a full-duplex environment (repeater antenna system, BDA/DAS systems, etc). The reason being, LMR type cables tend to use a copper braid sitting on top of an aluminum foil shield for the coaxial cable’s shielding which can lead to pops and cracks being heard in the audio from the repeater overtime (you won’t hear it on a digital repeater) due the dissimilar metals (called galvanic corrosion). Professionally speaking, average service life of LMR-400 in a repeater environment seems to be about 5 years. In comparison, 1/2" heliax isn’t much more per foot (connectors are 4-5 times as expensive though) and typically has a 15 year service life. Also take the time to note, there is such thing a 1/4" and 3/8" hardline (called superflex) though you don’t see it very often compared to RG-179/400 and RG-214 type coax.
The Messi & Paoloni coax does appear to use a similar braid on foil construction like Times Microwave however, Messi & Paoloni use a copper foil shield instead of aluminum foil. Kudos, they understand the issue. Comparing spec sheets, the M&P uses far superior components in their coaxial cable compared to what you would find in a Times Microwave LMR type cable (all copper, the center conductor isn’t CCA).
When it comes to connectors and what are common, I think it really depends on the equipment. For mobile radios for example, anything Kenwood makes for use over 480 MHz typically will have a Type N connector on it. L3-Harris (going back to the Ma/COM days) will typically have a TNC connector. A lot of the Austrailian based manufacturers use BNC on their mobiles (Simoco, GME, etc). Non-North American regioned amateur mobiles from Icom and Kenwood also tend to use type N for VHF/UHF applications. Motorola of course uses their Mini-UHF standard that they’ve been using for nearly 40 years (except for a few exceptions such as the APX8500).
Repeaters fairly universally use BNC or N these days (or a combination). Test equipment typically uses BNC and N unless your name is Aeroflex/Viavi then you use TNC instead of BNC for some unknown reason and in talking to those guys…I’m pretty sure it’s simply to be different and more inconvenient.