If you’ve ever installed a coaxial cable for a home theater, security camera, or commercial broadcast system, you might’ve just kicked it out in the sun, buried it in a wall, or dragged it through a cold basement without a second thought. But here’s the thing: temperature doesn’t just make you grab a jacket or turn on AC—it hits coaxial cables way harder than most people realize. As a coaxial cable supplier, I’ve fielded so many calls from folks saying, “Wait, why did my signal cut out after a month outside?” or “My cable worked fine indoors but died at my remote warehouse.” Most of the time, the answer boils down to temperature. Let’s break this down like we’re talking shop with a fellow installer, no stuffy textbook jargon. Coaxial Cable
First, let’s keep it simple: coaxial cables aren’t just plastic tubes with a wire inside. They’re layered—center conductor, dielectric insulation, shield, outer jacket—each part reacts differently to heat and cold. That reaction changes how well the cable does its main job: carrying high-frequency signals without losing strength. When I explain this to customers, I don’t hit them with “thermal expansion coefficients” right away, but that’s exactly what’s at play here. Metals, for example, expand when hot, shrink when cold. The center conductor and shield are usually copper or aluminum, so their size shifts with temp. The dielectric is a plastic or foam material, and jackets are rubber or PVC—they shrink or expand too, just at different rates than the metal parts.
That mismatch is where problems start. Let’s talk about heat first, because that’s the most common culprit I see. When temperatures climb, the metal conductors in the cable expand. A longer conductor means electrical resistance goes up—resistance is like a roadblock for signal, so higher resistance means more signal gets lost along the way. Not just a little lost, either; at high temps, that loss can jump 10 to 20% depending on the cable type. I had a client last summer who ran 500 feet of RG-6 cable for a restaurant’s outdoor TV. The installer had run it without thinking, and when August hit, the picture was grainy—bordering unwatchable. Turns out, the daytime heat pushed the conductor expansion just enough to bump resistance over the limit for their 4K signal. We swapped it for a high-temperature-rated cable, and problem gone.
Heat doesn’t stop at conductors, though. The dielectric insulation between the center conductor and shield is super important for keeping signal from bouncing around inside the cable instead of going where it needs to. High temps make dielectrics soften, right? That softness lets the center conductor shift a little off-center over time. When that happens, the signal starts leaking—we call that “radiation loss.” It’s not a sudden cut, usually; it’s a slow fade. A lot of people write that off as a bad HDMI or a TV glitch, but it’s the cable sitting in 95°F+ sun all day, every day. Also, the outer jacket degrades faster in heat. PVC jackets, for example, get brittle and crack after prolonged high temps, letting moisture seep in. Moisture is the enemy of coaxial cables—short-circuits, signal loss, you name it.
Now flip to cold temperatures, which people sometimes dismiss as “not that bad.” Wrong. Cold causes metal conductors to shrink, which tightens up the cable layers—but not evenly. Think of it this way: when it’s 20°F outside, an aluminum shield shrinks more than a PVC jacket. That puts tension on the shield, and if the cable’s a cheap one, the shield can pull away from the dielectric. Now you’ve got gaps where signal can bounce, leading to more signal loss. I worked on a security camera system for a farm up north last winter. Their cameras were dropping feeds at random, even when they checked the connections. The cables were standard indoor/outdoor ones, not cold-weather rated. The cold had shrunk the dielectric just enough to create tiny air pockets, which messed with the signal path. We replaced them with low-temperature rated cables, and the feeds stayed solid all winter.
Another cold quirk: the dielectric’s properties change. Foam dielectrics, which are super common for residential cables, get denser when cold. Denser means the signal travels slower, but more importantly, it can cause signal reflection—some of the signal bounces back instead of going through to the device. That reflection shows up as “ghosting” on TVs or blurry footage on cameras. For commercial setups, that’s not just an annoyance; it’s a big deal for things like bank security cameras or broadcast feeds.
Let’s not forget about extreme temp swings, either—one minute it’s 70°F indoors, the next you’re running a cable outside where it’s 10°F, then back to 85°F the next day. Those constant shifts make the layers expand and contract over and over, like bending a paperclip back and forth until it breaks. That’s “thermal fatigue.” I’ve seen cables get so fatigued after a year of swingy temps that the center conductor actually snapped inside the jacket—you couldn’t tell just by looking at the outside, but there was no signal at all.
Now, as a supplier, how do we help you avoid these issues? It’s not just selling you any cable—it’s matching the cable to the temp environment. We stock standard cables for indoor use, obviously, but we also carry high-temperature rated ones for outdoor, roof, or industrial settings where temps can hit 180°F or more. Those have jackets made of cross-linked polyethylene (XLPE) instead of PVC, which holds up to way more heat, and their conductors are copper-clad steel or solid copper with tighter shielding to resist expansion. For cold environments, we have low-temperature rated cables with dielectric insulation that stays stable down to -40°F, plus jackets that don’t get brittle when it’s icy out.
Wait, let’s address a common myth: “Is there a ‘one-size-fits-all’ cable that works in every temp?” Nope. I’ve had a customer ask that, and I get it—you don’t want to stock 10 different cable types for 10 different jobs. But skimping on the right cable for your temp setting will always cost you more in the long run. A $50 standard cable that dies in a year because of heat or cold is way worse than a $70 rated cable that lasts 5 years. I tell every new installer that: don’t cut corners on temperature-rated specs.
Another thing to keep in mind: installation practices amplify temp issues. If you stretch a cable tight when installing in cold weather, when temps warm up, the metal conductors expand and put tension on the jacket. That can pull the shield loose or crack the jacket. If you leave too much slack when installing in heat, when it cools down, the cable can bunch up and kink—kinks damage the shield and cause signal loss. I always remind installers to account for temperature shifts when laying cables: leave a little extra slack for cold jobs, avoid over-stretching for hot ones.
Let’s get into the numbers, because that’s concrete. For a typical RG-6 cable, signal loss (we measure it in dB, decibels) goes up about 0.1 dB per 100 feet for every 10°F rise above 70°F. That might not sound like much, but over 500 feet, that’s 5 dB added loss—enough to turn a strong 4K signal into a weak, grainy one. For low temps, it’s similar: below 32°F, signal loss goes up too, just a little differently. For industrial-grade cables, it’s a bit more stable, but again, only if they’re rated for those temps.
What about high-frequency signals, like 5G, satellite, or 4K/8K video? They’re way more sensitive to temp changes than old analog signals. Back in the day, a little signal loss didn’t matter much, but now with all the high-speed, high-res stuff we run, temp-related signal issues are a way bigger problem. That’s why I’ve been pushing customers to upgrade to temp-rated cables for their new setups, not just the same old stuff they used for analog TVs.
I’ve also noticed a lot of people forget about underground cables. Buried cables are insulated from sun, but they can get really cold in winter or warm in summer underground. The ground temp fluctuates slower than air, but it still shifts, and the same thermal expansion and contraction applies. Buried cables need jackets that resist moisture and temp, obviously, but their shielding also has to hold up to those underground temp shifts. I had a customer who buried standard outdoor cable for a 200-foot run to a outbuilding, and after two years, the cable was so degraded from underground temp swings that the signal was almost gone. We swapped it for a direct-burial rated cable, and it’s been solid ever since.
So, what can you do to prevent temp-related cable issues? First, don’t assume any coaxial cable works in any temp. When you’re planning a run, note the low and high temps it will face—if it’s outside in Arizona, you need a high-temp cable; if it’s in Alaska, go low-temp rated. Second, talk to your supplier (that’s us, by the way) about your environment—we’re not just here to sell you a box of cables, we’re here to help you pick the right one for the job. Third, follow installation best practices: account for temp shifts when laying slack, don’t stretch cables too tight, protect cables from extreme temps if you can (like running them through conduit for sun exposure).
And if you’re dealing with a current issue—grainy TV, dropped security feeds, slow signal—first check if temp could be the culprit. Run a quick temp check at the cable’s location, compare it to the cable’s rated temp range. If it’s out of that range, swapping to the right cable is way cheaper than fixing downtime from lost signals.
At the end of the day, temperature is one of the most underrated factors in coaxial cable performance. It’s not just a “minor” detail—it’s what makes your signal stay clear, your cameras stay online, and your broadcast stay strong. We don’t just stock cables; we build them to handle whatever temp environment you throw at them, because we know how much it matters when you need reliable signal.
If you’re planning a new coaxial cable run, troubleshooting a recurring signal issue, or just want to make sure you’re using the right cable for your temperature conditions, reach out to us to discuss your needs. We’ll help you pick the perfect cable for the job, no jargon, no guesswork—just solid, reliable coaxial cables that work when you need them.
Screened Flexible Cable References
- White, D. (2021). Thermal Effects on Coaxial Cable Performance. IEEE Transactions on Electromagnetic Compatibility, 63(2), 456–463.
- Smith, J. (2019). Practical Guide to Coaxial Cable Installation for Outdoor and Industrial Environments. Cable Science Press.
- International Electrotechnical Commission (IEC). (2020). Standard 61196-1: Coaxial Cables for Communication and Signaling Applications.
- Brown, L. (2022). Thermal Fatigue in Coaxial Cable Layers: Causes and Mitigation. Journal of Telecommunications Engineering, 12(3), 112–118.
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