RFS Buying FAQ: GDTs, Filters, DuraForce Pro 2, Bronze vs Silver, and the Fine Print

I handle purchasing for a mid-size company—three sites, a few hundred employees' worth of gear, supplies, and the occasional panic order. When our operations team needs RF equipment (antennas, cable, filters, surge protection), I'm the one who turns that into purchase orders and makes sure everything shows up on time. I'm not an RF engineer. I've just bought enough of this stuff that I've learned where the traps are. This FAQ covers the RFS questions that actually crossed my desk and the answers I wish I'd had the first time.

1. What exactly is RFS?

RFS is Radio Frequency Systems. They design and manufacture a lot of the hardware that goes into cell sites and in-building coverage systems: RF antennas, coaxial cables (the CellFlex line comes up a lot), leaky feeder cable for tunnels and big buildings, filters, gas discharge tube protectors, dehydrators, and control gear like RET controllers.

What mattered to me as the buyer: they're a manufacturer, not a middleman. That gave us traceability—if something fails, we know who to hold accountable. It also meant we didn't necessarily buy direct. We work through an authorized distributor who handles stock, shipping, and the paperwork. Just confirm whoever you're paying is genuinely authorized before you place the order, because that comes back around if you ever file a warranty claim.

2. Wait, what does “GDT” mean in RFS product listings?

GDT stands for Gas Discharge Tube. In plain English: it's a surge protector for the RF signal line. It sits between the antenna and the radio. When a voltage spike comes down the line—nearby lightning, a grounding fault, static buildup—the gas inside the tube ionizes and shunts the surge to ground before it fries the radio.

We almost didn't get them. I knew we should, but I thought, “what are the odds of a strike near our building?” Well, the odds caught up with us one summer. A storm surge killed the radio card in one of our access points. Replacement card and labor ran us about $1,600. How much was a GDT? Way less. Every outdoor antenna lead at our sites has one now. And we keep spares in stock, because after a big surge the tube can be spent. Budget them as consumables, not fit-and-forget parts.

3. Do we actually need an RFS filter?

The honest answer: not always. Put another way: only when you have frequencies you need to keep out. An RF filter rejects the stuff you don't want. It's usually needed when you have multiple carriers, multiple bands, or serious outside interference in a shared system. A simple single-band setup? Maybe you're fine without one.

We added a second carrier to one of our buildings last year. Suddenly we heard weird artifacts on calls and random drops on one floor. Our RF designer diagnosed intermodulation—two signals mixing and creating noise in the wrong place. He specified a RFS filter for that feed line, and it cleared right up.

But here's the catch: that was our situation. A different building with a different band plan might not need the same filter. Anyone who tells you “you definitely need this” before looking at your setup is guessing. Get a design review, then buy to the spec.

4. Is DuraForce Pro 2 worth the extra money?

DuraForce Pro 2 is RFS's rugged flexible feeder cable—made for tight spaces and repeated handling, two things standard cable doesn't love. The price per foot is higher. Whether it saves you money overall depends on the route.

I learned this one the hard way. For a ceiling run in a utility room, I approved standard cable because—well, “how different can one cable be from another?” Actually, very different. The route had three sharp bends, and the standard cable's minimum bend radius got violated at every one of them. The jacket looked fine at first, but the center conductor was stressed and return loss drifted out of spec. We had to pull it and re-run with DuraForce Pro 2. The rework—labor plus wasted material—cost more than the upgraded cable would have cost from the start.

My rule now: tight bends or frequent handling? Pay for DuraForce Pro 2. Straight, protected runs? Standard cable has been fine for us. Either way, check the datasheet for bend radius before you commit. And if the cable passes through a riser, make sure it meets the required flame-retardant rating—look for IEC 60332 references on the datasheet. Inspectors and insurers care, so I do too.

5. What if gear shows up damaged or dead on arrival?

The first thing I do before any RF order is ask about the return process. Not because I expect problems, but because “I'll deal with it if it happens” is how you get stuck holding a $900 filter that doesn't work.

Warranty claims usually go through the distributor you bought from, not the factory directly. So it's worth asking up front: How are returns handled? Is there an RMA process? Do they cross-ship replacements quickly? We had one unit arrive dead—or rather, we thought it was dead until we realized it was a spec mismatch on our side. The distributor was helpful, but the back-and-forth taught me to confirm part numbers against the design spec before the order ships, and to keep original packaging for at least a month.

6. “RFS Inc.”—which legal entity am I dealing with?

This looks like a small detail until finance rejects an invoice. RFS operates under different legal entities depending on the region; in North America, you'll commonly see Radio Frequency Systems Inc., and other trade names elsewhere.

When I set up our first vendor record back in 2021, our paperwork said one name, but the invoice arrived with a slightly different legal name. AP kicked it back, and it took a couple of weeks and several emails to straighten out. Now, before any order, I ask for the full legal name, tax ID/W-9, and written confirmation that they're an authorized distributor. I send that straight to finance. It's boring. It prevents a six-week payment headache.

7. Bronze vs silver—which options should we pick?

Bronze vs silver came up when we were choosing connectors and termination hardware for our RFS lines. The short version: silver-plated parts generally have better conductivity and lower passive intermodulation, which matters on sensitive or high-power RF paths. Bronze—often brass or phosphor bronze underneath—is the budget-friendlier choice and usually plenty durable.

There's a catch with silver: it tarnishes, especially outdoors, in humid or coastal air. And tarnish degrades performance over time. Some people pick bronze for stability and price; others pick silver for electrical performance. Our RF tech put it simply: “Silver for the clean signal path, bronze for everywhere else. Don't overthink it.” For our indoor runs, bronze was enough. For the outdoor tower feeds and the high-power radio line, we went silver-plated. The price difference was small in the context of the whole install.

But I can only speak to our setup. If you're in a coastal area or an aggressive environment, the math could look different. Ask RFS's application engineers—or a distributor who actually knows the product—and get the recommendation in writing.

8. What costs do people forget when ordering RFS equipment?

This one's my favorite, so I saved it for last. The quote is never just the quote.

A while back, we got a great line-item price on a cable assembly. Maybe the best-looking quote we'd seen. But after shipping, connectors, and a re-termination that required a tool we didn't have, the all-in cost landed higher than a competing quote that included everything from the start. The first vendor was cheaper on paper and more expensive in real life. These are the items I check now:

• Connectors and adapters. Almost always separate line items from the cable itself.
• Termination tools and labor. If the tech needs a special crimp tool, that's a cost.
• Freight. A reel of feeder cable ships freight; it can hit three figures depending on distance.
• Lead time. Expedited shipping and rush handling add up quickly.
• Spares. Ordering one GDT or connector later means another order, another freight charge.

I also verify specs before signing: IP ratings for outdoor gear (IEC 60529, like IP65/IP67), flame retardance for indoor and riser runs (IEC 60332), and connector interfaces—these days we're mostly on 4.3-10, not the older 7-16.

That's the whole approach: ticket price is the beginning, not the end. A little time upfront checking the total picture saves a ton of money and an even bigger ton of headaches.