Below are the questions we are asked most often. If yours is not here, technical questions come straight to me and I will answer them personally.
Ordering, Policies and Lead Times
Do you build custom sized enclosures?
Yes. We can modify an existing design or design an entirely new chamber to your dimensions. Before you go down that road, though, it is worth knowing what custom actually costs you. A custom chamber typically runs two to three times the price of a standard model, because it is a one-off build, plus roughly $3,500 in NRE for the design and manufacturing setup. Lead time is 12 to 16 weeks for a completely new design.
Our advice, honestly, is to look hard at the 21 standard models first. They are in stock, they ship within days, and because every one of them uses a removable I/O plate, the chamber gets customized by machining a flat plate rather than by rebuilding the box. Most customers who arrive asking for a custom size find a standard model that fits once they see the full range.
Do you offer samples, loaners, rentals or returns?
No, and here is the reasoning rather than just the policy. The variety of configurations needed to satisfy different interfaces and connections is simply too great to maintain a sample or rental pool. We also cannot offer returns, because we cannot legally resell a previously purchased test chamber. We stand fully behind every purchase as meeting all specifications for its intended use.
What protects you instead is the I/O plate. Because the plate is removable and field replaceable, your chamber never becomes obsolete. When your test needs change, you change the plate, not the chamber. One enclosure can serve many different test setups over its life.
Before you specify anything, we encourage you to read through our Resources section. The whitepapers there cover how to select, configure and verify an RF shielded test enclosure, and they will save you money.
Do you sell through distributors or reps?
No. We sell factory direct, worldwide, with no distributors, dealers or sales representatives anywhere. The range of chambers, filtered interfaces and connector combinations is far too wide for any third party to stock meaningfully. Selling direct means the person who answers your technical question is the person who builds your chamber. We ship daily worldwide and have very good air freight rates.
Do you offer volume discounts?
Discounts begin at the $50,000 level. Below that, everyone pays the same published price.
What are your lead times?
Standard enclosures are in stock and can ship within days. A configured chamber is the enclosure plus its populated, filtered and tested I/O plate, and the plate is what sets the schedule: 3 to 5 business days for a standard configuration, 7 to 10 days for a specialized one.
One clarification worth making, because it causes confusion: "in stock" refers to the raw enclosure on our shelf, not a finished shippable product. We build and final test the chamber in the exact configuration you will be using it in, and that final testing is only possible once every connector and filter you ordered is installed.
Configuring Your Chamber
What capacitance should I specify for filtered D-sub connectors?
Filter capacitance trades data speed against RF rejection. More capacitance gives you better shielding and slower maximum data rate. The two we stock are:
- 1000 pF per pin — data rates up to 10 Mbps. The right choice for thermocouples, DC control lines, enables, RS-232 and similar low speed signals.
- 100 pF per pin — data rates up to 100 Mbps
If you are not sure which you need, tell us the fastest signal that will pass through the connector and we will specify it. There is more detail in Understanding Data Signals Through Filtered I/O Connectors.
How can high speed data get into the chamber without letting RF in with it?
This is the central problem in shielded testing, and it is worth understanding rather than taking on faith. Your data signal is modulated RF. A filter that simply blocks RF above some frequency will also block the data you are trying to pass, and the faster the data, the worse the conflict gets. At 10 Gbps the signaling energy sits squarely inside the wireless bands you are trying to keep out.
We solve it two different ways depending on speed:
- Low pass filtering works when the data and the interference occupy different frequencies. Our USB 2.0 filters pass the data and reject RF above roughly 700 MHz, while everything below 480 MHz passes through unimpeded. Our LAN-1 Ethernet filter (10/100/1000) is the same idea: flat response below 480 MHz, over 80 dB of attenuation above 1 GHz, which puts cellular, LTE and WiFi firmly on the outside.
- Signal phasing takes over when the data and the interference overlap in frequency and no low pass filter can separate them. Our patented topology discriminates between the wanted differential data signal and unwanted common mode interference, rather than filtering by frequency at all. This is what makes our USB 3.0, USB-C, HDMI and LAN-10G interfaces possible. Because there is no low pass element, there is no upper frequency limit imposed by the filter itself.
A practical note on the phasing designs: they depend on the data signal being well balanced, so use good quality, properly shielded, low loss cable on both sides. And note that our LAN-10G filter is designed specifically for 10GBASE-T copper twisted pair on RJ-45. It does not support 10GBASE-R, SerDes or SFP+ architectures, which use a fundamentally different signaling scheme. For those, use a fiber pass-through instead.
Does adding capacitive filters change the chamber's isolation specification?
Yes, and this is worth being clear about. The enclosure itself provides better than 100 dB of isolation up to 1 GHz. Once you add filtered interfaces, overall system isolation is set by the weakest link in the path, and that is almost always the I/O filters rather than the enclosure. Every filtered interface has its own isolation specification on its product page.
In practice, a properly configured system delivers well in excess of 80 dB across its operating range. What matters is choosing the right filter for the signal, not adding the most filtering possible. We have written this up in detail in The Effect of Adding Multiple I/O Filters to a Test Enclosure.
Can I use an Amphenol style mil circular connector?
You can, but understand what you are getting. The connector body seals RF properly. The conductors passing through it have no filtering at all, so any RF riding on that wiring passes straight through, in both directions.
If the cable is well shielded, at least four or five feet long, properly grounded, and there are no strong RF sources nearby, you can expect something on the order of 60 dB of isolation on that path. That is a general guide from experience, not a guarantee, because the result depends heavily on your specific setup. If you need the isolation the rest of the chamber is capable of, use a properly filtered interface instead.
Can I run cables through a pipe or tube pass-through?
This question comes up from customers used to walk-in shielded rooms, and the answer surprises people. A pipe acts as a waveguide beyond cutoff only when nothing conductive passes through it. It is an excellent solution for ventilation or for fiber optics.
Put a conductor through that pipe and the physics changes completely. The pipe stops being a waveguide and becomes a transmission line, with your cable as the center conductor and the pipe as the shield. Outside the chamber, the conductor acts as an antenna and picks up whatever is in the room. That energy travels the transmission line into the chamber, where the conductor acts as an antenna again and re-radiates it. Each of those transitions costs you roughly 25 dB, so you end up with about 50 dB of isolation maximum no matter how good the chamber is.
If 50 dB is genuinely enough for your application, that is your call to make, but we will not guarantee our shielding isolation on a chamber configured that way. The proper solution is the filtered interface built for that signal.
Should I use shielded cable on the RF bulkhead connectors?
Yes, on every connection. Double shielded cable is better still. The chamber can only be as good as what you attach to it, and an unshielded or poorly shielded cable on a bulkhead connector is a direct path in and out.
Do you offer turntables?
No, we do not make them. Plenty of third party turntables fit and work well inside our chambers.
Do you offer shelving, or a way to use the vertical space?
We do not build or sell shelving, but there is an easy answer. The chamber floor is a removable ABS plastic panel sitting over the floor foam. It is non-conductive and it is not part of the shield barrier, so you can lift it out, take it to the bench, drill and tap it for standoffs, posts or brackets, and drop it back in. No modification to the chamber itself.
Build your shelf from non-conductive material, acrylic, polycarbonate, Delrin or 3D printed brackets, so you are not introducing a reflective metal surface inside the test volume.
Do you provide mounting holes or fixturing for my device?
No, and that is deliberate. Device specific mounting stays with you, because you know your fixture and your DUT, and it keeps our build free of modifications tied to one customer's hardware. The removable I/O plate, the open interior and the drillable ABS floor panel give you everything you need to add your own mounting.
There is a testing benefit to this too. A repeatable, unmoving fixture is what makes chamber measurements consistent run to run, and you are better placed to design that than we are.
I want an internal power strip. Is that all I need?
No. Any AC outlet strip inside the chamber must be fed by a PEM-1 filtered power entry module ($249). Unfiltered mains power entering the chamber bypasses the shielding entirely, and conducted emissions on the power line are one of the most common causes of unexplained RF appearing inside a chamber. We quote the PEM-1 alongside every internal strip as a matter of course.
The PEM-1 is a 10 A unit, which is 1,200 watts. Customers occasionally ask for 15 A because that is what a wall outlet provides, but actual consumption inside a test chamber is typically a few hundred watts at most. 15 A would be 1,800 watts, which is roughly a space heater running inside your chamber.
Can I specify a connector you do not normally stock?
Usually yes, but it carries a charge and we would rather tell you that up front than surprise you on a quote. A non-standard connector means redrawing the I/O plate cutout and setting up a new mill program for that footprint, and it means sourcing and purchasing a part specifically for your build. Some non-standard parts also take significantly longer to assemble than our standard hardware. All of that goes on the quote as a line item.
There is a second consideration. We stand behind our own stocked connectors and filters because they are proven over decades and thousands of installations. We cannot offer the same warranty standing on a part we do not stock and have not validated in our chambers.
Before you go that route, tell us what you are actually trying to achieve. More often than not the goal is already met by the standard part. As one example, customers sometimes request flange mount connectors so they will not rotate over time. Our bulkhead feedthroughs already seat in a D-shaped mounting hole that mechanically keys the connector body and prevents rotation, so there is nothing to buy.
Performance and Specifications
What isolation do your chambers provide?
All standard enclosures: −100 dB from DC to 1 GHz, −95 dB to 3 GHz, −85 dB to 6 GHz. All standard chambers are specified for use up to 6 GHz. The MW (microwave) option extends shielding to 28 GHz at better than 85 dB. It adds a conductive fabric gasket for $480 over the standard enclosure price. If you order an MW chamber, you should also use MW-rated I/O filters, which add $80 per filter section. We have not operationally tested beyond 28 GHz, so we do not publish specifications above that.
How is isolation specified and measured?
Industry practice is to measure field strength at one meter, in the far field. For field verification at close range you can place a signal source inside the chamber, measure just outside, and add a 20 dB path loss factor to refer the reading back to the one meter standard.
Our TVK-2 test verification kit is built for exactly this, and it is equally useful for finding leak paths in walk-in shielded rooms. There is a full write-up in Measuring and Verifying Shielding Isolation.
How flat is the isolation response across frequency?
Flatness is rarely the specification that matters, and it is worth asking why you want it. What matters in practice is the minimum isolation across your band of interest, and that is what we publish. If you need documented measurements at specific frequencies for a customer mandate, an audit trail or a contractual acceptance document, we can do that work at additional cost based on engineering time.
If the reason is simply that a particular frequency makes you nervous, talk to us first. We would rather run the numbers with you than sell you a measurement that will not change any decision you make.
How effective is the chamber at low frequencies?
Isolation approaches −100 dB. At low frequencies the limit is almost never the enclosure, it is the I/O interfaces, because conducted emissions traveling on power and signal cables bypass the shielding completely. This is why proper filtering on every penetration matters more than anything else you can do. For key fobs and similar low frequency RF devices, isolation is beyond practical measurement.
Does the chamber shield magnetic fields?
Not meaningfully. Aluminum construction short circuits electric (E) fields but does not shield magnetic (H) fields. RF signals, which are E and H combined, are shielded very effectively. If you are working with transformer coupled or purely magnetic signals, expect limited isolation and plan accordingly.
What about the ventilation openings and fans?
Ventilation uses honeycomb waveguide vents that maintain full shielding isolation, better than 100 dB at 1 GHz and better than 95 dB at 10 GHz.
RF shielded fans are available in several configurations (60 mm and 80 mm, 12 VDC and AC, standard and high airflow) at $95 each. They mount directly into the chamber wall behind the honeycomb vent and run from an independent filtered external supply, completely separate from the I/O plate, so fan power cannot introduce noise onto your device's power rails.
What is the interior lined with?
LS-30 RF absorbing foam on all walls, floor and top. It is 3/4 inch (19 mm) on all models except the JRE 0709-P, which uses 1/2 inch (13 mm). The foam is rated to 90 °C with a UL 94V-0 flammability rating.
The foam is a lossy, resistive material, so it attenuates RF as the wave travels through it. For a reflection the wave has to pass through the foam to reach the aluminum wall and then pass back through it again on the way out, so it sees the material twice. That gives better than 40 dB of round-trip damping on wall reflections, which is what keeps standing waves and multipath from distorting your measurements.
Two things customers regularly ask about. First, the published interior dimensions already include the foam, so do not subtract foam thickness when checking whether your device fits. The interior number is what you actually have to work with. Second, the I/O plate area is intentionally left unlined, so that you can swap connectors and replace plates without peeling foam. That small bare area does not meaningfully affect testing.
How We Build Them
Where are JRE chambers made?
In our own facility at 75 Victor Heights Parkway, Victor, New York. Not assembled here from parts made elsewhere, made here. We run our own sheet metal fabrication, our own welding, our own CNC machining, our own electronic assembly and our own final testing under one roof.
What manufacturing equipment do you have in house?
6 kW fiber laser cutter. Every sheet metal part in every chamber is cut here. It runs aluminum, stainless and mild steel up to an inch thick. Fiber laser cutting gives clean, accurate, repeatable parts with tight tolerances, which is what lets panels, doors and gasket channels fit together the way RF shielding requires. The heavy end of that range is well beyond anything a chamber needs, and that is the point: it means our own tooling, fixtures and stands get made here too, and it means capacity is never the reason your job waits. We brought laser cutting in house two years ago and have not sent a part out since.
- 5 foot, 40 ton press brake. All forming is done in house. The 5 foot bed handles the largest panels we make, including the big enclosures like the JRE 3036, without breaking a part into sections and adding a seam that would have to be sealed.
- Laser welder. Laser welding puts very little heat into the part, so seams come out strong without the distortion that conventional welding causes. On an RF enclosure that matters more than it might sound: a warped panel is a gasket that does not seal evenly, and a gasket that does not seal evenly is a leak. It is a significant investment for a shop our size, and it is there specifically because shielding integrity depends on flat, true, undistorted metalwork.
- CNC milling. Every custom I/O plate is CNC milled here, which is why we can turn a custom plate configuration around in 3 to 5 days rather than weeks.
- SMT assembly line with reflow oven. Every filter we sell is built on it. Our patented USB, USB-C, HDMI and Ethernet filter designs are our own work, populated and reflowed on our own line and tested by us. Nothing is contract manufactured and nothing is bought in.
- Final test. Every chamber is tested in the exact configuration you ordered, with all of your connectors and filters installed, before it ships.
The one operation we do not currently do ourselves is powder coating, which goes to a local finisher here in the Rochester area. We are bringing that in house as well once space in our building opens up. Everything that affects shielding performance, the cutting, forming, welding, machining, filter assembly and final testing, already happens here.
Why does that matter to me as a customer?
Three practical reasons.
Lead time. When every process is in house, nothing sits in an outside vendor's queue. That is how standard chambers stay genuinely in stock and how custom I/O plates go out in 3 to 5 days instead of taking weeks.
Quality control. Shielding performance depends on things that are easy to get slightly wrong, seam flatness, gasket channel geometry, filter board assembly, screw torque. When all of it happens under one roof, a problem gets caught and corrected rather than shipped and discovered.
Flexibility. Because we own the equipment, a special plate layout or a modified configuration is a scheduling decision, not a negotiation with a supplier. It is also why we can build one chamber exactly the way you need it, rather than telling you to pick from what happens to be on the shelf.
Do you make the filters yourselves, or buy them in?
We design and build them. The signal phasing topology used in our USB 3.0, USB-C, HDMI and LAN-10G interfaces is our own patented work, and every board is populated and reflowed on our own SMT line here in Victor. No contract manufacturer, no third party filter modules dropped into our plates. That is why we can tell you precisely how a filter behaves at a given frequency, and why we stand behind it without hedging.
We work in a controlled environment. Where are your chambers and filters actually made?
Here, in Victor, New York, start to finish. The metal is cut, formed, welded and machined in our building. The filter boards are assembled and reflowed on our own line in the same building. The chamber is configured and final tested in the same building. Nothing in the shielding or filtering path is contract manufactured, and no third party filter modules are dropped into our I/O plates.
For customers with supply chain scrutiny, defense, intelligence, government labs and their contractors, that matters as much as the dB numbers. The people who designed your filter are the people who built it, in one facility, and we can tell you exactly what is in it and where it came from. If your program has specific documentation or sourcing requirements, tell us early and we will tell you plainly what we can and cannot support.
Maintenance and Service
How often does the RF door gasket need replacing?
The door seal is the one wear item on the chamber. It is rated for more than 20,000 open and close cycles, or about a year of normal use, and replacement kits are available for every model. The seal is a set of four individual straight gasket pieces that seat in channels on the door and enclosure wall. Each piece is neoprene rubber wrapped in stainless steel mesh: the neoprene provides the spring that maintains contact pressure, the mesh makes the actual RF seal. They are sold as a set of four.
The wear mode is compression set. As the neoprene takes a permanent set, contact force drops, and isolation softens at the top of the band first. At 28 GHz you would see it long before you saw anything at 1 GHz, where performance is essentially unchanged for the life of the chamber. A periodic top of band isolation check with an STA-1 or TVK-2 is the early warning.
One free tip that extends gasket life considerably: when the chamber is not in use, leave the door ajar or unlatched so the neoprene is not sitting compressed.
What about hinges and latches?
They are heavy duty stainless steel structural hardware, and they are life of product. There is no service interval and no published cycle life, in the same way there is no published cycle life for the hinges on your front door. If one is ever damaged, it can be replaced in the field.
Can I add connectors later, or change the configuration?
Yes, and this is the whole point of the I/O plate system. Plates are removable and field replaceable, so one chamber can be reconfigured for many different test scenarios over its life. When your needs change, we build a new plate to your new configuration and you swap it in with a screwdriver.
A word of caution in the other direction: do not add penetrations yourself. Every hole through the shielded wall has to be properly filtered or properly sealed. Copper tape over an opening, an unfiltered drilled hole, or a bolted cover plate without conductive gasketing will all leak, and at 6 GHz, where a wavelength is only about 50 mm, small gaps are wide open windows. If you do drill the chamber, every hole must be filled with a metallic, preferably stainless steel, fastener.
Do the I/O plate screws need to be tight?
Tighter than you think, and this is worth knowing because it accounts for a real share of the "my chamber is leaking" calls we get. Our production floor torques them to 19 to 24 in-lb (about 2.1 to 2.7 Nm) for 8-32 stainless screws. Without a torque driver, hand tighten with a standard screwdriver until the screw is very firmly seated, noticeably tighter than finger snug. A screw that looks tight but is not fully torqued will leak RF, and it is the first thing to check before troubleshooting anything else.
Documentation and Certification
Can I get a Certificate of Conformance?
Yes, on request, at no charge. Every enclosure is tested before it ships. Individual, documented test results for a specific unit or a specific frequency band are available at additional cost based on engineering time.
We will tell you honestly if a document you are asking us to produce will not change any decision you make. We would rather keep your money in your pocket and have you trust the next thing we tell you.
Still Have a Question?
Technical questions come straight to me.
Before you specify a chamber, it is worth an hour with our Resources and Notes section, and the Configuration Worksheet will help organize your thinking on what connections you need.
John Ramsey, Engineering
john@jretest.com
JRE Test LLC, 75 Victor Heights Pkwy, Suite B, Victor, NY 14564
1-585-298-9596 | sales@jretest.com
