TekBox TBCAS1 Coaxial Adapter Set, 44 Pieces (N, SMA, BNC, SMB, RCA), 50 Ohm, to 6 GHz
TekBox TBCAS1: 44 coaxial adaptors in 25 types between N, SMA, BNC, SMB and RCA, 50 ohm, N and SMA rated to 6 GHz, in a beech-wood box with foam inlay.
TBCAS1 — 44 coaxial adaptors between N, SMA, BNC, SMB and RCA, in one beech-wood box
Twenty-five adaptor types, 44 pieces, all 50 Ω: N and SMA adaptors rated to 6 GHz with a VSWR of 1.1 to 1.15, BNC to 4 GHz at 1.2, and two RCA transitions for the audio and video side of a bench. Each sits in its own cut-out in a foam inlay, so a missing one is obvious.
The set is built around the connector on the instrument. 22 of the 44 pieces have an N side, because the RF input of every Siglent spectrum analyser, network analyser and RF generator is N-female and almost nothing that arrives at it is N: the cable is SMA, the oscilloscope is BNC, the module under test is SMB. Four N-male to SMA-female adaptors — the single most-used piece on an analyser bench — are in the box rather than one.
The rest covers what the N side cannot: BNC to SMA in every gender for taking an oscilloscope-world cable into RF, SMA and SMB barrels to join two cables or change gender, and BNC to RCA for the one time a year somebody brings in a composite video or audio lead.
Parts list — 25 types, 44 pieces
TekBox’s parts list, grouped by the connector family on one side. The rating is the frequency up to which TekBox specifies the VSWR figure.
| Qty | Adaptor | Rated to | VSWR |
|---|---|---|---|
| N-type adaptors | |||
| 1× | N-male to N-male | 6 GHz | 1.1 – 1.15 |
| 1× | N-female to N-female | 6 GHz | 1.1 – 1.15 |
| 4× | N-male to SMA-female | 6 GHz | 1.1 – 1.15 |
| 2× | N-male to SMA-male | 6 GHz | 1.1 – 1.15 |
| 2× | N-female to SMA-female | 6 GHz | 1.1 – 1.15 |
| 2× | N-female to SMA-male | 6 GHz | 1.1 – 1.15 |
| 2× | N-male to SMB-female | 6 GHz | 1.1 – 1.15 |
| 1× | N-female to SMB-female | 6 GHz | 1.1 – 1.15 |
| 4× | N-male to BNC-female | 4 GHz | 1.2 |
| 1× | N-male to BNC-male | 4 GHz | 1.2 |
| 1× | N-female to BNC-male | 4 GHz | 1.2 |
| 1× | N-female to BNC-female | 4 GHz | 1.2 |
| BNC adaptors | |||
| 1× | BNC-male to BNC-male | 4 GHz | 1.2 |
| 1× | BNC-female to BNC-female | 4 GHz | 1.2 |
| 1× | BNC-male to SMA-male | 4 GHz | 1.2 |
| 2× | BNC-male to SMA-female | 4 GHz | 1.2 |
| 1× | BNC-female to SMA-male | 4 GHz | 1.2 |
| 2× | BNC-female to SMA-female | 4 GHz | 1.2 |
| 1× | BNC-male to RCA-female | 100 MHz | 1.2 |
| 1× | BNC-female to RCA-male | 100 MHz | 1.2 |
| SMA and SMB adaptors | |||
| 3× | SMA-female to SMA-female | 6 GHz | 1.1 – 1.15 |
| 3× | SMA-male to SMA-male | 6 GHz | 1.1 – 1.15 |
| 2× | SMA-male to SMB-male | 6 GHz | 1.1 – 1.15 |
| 2× | SMA-male to SMB-female | 6 GHz | 1.1 – 1.15 |
| 2× | SMA-female to SMB-female | 6 GHz | 1.1 – 1.15 |
Four jobs it does on a Siglent bench
SMA cable onto an N input
N-male to SMA-female is the adaptor every analyser bench wears out first, which is why there are four. It takes any SMA test cable onto the N input of an SSA, SVA or SNA, or onto the tracking-generator output.
BNC world into RF world
An oscilloscope’s BNC cable onto an SMA port, or an SMA cable onto a BNC input: eight BNC-to-SMA adaptors in all four gender combinations.
Join two cables, or change a gender
Female-female and male-male barrels in N, SMA and BNC. Two SMA cables become one long one; a male-ended cable fits a male port.
SMB modules and RCA leads
SMB is the push-on connector on RF modules, GPS and tuner boards — and on the TBPS01 probes. The two RCA transitions take an audio or composite-video lead into a 50 Ω instrument.
What the frequency ratings mean on a Siglent bench
The rating is the frequency up to which TekBox guarantees the VSWR figure; above it the adaptor still works but the mismatch grows. The figures line up with what each connector is for.
N and SMA: 6 GHz, VSWR 1.1 – 1.15
Return loss of 23 to 26 dB — a reflection of 5 to 7 % of the voltage. For spectrum analysis and generator work this is well below the instrument’s own uncertainty. For a VNA measurement put the adaptor inside the calibrated path.
BNC: 4 GHz, VSWR 1.2
BNC is a 4 GHz connector by design, which is why every BNC adaptor here is rated there. Fine for every Siglent oscilloscope input and for the analyser range below 4 GHz.
RCA: 100 MHz, VSWR 1.2
RCA is not an RF connector. The two transitions are for audio and video signals — the rating says so.
Every adaptor adds a small loss and a small reflection. Where two adaptors would do the job, one from this set in the right gender usually does it in a single step — that is the point of having 25 types rather than five.
Specification
| Order code | TBCAS1 (TekBox) |
| Contents | 44 coaxial adaptors, 25 types (see parts list) |
| Impedance | 50 Ω |
| Connector families | N, SMA, BNC, SMB, RCA |
| N and SMA adaptors | Rated to 6 GHz, VSWR 1.1 – 1.15 |
| BNC adaptors | Rated to 4 GHz, VSWR 1.2 |
| RCA transitions | Rated to 100 MHz, VSWR 1.2 |
| Packaging | Beech-wood box with foam inlay, 190 × 170 × 65 mm · 1.3 kg |
From the TekBox TBCAS1 manual V1.2 and TekBox’s parts list. Return-loss figures in the text are converted from the VSWR values.
The other TekBox products we stock
Everything from TekBox on siglent.eu, chosen to work with Siglent spectrum analysers. The TekBox category page explains how they fit together.
Radiated emissions and immunity on the bench. 50 mm septum, room for a 19 × 13 × 5 cm board, usable to 3 GHz. 25 W termination and DC block included.
Three H-field loops (20, 10, 5 mm) and an E-field probe, with a 20 dB or 40 dB preamplifier powered from the analyser’s USB port. 2 MHz to 6 GHz.
3, 6, 10 and 20 dB N-type attenuators, DC to 6 GHz, 2 W, VSWR below 1.2, in a beech-wood box. Fifteen values from 3 to 39 dB when stacked.
Seven pieces: BNC to 4 mm banana plugs and jacks, BNC to screw terminal block, and a 50 Ω feed-through termination.
Prices ex VAT.
Questions about the TBCAS1
Why no TNC, 7/16 or 3.5 mm pieces?
TekBox chose the five families found on a general test bench. A 3.5 mm precision connector mates with SMA, so the SMA adaptors fit it mechanically; TNC and 7/16 are field and base-station connectors that need single adaptors, which we can quote.
Do the adaptors spoil the measurement?
Each adds a fraction of a dB of loss and a reflection of a few percent. For spectrum-analyser and generator work that is far below the instrument’s own level uncertainty. On a vector network analyser, calibrate with the adaptor in place so it becomes part of the reference plane.
Can I use the set with the SNA5000A or SVA1000X network analysers?
Yes — everything is 50 Ω and the N and SMA pieces are rated to 6 GHz. Include the adaptor in the calibration, as above.
Are the RCA adaptors 75 Ω?
TekBox lists the whole set as 50 Ω and rates the RCA transitions to 100 MHz. At the audio and video frequencies they are for, the impedance of an RCA plug is of no consequence.
How many of each gender are there?
Where it matters the box has several: four N-male to SMA-female, four N-male to BNC-female, three SMA barrels of each gender, two of most other SMA and BNC types. The parts list above gives every quantity.
Can I replace a lost adaptor?
Yes; send us the type from the parts list and we quote a single piece. The foam cut-outs make it easy to see which one has gone.
Missing one connector?
Tell us the two ends and the highest frequency that matters. We will tell you whether a piece from this set, a single adaptor or a made-up cable is the right answer.