Cable
RG178
End A
SMA FEMALE
End B
TNC MALE
Specs Summary
25 ft RG178 — SMA FEMALE to TNC MALE
RG178 cable assembly, 25 feet, with SMA FEMALE and TNC MALE connectors. Hand-assembled, tested, and ships free within the US.
25 ft — SMA FEMALE / TNC MALE
$23.98
Free shipping • In stock
Other lengths:
Signal Loss — 25 ft
Approximate insertion loss for this 25 ft RG178 assembly at common RF frequencies.
| Frequency | Loss / 100 ft | Loss — 25 ft |
|---|---|---|
| 100 MHz | 7.5 dB | 1.88 dB |
| 450 MHz | 16.5 dB | 4.13 dB |
| 900 MHz | 24 dB | 6 dB |
| 1.8 GHz | 35 dB | 8.75 dB |
| 2.4 GHz | 42 dB | 10.5 dB |
| 5.8 GHz | 70 dB | 17.5 dB |
About This Assembly
RG178 Cable
RG-178 is an extremely thin 50-ohm coaxial cable measuring just 1.75mm in diameter, designed for space-constrained RF assemblies. Its PTFE dielectric and silver-plated conductors deliver reliable performance from DC up to several GHz. Commonly used for internal wiring in test equipment, medical devices, and cellular module pigtails.
SMA Connector
SMA (SubMiniature version A) is the most widely used RF connector in the industry, offering a threaded interface that provides a secure, low-reflection connection from DC to 18 GHz. Its compact size, 50-ohm impedance, and broad frequency range make it the default choice for WiFi equipment, software-defined radios, cellular antennas, GPS receivers, and RF test instruments.
TNC Connector
TNC (Threaded Neill–Concelman) is the threaded version of BNC, offering improved performance up to 11 GHz and better vibration resistance through its screw coupling. It is commonly used in mobile radio antennas, avionics, and outdoor installations where BNC's bayonet lock would not provide sufficient mechanical security.
Common Applications
This SMA and TNC cable assembly is well suited for ultra-compact internal wiring in test equipment and small wireless modules. The combination of reliable SMA and TNC connectors and custom-cut cable length makes it a practical choice for both field installations and bench setups. Every assembly is hand-terminated, continuity tested, and ships free within the USA.
Frequently Asked Questions
Is this cable hand-assembled in the USA?
Yes. Every CoaxRF cable assembly is hand-terminated and continuity tested at our US facility before shipping. We do not drop-ship pre-made cables from overseas — each cable is built to order.
Can I order a different length than 25 ft?
Yes. This page is for the 25 ft assembly. Use the length buttons above to select a different standard length, or use the Cable Builder for any custom length.
How much signal loss will I see with this 25 ft cable?
At 1800 MHz, RG178 loses approximately 35 dB per 100 ft. This 25 ft assembly will have roughly 8.75 dB of insertion loss at that frequency. See the signal loss table for all frequency points.
What is the maximum frequency for this assembly?
This assembly is rated DC – 3 GHz. The effective frequency limit is set by the lowest-rated component — either the cable or one of the connectors. Both SMA FEMALE and TNC MALE connectors must be within spec at your target frequency.
What is your return policy?
We accept returns within 30 days of delivery. Custom-length cables are accepted as long as they are in original condition. Contact us and we will provide a prepaid return label at no charge.
