Best coaxial switching device for my 1420 MHz for reference samples. Does not need to be fast.
ChatGPT: For 1420 MHz reference switching where speed doesn’t matter, go with a latching electromechanical DPDT transfer (coaxial) switch. It gives you the cleanest path, excellent isolation, and rock-solid matching. It’ll beat solid-state on isolation and linearity, and at H-line power levels the lifetime is huge.
Top pick (bulletproof, easy to drive)
- Teledyne ECS-37S (SMA, latching, DC–26.5 GHz). At 1.42 GHz you’re in its best region: insertion loss ≤0.2 dB, isolation ≥80 dB, VSWR ≤1.20:1. Magnetic latching, optional self-cutoff and indicators.
Good alternatives
- Radiall RAMSES DPDT (e.g., R577452012, SMA, 12 V, latching, DC–18 GHz). Well-known workhorse in radio astronomy labs; configurable options (self-cutoff, suppression diodes). (radiall.com)
- Mini-Circuits MTS-18XL-B+ (SMA, DC–18 GHz). Simple, readily available transfer switch; typical IL ~0.2 dB, isolation commonly 80–90 dB in this band per their RC-series performance curves. (minicircuits.com)
Why a DPDT transfer switch here
- Keeps both paths 50 Ω and simply swaps “antenna ↔ reference” into the receiver without leaving a port dangling, so your chain stays well matched during slow calibration cycles.
Practical setup notes
- Choose latching (not failsafe) so it holds state with power off and doesn’t inject coil current noise continuously. Self-cutoff option is nice.
- Wire it as a classic transfer: J1–J2 for Path A, J3–J4 for Path B. Put the antenna on one side, your reference (terminator/noise diode) on the other, and the receiver on the common side. Use short SMA jumpers and keep the switch close to the front-end.
- Avoid hot-switching; toggle between integrations. These units are spec’d for very high cycle life if you don’t switch under RF.