Reply to thread

Message: [QUOTE="Bombastus, post: 92216, member: 2178"] Spectera can operate in TV UHF or the 1.4 GHz range, but those two versions do not give an RF engineer the same working canvas. The system supports UHF from 470 to 608 MHz and 630 to 698 MHz, while 1G4 spans 1350 to 1400 MHz and 1435 to 1525 MHz, with local rules narrowing those ranges. The audio architecture stays familiar across both versions. A [B][URL='https://goldmidi.com/community/threads/sennheiser-spectera-skm-starts-shipping-with-1ms-latency.77489/']Spectera SKM wireless system[/URL][/B] still uses the same bidirectional WMAS approach, the same Audio Link Modes, and the same Base Station concept. Choosing UHF or 1G4 is mainly a decision about spectrum access, propagation, antenna hardware, and where you need RF capacity. In the United States, the distinction gets sharper. Spectera’s U.S. license covers UHF at 470 to 608 MHz plus 657 to 663 MHz, while 1G4 operation sits at 1435 to 1525 MHz and requires AFTRCC coordination for eligible Part 74 users. You cannot treat the 1.4 GHz version as an open alternative band and simply tune into it on arrival. [HEADING=2]The band choice starts with spectrum, not sound quality[/HEADING] UHF remains the more familiar territory for professional wireless because engineers already understand its television-band occupancy, propagation, and coordination habits. Spectera changes how much audio can share one wideband carrier, but it does not make local spectrum conditions disappear. A usable 6 or 8 MHz block still has to exist where the system is being used. 1G4 earns attention when suitable UHF spectrum is crowded or strategically valuable for other equipment. It moves Spectera into a separate part of the RF landscape, giving a production another place to build a wideband carrier instead of squeezing every microphone and IEM into the same television spectrum. For large shows, the extra band can be capacity, not merely a substitute. The trade is propagation. Around 1.4 GHz, wavelength is much shorter than it is around 500 to 600 MHz, and free-space path loss is roughly 8 dB higher at 1.45 GHz than at 600 MHz when distance and antenna gains are held equal. Human bodies and antenna placement also become important parts of the link, a behavior visible in [B][URL='https://doi.org/10.1155/2015/319894']measured wearable antenna performance near 1.5 GHz[/URL][/B] rather than something an engineer should dismiss as bench-only trivia. [HEADING=2]Spectera’s antenna hardware changes with the band[/HEADING] The Base Station itself does not lock you into UHF or 1G4 because its RF hardware lives in the remote DAD antennas. Sennheiser lets the same Base Station connect both DAD variants, and its two independent RF channels can be used across the available bands. A mixed UHF and 1G4 deployment is therefore a system-design option rather than a reason to buy a second kind of Base Station. The antennas are physically and electrically different. Sennheiser specifies 5 dB gain and a 109-degree horizontal apex angle for the UHF DAD, compared with 6.5 dB and 93 degrees for the 1G4 version. The 1G4 panel is also substantially smaller at 231 by 205 mm, versus 349 by 292 mm for UHF, which can matter when antennas have to disappear into scenery, balconies, broadcast positions, or temporary truss. Neither set of numbers makes one band universally better. The narrower horizontal pattern and higher specified antenna gain of the 1G4 DAD can help shape coverage, while UHF starts with friendlier propagation physics. Real placement still decides whether those advantages survive once people, scenery, walls, and antenna orientation enter the room. [HEADING=2]US 1G4 access changes the deployment workflow[/HEADING] For a U.S. production, 1G4 carries an administrative step that UHF users may not expect. Access to 1435 to 1525 MHz is coordinated because the band is also used for aeronautical mobile telemetry, so Spectera’s U.S. workflow uses AFTRCC approval and an electronic key to unlock the authorized portion for a specific operation. Sennheiser added support for that e-key workflow in Spectera firmware 1.3.0. Touring crews therefore need to decide on the band before load-in, not after discovering a busy UHF scan during soundcheck. A 1G4 system can be extremely useful where the authorization and RF plan are already in place, but it is not emergency spectrum you can assume will be available everywhere. Regional licenses differ too, so a touring inventory should be checked against each destination rather than relying on the broad global tuning range printed in the product specifications. The hardware split reaches the transmitters as well. Spectera SKM, SEK bodypacks, and their associated antennas are sold in band-specific UHF and 1G4 versions even though the Base Station can serve both. Buying 1G4 therefore makes the most sense when the production has a repeatable spectrum reason for using it, while a mixed inventory gives larger systems a second RF lane without changing the central control platform. [/QUOTE]

Name