Ja tuo maininta kierrettävien F-liittimien kiellosta on huuhaata.
Niitä ei saa käyttää ammattimaisissa asennuksissa joita tehdään uudisrakennuksiin tai niihin verrattaviin linjasaneerausprojekteihin.
Mutta jokainen saa edelleen käyttää niitä omissa piuhoissaan niin halutessaan.

-M-

Documentary of the construction of a transmission transformer with a ratio being 1.5.1 power handling 1kW 100% duty.
This transformer can be used for matching different feeders or equipment in the 1-30Mhz HF region. I will be using this as a buffer transformer to feed a 4:1 balun thus creating a 6:1 balun.
I hope this is useful for someone out there. 73
Parts recipe:
4 lengths about 300mm of 1.25mm copper enamel wire
1 length of about 300mm of 1.7mm copper enamel wire
1 Jaycar LO1238 (Mid Perm) core warped with plumbers tape.

When it comes to 50 vs 75 Ohm, it’s all about two things: footprint & power.

Especially when it comes to 50 Ohm vs 75 Ohm coax cables.

Signal loss on 50 vs. 75 Ohm cable depends heavily on what radio frequency you’re trying to transmit. At very high frequencies, certain 75 Ohm cables work better than 50 Ohm.

However, for boosting cellular signal, the common 50 Ohm solutions (Wilson400, LMR®600, etc.) always provide better loss than a 75 Ohm cable such as an RG-6.

Most home cellular boosters come in 75 Ohm systems with 75 Ohm cables such as RG-6 with F-connectors.

Most commercial cell signal boosters come in 50 Ohm systems with 50 Ohm cables such as LMR®400 with N-connectors.

75 Ohm: The Friend You Already Know

Why consider 75 Ohm?

That’s because 75 Ohm cables are the standard coax cable you find everywhere inside your home and offices.

From the back of the tv to cable & satellite tv boxes and internet routers, they’re commonly used and are often pre-wired in many homes and businesses.

75 Ohm is primary used for video and audio, hence why its rapid adoption and use as standard in the country.

For home applications, they do a perfectly fine job of transmitting signal up to 50 feet of cable with home or small building installation topping out at 5,000 sq ft.

50 Ohm: The Big Gun

For commercial installations running cable 100+ feet with building coverage at 7,500 to 100,000+ sq ft, then high-quality 50 Ohm cable is the clear winner.

50 Ohm cable is primary used for data, and there’s this thing called “the internet” that uses a lot of it. It’s a much better cable for cell phone booster systems since 4G LTE data (and soon to be 5G) is what we’re looking to get a lot of.

But what’s the trade-off?

Aesthetics.

50 Ohm cables tend to be thicker and have larger connectors. And since 50 Ohm cables aren’t as ubiquitous as 75 Ohm cables, running cable is potentially more difficult if your building is not prewired for it.

There are, also, certain varieties of 50 Ohm cable which have greater signal loss than a 75-Ohm RG-6 cable, so make sure you’re getting LMR®400 spec cable or above when looking for a cellular solution.

Choose 75 Ohm if:

Cable run is under 50 ft.
Home coverage is under 5,000 sq ft.
House is pre-wired with F-connectors.
Best solution for most homes & small buildings.

Choose 50 Ohm if:

Cable run is over 100 ft.
Building coverage ranges from 7,500 to 100,000 sq ft.
Want the absolute best in terms of power.
Best solution for buildings and commercial spaces.

For those who understand dB gain, 75 Ohm can lose as much as -1.1 dB compared to 50 Ohm per 100 feet of cable. In essence at 100 ft of cable, 50 Ohm is roughly 1.3x more powerful than the 75 Ohm in terms of maintaining signal coming from the same source.

If you play with coax, short for coaxial cable, you probably know this it is available in a number of different impedances. The most common is 75 ohm, like video cable or antenna cable, but in fact our products range from 32 ohms up to 124 ohms.

Why all these different numbers? It’s not an accident of course, and there is a reason for each one. Today, we’re going to take a quick look at 50 ohm coax cable.

Belden makes hundreds of 50 ohm cables, including a whole line of ultra-low loss versions (Belden 7805 to Belden 7977). The two largest versions (Belden 7976 and 7977) are shown in the photograph below. They are HUGE. The 7977 has a diameter of .600″ six-tenths of an inch! This is the largest coax cable that we make.