### Install Py1812 Package

Source: https://github.com/eeveetza/py1812/blob/main/README.md

Install the Py1812 package from GitHub using pip. This command downloads and installs the latest version of the library.

```bash
python -m pip install "git+https://github.com/eeveetza/Py1812#egg=Py1812"
```

--------------------------------

### Import P1812 Class

Source: https://github.com/eeveetza/py1812/blob/main/README.md

Import the main P1812 class from the Py1812 library to begin using its functionalities.

```python
from Py1812 import P1812
```

--------------------------------

### Call P1812.bt_loss with all arguments

Source: https://github.com/eeveetza/py1812/blob/main/README.md

Invoke the `bt_loss` function with both required and optional parameters. Optional arguments can be passed as key-value pairs in any order.

```python
Lb, Ep = P1812.bt_loss(f, p, d, h, R, zone, htg, hrg, pol, phi_t, phi_r, lam_t, lam_r, \
            pL = val_pL, sigmaL = val_sigmaL, Ptx = val_Ptx, Gtx = val_Gtx, Grx = val_Grx, \
            DN = val_DN, N0 = val_N0, dct = val_dct, dcr = val_dcr, \
            flag4 = val_flag4, debug = val_debug, fid_log = val_fid_log)
```

--------------------------------

### Call P1812.bt_loss with required arguments

Source: https://github.com/eeveetza/py1812/blob/main/README.md

Invoke the `bt_loss` function using only the essential input parameters. Ensure all required arguments are provided in the correct order.

```python
Lb, Ep = P1812.bt_loss (f, p, d, h, R, zone, htg, hrg, pol, phi_t,  phi_r,  lam_t,  lam_r)
```

--------------------------------

### P1812.bt_loss

Source: https://github.com/eeveetza/py1812/blob/main/README.md

Calculates the basic transmission loss (Lb) and excess path loss (Ep) between two points. It supports both required and optional arguments for detailed environmental and signal parameter configuration.

```APIDOC
## P1812.bt_loss

### Description
Calculates the basic transmission loss (Lb) and excess path loss (Ep) between two points. It supports both required and optional arguments for detailed environmental and signal parameter configuration.

### Method
`P1812.bt_loss(f, p, d, h, R, zone, htg, hrg, pol, phi_t, phi_r, lam_t, lam_r, [pL, sigmaL, Ptx, Gtx, Grx, DN, N0, dct, dcr, flag4, debug, fid_log])`

### Parameters
#### Required input arguments
- **f** (scalar double) - GHz - 0.03 ≤ `f` ≤ 6 - Frequency
- **p** (scalar double) - % - 1 ≤ `p` ≤ 50 - Time percentage for which the calculated basic transmission loss is not exceeded
- **d** (array double) - km - ~0.25 ≤ `max(d)` ≤ ~3000 - Terrain profile distances (in the ascending order from the transmitter)
- **h** (array double) - m (asl) - Terrain profile heights
- **R** (array double) - m - Representative clutter heights
- **zone** (array int) - 1 - Sea, 3 - Coastal land, 4 - Inland - Radio-climatic zone types
- **htg** (scalar double) - m - 1 ≤ `htg` ≤ 3000 - Tx antenna height above ground level
- **hrg** (scalar double) - m - 1 ≤ `hrg` ≤ 3000 - Rx antenna height above ground level
- **pol** (scalar int) - `pol` = 1, 2 - Polarization of the signal: 1 - horizontal, 2 - vertical
- **phi_t** (scalar double) - deg - -80 ≤ `phi_t` ≤ 80 - Latitude of Tx station
- **phi_r** (scalar double) - deg - -80 ≤ `phi_r` ≤ 80 - Latitude of Rx station
- **lam_t** (scalar double) - deg - -180 ≤ `lam_t` ≤ 180 - Longitude of Tx station
- **lam_r** (scalar double) - deg - -180 ≤ `lam_r` ≤ 180 - Longitude of Rx station

#### Optional input arguments
- **pL** (type) - Description
- **sigmaL** (type) - Description
- **Ptx** (type) - Description
- **Gtx** (type) - Description
- **Grx** (type) - Description
- **DN** (type) - Description
- **N0** (type) - Description
- **dct** (type) - Description
- **dcr** (type) - Description
- **flag4** (type) - Description
- **debug** (type) - Description
- **fid_log** (type) - Description

### Returns
- **Lb** (type) - Description
- **Ep** (type) - Description
```

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