An affordable base station antenna for GMRS, MURS, or CB radio can be made from a mobile antenna at roof or balcony level.
Be sure the antenna is well away from power lines for safety and noise.
It’s important to get the tip of the antenna higher above ground level vs. antenna length.
That is, a shorter antenna up high is often better than a longer antenna at ground level.
A mobile antenna near the roof peak using half a mirror mount can screw into the metal eaves for groundplane.
A satellite TV dish mount can also be used, assuming a lightweight CB antenna that doesn’t significantly exceed the weight or wind load of the dish mount.
If the antenna is not mounted to metal, a counterpoise / groundplane can be employed at least by drooping a wire or wires 1/4 wavelength long (27 MHz CB ~ 9 feet) from the ground of the antenna base, connected to the coax cable shield.
For higher frequency MURS and GMRS or as a compromise at CB 27 MHz, a magnet mount antenna could be attached to a large dog kennel or magnetic baking sheet.
A mobile antenna on the roof will perform poorly without a large magnetic surface to attach to.
For safety, put weight on the groundplane or screw it into the balcony or roof to prevent it from blowing off in the wind.
Important factors for maximizing communications range include:
antenna tip height above average terrain
freedom from interference (noise, undesired signals)
antenna efficiency – 1/4 wavelength radiating element is desired – balancing length, weight and aesthetics. The mobile antenna should be of a type at least 3 feet long to be worthwhile as a base antenna for effective communication range.
antenna blockage by the roof or adjacent structures
ensure the power supply is linear to avoid noise–especially important at 27 MHz CB.
Depending on favorable terrain, base-to-base communication range on CB using omnidirectional antennas with at least 1/4 wavelength antenna with base (bottom) height of the antenna about 20 feet above ground, in clear terrain, and with clear channels can legally reach using various emissions modes:
AM: 20+ miles
FM: 15+ miles
SSB: 30+ miles
In contrast, a base station antenna in an urban area on a first-floor deck (say 5 feet above ground) may have only 1/2 mile to 3/4 mile range on CB, MURS, or GMRS to mobile or portable units–similar to simply having a portable unit at the base location.
Estimate communications range using a voice activated recorded at the base station and drive around, giving location on each transmission.
Compare CB range to MURS or GMRS range with multiple radios near the recorder.
FM mode is strongly preferred for family and neighborhood communications.
For CB radios capable of
FM and CTCSS,
the squelch can be set to only open for the group’s chosen CTCSS tone.
The choice of FM mode and CTCSS is not about maximum communication range, but about reducing interference from other users on the same channel.
If the family members or group turns off the radio because of static and interference, that’s no radio at all.
Better to have shorter range village communication than no communication at all.
CTCSS on CB radio finally largely levels the playing field with other license-free radio bands like MURS and GMRS that could always use FM and CTCSS.
A CB radio gives a heads up when members of a family or group are coming back home.
This gives some peace of mind in case of a breakdown, in that the home base or another base station can be reached on the local channel.
Many developers already use
Visual Studio Code,
which is a free open-source program available for Linux, macOS and Windows.
VS Code can do
Git 3-way merge.
On Windows, when building an executable target in Debug mode using Visual Studio or Intel oneAPI, it may be necessary to also have the libraries linked by the target to have Debug symbols.
For example, when building in CMake:
error LNK2038: mismatch detected for '_ITERATOR_DEBUG_LEVEL': value '0' doesn't match value '2' in main.cpp.obj
error LNK2038: mismatch detected for 'RuntimeLibrary': value 'MD_DynamicRelease' doesn't match value 'MDd_DynamicDebug' in main.cpp.obj
The solution is to build the libraries with Debug mode as well.
macOS package managers allow easy download, build and install of developer programs and libraries.
Homebrew
is by far the most popular macOS package manager.
Homebrew has a large number of packages and the ability to create unofficial “taps” to easily distribute software.
Homebrew taps allow distributing binaries via Homebrew before going to include in the main homebrew package repo, which takes time and justification.
Homebrew distributes per-OS compiled binaries, so package install time is almost instant.
It is possible to also download source and build locally with Homebrew if desired.
MacPorts
generally distributes source code that is compiled on install, although it can also use precompiled binaries.
Macports installs packages under a
prefix.
Homebrew is much more popular than MacPorts or
Fink.
Anaconda Python puts itself first on PATH when activated.
This can become a problem for libraries like HDF5, where “conda install h5py” puts
compiler script h5cc
on environment variable PATH before the intended script path.
For systems where Homebrew is used to provide packages to find from CMake, tell CMake to prefer a package location with
CMAKE_PREFIX_PATH.
CMake Git operations such as shallow clone can cause unexpected failures due to too small INACTIVITY_TIMEOUT in ExternalProject or FetchContent.
Be sure to set INACTIVITY_TIMEOUT to a large enough value.
15 seconds is too short a timeout for Git shallow clone, for example.
Consider 60 seconds or larger INACTIVITY_TIMEOUT.
lowSpeedLimit might be set to 1000 (bits/second) or as appropriate for the network.
If lowSpeedTime is too short, this download failure can also occur.
Set to 60 seconds or more.
Normally it is not necessary to specify the path to the CMake generator backend, assuming the generator executable is in environment variable $PATH or
CMAKE_PROGRAM_PATH.
For special use cases such as testing CMake with different versions of a generator the generator executable absolute path may be specified via
CMAKE_MAKE_PROGRAM.
The absolute path to the generator is necessary or CMake will not find it.
Suppose a GitHub Actions Linux image has ninja-linux.zip containing executable file “ninja”.
Get the absolute path using realpath.
CMake Find modules are by their nature a little aggressive about finding libraries and executables.
This becomes a factor on Windows in particular when Anaconda Python is not active in the current Terminal.
CMake find_package(Python) by default prefers Anaconda Python over system Python unless overridden as below.
Anaconda Python won’t operate correctly without conda activate, which presumably the user has either forgotten to do or doesn’t desire at the moment.
To decrease the aggressiveness and find Windows Store Python etc. when conda isn’t activated on Windows, add to the project CMakeLists.txt beforefind_package(Python):
set(Python_FIND_REGISTRYLAST)# this avoids non-active conda from getting picked anyway on Windows
set(Python_FIND_VIRTUALENVSTANDARD)# Use environment variable PATH to decide preference for Python
find_package(Python)
Anaconda Python by default auto-activates the “base” environment each time a new Terminal is opened.
This slows opening new Terminal, particularly on systems with slow disks or virtual disks.
Particularly if the user isn’t constantly using Python, it can be beneficial to make conda only active when specified.
To disable conda auto-activation on new Terminal, type: