Searching for Frequencies
Pressing the Search button next to the tuning arrows opens the search drawer. With the controls in this drawer, you can have MacR–1000 tune your radio through a range of frequencies, pausing at each active one, and optionally saving a list of active frequencies.
In MacR–1000, “searching” refers to rapidly tuning through a continuous band of frequencies. This is distinct from rapidly tuning through a list of known frequencies, possibly widely separated, which MacR–1000 calls “scanning.”
A search always runs from a lower frequency to a higher one. Searching every frequency (or at least every Hertz) between the two is possible, but slow and not very valuable compared to sampling every few hundred or thousand Hertz in the interval. The search drawer allows you to set the lower and upper bounds of the search in the two upper fields, and the size of the sampling step in the field below.
Just like the main frequency display, the upper, lower, and step tuning fields always display frequencies in Hertz, with billions, millions, and thousands separated by spaces. If you type a number followed by an upper- or lower-case G, M, or K, the number you enter will be multiplied by a billion, million, or thousand, respectively. Numbers with decimal points are interpreted by default as megahertz; you can change this default in the preference panel.
Press the large Search button in the search drawer to start the search. MacR–1000 will silently tune your PCR1000 to the lower-bound frequency, and sample at that frequency long enough to determine if it is busy. If it is not, MacR–1000 adds the search step interval to the current frequency, and samples again. When the search passes the upper-bound frequency, searching resumes at the lower-bound frequency.
Stop the search by pressing the large Search button in the search drawer again. Searching will also stop if you start a library scan, or a search for a CTCSS tone.
If a signal is found at a frequency, the PCR1000 will unmute, and search-tuning will pause. The radio buttons in the middle of the search drawer give you a choice of how and when that pause will end:
- You can listen to the frequency so long as it’s active, but no more than a set time limit. When that time limit expires, the scan resumes. Select Pause for a period of:, and choose a time limit, for this option.
- You can listen to the frequency as long as it is active. If it becomes inactive (as when one station stops transmitting and another takes a second or two to reply), MacR–1000 waits a set period of time for activity to resume. If that period expires with no new activity, scanning resumes at the next frequency on the list. To use this option, select Wait for a silence of: and choose a time limit for the wait.
Frequencies in the “Locked-out Frequencies” list of the frequency library will not be searched, even if they fall in the range you specify for the search. In this way, you can exclude receiver “birdies,” persistent signals like data or pager channels, or other uninteresting frequencies from the search.
If auto-mode is selected in the preferences panel, the radio will be set to an “appropriate” modulation and filter width for each frequency visited in the search. If auto-mode is not selected, the radio will stay in the same mode and filter width that were set when the search began.
When Save the frequency in this list is checked, MacR–1000 will record the frequency, mode, filter width, and signal strength of every active frequency encountered during a search. The saved-frequency list will clear with each new search, or when you press the Clear List button.
When you press Put in Library, the saved-frequency list will be copied to a new frequency list, named for the present date and time, in the frequency library. Once the frequencies are in the library, you can add descriptions and edit frequencies, filter widths, and tuning steps. You may want to add some of the found frequencies to the “Locked-out Frequencies” list, to exclude them from future searches.