CO-PHASING ANTENNA PACKAGE
The purpose of co-phasing receiving antennas is to add receiving strength in directions that you may have weak, distorted reception using just a single wideband scanner antenna such as a discone or Austin Ferret. The package was developed and put into use by an Extra Class Ham operator in the Providence area who was using a discone antenna on his roof to receive all the VHF and UHF public safety radio traffic in Rhode Island but he was unable to receive the southern Rhode Island state RISCOM trunking system at 800 MHz. He wanted to receive it with the addition of a single antenna and without an additional coax line. This was to save cost and the hassle of mounting a second length of LMR-400 coax. More importantly he wanted his scanner to receive all the bands well with a single coax feed from his antennas. By mounting the Co-Phasing Package unit on the tower and connecting up the two antennas using the attached coax harness with its jumpers to the two antennas (a wideband discone and an 800 MHz yagi aimed at southern Rhode Island), the Ham was able to receive both the high-band and 800 MHz systems perfectly on a single scanner.
In addition to a wideband discone type antenna you can add directional antennas (known as Yagi's after the Japanese inventor) and point them in the direction that you require improved reception. Each yagi that is added will achieve approximately a 5 to 12db gain in that direction depending on type of yagi. By adding yagis to a discone using the Co-Phasing Package you can either:
1. Add gain to a single band (150-174 MHz, 450-512 MHz, 746-860 MHz or 806-960 MHz) by mounting one yagi mid-mast with a discone or Ferret antenna on top, or
2. Add gain to multiple different bands using a mixture of yagis with different band coverages, or
3. Add significant gain on a single band by "stacking" the same make/model yagis in a single direction
4. Mount four yagis on the same band all aimed in a different direction, such as North, East, South, West. This is particularly useful in areas where you have multiple 700 and/or 800 MHz non-simulcat towers that you want to try to reach.
One of the great features of the system is that whether you're using 2, 3, 4 or 5 antennas you only need one coax feedline going from the scanner(s) to the antenna.
The co-phasing harness system includes all the correct length coax jumpers to attach the antennas and rfi (radio frequency interference) suppression to help keep your coax from picking up unwanted spurious signals. These harnesses are capable of using a discone type antenna and adding up to four additional directional antennas (select the model for your needs below or provide your own separately), or a discone and a single yagi or four yagis, etc.
Included in the black box unit is a toroid which helps to eliminate stray RF gathering and passing down the coax. In other words it helps stop the coax from being part of the antenna. The length of coax between antennas helps to keep the system stay in-phase so that means the antennas will be receiving at same time thus to provide maximum gain.
Wire ties are also supplied to mount the co-phasing unit to your antenna mast.
All the user will have to supply is the coax from the receivers and a mast long enough to mount all the antennas needed. Spacing required for a complete discone and 4 yagi system would need free space of less than seven feet. Choose your package below based on the number of antennas you'll be mounting.
IMPORTANT NOTE: If you are ordering a harness package with 3, 4 of 5 antennas we need you to tell us which radio bands the yagis you'll be using are covering. That's important in the layout of the harness. All these harnesses are custom built and will take approximately two weeks before shipping. Please send the specs along with your order number to firstname.lastname@example.org.
Please email any questions to email@example.com or call 1-800-SCANNER weekdays 10-4 ET.