1. Antenna site selection
    1. Site study
      1. Do it yourself ...
        1. Check arc clearance
          1. Use a compass and clinometer (available from Dawn Satellite or from architect's or surveyor's supply house) to check whether all desired a satellites can be seen from proposed site.
          2. The satellite you are pointed to today will not last forever. Service may move to another bird.
        2. Zoning Laws
          1. Are there any local regulations about land use?
          2. Are there limits on dish visibility from the street?
          3. Are you in a historic district or a landmark property?
        3. Property
          1. Cable route and dish should be entirely on your owned or leased property.
      2. ...or hire a broadcast engineering firm or a local satellite installer to look at the proposed site
    2. Locate terrestrial interference
      1. Telephone companies still use terrestrial microwave links in the C-band frequencies used by your satellite terminal.
      2. There are other, unpredictable sources of interference
        1. Mobile cellular phones operating between 806 and 890 MHz
          1. fifth harmonics are between 4,030 and 4,450 MHz
            1. can affect transponders 16 through 24 on 24-transponder satellites
            2. ABC's news and talk feeds (on Satcom C-5, transponder 23) and Real Country and Country Coast to Coast (on GE-3, transponder 17) are in this potential interference band.
          2. The problem is usually from car-roof-mounted 3-watt mobiles, not from 0.6-watt hand-helds, and not from cellular towers, which have better filtering.
        2. Microwave ovens operate near 2,000 MHz. Second harmonic is near 4,000 MHz, within the satellite band.
        3. Radio altimeters and airport radars operating just outside the satellite band have also caused problems.
        4. Comsearch field engineers say these sources cause more problems to digital transmissions than to analog ones.
      3. Frequency coordination
        1. What's frequency coordination?
          1. Unlike broadcast station licenses, the FCC does not allocate the frequencies and powers of C-band transmitters (and receivers) to be free of interference. Each licensee must prove that his site (transmit or receive) will not cause interference to or receive interference from pre-existing sites.
          2. The C band is shared by terrestrial microwave users (mainly telephone companies) and C-band satellite links.
          3. C-band downlinks are not required to be licensed. If you coordinate and license yours, you can force other microwave users not to interfere with you. Interference protection is first-come, first-served. If your downlink is licensed, a telephone company cannot legally license or construct a microwave tower than can interfere with you.
          4. Comsearch is the only firm we know of that performs this service.
        2. Frequency coordination services
          1. Expect to pay $400 per site for a "database cull" and a preliminary analysis of potential interference cases.
          2. Full coordination costs an additional $700 per site.
            1. They send out letters to other users of the band which say "speak now, or forever hold your peace."
            2. Any return letters of protest are cleared by engineering showings, shielding, relocating dish slightly.
          3. Once all interference cases are cleared, you can apply for an FCC license on Form 493. Do it yourself or Comsearch will also prepare license applications for $375 per site.
          4. Expect to pay $228 per year ($19 per month) for protection service in which Comsearch goes to bat for you when threats or actual interference to your reception occur.  This price is for one site. Volume discounts are offered for group owners.
          5. Any on-site work requiring travel or test equipment will be quoted separately.
        3. Coordination and FCC licensing protect only against legally licensed sources of interference on the satellite frequencies you specify.
          1. Illegal pirate transmitters and military installations may not comply with FCC civilian regulations.
          2. Strong transmissions on frequencies outside of the band you specified may cause interference in spite of careful frequency coordination.
          3. Comsearch can locate such interference sources which can help you to file an FCC interference complaint.
      4. Artificial shielding
        1. Walls, fences (with a fine metal screen attached), or buildings may be used to block interference from specific directions.
        2. Dawn Satellite sells a book, "Use of Artificial Shielding."
        3. Filters
          1. If you can't relocate the satellite dish site, bandpass filters may work to reduce interference. Caution: Filters may also hurt the desired satellite signals.
          2. If interference is from a source that is outside the satellite band, but its strong levels are overwhelming your LNB or satellite receiver, consider a C-band bandpass filter, which fits between the feed element of the antenna and the LNB. About $550. Good for eliminating airport radar or radio-altimeters.
          3. If interference is within the C band, but not at the same frequency as the signal you wish to receive, try a tunable L-band notch filter (about $250 for a single notch; about $450 for a dual notch).
          4. If you want to limit reception to a single transponder of interest, and eliminate all other signals, a tunable L-band bandpass filter (about $500) would be useful.  (Ask the vendor if you can get return privileges and a refund if the filter doesn’t work in your case.)
    3. Advantages / disadvantages of roof locations
      1. Advantage- may be at the studio location.
      2. Disadvantage- terrestrial interference is greater and harder to avoid on roofs.
      3. Disadvantage- may have difficulty getting roof rights from landlord.
      4. Disadvantage- may have difficulty securely anchoring the dish.
      5. Disadvantage- roof mounting jobs often cost more than the dish and receiver themselves.
    4. Advantages / disadvantages of ground locations
      1. Advantage- may be at the transmitter site, which you may own.
      2. Advantage- if at the transmitter site, may be away from terrestrial interference.
      3. Advantage- can pour concrete slab and have sturdy installation.
      4. Disadvantage- if not at the studio, getting audio and cueing contact closures back to the studio adds expense and unreliability.
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