Quote:
Originally Posted by
jefbal99 
Damn, all of last weeks posts are gone....
Antennaman, if you can recreate your antenna post, i'd love to add it to the first post of the thread.
Also, I've completed all of the updates to the first post (i think). I'll be updating it on thursday after the planned D* reorg and expansion.
A proper installation of any omni-directional or directional antenna should utilize the following guidelines:
Height is everything. I normally install all antennas at least 10’-12’ above the highest roof line. 30’, 40’ & 50’ towers are great. I have put “saucers” or directionals on 30’ yard light poles and old wind mills.
Always try to position the antenna so that trees, buildings and other obstructions are out of line with the signals you are trying to receive.
Keep the coax run as short as possible. Only use RG-6u as opposed to RG-59u. In the distribution primer you will see why this is important given the losses involved at high UHF freqs up to 750Mhz. Coax should be secured every 24”-36” with proper fastening devices. I use tape or ty-wraps down the TV antenna mast or tower and 360 style clamps with a ¼”head using a cordless drill to install. I never use a clamp that has to be installed with a hammer—if you miss, the coax gets flattened, digital does not like coax that is flattened or bent in an acute angle—smooth bends in the coax only.
Use high quality one piece F-connectors (compression type) with good mechanical specs at high freqs and under digital conditions. If you cannot properly apply a good F-fitting, buy cables with good fittings already attached—this means every fitting in the network—one cheap jumper with push on connectors or bad integrity will drive you crazy. Many jumpers that come with the DTV converters VCR’s and other devices have push on connectors and are of very poor quality. I never use a push connector and every F-fitting should be tightened with a 7/16th wrench---if torqued properly, you should not be able to remove F-connecter with your fingers. You must be very careful tightening connectors on devices like the TV, VCR, DVD player, DTV converter as the F-81 connector on the device may turn if too much pressure is applied and the internal connector may break—finger tight, then a little torque with the wrench. Remember, digital signals do not like loose connectors!
Digital signals also do not like water or moisture. Every connection and device outside or in wet areas need to be impervious to water—completely water-proofed and sealed. If you are using 300ohm to 75 ohm matching transformers, splices, grounding blocks or pre=amps, make sure no moisture can compromise the connection or the device outside. I use a special pliable putty type sealer on every connector that 100% covers the whole connector. There are weather boots and other sealers that may work well also.
All outdoor antenna installations should be grounded (does not affect the signal integrity, but is code & might help save a device or protect from fire or electrocution) I always install a coated #10 copper grounding wire to the antenna mast, tower or tripod and bond it to the electrical mast, grounding wire or electrode. I also install a ground-block (F-81 with mounting holes & grounding lug) to ground the coax shield, this should be done at the lowest possible point before the coax enters the building.
Keep splits to a minimum. Only use a splitter that feeds the quantity of devices you are actively sending signal to. Use good quality splitters with an upper band-pass of 1Ghz (1000Mhz) If you are feeding two TVs, use a 2-way splitter, 3 TVs, a 3 way splitter etc. Un-terminated splitter ports can cause reflections that can disrupt digital signals. If you do have an open port, install a 75ohm terminator until you can replace the splitter. Make sure you keep your distribution network balanced. All cables should be home run to a central point and managed from one location if possible. If you have un-active cables in the building, mark them and only install them when they need to become active and terminated with a device like a TV.
If you are hooking your antenna lead to an existing network, try to inspect every inch of this network to make sure it has not been compromised with bad connections, unwanted splits or 300ohm flat lead.
If installing a pre-amp or post amp, make sure the power supply is installed in an area that is easy to get at. If installing a pre-amp, the power supply & power inserter should be installed before any splits, if this is not possible, a special splitter is necessary to pass power only to the antenna in port. I normally only use pre-amps when necessary to overcome the distribution losses and only use a pre-amp to overcome the cable & splitter loss and add a little additional gain for fringe signals. Remember, once you lose the digital info (the 1’s & 0’s) you cannot regain them---amplify early, overcome all combined losses to worst case leg of network.
Once you get to a device, utilize best interface with TV or between devices---HDMI, S-Video, Baseband cables etc. keep these interface cables short as possible, but leave enough slack to move and maintain equipment easily.
If installing a “saucer” antenna, optimize the signal on marginal channels by rotating the antenna until the desired channels are stable (most digital TVs or DTV converters have a simple signal meter feature) two people, two cell phones or FMRS radios make the job easier—one on roof, one at TV charting results. Note: there are also “saucer” antennas with a built-in rotor that has excellent gain and back side rejection—I use on for my primary digital TV.
Summary:
Get antenna as high as possible
Keep trees, buildings out of path between transmitter and antenna if possible
Use best antenna you can afford & best cables & passive devices-digital certified
Directional antenna with rotor with gain is best
Use pre-amp if necessary to overcome network losses
Keep moisture out of network
Tighten all connectors
Remember, most signals are or will be at Ultra High Frequencies and the distribution network cables and passive devices have very high insertion losses!---Digital info---once lost, it’s gone.
Migrate from RF to best available interface at each device whenever possible (TV, VCR, DVR, DVD, etc.)
Make diagram of your network for future reference.
Mike
