|Joined:||Sat, Apr 4th 1998, 00:00||Roles:||N/A||Moderates:||N/A|
|Antenna Modeling for Beginners||Feb 8th, 18:19||3||948||on 14/2/13|
|Roller Inductor Tuner||Dec 20th 2011, 19:26||1||899||on 20/12/11|
|Using Ladder Line||Jul 27th 2011, 19:43||3||1,676||on 29/7/11|
|Weather protection for uhf connector||NT2F||1 week, 1 day ago|
|It is a good idea (and required by the National Electrical Code) to keep the coax shield connected to ground at all times. You should also have an antenna surge suppressor on the coax as well. If you have your station grounded correctly and use antenna surge suppressors it is not necessary to disconnect your antennas. In fact you loose some protection from lightning if you disconnect your antenna.
A common method is to mount the surge suppressor in a weatherproof box just outside the entrance to your house. Connect a ground rod to the surge suppressor (which also grounds the coax). Don't forget that all external grounds need to be connected to your house electrical ground.
|Push on BNC Connector||kd4gcf||1 week, 1 day ago|
|Not sure what you have as all BNC connectors are "twist lock". However a male "N" connector will push on to a "BNC" female connector. You might have a "TNC" connector as they are very similar to a "BNC" but the male and female screw together.
|Inline Lightening Arrestors||KC8UGV||on 9/10/13|
|Actually "bleeding off" is really equalizing the charge. This is why you ground the coax braid just before it enters your shack. This is also why you should use DC grounded antennas. DC grounded antennas will show a short between the center conductor and the outer shield. You should also ground the metal mast or tower supporting the antenna. And last be sure that ALL grounds are connected together at some common point (usually the house electrical system ground).
|2m/70cm mobile antenna to clamp on roof rail||N1IEC||on 2/10/13|
|It would depend on how far above the roof is the actual mount. Like any antenna that is not mounted in the center of the roof it may need to be adjusted to provide an acceptable match. The radiation pattern will also be skewed to one side. Depending on your particular installation it may difficult to detect if or how much it affects the radiation pattern.
|Fiberglass vs metal for mast material||KB9MDQ||on 29/7/13|
|The antenna performance shouldn't change as the mast and tower provides little or no effect on the ground plane. However from a "grounding" stand point you need to ground the top vertical antenna to the tower. In the commercial world we would NEVER use an insulating material for a mast. In some instances we would run a separate ground wire from the antenna mounting clamps down the tower to a ground ring buried around the tower. This provides additional lightning protection. Also be sure you follow the NEC guidelines by grounding the shield of any coax entering the building.
If you were extending the point at which you mounted the OCF dipole with an insulating mast you would be Ok as dipoles do not use a ground for their operation and can perform better if they are not near the metal supporting mast. That is why you see most tower mounted dipoles hung from an insulated outrigger arm to get it away from the tower.