Antenna and Coax help

[learfixer]

Hello! I am new to GMRS and I am looking to put up an antenna behind my house. I have a pole and a tree that I can use, but both are about 150 feet from the house. Both are about 30 feet tall. I am estimating I need about 200 feet of cable to connect to an antenna and run into my house. I was thinking about a GP-1 or GP-3 antenna. I am confused about what coax I need to use. Any suggestions would be greatly appreciated. Thanks! 

[gortex2]

If your really talking 200' you want hardline. I would use 7/8" LDF for that distance if you want any favorable results. You may be much better putting an antenna on the house and shorten less than 50' then use LMR400.

[WRAK968]

If your really talking 200' you want hardline. I would use 7/8" LDF for that distance if you want any favorable results. You may be much better putting an antenna on the house and shorten less than 50' then use LMR400.

I agree with this, you're likely to get about 20' up for a one story house, and nearly 30-35' for a two story house which would save you a ton of purchasing feedline to reach a remote pole or tree. You can go the route of the pole, though the question would be how difficult it is to get the antenna mounted if it doesn't fold over. As for a tree, I know of people who use permanent antennas in them, however you should weigh the risks which include branches breaking and damaging the antenna and feedline. Usually a wire antenna is used in such applications as a temporary antenna.

[learfixer]

Thanks for the feedback. I can't mount one on my house because of restrictions. The pole and the tree are on property behind my house and both would be hid from the neighborhood. I have thought about mounting one in my attic, but I like the idea of it being outside and up higher. As for mounting it, I have access to a bucket truck so there is no issue getting up the pole or the tree.

[Lscott]

Have you considered a ground mounted push-up mast? If you don’t use the radio often you leave it down when not operating.

 

https://mfjenterprises.com/products/mfj-1906hd

[WRAK968]

Thanks for the feedback. I can't mount one on my house because of restrictions. The pole and the tree are on property behind my house and both would be hid from the neighborhood. I have thought about mounting one in my attic, but I like the idea of it being outside and up higher. As for mounting it, I have access to a bucket truck so there is no issue getting up the pole or the tree.

LScott has a good point about push up masts. There is also the ghost antenna option. This would likely require you to build your antenna, (Or hire a ham to make one for you) Ghost antennas use thin wire which can be run along a roof line getting your signal outside of the house without neighbors seeing them. The nice part is that they do not have to be in a straight line. This is the go-to antenna for hams living in HOA's or rental property's.

 

If you have no choice but to use the pole, you'll have a fair bit of work (and expenses) ahead. I would recommend running a 1.5-2" PVC conduit from your house to the base of the pole and up about a foot or so above grade. Use long sweeping elbows as hard-line can be difficult to bend in a run. I would separate the feed-line into three sections, radio to conduit, conduit run, then conduit to the antenna. At each end of the conduit place a good size weatherproof box where you can make your connections. For the feed line going up the pole, add a small drip loop and bring the feed-line in from under the box. This will better protect the expensive feed-line from damage due to water or from being crushed or struck from persons digging in the yard. At the box going into the house, consider installing a ground wire or rod and a lightning arrester. This will protect from near strikes from lightning, and will also dissipate static charge caused from wind, rain, and snow.

 

Finally, given the length of the run, be sure to use "N" type connections wherever possible. PL259/SO239 connectors tend to have signal loss on frequency's over 300MHz.

[mbrun]

A agree with keeping the coax as short as practical. The longer the run the higher the performance of the coax you will need.

 

Here is a picture of me within the last 30 days having my own field day with the push-up mast for my home. Antenna is 56’ in the air.

From a step ladder the antenna can be raised to full height and the coax secured to the mast in just a few minutes. It can be lowered in the same same amount of time.

 

 

The mast will soon move to its permanent home immediately next to the house where it will secured and guyed. I was amazed how plumb this unit remained at full extension, even without guys.

 

Here is the unit I am using. https://www.dxengineering.com/parts/dxe-tfk46-hd

 

 

Michael

WRHS965

KE8PLM

[learfixer]

Thanks for the ideas and suggestions. You guys helped me with a few things I did not think of. I will probably go with the pole because it is already there and that will save me a little money. Thanks WRAK968 for the suggestions of using junction boxes. That will help me greatly. The money I save by not having to buy a pole and put it up can be used to buy the needed coax. I do like the portable pole, but I want this to be a permanent fixture. I'll try to remember and post pictures of the process once I start putting this together.

[PRadio]

Thanks for the ideas and suggestions. You guys helped me with a few things I did not think of. I will probably go with the pole because it is already there and that will save me a little money. Thanks WRAK968 for the suggestions of using junction boxes. That will help me greatly. The money I save by not having to buy a pole and put it up can be used to buy the needed coax. I do like the portable pole, but I want this to be a permanent fixture. I'll try to remember and post pictures of the process once I start putting this together.

 

Hardline will be about $1.80 per foot for 1/2 inch, and $2.39 for 7/8 inch, so I doubt you will be saving much. 

[learfixer]

I think you misunderstood what I said. I know I am not saving any money. What I said is by not having to pay for a pole, that money will be put towards the coax.

[uhfvhf500]

Hey Michael, 

Thanks for posting the pic of your telescopic mast ! I have been considering that same DXE model for use at my station.

The mast is straight while holding the weight of the antenna and coax ! says alot for it's rigiddity , and thats without guy lines, very nice !

-Rich

[smokechaser75]

I went to Home Depot and bought a painters stick made of fiberglass used for painting in high places and it is collapsible have it up at about thirty feet holding my j-pole