Outdoor Antenna - Think Spring

[fuzzymoto]

OK so I know it's still January and I won't be able to even see my roof for another 6 weeks but I thought I'd start planning out an outdoor antenna. I'm pretty sure it will make my reception even better and of course lately there are a few things I'd like to hear a little better. ( I was listening to a good fire call and they switched to their fireground (no repeater) channel and faded out on me).


As I started to plan out the setup I ran into a few questions and also realized some of the complexities involved here. The basic setup I'll do is on the side wall of my house near the highest point of my house, just below the peak of the roof (I do NOT want to mess with shingles). This gets me up to the highest point on my house and still allows me easy access from the lower roof and easy cable access through a ridge vent. My antenna for now is a 20-176 with a PL-259 to F-type adapter.

Setup:
(2) 12-inch wall mount brackets
(1) 1.25-inch 10-foot mast
(1) F-type patch cable 8-feet RG-6
(1) F-type Grounding Block attached to ridge wall
(1) Grounding Rod
(3) Copper grounding brackets (1 for mast, 2 for rod)
(1) Roll Grounding wire
(1) Roll Coax Seal Tape

I plan to use this grounding setup:
http://www.videocommtech.com/uploaded_files/pdf_archive/SafeAnt.pdf

Questions:

-Should I isolate the antenna U-Bolt from the mast with tape or something else so it is not making metal to metal contact with the antenna base?

-Doesn't adding a grounding block and the patch cable increase the loss in my signal (more connectors to lose signal)?

-My two grounding wires will follow the same path to the grouding rod. Should they/can they touch on the way down to the rod or be seperate somehow?

- Am I missing anything on my shopping list?

-I see Radio Shack carries much of this stuff, but of course their prices aren't great since they are labeling a piece of pipe an "antenna mast" and raising the price. Any other good sources for some of this stuff? I suspect Lowes/Home Depot have pipe, but which pipe shoudl I use? I suspect they also have wire, but which wire specifically should I use for grounding? Same for the grounding rod and clamps??

-I have a grounding block that came with my former sattelite system. I believe it is low-loss because all of their cable setup was. It this OK to use for my grounding block?


I believe once all the parts are collected it won't be a very difficult install. I'm not going very high and I don't need guy wires. MY MAIN CONCERN with all of this is all of the cables and connectors necessary to get to my scanner.

Currently: Antenna > PL-259/F Adapter > 50-foot RG-6 cable > F/BNC Adapter > BNC/SMA Adapter > Scanner (Still trying to get a 90-degree in at the scanner end)

After: Antenna > PL-259/F Adapter > RG-6 Patch cable > Grounding Block > 50-foot RG-6 cable > F/BNC Adapter > BNC/SMA Adapter > Scanner (Still trying to get a 90-degree in at the scanner end)

Am I being overly concerned about all of the connections/adapters causing loss or will getting up higher and outside make enough difference that it won't matter? If not, how can I do this better to miniimize loss without leaving out the grounding block and risking lightning/static (or is the coax ground purely for static??)?

Can't wait to hear what my reception will be like outside, up higher and out from under a snow covered roof. Thanks in advance and Think Spring!

 

[mgosdin]

Fuzzy, I will try to answer some of your very good questions.

A 10' mast from Radio Shack costs $15.99, same type of pipe sold as a chain link fence top rail cost $8.49 at Lowes. The main difference is that the Radio Shack mast is painted grey, the fence rail is galvanized.

F-type grounding block, I used 10 guage copper grounding wire with mine ( Lowes ) and my masts are grounded with 6 guage copper grounding wire ( Lowes again ). Yes the block will cost you some signal, but you will gain more by having the 20-176 out of the attic and up in the air.

50' of RG6 already in place, this is OK but is their any excess? If you've got some coiled up in the attic or the house after you put your Mast up you may want to look at removing some of the line. On the other hand, it doesn't cost much in terms of lost signal per foot with RG6, so you may not want to fool with cutting off any excess.

F-type to SMA right angle adapter. This is a hard one, I made up a short cable out of RG6 that has an male F-type on one end and a right angle male BNC on the other.

This works good with my BC246T. I don't see any noticable loss in signal versus using a regular F-BNC adapter. It might be possible to create a F to SMA cable if the correct type of SMA connector could be found.

Mark Gosdin

 

[fuzzymoto]

Thanks. Great answers. No there is really no slack in the 50-feet. In fact the more I look the more I realize the patch cable to get me to the grounding block may be necessary just to reach the antenna since I believe the 50-foot RG-6 will come up short. I will check out Lowes for the grounding wires and mast (chain link fence top rail). I know the U-Bolt on the 20-176 is small so I want to be sure it will fit on even a 1.25" mast. I'll have to measure for that since it is not on the RShack web site...but I'm pretty sure it will fit.

I like your solution for the 90-degree. Perhaps I can find a 90-degree SMA to F-type Male patch--but more likely I'll go with the BNC to F-type Male (HOPEFULLY I CAN FIND ONE!) I was concerned about using the female-female F-type. I have ordered a BNC 90 also which I will test. Perhaps that will get me my 90 without much loss. In any case with a patch cable or adapters I'm still at 3 connectors so I will test mu BNC 90 while seeking out a patch cable.

I know there is much debate on here about adapter/connection loss. I do want to minimize that without getting too crazy about it (please do not restart the connector loss debate).


Anyone know if I should isolate the antenna U-Bolt on the base of the antenna from touching the metal of the mast or if my grounding wires can or cannot touch???

 

[KC4ZEX]

For adaptors try Pasternack Enterprises. www.pasternack.com Do not isolate the antenna base from the pipe that is where you get the ground plane to ground connection. The base and ground radials need to be grounded. Only the vertical element is isolated by the insulator in the base. The grounding block is really not necessary you can attach the ground wire at the clamp where you attach the pipe to the wall mount .

 

[tspainiv]

My antenna is up using a fence rail top post. Alot cheaper and heafty piece of pipe. I use RG-6 at about 75-80 ft with a regular sat cable grounding block. with 8 guage copper ground wire. The tower is grounded with 6 guage solid copper wire. There is a f connector at the antenna, two at the grounding block and one at the end with a bnc adapter and I don't think my reception could be better!

Good luck!

 

[fuzzymoto]

Thanks. I have a feeling my existing coax won't reach all the way so the grounding block is probably IN just so I can get another 10-foot patch of RG-6 easily up to my antenna. I'll check on pasternack further but they don't seem to have the connectors I'll need.

 

[Al42]

The grounding block is really not necessary you can attach the ground wire at the clamp where you attach the pipe to the wall mount .

The grounding block is necessary to bleed off static charge.

Doesn't adding a grounding block and the patch cable increase the loss in my signal (more connectors to lose signal)?

Normally it should give you less than 0.1db loss. If it flashes over (protecting the scanner from a large static charge), the loss will be almost infinite (it'll be shorted) - but it's a work-once-and-throw-away device anyway.

I have a grounding block that came with my former sattelite system. I believe it is low-loss because all of their cable setup was. It this OK to use for my grounding block?

If you don't need it for the satellite system, it's not shorted from flashover and the connectors are the right ones, sure.

Am I being overly concerned about all of the connections/adapters causing loss

If you're using quality connectors and adapters, yes. At most you're using about 10 connection interfaces - that should give you something under half a db loss.

Can't wait to hear what my reception will be like outside, up higher and out from under a snow covered roof.

With the same cable? Probably not too much difference, except for transmitters that are just under your horizon now, and will be just above it with the higher antenna.

 

[fuzzymoto]

Thank you. I do plan to do a mast and cable ground. Honestly my current coax wil l not reach another 10 feet to the antenna so adding a grounding block and patch cable is a must. It's a simple enough move to get the antenna outside that I have to try. Plus it sets me up for a different antenna in the future if I want to upgrade (everything will work with a new antenna). It is nice to hear a voice of reason instead of the doom and gloom signal loss per connector stuff. I understand there is loss. I just don't want to get so crazy about it that it is no longer fun. If one more connector makes me lose some signal I want to hear then it is certainly worth it BUT I doubt that will happen in my situation. I'm trying to minimize connections and use good cable. Beyond that I'm not sure what else I can do given my existing coax cable. Maybe some day I'll put in the perfect antenna on the perfect mast with the perfect cable and the perfect connectors and minimize that 1db loss. For now I'm just trying to have fun and hear the most stuff I can possibly hear without getting too crazy about how I get my antenna connected to my scanner or how much db is leaking out. Thanks again.