Largest GMRS Base Station Antenna Avalible?

[badspell68]

I'm setting up an 50W Base Station, mounding antenna 15 to 20 feet on roof top. Are there large Base-Station antennas that can be roof mounted and what are the largest types for maximum transmission/reception?

 

Thanks all!

[marcspaz]

Exactly what I thought...Thanks! Going with the Diamond x300 off of amazon.

 

Could you suggest a crimping tool and quality connectors?

 

Are you running hard line or LMR400?

[tweiss3]

Exactly what I thought...Thanks! Going with the Diamond x300 off of amazon.

 

Could you suggest a crimping tool and quality connectors?

For LMR400, I use the DX Engineering crimp tool, prep tool and their crimp connectors.

Connectors DXE-PL259CS8U-# (quantity)

Crimp tool DXE-UT-CRIMP2

Prep DXE-UT-405C-P2

[badspell68]

I'll be running 400 ultra flex

[marcspaz]

I won't use crimp connectors on soft line.  I would buy any major brand silver teflon screw on PL-259 Male UHF connector.  HRO, DXE, DAS are all good. They thread over the outer housing.  You fold the ground braid down, around the outer housing, screw the connector all the way down, drop a bead of solder on the ground braid through the access hole and solder the tip.  Its super strong and you won't have to worry about a poor ground connection.

 

Edit... Most of the time, the layers are thin enough to cook off while soldering, but sometimes you need to use a file to clear some of the silver teflon off a small area for the solder to take. 

[jec6613]

I won't use crimp connectors on soft line.  I would buy any major brand silver teflon screw on PL-259 Male UHF connector.  HRO, DXE, DAS are all good. They thread over the outer housing.  You fold the ground braid down, around the outer housing, screw the connector all the way down, drop a bead of solder on the ground braid through the access hole and solder the tip.  Its super strong and you won't have to worry about a poor ground connection.

 

Edit... Most of the time, the layers are thin enough to cook off while soldering, but sometimes you need to use a file to clear some of the silver teflon off a small area for the solder to take. 

 

Just FYI, TMS recommends crimp-on connectors over soldered for UHF, as they provide higher consistency than a soldered joint and better waterproofing.  Then again, their connectors are $15-$20, and the tooling to put them on is similarly expensive.  On UHF with PL-259, especially low power like GMRS, it tends to be more sensitive than VHF or HF.

 

(Also one big reason I use N connectors when possible).

[marcspaz]

Just FYI, TMS recommends crimp-on connectors over soldered for UHF, as they provide higher consistency than a soldered joint and better waterproofing.  Then again, their connectors are $15-$20, and the tooling to put them on is similarly expensive.  On UHF with PL-259, especially low power like GMRS, it tends to be more sensitive than VHF or HF.

 

(Also one big reason I use N connectors when possible).

 

The connectors I use are screw on.  The bead of solder on the ground is to help prevent the connector from backing or pulling off... not an electrical ground.  The screw on type has a full 360 shield with perfect pressure application all the way around.  I haven't used a true solder on connector since 1988 or 1989.

 

N type is really the best way to go.  Worth the few extra bucks, all day.

[badspell68]

Perfect!

 

What connector then would I use from the antenna, it has one of the standard connectors? What "N" would you recommend (brand) for the rest of the wire and to the radio that also has one of the standard connectors?

[marcspaz]

For N type, I like CXP and ABR.  There are not a lot of high-end brands, but these mid-range brands are great performers at a fraction of the price.  You will get 20 years out of them if you set it up correctly.

[badspell68]

Could you recommend a purchase source?

[marcspaz]

For personal Ham radio and low-budget pro, DX Engineering and Ham Radio Outlet are the two resellers I use the most for miscellaneous supplies. 

 

I stay away from the pro/commercial distributors unless I am working a contract for a customer.  Commercial distributors typically have really high single item prices or won't sell at all unless you are a reseller buying in bulk.  Like, half a tractor trailer, minimum, kind of bulk. 

[dwmitchell61]

"as well" as well as witch antenna?  The Comet 712EFC will work on gmrs as a base?

Yes, the Comet 712EFC will work for base operation. I bought one.

 

I am now shopping around for a mast solution. I am considering Max Gain systems MK-8-HD push-up fiberglass mast with appropriate guying lines. I am mounting multiple antennas (scanner, Par EndFedz-SWL sloper for HF listening, etc)

[dwmitchell61]

Omni-Gain Vertical Collinear Antenna by WA6SVT

 

I am also going to build one of these and see how it performs. I have some RG-8X laying round.

 

It seems a lot of the commercial antennas sold use this inside the fiberglass "radome".

[badspell68]

For a mast I picked up 4 galvanized 10' "horizontal" steel fence pools from Lowe's, they are slotted so all will insert into each other, $10 each. Doing a 40' pole bolted to the side of the house.

[marcspaz]

For a mast I picked up 4 galvanized 10' "horizontal" steel fence pools from Lowe's, they are slotted so all will insert into each other, $10 each. Doing a 40' pole bolted to the side of the house.

 

 

That is a very bad idea. Your antenna is at risk on its own, but now you are building a giant lightning rod. Also, its heavy.

 

All of my masts or fiberglass.

[jec6613]

 

That is a very bad idea. Your antenna is at risk on its own, but now you are building a giant lightning rod. Also, its heavy.

 

All of my masts or fiberglass.

 

Ugh, fiberglass or steel, it's still a lightning rod with a grounded conductor at the top.  Steel will just last much longer and is less prone to catastrophic failure, but fiberglass is easier to work with and lighter.

 

http://www.arrl.org/lightning-protection

[marcspaz]

LOL... I know the feeling.  I mean, if you are going to do a proper mast with full lightning arrestors, properly bolted and very deep grounding rods and lines, etc, then that would be a different story.  Otherwise, you're risking burning the house down.

 

At my house, not only is everything fiberglass with grounding and arrestors on the line, between the mast and house the transmission line is buried underground about 3 feet deep and over 50 feet.  If I take a direct hit, I'm likely still screwed, but close-by and partials will be 100% fine.

 

Here on this forum, there are some great discussions and several links about commercial grade grounding at home. 

[badspell68]

Did not know. Where does one get a fiberglass mast?

[marcspaz]

Did not know. Where does one get a fiberglass mast?

 

Many Amateur Radio suppliers sell them. The best two that I have used are the MFJ-1908HD and the MFJ-1906HD.

[badspell68]

Received this message from another ham...what do you guys think?

 

"Metal mast is fine, its not much different than the antenna and its coax running down an insulated mast. You might want to check into grounding per the National Electrical Code, do a search on NEC article 810 which is specific for antennas."

[tweiss3]

At a minimum, you need to meet NEc for grounding, including ground the mast/tower and ground the coax entry.

[marcspaz]

As mentioned previously (and noted above by Tom)... metal is fine, but requires much more (proper) grounding and lightning protection.  You are significantly increasing your risk of a strike.

[axorlov]

Cmon, lightning rods do not attract lightning.

[BoxCar]

Cmon, lightning rods do not attract lightning.

Depends on your definition of attract. By raising the ground potential to a higher point than surrounding possible paths and providing a path with lower resistance a lightening rod provides a more likely path than any other path within the immediate area.

[mbrun]

Here is an interesting article on Antennas and Lightning.

 

https://eos.org/research-spotlights/antenna-towers-attract-additional-lightning-strikes

 

From what I have read thus far, it seems that higher something is in the area, the more frequently the area surrounding the high object will be hit compared to areas further way.

 

Michael

WRHS965

[axorlov]

We are talking about 20' mast on top of 20' roof, not the Empire State Building, and not even a cell tower. Naaww, I do not believe 40' grounded mast changes charge field enough to truly attract lightning from the clouds. However, if lightning strikes in close proximity of said rod, the charge will likely to go through the rod, and not through the porch and your cat on that porch.