KB9VBR Slim Jim GMRS Antenna versus Ed Fong DBJ-UHF GMRS Antenna

[WRPG745]

nice build!

[DominoDog]

I picked up one of the N9TAX single band slim jims for GMRS, it seems to do really well. I would say it probably performs at a similar level to the ones reviewed here.

[WSEN982]

Anyone try out either the Hyshikra FB17UV (1.7 meters length) or the FB22uV (2.2 meters length)  base station GMRS antennas? I really would like to get at least 7-8db gain. These claim that. Amazon.

[SteveShannon]

24 minutes ago, WSEN982 said:

Anyone try out either the Hyshikra FB17UV (1.7 meters length) or the FB22uV (2.2 meters length)  base station GMRS antennas? I really would like to get at least 7-8db gain. These claim that. Amazon.

I haven’t, but is that gain dBi or dBd?

 

[WSEN982]

that'd be dbi - thanks for catching.

[WSEN982]

Also, just read this on digi.com. Any comments to this?

"Also note that antennas with higher gain focus the energy over a smaller area. Digi recommends avoiding the highest gain antennas in most applications because they are more difficult to work with.
Recommended antenna gains:

• Omnidirectional: 3 dBi to 6 dBi
• Directional: 8 dBi to 11 dBi
  Note: High gain antennas are of limited use in extending the range in a non-Line-of-Sight (non-LOS) environment. In a non-LOS environment the obstructions contribute more losses to the system than the antennas are able to overcome. Also, the obstructions cause the signals to bounce and arrive at the antenna from different angles so it is desirable to have an antenna with a wide beam width and a lower gain.

[SteveShannon]

4 minutes ago, WSEN982 said:

that'd be dbi - thanks for catching.

What Digi said is exactly right. Gain in one direction is stolen from somewhere else. 
What are you using the antenna for?  Do you expect to turn it to point in a particular direction, such as pointing it at different stations? Or do you want to just receive every station in a circle around you? Wil they all be at the same level as you or will some be higher and some lower?

Personally I’m satisfied with a 6 dBi gain antenna on my roof. The repeater that’s 3000 ft higher is still easy to reach. 

 

[Frdbronco8]

Thanks for the thorough review. I would love to see someone with your knowledge and equipment compare this $25 amazon antenna to the Ed Fong as well. I put up an Ed Fong (GMRS) and was having some issues so I ordered one of these to help trouble shoot. My problem ended up being a connection not related to the antenna but I did back to back comparisons from a mobile unit at my house (antenna in the attic) between the two antennas and the Amazon antenna seemed to work better on simplex talking to a HT a few miles away. Both work fine on my local repeater. Might be due to the lower gain in my hilly tree filled area?  Curious if anyone else had tried it. 

 

https://www.amazon.com/Fiberglass-400-470mhz-Connector-Repeater-Transceiver/dp/B08TWN78MM/ref=sr_1_1_sspa?crid=2KCREX3K8TGKZ&dib=eyJ2IjoiMSJ9.UdX0qOdqj1XnPHqy7flXAdCzfdv7AzdHKB-cPWlByVWWCE_awFMGgJmN-hZRq758_LGcdK9QM13Ldl404Q_e18KSRZ9JDdss5jnwBUhTNMsMiYn51h7D3-lvevl8vvVSxwt1SPFX7Q_n7eCLKcIjfosSZLiuqditX53kmVCf1hYhlMyQ9Il6pVDBojVYjTWHi94J6AIsWZKO7rRPSSj5xkydlxUMZhLqC4p9mHFhZB8.MSAUAn6Lt8yY_AbuYJyv56SvHPfuGgrnyoLxuZV0XyU&dib_tag=se&keywords=gmrs+antenna&qid=1735455855&sprefix=gmrs+ante%2Caps%2C212&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

[SteveShannon]

4 hours ago, Frdbronco8 said:

Thanks for the thorough review. I would love to see someone with your knowledge and equipment compare this $25 amazon antenna to the Ed Fong as well. I put up an Ed Fong (GMRS) and was having some issues so I ordered one of these to help trouble shoot. My problem ended up being a connection not related to the antenna but I did back to back comparisons from a mobile unit at my house (antenna in the attic) between the two antennas and the Amazon antenna seemed to work better on simplex talking to a HT a few miles away. Both work fine on my local repeater. Might be due to the lower gain in my hilly tree filled area?  Curious if anyone else had tried it. 

 

https://www.amazon.com/Fiberglass-400-470mhz-Connector-Repeater-Transceiver/dp/B08TWN78MM/ref=sr_1_1_sspa?crid=2KCREX3K8TGKZ&dib=eyJ2IjoiMSJ9.UdX0qOdqj1XnPHqy7flXAdCzfdv7AzdHKB-cPWlByVWWCE_awFMGgJmN-hZRq758_LGcdK9QM13Ldl404Q_e18KSRZ9JDdss5jnwBUhTNMsMiYn51h7D3-lvevl8vvVSxwt1SPFX7Q_n7eCLKcIjfosSZLiuqditX53kmVCf1hYhlMyQ9Il6pVDBojVYjTWHi94J6AIsWZKO7rRPSSj5xkydlxUMZhLqC4p9mHFhZB8.MSAUAn6Lt8yY_AbuYJyv56SvHPfuGgrnyoLxuZV0XyU&dib_tag=se&keywords=gmrs+antenna&qid=1735455855&sprefix=gmrs+ante%2Caps%2C212&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

Although I don’t have one, I would offer this advice.  Waterproof the connection and have extra cable.  The antenna appears to have a weirdly short UHF connector, rather than an N connector, and it’s not recessed as it would be in many professional designs.  Thus, all water that runs down the body of the antenna will eventually end up at the UHF connector. Unless sealed it will eventually permeate the end of cable. Once moisture gets into the dielectric between the center conductor and the shield, you’ll need to replace the last several feet of coax and re-terminate it and then seal it.

Other than that I know nothing about the antenna and the specs reveal nothing.  It’s a piece of wire in a fiberglass radome (tube).  The only things that matter are does it work for your particular situation and how long will it last? The answer to the first appears to be yes.  You seem satisfied. As long as the fiberglass holds up against UV and the metal doesn’t corrode and the cable doesn’t fail due to moisture permeation, you might get years of satisfaction.

 

[WRUE951]

i have both versions of the J-Pole, both home brew and favor the Copper J-Pole over the Twin Wire J-Pole..   I use the copper j-pole for a portable repeater while camping.  Getting the SWR's to perfection on the Copper J-Pole is a major PITA so i came up with  a method for adjustability (see pics).  Not shown in the attached picture, i had to grind down 1/2 inch on one side on each of the adjusters.  The adjusters are made from a modified crimp on copper splice (Home Depot) and removing the internal rubber gaskets, cutting the splice in half then tapping for the set screws.  It works great, i'm able to get 1:2 - 1:3 on my repeater channels (18)...  The Copper J-Pole has talked roughly 90 miles, I've gotten about 60 with the Twin Lead version..  Both better than my home Base Laird FG-4607 and i can't figure out why on that one..   

[AdmiralCochrane]

Slick!