KB9VBR jpole antennas

[WRQK522]

I’m thinking about getting a j pole tuned for GMRS from KB9VBR . It’s for base station has anyone have experience with this antenna? Trying to get the best range I can here in southeast Ohio. Trees and hills cover most of land . I’m at a high level I get around 8 miles maybe a little more in the winter.

 

 

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[KAF6045]

8 miles is close to radio horizon unless you can mount the antenna really high.

Radio horizon for an antenna at 30 feet is 7 miles.

[WRQK522]

I can’t go that high . The only thing is base is higher up than the places I’m trying to transmit to. Once I can reach my max distance I’m going to set up a portable repeater. That’s to reach where my brother’s home is . He lives at the bottom of a hill that’s between us so I will set one up on the ridge above his house . I just wanted to see how good the jpole would be . Now I’m using a Mobile antenna and ground plane.


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[MarkInTampa]

8 hours ago, WRQK522 said:

 

I’m thinking about getting a j pole tuned for GMRS from KB9VBR . It’s for base station has anyone have experience with this antenna? Trying to get the best range I can here in southeast Ohio. Trees and hills cover most of land . I’m at a high level I get around 8 miles maybe a little more in the winter.

 

 

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I've got one. It's a solidly built antenna but hardly use it. SWR is kinda high for the simplex channels (1.77/1) but is a bit better (1.3/1) on repeater input channels. I've also hot a N9TAX SlimJim that costs about the same and adds a bar of signal on receive over the J-Pole at the same height so tend to use it more than the KB9VBR.

 

[gortex2]

Id spend a bit more and get a better antenna. The browning 6140 is about $60 and will outlast the J pole especially in your area. 

[WRQK522]

Thanks gortex2 , I have been debating on the browning 6140 also came across one that is very similar to it on Amazon. Seem’s to have a lot of good reviews & is the top pick from aAmazon.


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[WRUE915]

Not to say his antennas are bad by any means, as I've never used one. But I love mine from Ed Fong. The roll up and PVC version are great. Fong is also an electrical engineer who specializes in RF engineering.

Again, not to knock others who have copied his design. Just my experience. So take my 2 cents for what it's worth...

[tcp2525]

On 3/4/2023 at 6:36 PM, WRQK522 said:

Thanks gortex2 , I have been debating on the browning 6140 also came across one that is very similar to it on Amazon. Seem’s to have a lot of good reviews & is the top pick from aAmazon.


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Gortex2 gives great advice on antennas.  For a few dollars more you can get the Tram 1486-B antenna that will give you a bit more gain. I have one on the side of my tower and it performs really well for its small size.

https://www.amazon.com/TRAM-1486-B-Tunable-Black-Antenna/dp/B092DWP4NG/ref=sr_1_2?crid=2ZYF5H8KAOIT2&keywords=tram+1486&qid=1678122509&sprefix=tram+1486%2Caps%2C72&sr=8-2&ufe=app_do%3Aamzn1.fos.006c50ae-5d4c-4777-9bc0-4513d670b6bc

[WRQK522]

Where I live is in southeast Ohio lots of tree’s and hills . My understanding is that unity gain antenna would be more useful for my area . I’m on a hill my location on that hill puts me at the same level as all the trees . If I raise my antenna to 20 feet that puts the top of the antenna approximately the same level as the tops of the trees in front of me and behind me. I can’t go much higher either. Worst part is 50yards from my house the hill I live on goes just a little higher and you can see clearly for 10 miles or more. Now in the winter I can reach 7 miles one way and 10-12 miles the other way . If that helps what kind of antenna would be best for my location? I guessing the Browning/ Tram 4160 seems to be the one to me that makes the most since. I’m using a mobile antenna with a ground plane. Like I said one way from my home I’m getting out 7miles & 10-12 miles the other way . Thats with a radio that is only putting out 20watts.
I had the BTech U25 amp when it was working it put out around 30-35 watts hooked to the same antenna setup , I would be able to reach 12-15 miles in the direction I’m reaching 7 miles now . In the other direction using the amp I was getting the same that I am now . I know why that I only got the the same on 10-12 mile direction is because of a hill . Now that is on the road I haven’t tried to see how far out I’m reaching going through the woods. My guess on that is I would reach out further because I could get on hill tops etc. on the road I can’t do that. Also I didn’t mention the distance I was getting with the U25 amp was also during the summer with all the foliage on the trees.
I’m assuming that if I upgraded my antenna & power converter and switched to a 50watt radio I most likely would easily reach out 10 mile radius around my base radio . That’s talking the roads around my house. That said through the woods and staying on the ridge tops I could go further.
Maybe that bit of information will help you guys have a better idea of what I’m dealing with.
I have also went to a bigger coax . It’s not LMR-400
It’s Brownings equivalent there version of LMR-400. Eventually I will , after I get a better power converter,50watt radio and the proper antenna for my area’s conditions I’m sure in certain conditions I might be able to 2-3 miles to what I’m getting now. Still I would like to here from you guys.


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[WRQK522]

Sorry that was a lot of typing.


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[WRQK522]

In a way I’m glad that I didn’t order one of those jpole antennas. More I dig the more I see that I would not get what I need out of the jpole. I still may get one for a portable repeater project that I’m going to work on at a later date.


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[gortex2]

I can assure you a 50 watt mobile vs a 35 watt wont gain you much if any. Antenna systems are the important part. The longer the antenna cable the more loss. As reference a 100' of LMR 400 will be 3db. That means at your antenna its 25 watts on a 50 watt mobile (in a perfect scenario). Receive signal is the same. 3db isn't a lot but it can be the difference between hearing a user and not. I'd focus on a decent antenna and figure out how you can eliminate as much feedline as possible. You didn't say what antenna your using now so its hard to tell if one antenna is better than the other. 

The Tram/Browning seems to be a good base antenna from what I have seen. Personally I go for the Laird FG series for my stuff. Most dont want to spend the extra cash but I like purpose built quality antenna's so i do stuff once and not many times. I run the FG4500 on my portable repeater for camping. I use the FG4603 on my parents house and others who want a basic control station and I use the FG4607 on one of my repeaters. All other repeaters have the DB404 as they are on commercial LMR towers. 

Most of my hobby stuff comes from Antenna Farm as they are simple to work with and decent priced. Here is a list of GMRS base antennas they offer.

https://theantennafarm.com/shop-by-categories/shop-all/base-antennas/gmrs-base-antennas/gmrs-omni-directional-base-antennas

For work stuff I use Talley and Tessco.

[WRQK522]

I use the Tram ground plane & Tram 1173 NMO mobile antenna. It does fairly well. I think a more dedicated antenna would do better


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[wqzw301]

They are great!

Ham antennas are usually brass wire in a fiberglass random and or not enough ground plane radials. 

The J-Pole's copper 5/8 inch outer diameter has a wider bandwidth and a lower noise floor for receiving.

Plus it's an end fed 1/2 wave that doesn't have any loss, due to, not needing a 50 ohm matching system. 

Only problem, it is exposed to the elements, like rain....Swr will go up slightly, And as long as it's below 2.0:1, your transceiver, will be good.  Also, if you think of it,  most commercial antennas are aluminum exposed folded dipoles. 

The tarnish on the copper will not make a difference. I know someone who had made his own.  It worked for 10 years until he took it down to give it to his friend.

For the best experience - Don't just click the "buy button" on the website. Contact KB9VBR by email and ask for the j-pole to be tuned for the exact frequency center you want. 

Also make an air choke with your coax, five or six turns of coax at the base  . This will prevent a radiating feedline and prevent distorting the antenna's radiation pattern.  Or add sum uhf ferrites to the coax - makes a big difference in swr. I don't think antenna modeling programs take that into account.