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Scanner / Receiver Antennas For discussion of any type of receiving antenna used by a scanner or receiver base, mobile or handheld.

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Old 06-10-2010, 9:53 AM
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Default Jetstream JTB3

Here are a few pics of the Jetstream 2/440 base antenna whose model name is in the thread title. I scoured the WWW looking for an idea of what to expect from this product in terms of fit and finish to no avail when deciding on a second base antenna for a portable application. All that are available are three dimensional drawings and pictures of the antenna mounted from a high level viewpoint, which didn't serve my needs at all as a consumer looking to be better informed. I hope that by sharing these pictures, another new ham may not have to make a purchase decision in the blind as I have. Needless to say, so far, I am very pleased with the construction and materials used in the manufacture of the antenna. My expectations have been met for a change.

As time allows, I will update this thread with impressions after I've had a chance to make contacts while portable in simplex and by repeater from various locations. Now, without further adieu:























Also, props to R&L for getting the kit to me in two days. I wasn't expecting to see a delivery until Monday next at the earliest. Will certainly look to the outfit again in confidence to fill my future needs.

Cheers.

Last edited by Thunderbolt; 06-11-2010 at 2:51 AM..
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Old 06-10-2010, 11:21 AM
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Thanks for posting this.

It looks typical and comparable to a lot of the Diamond or Comet(NCG) products.
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Old 06-21-2010, 10:30 AM
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Last night I worked some distant stations on two meter FM simplex that barely broke the RX squelch. I decided to run in side quickly and key up, asking for a signal report. Some intermediate-distance guys who were on frequency relayed that the far away stations reported that they could hear me better while operating from the rear deck than when transmitting from my base station. Mind you the base antenna is roughly twice as high with an unobstructed view due to nearby houses. The JTB3 was mounted to a surplus mast of about sixteen feet which in turn is lashed to the posts of the deck. The JTB3 wasn't mounted high enough to get over the roof of my garage, let alone nearby houses. The radios and coax of the indoor and outdoor stations are the same.

That's a pretty convincing observation of the efficiency of this antenna system IMO. Just thought I'd share.
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Old 06-21-2010, 12:10 PM
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Yep, good antenna. And R&L has always treated me right!

I have the JTB3 on my tower, side mounted at about 32ft, right now its just being used for VHF on the scanners and works very very well for that. Previously it was being used for my APRS digipeater but that got moved to another antenna with further improvements.

Definitely a darn good antenna for the price, and only like a third of the price of the comparable Diamond X50.
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Old 12-25-2010, 2:53 PM
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Angry Dud out of the box?

My antenna arrived Dec 22... I thought great, I can get it up over the holidays. Well I had time today. I'm in a condo, so I had to put in the attic. I had it mounted then checked the SWR. I can't get the SWR below 1.5 to 1. On the band edges it is just above or just below 2.

I'm not saying this is a band antenna, I could have a dud out of the package. Even with the best and most reliable manufacturers this can happen. Any ideas? How does the SWR on your JTB3 come out?
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Old 12-26-2010, 11:08 AM
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Quote:
Originally Posted by VE8AA View Post
My antenna arrived Dec 22... I thought great, I can get it up over the holidays. Well I had time today. I'm in a condo, so I had to put in the attic. I had it mounted then checked the SWR. I can't get the SWR below 1.5 to 1. On the band edges it is just above or just below 2.

I'm not saying this is a band antenna, I could have a dud out of the package. Even with the best and most reliable manufacturers this can happen. Any ideas? How does the SWR on your JTB3 come out?
Put it in the attic? Nearby metal objects? Metal near the antenna can detune it. Mine shows about 1.2:1 across the entire 2m band and about 1.1:1 across 70cm. It's actually very typical for a 1.5:1 or slightly less on these dualband antennas, nothing to worry about. I have swept a Diamond X50 which is similar in size and design to this JTB3 and the SWR results are about the same, they best i ever got on that antenna was about 1.4:1 across VHF and 1.2:1 across UHF. So it was actually worse than my JTB3.

Mounting location and such has a big effect as well. I don't think you have any problems. What are you using for feedline? Is it a good quality low loss coax?

Either way i wouldn't worry, your radio isn't going to care about transmitting with a 1.5:1 match, most radios on the market for ham gear don't even fold back power until its 2:1 or worse.
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Old 12-26-2010, 12:58 PM
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Yeah, whatever you do don't skimp on the coax! Better check the charts and get the lowest loss available regardless of the price. You'll quickly discover loss on 2M is bad enough but it gets pretty horrible on 70cM so the best you can get is well worth the price. Hard line is best if you can afford it, to borrow a phrase from an old tape Crepitation USA (sp?) if you want to go with the pros you have to blow (signal) like the pros.

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Old 12-26-2010, 1:45 PM
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Old 12-26-2010, 2:07 PM
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I use 2 of these antennas, one for a repeater and the other for a link transceiver for the repeater. Both work great and have low swr on both the 2/440 bands.

Both antennas are fed with RG213 coax.

One is at the top of my tower at 55ft. The other is at the top of an apartment building at 200 ft.

No issues with it surviving the elements at either locaction

Last edited by cpitre; 12-26-2010 at 2:11 PM..
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Old 12-26-2010, 2:25 PM
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No, there is definitely something wrong with the antenna sent to me. On the low end, swr around 2.2, at the high end 1.9. No metal anywhere near the antenna in the attic, and I have no problems with the HF/6m ant in the attic. Using excellent cable - RG-214/U, however, bad cable will tend to show a lower SWR as the loss in the cable in both directions fwd and rev will cuase a lower swr reading. It seems others are all saying well under 1.5 to 1 across the band.
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Old 02-09-2012, 3:24 PM
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Has anyone hit this antenna with an analyzer? How does it do up at 462-467 for gmrs?
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Old 02-09-2012, 5:28 PM
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Default Sweeps

I have a couple of sweeps,however, I'm not sure how to get them onto the thread, I don't see anywhere to upload files. Anyone have any ideas?
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