| KE5XV |
Rating:      |
2013-02-26 | |
| Meets my requirements |
Time Owned: 0 to 3 months. |
There's an article in the June, 2012 QST Magazine about the 43 foot vertical. At the top of the article, the author says 'All antennas are compromises'. This is certainly true. We only get to decide what compromises are acceptable to us, put up the antenna, and get on the air.
I'm not a contest operator, I don't run high power, I only operate from time to time, and I'd gladly trade ease-of-use for performance. I want an antenna that's convenient to deploy, works on multiple bands, has a reasonable cost, and won't require a lot of maintenance. The antenna I want is one that is, as the British would say, not very 'fiddly'.
After considering my options, I got the Jetstream JTV680, and I think it's the right choice for me. It's not for everyone.
I only recently got it set up, so this is an initial impression of the antenna.
Construction -- excellent. It uses aluminum tubing that seems to me to be robust enough to handle the weather conditions we normally get in southeast Texas. A hurricane? Maybe not.
Assembly -- Very easy with nice fittings to connect the pieces of the antenna together. There are four sections, so there are three connecting points. Some antennas use hose clamps to connect sections of the antenna. This one uses screws and attachment rings (easy to understand once you see it, but hard to describe). The piece positions are measured in millimeters, so I used a school ruler (with a metric scale) to do the job.
Installation -- The U bolts at the bottom of the antenna will fit around 1.25" pipe but not 1.5". My mast has 1.5" pipe at the top, so I bought a reducer fitting and a one foot piece of pipe at the hardware store to provide an attachment point. The assembly sheet that came with the antenna has no step-by-step instructions, but you don't need them. It's obvious how the pieces go together. The sheet shows a loop of coax below the antenna but there is no information about the size of this loop or the number of turns. I used one loop because that's what the drawing seems to show. At my site the antenna is at the top of a 40' mast.
SWR -- It's low everywhere. I used a MFJ SWR analyzer to determine the SWR on ham bands between 80 meters and 6 meters. I didn't record the data at every frequency but it was about 1.5 or so throughout the range. Looked good.
Performance -- Everything I say here will be subjective, since I have no capability of making any kind of meaningful measurements and I only had a little while to try the antenna out since I installed it. I worked a few stations on 20 meter PSK and made a SSB contest contact two states away on 75 meters. The 75 meter contact was fun for me; I don't think I've been on 75 meters since high school, and (trust me) that was a long time ago. I like having the ability to operate over a wide range of frequencies with one antenna. Performance seemed adequate and met my expectations.
How stealthy? -- This antenna, and other similar antennas, are sold on the basis that they're stealthy and can be installed inconspicuously. That depends -- it's pretty shiny, so if you want to hide it you may want to paint it or install it behind a tree.
Bottom line -- I'm giving the antenna a 5 rating because it does what I expected, it performs adequately, it was easy to set up, it is high bandwidth, and it shouldn't require much maintenance to keep it on the air. If those features are what you want, in a reasonably priced antenna, you should consider this one.
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| W5LRU |
Rating:     |
2013-01-22 | |
| My Experience |
Time Owned: 6 to 12 months. |
All bands tune to 1.2 to 1 with 940sat except 80 which my Kenwood 940sat can not tune at all. Have had moderate success with it mounted 15 above ground on side of house. Using 100 watts PEP with no amp. Lots of noise especially on 20 meter band.
I would recommend to those with limited space for antenna installation.
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| WW3K |
Rating:      |
2012-12-16 | |
| CHA-250 Alternative |
Time Owned: 3 to 6 months. |
It is what it is, and if you really think about it, it is (essentially) a one-half-sized 43' vertical, less the extensive radial field.
First off, the JTV680 is just about the same antenna as the almost twice as expensive CHA-250, only in a longer package (therefore, you're NOT gonna be able to place a disassembled JTV in your trunk like you can the CHA-250 for portable operations.) This is because even when disassembled, the JTV is over 6' long.
Secondly, the antenna DOES indeed work to provide an approximate 50 ohm load to modern transceivers. Therefore, a tuner will not be necessary.
Thirdly, like most antennas, the higher you mount this thing, the better. I started off with it on a 10' pole driven into the ground 4', thereby leaving 6' above ground with which to mount the antenna. However, it didn't work too well so close to the ground (no doubt ground loss / ground absorption.) So, I moved it to 25' above ground, and it plays much better at this height.
Fourthly, I really thought this thing would be an EXCELLENT 17M and/or 30M antenna for PSK-31 operations, however, because it is SO broadbanded, it picks up quite alot of white noise on these frequencies even WITH DSP engaged. It HAS however, become my primary 20 and 40M PSK31 antenna. Band by band results at this QTH follow:
- 6M = Performance is poor. I think due to a combination of transformer loss, coupled with an extremely high angle of radiation, this thing is pretty much a dog on 6M. I am feeding mine with approx. 120' of quality RG-213, so don't think my feedline losses are factor.
- 10M = Performance is poor as compared to a Shakespeare ABS-1600 or an MQ-1 mounted at the same heights. The performance is so poor in fact that there are stations on 10M which are completely uncopiable on the JTV, and yet quite workable on the other antennas.
- 12M = Same as 10M. Performance is quite poor.
- 15M = Down 2-3 S Units (approx. 15 dB) from an MQ-1 (2 element horizontal at same height).
- 17M = Almost useless at this QTH due to white noise. Half (51' long) G5RV at 20' beats it in all directions. Too much white noise on receive for me. Don't think it's locally generated QRN, rather instead, a function of it's broadbandednes, and/or natural resonance? Really dunno, but had expected it to work quite well here.
- 20M = Works better than expected at 25' height. Has become my primary PSK-31 antenna on this band.
- 30M = Same white noise problems here as on 17M, perhaps for the same reasons. Half G5RV kicks it's butt (again) here, (at a tenth the cost!)
- 40M = Surprisingly, works quite well on this band for BOTH local and long-haul DX. This surprised me because I was expecting it to work better on 30M than 40M, but I was wrong. Kicks butt on 40M! No, it is NOT as good as the Half G5RV for local contacts, but holds it's own for DX. Approx. 1 - 2 S Units down from a ground mounted GAP Challenger Vertical on this band, and approx. 2 - 3 S Units down from a full sized (Cushcraft AV-5) trap vertical, ground mounted with extensive radial field. However, for what it is, it performs well on this band. It has become my primary PSK-31 antenna on 40M
- 80M = Well, if you've got nothing else, then use it, but be advised that it is seriously deficient on this band. I've never worked (even PSK-31) a two-way contact on this band. I HAVE however, used it as an effective RX antenna on both 80 and 160M during high atmospheric QRN condx.
- 160M = Although not 'designed' for this band, it does offer an acceptable SWR through the whole range of 1.800 - 2.000 MHz, but no one will hear you due to the extreme lack of radiation efficiency here (probably <1.0%). However, as stated above, it makes a GREAT RX antenna for 160M.
- BCB Receive = A highly effective AM Broadcast band receive antenna for AM DXing (vertical polarization). There are AM Broadcast stations I can hear on this antenna (Wyoming, California, Etc.) which I can't hear on horizontal antennas. Conversely, radio stations in NYC (approx. 60 - 80 miles away), which are booming on my larger horizontal antennas are barely (if at all) heard on the Jetstream
- SWLing = If you stay away from the white noise / natural resonance(s) frequencies of this antenna, it does a auitable and quite effective job for Shortwave listening without the need for a balun, tuner, Q multiplier, preselector, or preamplifier. An added benefit.
- Portable / Temporary / Field-Day Use = This antenna is perhaps the EASIEST antenna I've ever assembled. Went together in (literally) less than 5 minutes. It would make the perfect field day or emergency QRV antenna. Once I determine a suitable replacement for it in it's existing mounting location (perhaps a 6M 5/8 wave vertical), I'm probably gonna use the Jetstream as a portable antenna for when I visit my grandkids out of state. (However, again remember that even when disassembled, it is quite long (6' or so) because it is only in 4 sections.) I may also experiement with it by capacitively (top) loading it to see if I can improve it's performance on the lower frequencies, and/or, eliminate the white noise issues I am experiencing on 17 and 30 meter bands.
That's it (for me) in a nutshell. It is what it is, a highly compromised and yet highly effective antenna that truly performs as designed. It is ingenious in its simplicity, ease of installation, and ease of use. Its effectiveness on the 20 and 40 meter bands (at approx. 1/2 the size of a 43' vertical radiator) have confirmed the effectiveness of a 43' vertical on the 40 and 80 meter bands, and although I don't currently have one, I can now see WHY a 43' vertical can be so appealing to so many people. It also makes me wonder if the white noise I experience on 17 and 30M on the JTV would be white noise on 30 and 60M bands on a 43' vertical. Hmmmmmmmm............ |
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| VE7BGD |
Rating:    |
2012-11-14 | |
| Not what I thought |
Time Owned: 6 to 12 months. |
| I also have a ground mounted vertical which I went back to. I installed the JTV680 on a metal pipe approx 30ft above the ground so it would clear my roof edge. Hope was I would get out better, in fact both tx and rx were lower than my ground mount so a lot of effort and time was wasted so far. It was suggested by a friend that a counterpoise wire may help. Wonder if anyone out there has tried this or has any suggestions. |
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| AI5L |
Rating:      |
2012-10-18 | |
| Excellent all band vertical |
Time Owned: 6 to 12 months. |
| Assemble per instructions, use the metric values. Mine is mount 3 inches off the ground, no radials and 2 feet from the house (to hide from the HOA). Great QSO's everywhere. PSK-31 with New Calidonia using Kenwood TS-2000. 1:1.1 to 2.0 across all bands, measured with RigExpert. |
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| W5GGH |
Rating:     |
2012-10-04 | |
| Excellent |
Time Owned: 3 to 6 months. |
| I do have a radial field under mine from a previous antenna and I'm sure that it is helping the performance....ground mounted. |
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| FORMER_K6AKW |
Rating:    |
2012-07-25 | |
| Just assembled as instructed |
Time Owned: 0 to 3 months. |
| Ok, read all the reviews. Looking at it with my MFJ-259 the SWR is pretty much all over the place except for 20m...not bad there but not really acceptable on other bands. I haven't attempted to change element lengths because there's no guide as to how much...maybe someone has experience with this. |
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| FORMER_K0PD |
Rating:      |
2012-06-09 | |
| Excellent Vertical.. |
Time Owned: 0 to 3 months. |
| I just got my 680 a couple of days ago so this review is based only on these two days. First off the antenna is of excellent strong material and easily set up. It has a place at the bottom above where the antenna connection goes to attach ground radials which i did and instantly noticed a vast improvement in SWR's and reception. I do not have a SWR over 1.7 and those are on 10 meters and 75 meters.The rest of the bands are 1.2 and 40 meters is 1.4. I bought mine from GIGA parts $249.00 shipped and the shipping was very quick.I plan on laying down more radials and expect even more improvement. By the way it is only mounted two feet from the ground.... |
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| N6PCD |
Rating:      |
2012-05-26 | |
| GREAT Antenna! Especially at this price. |
Time Owned: more than 12 months. |
I've owned this same antenna that was sold by another manufacturer. It's been my my only HF antenna for the past 6 years, and I can't say enough good things about it!
I've worked all continents, worked all states, and am over half way to DXCC, with a very casual operating style.
It is a fine product for a compromised antenna location. I live in the middle a two story condo complex and am not permitted to roof mount the antenna, so I've put mine on a 10' lenght of 1.25" TV mast that is set into a 5 gallon bucket of concrete. This holds it securely, AND I can add sections to it for contests or special DXing on a temporary basis if I want to. Usually don't.
Works great for me, will do well for you too! |
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| KB3WQE |
Rating:      |
2012-05-23 | |
| great for the price |
Time Owned: 0 to 3 months. |
| This antenna is heavy duty and well made. I did not have a problem with SWR on any of the bands and I am not using a tuner. Be careful, measure twice since everything is metric. I have seen an antenna similar to this in every way at twice the price. |
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