Chameleon MPAS 2.0 VS JPC-12 vertical noise floor comparison.
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- Опубліковано 5 лют 2025
- Comparing the ambient noise floor of the Chameleon MPAS 2.0 in vertical configuration vs the JPC-12 vertical antenna. Feedline used is the ABR industries rg58u and the M&P Ultraflex 7. Radio used is the Icom 705 using the LDG-Z-100 plus antenna tuner for the Chameleon. No tuner needed for the JPC-12.
Thanks for taking time to do this video. I learned much from it and the comments it generated.
The one thing you are missing between the two antennas is that the Chameleon with it's 5 to 1 transformer is a full 12 db down on transmit compared to the JPC antenna. The Chameleon will also not pull out the weak signals as well as the the resonate antenna. Chameleon antennas have great quality, but the 5 to 1 transformer really hurts the performance of the antenna. It's advertised as super quick set up, but the loss from the transformer makes it a no go for me. Why would I want to give up 12db? Why would you want far less weak signal performance all around ? The JPC antenna is by far the better antenna. Very similar to the Buddistick. You can also get a far better match with the JPC without the need for a tuner. Just more loss due to the difference in SWR. All Chameleon antenna models with the 5 to 1 transformer have the same loss problem.
Great point.
If you want to use something like ALE or change frequencies a lot, you’d lean towards something like the Chameleon.
@@davistroy True, but I don't run ALE and have enough flexibility in frequency changes with what I run. Your needs may be different and if so, the Chameleon may be for you. It's not for the masses for regular communication for the most part. At least if performance matters.
@@johnk23705 performance is measured many ways and dependent on the user. Like u point out, for me I want jumps bands quickly without leaving the tent or dealing with rain. So performance to MANY is the ability to operate "remote" & "instantly" and that comes with compromise of signal loss. Maybe that's made up by a great receiver and built in tuner. You run out and chase the next dx band manually in the rain or snow.
Now like this video, I have both for best of both worlds.
@@nbookie To each his own. Todays receivers are all pretty darn good. You won't make up a 12 db loss with even the best receiver money can buy. If you are good with that much loss, rock on. Snow and rain don't bother me all that much. I've worked out in it my whole life.
This is an apples to oranges comparison. Please forgive me if you already know this information, but one is a center loaded vertical which presents a good match at the feedpoint, while the mpas uses a wideband and lossy 5:1 transformer. Maybe the "noise floor" is higher because received signals are also higher? I didn't notice....did you use any radials with this setup? Radials are the 2nd half of a vertical antenna, and your coax shield becomes the counterpoise if you did not use radials. The mpas is only really useful if you have limited knowledge about antennas and want something that is "tactical" and will work every time without much thought. Good luck.
One major thing I learned from this video is that more expensive radios and antennas doesn’t make for a better station.
That using the Xiegu G90 with the JPC -12 can make for a very good station for less than 50% of the money spent.
For travel to POTA Parks, lighter is better, especially when it comes to flying around the country on vacations.
I also think your testing methods could have been easier and better by using just one coax cable, no outside tuner for less connections or connectors, where most of your loses occur in the field.
I think the objective should have be to compare antennas and not antennas vs coax cables, those can be done separately in my opinion.
However, with your test, I think the comparison could have been bias towards one antenna vs the other but you did a fantastic job in preventing that bias from coming into play. 👍
You can order the MPAS 2.0 with an choke that you can add in line to the feed line or a feed line with the choke built in.
Comparing noise levels on ssb or any other mode is not even a remotely accurate test of both antennas. I did antenna testing for Loral Systems. To get real results you need a calibrated dipole transmit antenna for each band you want to use on a calibrated antenna range. The receive antenna should be a minimum of 10 wavelengths from the xmit antenna. The feed-lines have to be the same length, with no switches or other passive or active devices in between the antenna and the radio. The feed line with the lower loss will of course have a better TL on Xmit. On Xcve unless the difference between feed lines is more than 2db there will be no difference in reception. BTW Rf chokes on the feed line introduce no loss on the feed line on transmit or receive.
This is about hte worst antenna comparison test I have seen.
1. Placing two vertical HF antennas less than 1 m apart is disaster.
2. Testing the influence of the coax cables is meaningless. The differance
in loss for 5 m cable at 14 MHz is about 0.1 dB. This is insignificant.
3. Testing the JPC-12 without splitting the ribbon cable and distributing the
radials is a big disadvantage for this antenna.
Hi just got that green telescope whip antenna . The one you have in the middle of table . What connector would I need to connect to ft-891 and do you extend it all they way and user a tuner ???? Thanks
Hello. The antenna has a standard so-239 connection. I'm not sure what your 891 has, but I suspect it is standard so-239. So coax with standard pl-259s on the ends should work perfect. Also, the green whips are not adjustable. So depending on what band you're running on, you can not use the larger diameter whip. With the mpas 2.0 [the green whip antenna] you will certainly need a tuner. it is not resonant on any band. Thanks. I also have the JPC for sale if you're interested hit me up on qrz dot com along with the AL-705 loop antenna and a repeater. Thanks
@@HamRadio200Do you still have the JPC-12 antenna up for sale?
You actually mixed up the coaxes during testing. The Me&P coax that you say came with the JPC-12, is connected to the Chameleon antenna during this test. Hence, the validity of your findings are rather confusing !
He switched feeds to show the contrast of the antenna SWR and attenuation purposefully and with minimal variation.
No one is disputing his method of switching feed lines...
Buy a dead cat if you plan to record out of doors. It will reduce wind noise.
Thank you for the feedback! I will look into this.
Voice level too low to listen comfortably.
Sorry
Thank you for the feedback.
I sea sick watching this video.
Thanks for the feedback.