The JPC-12 - Third time's a charm?
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- Опубліковано 5 жов 2024
- The comments kept on coming on my last video, including one from @LA5PPA / Lasse with some instructions on how to tune the antenna. Also @HAMRADIODUDE made a video inspired by my attempts on tuning this antenna, so I had to give this another go.
Could I get it to tune now?
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I used this antenna for doing a /P QRP entry in the March CQ-WPX-SSB contest with an Icom 705. I'm in the UK and managed to work stations throughtout the USA and even as far as Argentina and Brazil on 20-10m. 40m was rammed with Europe but I did manage to get some contacts with the USA on 40m late in the night.
It's not a bad antenna. It is perhaps a bit lacking on the manual, but it works.
Finally found a reference for 10 meters. I would have never thought of removing the rods and coil and just using the whip. Thank you!
You’re welcome!
Fixing to try it now…been driving crazy but I’ll make those changes as well. Fingers crossed
I'm glad you did give it another go, regardless. Good job.. enjoy the POTA
. I'll be hydrating
Extremely useful video for a new JPC-12 owner, thanks a bunch.
73 from Paris, France.
Glad it was helpful!
So glad I watched this, I had totally forgotten to stay hydrated with setting up my antenna. Super useful information.
Happy to help, I sure hope you picked some of the other advice as well. See you down the bands!
PS: Sarcasm doesn’t come across well on a keyboard.
It was indeed a good and informative video, just thought that part was kinda funny.
Top marks Morten for persisting with the antenna rather than just thowing it in the "too hard basket" and writing it off as a faulty product......it shows the hallmarks of a reviewer that your viewers can trust. Cheers ZL2VTH
Thanks! I’m still not completely sold on the antenna, but we’ll see with a POTA tomorrow.
Many of those matches look more broadband than I expected. I’m going to buy one. I really don’t mind any extra tinkering. Every location has different ground conductivity and surrounding objects, so most similarly constructed antennas will give a similar experience. Most modern radios show SWR so its pretty easy to trim. Thanks very much for the good info and hi-res video.
It is by no means an easy antenna to tune, but if you follow these guidelines it will be easier at least. And yes it is pretty broadbanded.
Buy a longer 5.6m telescopic whip. Use it with the coil for 40m and remove the coil for any band over 30m changing the length of the whip to tune. If it’s ground mounted the provided radials are fine, if you raise the feedpoint with the mast sections the radials will have to be the right length for the band of operation. I see many videos with coils upside down, coil in different locations up the mast, raised feedpoint with no tuned radials - it’s all pretty simple really. PS if you don’t get the larger whip you can do as in the video use the mast sections to make the original whip to length. Or if not using the sections the coil will stay on as you move up the bands until 10m or so.
Yes, that would probably be more efficient. A quarter wave vertical is always more vertical than a loaded antenna, but that is not what this video is about.
Thanks for the video. Great explanation and instructions. I had mine working for the first time today. It’s fiddly, frustrating and now you’ve motivated me to persevere with it. Thanks. I’ve just subscribed! 73
It's not a half bad antenna, but it's cumbersome to tune. Once it is tuned it actually performs pretty well.
Good video. It is always good to see people be able to work out technical issues that they are having. I am a big believer in KISS method, so I get your concern about this might be to much for a new ham. I just release a video myself yesterday on the antenna. I am looking for an antenna that was small and compact that I could take on a trip out to the desert. I got great results with it on 20 and 40 during a POTA activation in Indiana. I banged out 50 voice QSOs in an hour across the US and Canada with 2 of them in Europe. The only issue I had was with the provided radials, but once I split them apart, the SWR came in to line. I will be replacing them with some homemade ones.
Looking forward to your video.
Thank you for the video, has anyone posted the tuning instructions for download?
You can find them in the comments.
Hello it is a great video
I did look in the comments but still can’t find the information.
Have a look at KB9VBR , he uses a aluminium window mesh instead of radials, I tried it with my portable ground spike and 17 foot whip, and it tunes all bands from 20 to 6 like a dream just by adjusting the whip length. With my slide winder it will do 30 or 40.
The only issue with that is that we don’t use window mesh here.
Found list in comments! Thx👍🙏 ps they are at 3 months postings!
Where are these instructions at in English, can't find them, would love to print them out ! Thx for doing this video,very helpful 👍🙏
Good luck on the POTA event. 73
Thanks!
Your furry helper might introduce strong em fields, as he started moving after you pet her.😂
This might be a good antenna but it seems like a bit of a pain in the Ar$3 to me... I think I'd stick with a EFHW (80m-10m) and a DX commander 80/40 upwards. I think those two (and variants) alone are the best compromise between effort/efficiency when it comes to multi-bands antennas and avoiding tuning or automatic tuner.
You are comparing two or three very different antennas for two or three very different use cases here. Sometimes you are space compromised, or just have too many people around for the two options you talk about, and then having something a little bit more flexible than a hamstick could be a good thing.
@@LB0FI Yes, that's true. I'm thinking of just the antennas alone - assuming that space etc don't matter. By the way you can use a EFHW vertically too - obviously that requires either a very long pole or only using higher bands. It has an advantage of a very low take off angle. Ultimately there are pro's and con's always I suppose.
Can we see more of the pos'za cat!
Shack Cat MVP
Add a link for the tuning cheatsheet.. or scan it, upload it somewhere and send us link plz
I have something even better, I have a video on it. Besides that there’s a comment on the previous video with the complete list.
Have you used an end-fed antenna and which is more efficient in your opinion? Thanks
As a rule of thumb you could say that more radiating element equals higher efficiency, so in most cases an EFHW or random wire would be better from a radiating perspective. It's not always about the most efficient antenna though, it is sometimes about the antenna you have room to put up.
Hi ? Can you pass on that list (notes) on to us as well please.
Lasse LA5PPA found this information somewhere on the net about a year ago and it has been of great help for tuning the antenna
It is DO1HFS who made it in German so I use google translate to English.
He also recommends adapting the radial set if you want to optimize for a particular frequency band
6m:
Earth spike/radials/feed point/telescopic
Extend the telescopic 3-4 sections. An average SWR of 1.2-1.7 is possible without further changes.
Fine adjustment via telescopic
10m:
Earth spike/radials/feed point/telescopic
Fully extend the telescopic. An average SWR of 1.2-1.5 is possible without further changes
12m:
Earth spike/radials/feeding point/2x aluminum rod/telescopic
Fully extend the telescopic. An average SWR of 1.2-1.7 is possible without further changes
Fine adjustment via telescopic
15m-1:
Earth spike/radials/feeding point/4x aluminum rod/telescopic
Screw all four aluminum rods together and screw onto the feeding point. Telescopic except for one link
Extend completely and screw onto the aluminum rods. Without further changes an average SWR of
1.2-1.5 possible
15m-2:
Earth spike/radial/feeding point/3x aluminum rod/telescopic
Just screw three aluminum rods together and screw them onto the feeding point. Fully extend the telescopic
and screw onto the aluminum rods. An average SWR of 1.2-1.5 is possible without further changes
17m:
Earth spike/radials/feeding point/4x aluminum rod/telescopic
Fully extend the telescopic. An average SWR of 1.2-1.7 is possible without further changes
Fine adjustment via telescopic
20m:
Earth spike/radials/feeding point/4x aluminum rod/coil/telescopic
Extend the telescopic completely and place the coil between the four aluminum rods and the telescopic
install.
Place the pickup sled on the top red mark for 14MHz. An average SWR of 1.1-1.4 is
possible.
30m:
Earth spike/radials/feeding point/4x aluminum rod/coil/telescopic
Extend the telescopic completely and place the coil between the four aluminum rods and the telescopic
install.
Place the pickup sled about EIGHT clicks below the top red mark. An average SWR of 1.1-1.5
is possible.
40m:
Earth spike/radials/feeding point/4x aluminum rod/coil/telescopic
Extend the telescopic completely and place the coil between the four aluminum rods and the telescopic
install.
Place the pickup sled on the lower red mark for 7MHz. If necessary, the slide can be moved by one or two
Coil turns are pushed up. An average SWR of 1.1-1.4 is possible.
Thanks Much aprpeciated.
@@LB0FIThanks for sharing these instructions and thanks to LA5PPA & DO1HFS for compiling them.
The problem of this antenna (and dipole variant, too) is not bad engineering or manufacturing. There is only one problem: the manual is idiotic.
I don't speak Mandarin (only all slavic languages, English, Old English, French, Old French and Latin :D ) so I don't know if the chinese manual is any better, but English version is basically unusable. What I did was similar to your attempt - it was crystal clear I must first find some "reference settings" (and the best attempt is having whip and/or tubular sections as long as possible with shortest possible coil length involved) and then fine tune changing the length of the whip.
It was almost immediately clear the coil must be taken out starting with 17 m band.
The measurements did take like 2 hours. Basically my results are identical with the document by DO1HFS.
What I did I bought JPC-7 version (dipole - so I have 2 coils and in vertical arrangement I can tune 60/80 m) with spare whip and bottom segment with ground rod and HF connector for JPC-12, so I have both vertical/dipole options. I made a set of 8 10 m radials instead of that crap provided with JPC-12. I didn't use dipole arrangement for now, but when I will have some time, I will make the measurements.
Manuals are absolutely an issue with a lot of Chinese products unfortunately.
Any ham that likes tux cats is OK by me😀 And the antenna video was good too!
Thanks!
Did you ever try this antenna out in a actual POTA activation? Where can we find that list to tell you how to tune the antenna on different bands,.
Yes, I have tried it several POTA activations, I have a total of four videos on this antenna. As for the list, I can't find that anymore, so you will need to take notes from the video unfortunately. Thanks for commenting!
Hi there! Could you tell me where to find that sheet?? I’m my instructions manual doesn’t come so many configurations. 73!
I am still rather suspicious of this antenna. Getting a usable impedance match is one thing, but does it radiate? It's easy to get a good match off a dummy load, but what makes an antenna good is how well it radiates.
Everything in this hobby is a compromise. And yes it radiates, but no, it does not radiate as well as a quarter wave, but you get the benefit of a more compact kit. And that being said, there's not really any magic in this, it's a vertical with a loading coil.
Worked SSB nice copy from VK8 Northern Territory Australia in a rural location to G/M southern UK with 80W ground mounted on 20m yesterday…..
Just bought my JPC-12. The slider is extremely hard to slide up and down. Do you have any suggestions to make it easier without taking it apart?
I just borrowed that antenna, so I don’t know unfortunately.
@@LB0FI thanks
Pretend it’s a quarter wave monopole, just like any other since the dawn of radio.
Electrically or physically?
@@LB0FI Electrically in this case, but if you can get your hands on the 1964 ARRL Antenna Handbook, a remarkably similar antenna with equally similar loading coil is described on page 308 (right down to the hardware used for the sliding contact), so when there are videos titled PAC12 fail and whatnot, I can’t read it any way other than “user fail”. I do happen to be aware that physical quality of the thing is surprising for a mass produced China thing.
@@BrekMartin Thanks for commenting.
hi. can i have a copy of the "manual" that you used. thanks
I have two options for you. Check the comments in the other video or take notes.
Will this antenna tune for 11m band
Yes, but it would frankly be a waste of money. Just get a quarter wave whip and a mount instead.
What do you need to make it work on 80m
You could add another coil and more inductance, but the radiating element is so short that it would not work well on 80 meters.
Thankyou for the video.....Persoanlly i think these Chinese aerials are awful and getting lots of negative feedback. Good Luck with yours keep the videos coming
It's not a half bad antenna, it is just very cumbersome to use it.
Where did you find the cheat sheet that you are referencing in the video?
Everything is explained in the beginning of the video. It was posted in the comments on the previous video of this antenna.
So why did they use 3/8 x 20 threads instead of the fairly standard 3/8 x 24 threads on all their stuff. Now it is incompatible with all my other coils and whips. Very stupid ... cant even use it on my mag mounts ... sending it back for refund as all my mounts are 3/8 x 24 thread.
The mounts are M10 - metric. Get an adapter.
The Thread is M10 metric
What is your cat's name? I hope she likes ham radio as much as LB6QJ's cat Odin. ;-) DE WA1KLI
Her name is Kathinka, but we usually just shorten it to Tinka. She loves wire antennas and radials more than radio itself :)
This helped. Thank you.
73, KK7BN
You're very welcome!
Good work dust you vna screen
I hope you are aware that this video is almost a year old, and shot in the middle of pollen season.
@@LB0FI 👍😆
Look above. I hoped you would understand that it was meant as good humor. You did figure it out.
I do not eat grass
The mower is Shawn, not Sean 🤣
Thank you, the instructions are helpful. 73 de ZS6KB.
You are most welcome!