Interally, the wire that connects that ground/radial to the SO-239 ground is small. It may have an intermittent connection. That ring terminal also has issues. If you look at it, if it is placed the wrong way ("Upside down"), it will not fully seat and create an intermittent short. If you haven't yet seen it, my first review on the JPC-12, I disassemble it and show how flimsy the wire can be. In fact, I broke it.
I just looked at the HamRadioDude video with the broken wire and it looked to me like it was not the ground wire but went to the center pin on the SO 239.
I know some Hams that uses the JPC-12 Antenna have scraped away the lacquer on the bottom of the Base unit to have a better connection to the counterpoise wires.
I used the optional radial plate. The ground stake goes through the radial plate which has the radials attached. Mine worked well right from the start and is my go to antenna for portable DXing. Congrats on the success with the antenna!
I have done the same and fitted 8 x 24/0.2 wire ( all 5m long). I also have the extra long telescopic antenna and worked out that I could get it to resonate on 14 MHz with the 4 rigid poles and the long telescopic. This removes the need for the coil on that band. I used my NanoVNA to get a minimum SWR at 14.2 MHz. I currently have it at our holiday cottage in Devon, UK and on Wednesday 3 July I worked a VK in Adelaide, S. Australia and got a 57 report! With the coil and above set up I can get it to tune on 60m as well. My rig here is FT-897 with just 100W. The VK worked an OE station and as he was ending that QSO he said, ‘Just the G0 portable station go ahead’! I was amazed that he heard me through the original pile-up! Delighted and a great antenna!
Thanks for calling them like you experience them, Walt. Several things can get gummed up in a production run of antennas with these types of connections. But the vertical racked up in the end!
Good to hear. Hopefully the manufacture will look at this and correct the ground plan problems. So many Chinese companies just put stuff out and ignore any feedback.
Another good video Walt, I’m glad you didn’t give up on it. I have that antenna and had to add 8 16’ counterpoise wires on 20 but it worked better on 40 with the ribbon cable split into 4. I might open the base up and add a better wire to the ground as recommended by several people.
I have one of those. I found it has a real preference for certain types of 259 connectors. I had some that would NOT screw all the way down and some that would. Once I found a cable the would seat all the way worked well. Also made my own radials and used a nice ring terminal to connect them. Oh yeah, connected the radials on top of the spike.
That was very interesting. I hate when the experiment ends up with a huge question mark and not too much recourse to discover the issue. I hope the builders can be of some help... You're having some great weather for playing though. Not so nice here in New England. Looking forward to your hunt for answers, 73 Bro, KC1MTM
Thanks for watching, that antenna was driving me crazy and I wanted to get to the bottom of the problem. Yes the weather here has been perfect. I’m just hoping it stays that way for a little while. 73! Walt
One thing I found out is that the coil on these systems are 5 ohms of resistance when at their lowest frequency setting. That alone is going to help it achieve a low VSWR, but will also tend to dissipate the RF in the coil rather than radiate it.
Nice follow up Walt. The G90 is good with its swr sweep function for these coils, I’ve a SlideWinder as well. If I have my nanovna with me I always measure return loss as well. You get real time readings as you adjust the counterpoise to achieve more than -20db (the more the better). Would be interesting to take measurements with your different dirt/sea setups 👍
Thanks for commenting, I just subscribed to your channel. I’m actually a graduate of the Westlawn School of Yacht Design and have a passion for boatbuilding as well. I work in shipbuilding now. Glad I found your channel. Yes I really need to get a proper antenna analyzer and take a bit more of a scientific approach to these antennas with greater detail. All the best and 73, Walt
@@COASTALWAVESWIRESthanks for the sub - ideal for insomnia 😆. Didn’t know about your Westlawn/shipbuilding, that’s cool, but looking forward to a low power qso across the pond one day 👍
Well done Walt. I have never used commercial ants, classic light and wire, don't have anything between the rig and the ant. But here just now, if I had a yagi and 1k, I still couldn't get a contact, bands are all dead, worst I've heard them for years. 73 mate
The base where the spike and ground wires attach needs to be sanded back to bare metal then good connection will help. Great videos I am enjoying. 73 ZL3AXL
Nice comeback video, Walt. I’m wondering too if you have a bad base connector. The anodized coating should not be a problem because the spike provides continuity to the inside thread. As an engineer narrowing down on the problem, I would test the noodle on the spike instead of in the PL259. If it works, you can confirm that it isn’t the base. Would be nice to get your follow up if you ever do come up with a definitive cause for the issue. After all, the center loaded ground plane is a simple antenna which should radiate as designed. Thanks again for the followup. 73 K8YX
I'm going to do those checks for sure. I'm a Field Engineer, we get it working via any hack we can come up with and then figure out the problem LOL. I'll probably do a Short checking conductivity at the base soon. Thanks for following along with this one. 73
I haven’t used it much yet, but I’m glad I didn’t just buy a dud. I do want to put better counterpoise wire on it though, and add a second coil for 80 metres. I’m told you need 20 metre long counterpoise for this though, but I wonder how many strands is enough.
Walt, thank you for doing another video but Im not convinced. I have a viewer request. One take a multimeter out in the field and test for continuity and 2 when in a qso as the ribbon is connected, attach your pool noodle to see if the signal goes up or down. And also ask if your signal went up. Thanks in advance KD2GIY from NJ.
Surprised you had that much trouble getting it to work with ground plane radials. I'd be probing around with a multimeter to see if those radials are actually connected to the shield of the coax. I've had pretty good success just using a 17 ft whip with a set of radials up here in the mountains in Utah.
Hey Walt, just a thought but I’d check the dc continuity between both the threads of the SO239 connection and the threaded section where you’re connecting the ring terminal for the radials then do the same but to the center pin of the SO239. I wonder if the radial connection is in the wrong place? Good luck and keep ‘em coming!
Hey walt,I used the noodle with counterpoise into the ocean using my efhw here in uk n boy oh boy what a difference!!! People kept telling me to turn power down.....I was only using 10w🤣🤣
Bought one of these when they first became available. The so239 connector on it would not allow any of my coax pl259's to screw on beyond like half of their normally used threads, almost like the connector was tapered larger further back. Ended up returning it. I have several WRC's to compare results to and have had a few Gabil antennas also (sold the gabils). Recently got a new jeep and wanted to have a compact ground stake type vertical antenna to keep in a bag, just to have on hand. Opted to give one of these antennas another try (branded Chelegance but with the usual JPC 12 logo). Same exact deal, the so239 only allowed any of my coax connectors to only screw on partially, not enough to let them snug up properly. Yesterday, I replaced the so239 with a new panel mount 239 and it now works perfect with all my pl259 connectors/lines. Antenna worked great on all useable bands hastilly set up out back, swr's as low as 1.06 on 20m phone realm (nice), averaged 1.2-1.6 otherwise, depending on radials (learned that with 10 & 11m bands, they were at their lowest with just bunching up the radials in piles right close to the ground stake). 40ft of rg8x on ground. Rigexpert meter. I like it, it made it to the "keeper" status. Do wish they woulda opted for 3/8x24 threads all around.
I have one of these and I noticed on first assembly that it's important to get the 'eye' connector up the right way otherwise the plastic connector spoils a good connection. I'm going to buzz up a mod on the lathe. If it works I'll send one over. 73 John
Walt, I really enjoy your videos. Is there any real difference between the set up on the beach and the single wire dangling in the drink? You certainly got a better performance when you changed the connection point for the earth/counterpoise. I guess your experience lead you to believe there was a solution. Cheers 73
Ok interesting. I got that antenna as well with the G-90, 20 meters worked great, couldn’t hear America at all on 10 meters but curaçao and Belgium. I raised the base of the antenna 5 feet using pvc pipe then ran the 8 radials sloping and 20 meters much better. I may work and improve the radial system as well. I am in a valley close to Smoky Mountains and that may hurt my signals.
Recently got this antenna and measured the resistance from the coax ground to the bottom threads, almost a 1 ohm difference. couldn't get SWR below 4 on 20 meters. Wonder if that's the issue. On 10 meters, I eliminated the coil and got it to about 2.
I am in Cape Cod I tried working off beach right in front of our hotel But it is windy raining and cold 🥶 I did do a POTA activation in Plymouth MA inside my truck
Walt: I think the threads of this antenna are metric....ie not 3/8 inch. Did you figure out a way to use this antenna with other antenna parts from your antenna toolbox. If so, could you put a link in the description to the adapter. I might have to hit the CFO/XYL up for an increase to my ham radio budget to get one of these....
Haha use me as a reference if you need to Steve. The threads on this are M8, I haven’t found an adapter jet but I’m sure there’s something out there. I’ll let you know when I find something. If you’re familiar with navy identifiers I call my xyl NAVCOMMWIFELANT 😂
Walt, on your previous video, I wonder if running a 2.4k bandwidth might give you punchier transmit audio? I saw that you were running 2.8k before. Just a thought...
Hey Walt. I had trouble once getting a good earth on an SO239 mounted on anodise aluminium. The problem might be connection from the back of the socket to the base.cheers Trevor VK3DCQ
Im not sure this is your case, but I found with my homemade version of the PAC12 The higher above my ground plane the antenna the worse it works. I use the meatal screen "Magic Carpet" for a ground plane and if I elevate the antenna more than 3 feet over the screen it wont tune without a tuner.
@@OverLordkv yes I’ve used several end feds and they are absolutely more efficient than this antenna. You can check out my channel, I have many end fed videos. 73, Walt
@@COASTALWAVESWIRESI get a few groundwave contacts from time to time on my activations. Usually all around 5 miles or less. Even had a groundwave P2P contact. I have a good idea of your groundwave contact’s QTH. Not too far from where my grandparents lived when I was growing up. 73!
I have found mine worked best with 3x 4m 20ga silicone wire for up to 20m and a second set for total of 6x 4m for 40m. The factory ribbon didn't work at all for me.
Hi Walt, I bought one of them JPC PAC 12 Antennas, Just to see how it is made, I have found loads of things that make it a bad radiator of RF, The first is what you found A coating on the spike & A bad ground connection at the base, Then there is them screw together sections that are press fit in the ends of each section that causes a bad connection & Rf lost as heat there, On to the coil the wire at each end is just bent round the bolts at each end of the tuning rod & tightened down so another bad connection there. In my opinion it's a very badly designed Antenna.
Interesting, thanks for the info! That also explains why it works so well on 10 meters compared to other bands as it's just the telescopic whip without the screw together sections. I'll stick with my favorite green coil in the future ; ) 73 my friend!
La argolla que tienen los radiales como unión a la base de la antena, aveces no hace buen contacto. Demasiado plástico que cubre la soldadura, o poca superficie metálica en la base de la antena. también demasiado placito. 73
Hi Walt good for you giving it a bash again. Honestly I think this antenna is a fail - there’s no way that the design can rely on a pool noodle s as Atwater amp and still consider it a success. I’ve seen videos where the uhf was taken apart and the connectivity was actually missing - I’m guessing that’s where it is. The only success you had was with the telescopic whip the rest giving multi band capability was a fail of note - I say move on and build yourself the 10m moxon before the band closes
Roger that, I was simply trying to show it's connectivity issue at the spike. It would have probably done as well with a good groundplane instead of the saltwater noodle. Yes I need to get that 10M Moxon built! 73 my friend!
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.
