Ham Radio - Taking the Chameleon P-loop 2.0 down to 60 meters.
Вставка
- Опубліковано 29 тра 2019
- After modifying the tuning box to work with standard coax, I play around with different outer loops. Kind of worked on 80, but easy to make it work on 60 meters.
Here's the video where I modify the tuning box:
• Ham Radio - Modifying ...
If you like my videos, please subscribe here: ua-cam.com/users/loughkb?s...
If you want me to keep making more videos like this, consider becoming my patron at Patreon: / kb9rlw
Discuss this and other videos on Facebook:
/ kb9rlw
I just recently got the F-loop. One of my first contacts was about 200 miles, 5 watts on 3.993. They provide a second piece of LMR-400 and you double the loop for 75-80 meters.
Great information Kevin keep the videos coming I'm really liking the the antenna tests and your vna scans
Thank you for metric units !!!
I almost used that loop of coax as a jumper for my Elk antenna one day since it’s the perfect length for hand holding working satellites. Damn that would have been a bummer, glad I watched this.. WOW,
Great stuff!!
Thanks Kevin. I'm not very good at math, but now I know a little about pie.
I forgot to mention that Chameleon seems to like your videos too! I found out about this video via Chameleon posting a link in the DIY Magnetic Loop group on Facebook. 👍 👍
I haven't tried the p loop but i have the f loop, the build quality is pretty impressive i think so i imagine the p loop is similarly nice
You can install the CHA P-LOOP 2.0 on a CHA JAWMOUNT with the help of the CHA SS ADAPTER.
Hi Kevin,
I think you need about another 10 inches in length of that loop. The coupling loop is now on the smaller size than what should be needed. 73 WB3BJU
The coupling loop still works fine and the SWR can still be brought down to 1:1. The 1/5th ratio isn't an absolute rule, just a best practice. I've experimented with smaller and larger coupling loops with success. I've also found that in some cases, the coupling loop can be brought up where it's edge is along side the outer loop to bring the SWR down if it doesn't quite get to 1:1.
Out Standing!! Way to go on experimenting. I've got 50 or so feet of LMR400 not being used, I just might try that too. From a couple of other comments maybe you should lengthen the aluminum loop too. I'm watching for more. What I'd like is to used a tuning cap to allow 100W without arcing and still have something I could carry around easily. W0YVY
You'd need a vacuum variable cap. Quite expensive.
@@loughkb Oh, to win the Lotto...
Would a proper 1/5th scale feeder loop lower the range or just broaden the bandwidth?
From past experiments, I don't think it would make enough of a difference to matter. I've found that the coupling loop size can make a difference in how low you can get the SWR. Since it still gets down to 1:1, I think the stock, very well built, coupling loop is fine.
I'm going to make a 'junkbox magloop' for experimental use with a newly purchased G90, especially for use with winlink and JS8Call. I understand that the loop will create high voltage at the main loop 'junction' to the capacitor. Regarding this capacitor for this loop: how large plate distance do the capacitor need to have for a typical QRP setup - say that I want to use the radios maximum of 20W? How high will this voltage be? 🤔
With a larger loop you might want to play with a larger coupling loop to increase performances.
Hey there Kevin,
Nice to see you experimenting away with the loop. As you were standing next to it, it inspired me to ask the following question:
Does the shape of the outer loop also influence the received/transmitted signals?
I think this question needs some more explanation:
Signals are best transmitted / received when the loop is in the correct direction, not being perpendicular through the loop.
If that is the case, whould it matter to change the shape of the outer loop from a nice circle to, lets say, an standing oval form in order to improve groundwave signals or a flat oval to improve nvis?
Keep the video's coming. Nice quality you upload nowadays btw!
73 de PC4AD
My gut says that it probably would change the pattern. But finding out is hard. It would take space and test gear that most of us just don't have access to.
I'm not sure if modeling software could do it or not. I have yet to dig into something like eznec.
Referring back to your previous loop experiments I am surprised that you have not changed the shape of the coupling loop away from standard round to something more flattened. Karl
It's machined aluminum and so well built I didn't want to mess with it.
If you added a capacitor in parallel with the tuning cap in the box, wouldn't that lower the tuning frequency range?
Dennis Thrush great question, I’m waiting for that answer also
Yes. However, it would also make the tuning much more touchy and more difficult. You'd also need it to be a high voltage cap. The RF voltages there, even at only 5 watts input, will be very high.
Hi Kevin good video, but I have two questions. first the 817 shows it's using the rear antenna and there's no microphone plugged in. I may have to get one of these loops to play with. Have a good one
Yes it is using the rear antenna connector, which goes to my switches and swr meter and then to the coax for the loop.
The microphone cable strain relief is clearly visible just to the right of the 3D printed stand holding the radio up.
@@loughkb ok thanks I like that stand wish I had a 3d printer maybe next purchase I make
Interesting. In the UK, portable / mobile operation is prohibited on 60m. I believe this is because we're secondary users to the military, so they want to be sure they could contact you directly if they need you off the frequency. Must be different over in the US?
I had to go re-read through the rules. No limitation on portable operation here.
is it time to make the Power Compensator video? does it affect the tuning (the knob position)? any changes in antenna Q?
Kevin, does the Faraday Loop (feed) stay at the same 20% diameter ratio, regardless of the turns? I have seen a 40% Faraday Loop construction on other multi-turns but I have never built one and I have no experience with multi-turn loops. Thank you for posting the video. Many people love the Magnetic Loop.
I've changed the size of the small loop in past experiments. Sometimes it needs to be bigger or smaller to get the SWR down.
Good morning from Dennis the 🐈.
Kevin, have you worked much 60 Meters? I have not and am wishing for a video of what to expect on 60. Wondering if it would be a good band for Mobile operation due to the fact it is channelized.
Why is there no tuning capacitor across the small loop? Wouldn't that benefit from being tuned also?
Nope. Tuning is simply changing the resonant point of the whole tuned circuit. The coupling loop itself is not a load to be tuned. It couples to the load provided by the tuned circuit of the outer loop and capacitor.
@@loughkb Couldn't this be considered to be an air core transformer? Who ever heard of tuning the primary of the transformer but not the secondary? I think you should try it.
It could be considered an air core transformer, with a capacitor across the secondary creating a tuned circuit there. The 'primary' is just coupling energy to the secondary and has little to do with the resonance of the tuned circuit. If you put a cap across the primary, it would become a second tuned circuit and at a very different frequency and probably throw the whole thing out of whack. Also, it might become a load at an harmonic and eat some power.
That's my thoughts anyway.
We already sell a CHA BOOSTER kit which is a 146" LMR-400 radiator which comes with the 8" diameter coupling loop.
chameleonantenna.cartloom.com/product/cha-booster-kit
Hi Kevin;
How about raising the capacitance instead of changing the loop diameter?
L.
That would work. But you need a high voltage cap, and the tuning would become sharper and more difficult.
@@loughkb Hi Kevin; I just realized the question had already been asked and answered. Sorry, and thanks. 73s L.
I don’t het why the chameleon is so damn expensive. What do they do that I haven’t seen you do on your magnetic projects?
Funny pi. A few years ago the post office decided to change my address from a route to a house number. I now live at pie! 314!
Used to know pi to quite a few decimal places - 3.1415926535... and I can't remember the rest!
J. Williams 22/7 is easier to remember 😂
Hi Kevin! Good video and great Russian flag in the background. 😉
Very expensive type of antennas
have you tried the antenna on digital modes like ft8 ?
I've run PSK31 with success. Other than that, some WSPR beaconing. FT8 is great if you're goal is filling log pages and gathering certificates for the wall. I'm more of a ragchew chat kind of guy.
@@loughkb FT8, like Wspr is great for antenna testing as you can use it to log a few contacts and then review your performance on PSK reporter. Also, for those of us who are QRM challenged, FT8 allows for getting out to DX I can't work from home but have to go portable to get. Great Video
Yo Kevin:!
Great video! Enjoying your experimentation! Still think some STEALTH antenna experimentation would be good also. My main goal is to get on 160 with a G5RV. Have had some success.. What say?
Have some wx comments to be saved for email.
de seeker/Jeff WA7LFP
160 is a tough one. You can use a tuner to load up an 80 meter dipole, but it won't radiate very well and you just won't do well. It's got to be a longer wire.
I had some success back at the house with a 98 foot end fed wire with a 9:1unun and my tuner. Made quite a few contacts.
Nothing like the performance I witnessed over at friends house. He had a half wave dipole that was only up about 20 feet and flat. Signals just booming in and everyone he called could hear him.
Your RV behave like a Faraday cage - so it shouldn't work from the inside anyway!
Not true, RV's are mostly fiberglass. Think of it as an "attic" antenna setup.