Ham Radio - Chameleon Antennas P-Loop 2.0 portable magnetic loop.
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- Опубліковано 20 бер 2019
- This magloop covers 40-10 meters at up to 10 watts CW, 25 watts SSB. I give it a test and overview.
chameleonantenna.cartloom.com...
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Another Ace Video.
Some mention should be made of the declaration that mag loops are intense radiators of non ionising RF.
The advice is that for mag loops, 10 watts needs a safety zone of 1.5 metres..100 watts needs 2.5m. spacing (EIRP) so without remote tuning, hand tuning should be done with the lowest feasible QRP and then sit away whilst operating with the power turned up.
Your explanation of the capacitor just helped me solve a problem I was having with my own loop antenna I've been making. Thanks!
Kevin, I purchased the F-loop plus on Black Friday... saved $100! I haven't had the opportunity to play with it outdoors, 3 inches of MORE snow in Upstate NY last night! Indoors its a great receiving antenna but marginal when transmitting. This really isn't a concern because I purchased it for outdoor/portable use. Also, there is a remote tuner for this antenna, it's costly but available. It's available from DX Engineering and here is how they have it listed - CHAMELEON ANTENNA CHA-RT-RR Remote Tuner/Rotators RT-RR. Oh ya, thanks for opening the enclosure! 73's
Thanks for the in-depth look at the Chameleon antenna system. It looks like a nice compact system and ideal for portable use. 73
Yeah, I have that very model and it works great. I work from inside the house so set up is not critical. I have about a 6 foot reach so I get between the radio and the loop and tune by sound. Then I sit at least 6 feet from the loop. Stays set up, works like a charm. Stay warm, Spring has sprung and it will soon warm up in the desert. W0YVY
Lew Archer, May I ask what band you use when you sit six feet from the loop? Also, what kind of home do you have? Is it a timber and plaster board home, or do you have a standard type of placement in some similar structure? I'm trying to picture a loop in my home in New Jersey. de KQ2E
My house was built in 1923 and had wood siding and old plaster walls. I worked Switzerland on 20 once with my home built magloop and 5 watts ssb.
Excellent video as usual. great Chameleon product as usual.
Thanks Kevin; Great information on this new antenna! Randy. California.
I'm very much liking mine. Even though its heavier than some of light stuff I drag out its a much easier setup.
Best explanation I've seen, thank you..
For windy conditions, perhaps some thin, non-conductive rope from some tent stakes to the center-ish of the loop, tied around the mast, right on top of one of the joints so that it doesn't slip. This would work better than weighting the legs due to leverage. You'll have to try again with your IC-7300 on low power.
Thank you for your very interesting upload on that mag loop I have been thinking of purchasing a vhf loop for mobile opps but they do tend to be a tad expensive, hope it works out well for you.73
Tuning that Cap is about as touchy as leveling the bed of the 3D printer! Glad you made it out there and are having a good time! Hope to see you in east TN sometime 73 K4RJJ
Yo Kevin!:
Great video again. Helps me understand mag loops better. Not for frequency hopping during a contest apparently. Good examination of the product, which I am sure chameleon appreciates! I'll be interested in your further use of this antenna..
73's
de seeker / Jeff WA7LFP
Jeffrey Eide
Excellent point. ..Very valid and sound technical comment but who in his right mind wants to fart about with contests?
I've got a baritone sax stand almost identical to that tripod..No dent but more paint missing!
Great video! That looks like a beautifully engineered capacitor. I imagine it would be easy enough to replace the coax loop with one made of copper pipe.
You could, but it would be less portable.
Enjoyed the video. I have/use a remote (mechanical) tuner and rotator with my Chameleon™ F-LOOP 2.0 Plus. Works well and allows the Loop to be about 25 feet away. I also have the power booster. I have a few pics of the loop in the antenna section on my QRZ page. KC3HUL
I can see the attraction in terms of portability. My issue with these loops is the constant need to retune if you want to move frequencies and basically the price. They do null out noise really well and are often used by home based ops as a 'last resort' antenna if QRM is high. Personally if operating at home I may use one as an RX antenna on the lower bands to improve S/N ratio. In that case a wellbrook loop or its MFJ equivalent are cheaper alternatives.
Fantastic review Kevin well done 73's G4POT
Hi kevin good review of the loop one note bandwidth can be increased slightly by using a larger diameter main loop as a note I just picked up two mag loops 3.5 -11mhz and 13.5-30mhz old capco loop antenna check wimo they still make them the diameter of main loop tubing is 32mm 1.250 big monster tubes they work well too regards Gw7lop
GreatKevin, well done. 73, George, K2WO.
Nice explanation and demonstration. Subbed. I own Alex loop. Any better Tx /Rx with Chameleon especially at 20-40 m? (Alex Loop I don’t think works at 40m)
Hi Kevin, I enjoy your videos. I have a chameleon Loop and how I tune it is with a MFJ 212 matchmaker noise bridge. I have an icom 705 and when I flip on the 212 the null within the noise is obvious on the display and then it's just a matter of twiddling the capacitor knob to get the noise centered on the frequency. That invariably give me the lowest swr and that's without putting out a signal on the air.
Thanks for the video, Kevin. Another thing worth mentioning about magnetic loops is that the shape of SWR/frequency plot depends on the band. The antenna is much more narrowband on 40m, not mentioning much less efficient. I'm looking forward to see the power compensator test. I really don't understand how it might work and my expectations are that it doesn't, definitely not in terms of RF field strength (in terms of heating an air - maybe). I would be happy to be wrong. 73 de R2AUK
Yeah, I'm looking forward to testing it too. I can't imagine how it could lower the voltage at the cap without just eating power or detuning the loop.
Love the fedora
Hell-o old friend!
I wonder if one of the old vernal knobs in additional to the one they have w?ould make the tuning less difficult
Could you please do another video on the VNA? I also don't remember details on your field strength meter. Thanks for the video! 73
Both are covered in previous videos. Search YT for my call and the subject to find them.
Great video Kevin. I have essentially same loop for RX only (maybe 2W TX) that isn’t portable as such but cost about $10 (and I guess I could make it portable for another $10). Video on my You Tube channel. Keep up the good work and hope you are enjoying your motorhome. Cheers, Nick M1DDD
A horizontal support across the centre of the primary loop, holding it into a better circle might not be a bad idea.
The shape is not as important as symmetry, I think. If you shift the center so both sides droop the same, it should still perform quite well.
You can test with any emf meter, Tesla or Gauss output?
That mount that holds the tuning box looks like a picatinny rail mount for a rifle scope.
Very nice review! Nice real test too. I wish you have many contacts with your MLA! 73 Paul OM0ET
Paul you make very good loops too! Neat and clean.
@@eduardopower5254 Thank you very much Eduardo 😊
Hey Kevin, come visit Australia!
Anybody knows who made that exactly capacitor or where can I buy ?
tnx fr the informative video Kevin ! Hopefully I'll have a qso with ya on 20 or 40M?
Hows the job search going ?
73 N8AUM
I've run a lot of QRP on CW....but I've found it an exercise in frustration trying SSB/QRP. Have you tried the RV service net yet?
Yes! I check 8n to the RV nets often.
I like the idea of the small loop antenna but the last time I went to their web site the one I saw was on the plus side of $400 US. Being retired, AKA being on a fixed budget that is a little out of my price range.
I have no need for the loop, very informative anyway, thanks kevin
You aslo don’t want a magloop perfectly round, adjusting the center support pole to make the loop slightly egg shaped con reduce the SWR! I can get way lower then 1.5 by adjusting the shape.
21.31. You're saying that they've wired the twin gang tuning.cap. as a split stator.to avoid current passing the through a lossy earth wiper or bearing. Of course the value of the cap sections is halfed!
My main gripe with the Chameleon loops is that telescopic support. It needs to be more compact when collapsed. I'm thinking of making my own with 2 or 3 svrew-together sections. Also, does voltage rating of capacitors really halve when on parallel?
If the caps are of the same value, the voltage rating will be cut in half. If the are of different values it will be reduced by a different amount related to their average voltage rating. But yes, it is reduced.
@@loughkb Why? If I have an AC source, say 100V, and I apply this to 2 equal value 100V rated caps in series, each cap sees 50V. In this way the 'voltage rating of each cap is doubled' (which it isn't, it just means that the voltage rating of the system is twice that of an individual cap. Now if I have any number of the same caps in parallel, they'll all see 100VAC. The system / network voltage rating is 100V, is it not? Because all the caps see 100VAC. The caps themselves don't change by being in series or parallel.
Think bout the caps as parallel flat pieces of metal with a gap between them. The voltage rating is how high the voltage has to be before jumping the gap, breaking through the resistance provided by the air or other dialecctric material.
Now if you put caps in series, you have effectively increased that gap since you add the gap of each cap together to get the total resistance the arc has to break through.
When you put them in parallel, you are effectively increasing the size of the plates, creating a larger surface area in contact with that resistance and therefore, less resistance.
I have a serious question. I am using ft857d but in a senior house apartment a small balcony. How close to my transceiver can this antenna be? I will run about 20 watts. Gone days of my 100 watts and linear. Sad!
No worries at that power level.
Putting typical capacitors in parallel does not reduce their voltage rating by half. I fail to see how using air capacitors would change that?
I was going on what my teacher back in ITT tech told us. Now I wonder. I know the series increase in tolerance is correct though.
Putting caps with equal voltage rating in parallel doesn't reduce the overall voltage rating of the circuit.
Kevin is the bracket from the pole to the small loop plastic or metal?
The coupling loop is all aluminium, even the short piece that threads onto the top of the shaft.
@@loughkb Wonder if a plastic bracket would change tuning greatly? The tripod and pole are part of the small loop at that point.
@@W4TRI The top of the tripod is your standard thumb wheel nut and molded plastic shell. No continuity to the shaft. That's the ground side of the connector anyhow.
Id be interested to see how much better it is if it were orientated the correct way up. Cap at the top.
Ah, that old argument. Look at the loop. The high voltage is at the cap side, the high current is opposite. Radiation is strongest at the high current points. Jeri Ellsworth set up a rig to measure that.
I've used them both ways, didn't really measure much if any difference in performance.
It's a moot argument.
@@loughkb My vac cap is going in the top of a length of 4 inch drain pipe. Its a design that evolved out of seeing what I can do with what I can get for free. Id be most interested in finding a stepper motor and ready made controller to auto tune it and follow an Icom or Yaesu radio. The F loop or Alex loop or Alpha loop all seem to have the cap at the bottom as its convenient to construct it that way, it dose not mean it works better. I particularly like the manufactured ones with a set of open plates at the top that form a large air cap.
A long thin stick of some sort fastened to the tuning knob would give you an improvised fine tune. Lb5kg
That's a good idea. Maybe I'll 3D print something the next time I'm hooked up to power somewhere.
I think VK3YE does exactly that.
Someone on Facebook wanted to engage me in an ugly argument the capacitance. What I observed is each gang is 500pf, combining both gangs and measuring there and at the rotor connection is 1000pf of total maximum capacitance. But when I only connect my meter to each gang with the rotor between them like a butterfly cap, I get 250pf fully meshed. It's being divided by 4, and I think the other guy isn't visualizing what I am trying to communicate to him. And in this video you are saying the same thing he is. Which is of course correct with pcb capacitors, but in this case it is also doubling the air gap too just like a butterfly which has a gap on each side and the rotor is in the middle and not connected electrically to anything. The charge has to go through one gang of stators, then the rotors, and finaly the other gang of stators. Would you mind looking closer at this because both of my capacitance meters are telling me the same thing I listed above.
"combining both gangs" gives you 1000pf because you are putting two 500pf caps in parallel. When you put two 500pf caps in series you get 250pf.
You're dividing the value of each individual cap in half, not the total you got when you put them in parallel.
@@loughkb So looking at the whole device as one cap was a mistake then? If that's the case your point is crystal clear now. Now why couldn't the other guy say that? Thanks Kevin, most appreciated.
@@JohnSmith-bb2np Yeah, it's two caps sharing the same frame. Sometimes variables will have three or four caps. It's useful when you have something like a radio receiver where you want to tune the vfo and pre-selector filters in unison. Two circuits, two caps.
Yes, caps act inversely to resistors. If you put caps in parallel of 500 pf, you would get half or 250 pf. IF in series, you would get 1000 pf. For the life of me, since the chassis of the caps is one side of the caps, and the plates the other side, I cannot see how you could put them in series.
My MFJ 1886 portable loop far easier to set up and use, but no transmit on it! I'd have to get a license for transmit, but my current location is not forgiving on transmit signals. The Chameleon P loop looks pretty good if I don't build my own.
#chameleonantenna. If the loop 2.0 antenna could get to $299.00 I thinks would sell like hot bread, just think of all the HOA HAM operators, GOV agencies that and purchase a couple at $299.00 price range. Even portable HAMs/POTA customers will be all over this. The price range is important because most Radio operators can not afford nothing more than a 100 watt radio, and a small directive antenna like the Chameleon Loop 2.0 would make a good pair.
it was 299.99 on Black Friday. that’s how i got mine.
We've a CLEARANCE for the CHA P-LOOP 2.0 chameleonantenna.com/shop-here/ols/products/cha-p-loop-20
Chameleon Antenna link reports "not active". } ;~(
We've a CLEARANCE for the CHA P-LOOP 2.0 chameleonantenna.com/shop-here/ols/products/cha-p-loop-20
Nice haircut kg6mn
Nice but incredibly expensive at 400 to 500 dollars.
Black Friday 299.99. I was there , where were you?
everything costs 500 600 bucks more in europe
jerome grzelak that’s odd, Every time i import something from Europe the exchange seems fair.
@@forgetyourlife You have a valid point
I built my friend one for $10 and a pack of kools.