I Took These Off My DX Commander and This Happened!
ฝัง
- เผยแพร่เมื่อ 30 ก.ค. 2024
- A viewer asks the question - can the DX Commander work without radials? Let's test it!
Yes, use radials... but today it's just a good old fashion unscientific test to try.
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⏱️Chapters⏱️
0:00 Will it work?
0:50 Baseline SWR test
1:58 Let's remove them
3:06 Test #1
4:42 Test #2
6:25 Should you run it like this?
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My own experiments with compromised radials (steel tape measures) of insufficient length, is that you get loads of rf back down the coax as the outer is being part of the counterpoise. I was attempting to do a WSPR test, but the USB connection dropped out as soon as I transmitted. I don't have such problems using the proper length of radials.
Excellent video, was waiting to see just this kind of test. Cheers, K7KS
a good quick test, nothing better than actual real results. Interesting how it differs throughout bands.👍
Thanks for watching Don!
Interesting experiment. Didn't expect it to work with no radials, but with one bunch, wow. And if that bunch was spread around the ground plate, even better I expect. As someone else said, interesting to see what a ground rod would do, not for everyone with different soil / ground though of course. I am glad there are folks like you to do the experiments I wonder about but done NEED to do as my DX pole has a good radial field. Nice video, thanks for doing it.
Excellent video. Thanks!
Missed opportunity Dos! Spread then radials out! Neat test! I knew it would work with just one set of radials - next up would be to demo the radiation patterns as you change how the radials are setup!
Directional test! Interesting. Thanks TO
Great video. Verticals are my go to ant every time, I actually tested Verticals with short radials in exceptionally small gardens and there worked. I just tested my 10 year old 40m vertical with lots of radials vs a new vertical with new radials, new ant was slightly quieter and 1 S point better in to Sweden from zl.
So iam thinking my old radials are disintegrating under ground maybe.
Thanks for sharing, 73.
Thanks for commenting!
lovely practical test ! really enjoyed this. As you say around the 6:55 mark, more radials, even if they are short, are better than no radials. Work with the space you have. I did notice a couple of 'crossed' over radials at the start of your video, its better if you can avoid that, especially further down the radial, it reduces its performance. Fanning them out nicely and with same distance between them really improves anytype of vertical based dipole, its really worth the effort to space, pin and then let the grass do its job taking them into the ground :D
Yeah the birds get in and rustle them up a bit! I would pin them to the grass but this place is temporary, so for now I just spread them out every so often 👍 thanks!
Nice test and you've confirmed what I tried myself.
The SWR kinda skyrockets the lower the frequency is.
I clicked on the video without looking too closely. Big surprise when Hayden's face appeared instead of Callum's. Nice test - maybe another time adding bunches whilst repeating contacts on FT8 would help quantify any TX / RX differences, as well as your VSWR measurements. 👍🏼
Glad you enjoyed it! Thanks Lee, yes Ron in another comment also mentioned trying WSPR on it, might be interesting to compare that over a few days!
This is how all reviews should be.
Very good review of your installation.
This keeps me joining your channel.
Perhaps another thing for your list; the DX commander at 2m height or higher from the ground with 1 elevated radial.....hi
Thanks Gino!
Had a DX Commander Classic and replaced with a DX Commander Signature (so I did not have to run inverted L for 80 meters and wanted an antenna I could leave up year round. Very happy customer.
Nice Chip! I've been thinking of doing the same myself here with the signature classic. The inverted L across the yard here is a pain.
@@HamRadioDX The Signature is noticeably bigger/heavier duty. I did guy it at second and fourth spreader plate. Currently we are having 40 mile wind gusts today and no issues. I put a PVC pipe in the ground about two feet and it sticks up about ten inches above the ground. I set my Commander over it. Not sure it needed it, but it let me put it up and take down by myself (as I trimmed antenna wires).
Nice to see. I've been looking at one and exchanging notes with Callum. Apartment tho, so it will be like a portable type setup tied to the Jeep I believe. Thanks for showing this!
No worries thanks!
@@HamRadioDX Haha, I just was recommended this and forgot I watched it. I bought the 12.4 Signature and surprise, forgot to connect the radials (they were laid out, but...). I thought "oh no, this antenna is crap", then realized my mistake. I connected them, measured again and wow. What a difference!
Mine are in a bowtie because it is behind an apartment building on a green strip possibly 5 feet wide or a smidgen more. Hardest part was wrangling the guy cords!
Fantastic antenna, now if I could find the noise source in the area. (I already checked my apartment and with the hurricane possibly coming, I may have an are power out to check if that does the trick.)
As a reaction to some of the comments, I went and measured the HF & 6m bands at my DX Commander Signature 12.4 with 0,4,8,12,16 and 32 radials as well as inside with 32 afterward.
Interesting results, at least to me.
1) For the most part, the minimum SWR frequency changed a fair bit on every band for each change. Keep that in mind for tuning. Change radials, retune suggested.
2) 10m had better SWR with less than the maximum radials. (1.01, -47.3 Rl with 16, 0.3 Xs, so bang on resonant) As I recall, it is using another bands element.
3) with the exception of that 10m anomaly, the Rl dropped with every addition of radials, with the most significant being the jump from 0 to 4.
4) The jump from 16 to 32 radials lowered Rl by 3-5 dB in the supported bands except 10m.
5) The 50 foot (I think) RG8x I am using definitely affected the results. There is no choke on it at the moment. In some cases lowering SWR on the lower bands and raising it on higher, which goes against the most recent learnings I had that said the coax lowers SWR because of return losses and those are higher at higher frequencies. I can do inside measurements with RG213 once I get the right connectors and put them on as a comparison.
If someone is interested, I can send the spreadsheet with data. One sheet per band within the spreadsheet.
I know someone is going to ask:
80m 1.36 & -16.3dB
40m 1.48 & -14.3dB
30m 1.32 & -17.3dB
20m 1.52 & -13.7dB
17M 1.74 & -11.3 dB
15m 1.09 & -27dB
12m 1.37 & -16.2dB
10m 1.26 & -18.7dB
6m 1.15 & -22.4dB
The software also gave 3dB and 2dB bandwidths around the minimum SWR, but I never transcribed from the screen shots. Nor did I grab screen shots of the Smith charts.
For those wanting to know about TX performance, we are getting the edge of Hurricane Fiona and I'm running WSPR. I have 30m reception from North of Brisbane in Australia and one of the Hawaiian islands as longer distance reports. I'm on the opposite side of Canada in Moncton, New Brunzwick.
I expect as the day progresses, there will be more reports. Unfortunately, I don't have WSPR receive capability at this time.
The antenna is still standing after near 90kph gusts, but we have a few hours of storm left.
I just ordered a classic and was wondering if I will have a problem with my single level house being situated between 2 - 2 story homes. The classic will reach over the 2 story home by about a meter.
I wonder how a ground rod attached in place of the radials would work. I had good luck with that on an EFHW with no counterpoise.
Also curious!! I am planning to put my DXC next to my house which means I only have 180degress of radial placement.... Wonder if i could hammer a ground rod, drill a hole in the plate, and mount it to the rod.
@@havok4103 I would not worry about pattern asymmetry from not having radials in every direction. I at one point had a ring of 8 ground rods around the base of the antenna at about 1m radius, to be honest they did not work well. (Subjectively and by impedance measurement). I have tried various somewhat ridiculous radial arrangements, to be honest stripped down CAT 5/6 cable is super cheap and yields 8 wires, You might be surprised at how well 32 or so radials as short as 2m long work. Ihad plenty of time on my hands so I have many more than that but it is diminishing returns. (I live in an area with conductive soil so results may vary).
many short radials rather than a few long ones. just put down what you can and give it a shot.
see you on the bands de OY1R ...-.-
Exactly! Thanks Reggy
Real issue is efficiency. A dummy load has a low SWR but it is not an antenna. There are plenty of articles and research that show how efficiency increases as radials are added. K9RJ
I get a perfect 1:1 SWR on my 50 ohm resistor, but I can't work anybody.
Would be interesting to run this test on a variety of soil conditions: sandy, clay, rocky, etc, and by the sea.
Nice video Hayden
Have been wondering how it would go with a smaller set of radials, as I’m looking at mounting a Rapide (with a 40m coil) on the back fence
Yes, HOA restrictions as well as wife allergic to any antenna
Phil VK2JDL
PS will be down there in Hobart in early August and looking at activating Mt Wellington on a 2m hand held - need the 4 to get the points - was wondering how I’d go and where to post to give locals a heads up (besides posting on SOTA watch)
Hi Phil,
If you post on SOTA watch or SOTA Goat/Parks n Peaks then the alert should go out. Should be plenty of locals on 146.500!
73
Hayden
Excellent Documentary Video, Hayden. Yes, Lord Callum is a multi Genius if you ask me. I still don't own a DX Commander Antenna yet because for my daily portable Mission it would be too much of an Act of installing and deinstalling. But everyone I made contact with who runs a DX Commander Antenna is happy with it like a Mexico Florida (muddafukka). And she seem to make you happy too. Keep up your good work. 73 & happy Wednesday Evening de YFUG from southwest Germany 💯👍🙋♂️🍻
Thanks Guenter!!
I am thinking about ordering the Signature 9. I have a hexbeam up 30' now and a alpha delta DDEE 40-10M and this would be used to replace the alpha Delta. My question is I have a metal roof on a setting room in the back yard. It is 12' x 12' and I was thinking of installing the signature 9 on the side of this room. Could I use the roof as part of the radials and could i install the antenna about 8-9' up off the ground to the roof line of the little room. What could i expect from this type of install. Love the channel, hope to work you soon as I am always working people in your area. Thanks for a reply.
Hi mate,
I know people who have installed it on the middle of the roof - but I dunno how it would go off to the side - it should work, I guess you'd have to experiment a little bit but I can't see why it wouldn't work.
very interesting. I constructed mine to spec and tuned it as best I could. My SWR has never been down to 1:1. In fact, most bands are 1.5:1 or even higher. 80/30 is just out of spec. I think one reason why is ground conductivity. We have very poor soil around here, and although I'm currently running 32 radials, it's still not enough. Oh well, I just use my HF auto tuner and work it.
That’s it! A 1:5:1 SWR is still pretty good results.. but as you say the tuner sorts out the rest.
Adding radials could actually raise swr. ESP if you go over 2*wave length of radials.
Surely the radials on a vertical quarter wave lower the angle of radiation making the antenna better for DX
newbie questions. What toroid do you use? that's to stop RF coming back down the shield right?. Is the coax RG8? should you normally have a 1:1? balun/unun or does the RF choke toroid replace that?
Hi Michael,
The toroid there is a FT240-43. A few turns around the toroid, I detail it in this video here - th-cam.com/video/r2deRuOXJfI/w-d-xo.html
The coax is just RG-58. No balun or unun is required with the DX Commander but the choke as you correctly mentioned is to stop common mode current flowing down the shield of the coax and into the shack.
A very good test. I wonder how it will work attached to a cyclone mesh fence using the fence as the ground? or a timber fence with a ground wire running along the top of the fence? Food for thought Hayden. 👍🍻
Good question! Unfortunately I have neither of those to test haha!
A great video. Your demo indeed shows how important having "some" radials is! Making the pattern more efficient is the key, and Fancy Hams who try to pump up the power into no radial antenna schemes of all kinds are just kidding themselves, as are those glossy pages of ads that tout them as being good. THAT being said? Of course every antenna is a compromise... IMO Callum is a right square guy with an Honest Antenna that makes Honest Claims. 73 DE W8LV BILL
I've had a Gap Titan DX with zero radials for decades and it works beautifully. I got my DXCC with that antenna.
It’s not surprising is it?, a quarterwave antenna needs something to work against.
Well it has the coax to work against. In any case, as I mentioned - completely unscientific and experimental.
Thanks for the neat video! Lots of good info. Also, looks like you need to update the firmware on the 7300! 73, K8JLW
Yes! I'm several firmware's behind on my 7300! 73 thanks Reid
Great tests! Next it would be interesting to see how it transmits with limited or no radials on wspr, a comparison on how many radials makes a big difference in how it gets out.
A WSPR test would be great idea, thanks Ron! I'll put it on the list!
Even *I* haven't done that test!! :)
I'm sure you could do it better than me - but hopefully for this particular chap he can maybe fit a DX Commander in his backyard with the smallest radials possible and still get on the air!
Hi great video. Sorry I am late to the party 🎉. Nice test. I would love a dx commander.
Motters M7TRS 👍🏽 73
I'd be interested to see how much RF current flows into the vertical elements with and without radials, do you have an RF current meter or field strength meter ? Cheers
No, but I have one I want to order... actually I had a RF probe that I need to build too, I must find that
You can get away with a lot when it comes to radials. I've been using four bunches in each direction, not spread out at all. I'd be curious to see what would happen if you had all thirty radials bunched together with the feed line. I know it would be a bit directional but would it affect impedance much?
Good question - this is what I love about amateur radio, experimentation. I reckon I'll add it to the list of ideas to try!
Probably a broad question but are vertical antennas generally known to be noisy. I have a minimum S6 to S7 noise level with a long wire at the moment.
Talking to guys at the club they think the DX commander will be noisier again.
Hi Ben,
Yes they are as most "man made" noise is generally vertically polarized.
Your noise floor may not improve - or indeed get worse with a vertical. I haven't seen that in my own experience, but that might be my QTH and lack of noise sources dictating that.
I have a local net on 80m that I have been trying to make work. This summer, I got the DX Commander Signature 12.4 and still had issues, but my DX transmit was crazy good from reports. I then put up a resonant dipole inverted V in the same spot and it is only *slightly* quieter, not enough to hear the net. S9 noise most days. Not my apt, did all power off and used battery, same noise.
Perhaps with a lower noise environment, it would make more of a difference.
The improvements in SWR at higher frequencies are likely to be due to co-ax losses.
It may perform better if fed against a ground spike. That would be a better test.
Great idea!
I’ve been wondering if a dx commander would work on top of my shed - barn style all steel. Weather I can use the shed as the radials or if I could have the radials draped on the roof or if they needed to be horizontal. Another problem is it would really stand out up there. Council and neighbours mightn’t be impressed…
Hey mate, yes you'd most likely be able to use the roof - as long as it was big enough (a small garden shed won't be big enough). Just have a couple of good connections between the antenna radial plate and the roof screws.
The neighbors - that might be a different story haha
I run a 1/4 wave vertical for 40mtr band the roof of my shed 12x7 mtr it works very nice
I wonder if a balun at the feed point could allow no radials possibly a 4:1 or even a 9:1?
Sorry I ment to say Un-Un
Depends on the feedpoint impedance of the antenna without the radials. I might get the analyzer out and see what it is.
@@HamRadioDX I just thought that removing the radials would essentially turn it into an end fed 1/4 wave.
While I don't know if it would work at all not being 1/2 wave an Un-Un may help the SWR.
What if you put in some ground spikes instead of radials? SWR drop at higher MHz could be coax loss. Interesting experiment, thanks.
Thanks, interesting idea! I have some stakes already which are used to hammer in guys for the antenna - maybe make use of those and see how it goes?
I'm a complete newb. If I'm not mistaken, one could shorten the length of radials and add more of them, no? Is there a limit on how short the radials can be?
You are correct. What matters is how much wire you have down. You generally want to have several wavelengths total. Yes there would be a limit on how short they can be, as a hundred centimeter long radials would certainly not work very well. As Callum says, just put out what you've got and what you can do, and it'll work. Callum has a good video comparing length vs number of radials.
Removing radials from ANY vertical antenna would give the same results. I'm sure Calum is happy for the free ad none the less :)
Except end fed 1/2 verticals.. they don’t need radials only a counterpoise, which is usually the mounting mast, pole or coax
@@HamRadioDX I like Calum as he is a stand up guy, but is an Antenna manufacturer, who also educates hams in Antenna's meaning Modeling, performance theory etc. I believe there is a danger when manufactures also teach. How can they remain unbiased? Well, they can't because it is a conflict of their interest. I truly believe Calum tries to stay somewhat neutral when he compares his vertical to say a dipole, but notice how he always jumps to 40Meter dipole that someone can't get up 1/2 wavelength high. He uses the disadvantage and all the while flies under the radar so that no one questions the motive. You may not care, and suspect many don't care, but there are some out there that are on to it, and have noticed cult like behavior from his followers (Mentioned in other TH-cam videos by other Educators/Influencers). Please keep an open mind about what I'm saying here, and don't just go into defense mode because this is about awareness. Best Regards 73 P.S. This takes nothing away from DX Commander and Calum's Fan Vertical as I believe it is a good product for the price. No arguments there ;)
the main idea is to avoid using a tuner. There is loss when a tuner is needed. You want the best signal and perfect match so the radio can be a radio and you make more DX contacts
Great practical test but really needs wspr to test actual output. I get perfect swr on 10.6 m (random) endfed from 160 to 10 using internal tuner of 991a but dont get great dx. From uk ft8 I get europe and east coast usa but only got VK once in a year. I can hear the world.
Of course, knowing where you are would help us visualize lol.
A more valid test would be to use an antenna analyzer at the feed point. Your SWR measurements show the loss your coax has. Even with no antenna, the SWR will be lower on 10 and 6. Coax loss “hides” a higher SWR.
Thanks Bruce. As per the video it was a completely unscientific test but you're correct and might be done in a future video.
WB4IVG Laurin here. A ground mounted vertical should not require radials because it is not a Ground Plain Antenna. GROUND PLAINS ARE ELEVATED VERTICAL ANTENNAS, ALSO THEY SHOULD BE ABOUT 45 DEGREES DROOPED. Now does the VERTICAL antenna need a ground counter-poise yes of one sort or another because a vertical of 1/4 wavelength needs both sides of the antenna. It is basically a dipole antenna standing on end. One of my professors told me, then proved it imperically that as little as 5% of a 1/4 wavelength will supply the antenna with a ground field because it is coupled with the real earth ground. In practice we use ground wells at commercial and military 🪖 communications sites these are often filled with copper-sulfate or similar 🤔 leaching salt 🧂 substances. 73 Laurin
If there is absolutely zero room for radials, drive a long ground stake in and connect the braid to that.
One option is to put antenna in a corner and run a single wire from one side of the DXC around the garden and back on the other side making a receiver “loop”. I’ve tried it once with about 100ft of wire and found it worked nearly as well as all my radials spread out in a circle. Also I put it in a corner and run all my radials along the floor bunched together along the fence and that worked just a good but obviously for optimum then a circumference layout works best.
a single ground rod would have helped without the radials
Your radials might work better if you spread them out equally.
Just because the swr is OK don't mean that the antenna is efficient just saying
What you say is very true. However, this is conceptually half of a fan dipole, which is considered a pretty decent antenna for a wire antenna.
The different elements are tuned to resonance like a fan dipole too.
Anyways, the one I have gets fantastic reports, now if I could get my receive noise figured out... noise is the same on the resonant 80m dipole I put up.
Your coax will radiate and make it an off center non reasonant dipole...
Didn´t watch the video sry
:-) Thanks Hayden - VK7ID
No worries mate