DX Commander Part 2
ฝัง
- เผยแพร่เมื่อ 1 ก.ค. 2019
- Now that I've added 80M and have some time into this antenna, let's talk about what works well and where I still have some tweaking to do.
Want your own DX Commander: Cehck out Callums channel: / m0mcx - แนวปฏิบัติและการใช้ชีวิต
Good product review. I also put faith in Callum’s DX Commander. Very pleased will the quality of the product and the customer support has been second to none. Anyone considering a multi band vertical will not be disappointed with this antenna. Paul
Such a pleasure to watch an informative, no bs, articulate video. Super work. Gotta try one of these sometime. 73.
PS I found the same issue with my hexbeam homebrew wires - nowhere near as rugged as real K4KIO elements.
Matt,
Thanks for your info on the hose clamps with knobs. I now understand the issue. Also your advice re using tape....... but I found differently. If exposed to weather for any length of time prevents the fiber pole sections from collapsing. In my experience they fuse, becoming one section. Thanks for a great set of videos. A great antenna.
Thanks for the detailed analysis. Very useful. 👍
Hi there , I have had mine up with no guys since dec 2018 and no worries . Pvc pipe in the ground three feet , up to first section of antenna . Works great . Just a little FYI . great video .
Enjoy the antenna Matt and Happy 4th to you.
You too Glen!
Thanks for the review. I may try the top guys like you did. Good catch on the pole for long term use. Mine may go portable but I am so green I haven’t had a HF QSO yet.
Good stuff. Happy DX :-)
Matt
Great Video.
Callum is a Great guy and he will help you out.
I am on Disability and can not afford to bye a DxCommander with shipping costs so I copied his design and made my own with my own touch.
I asked Callum before doing this.
I also give him Recognition when I
Tell people about this and I suggest they buy from Callum so as to save all of the headaches I’ve been through lol.
Ps. I have made contact with Callum once on air with my copy.
He sure is. Only qso I've managed so far has been Echolink during his live streams, but I'll get him on 20M one of these days!
Cal must of been up very late !!!!
I haven't a clue what you're talking about. But I will gladly watch anyway.
Thanks Matt for the great video's on the DX Commander Antenna. 73 KN4IFI
Thanks, Matt. I would love to see a time lapse of your POTA setup with that antenna! Happy 4th of July and 73’s - W2RSB (WNY) and F4WCM (near Paris). Over here POTA is still in its infancy but I have a feeling the locals would seriously wonder about my sanity erecting a DX Commander in a tranquil little village park.
Oh people wonder over here too Robin. The DX commander is my best performer, but I also have an end-fed wire antenna option for POTA. When I'm traveling by motorcycle, or headed to a park where the rangers aren't cooperative, the DX commander pole and radial field just aren't feasible.
Matt good video. I had problems with an 80 mtr 1/4 wave wire as a inverted L on a trapped vertical too. It was do to the 66 foot wire being a multilabel wave length of other bands. half wave on 40 etc.. if you leave the 80 meter wire on the mast but disconnect it from the feed point what do you see on 40 to 10? also remember that any losses do to length will reduce your vswr readings by that attenuation. Also the longer the coax it starts looking like the load impedance of the coax. Take your VNA to the feed point for the vertical and connect it to the feed point and see what the vswr is. That might give you some better input.
Thank you for sharing the DX Commander info. You might look into marine grade wire for the elements and ditch the plastic that comes on the "Y" connectors and replace it with the marine grade heat shrink tubing (the stuff with the adhesive in it.) 73
Hi Matt, just some suggestions.....put a tiny loop in the 80 meter wire below the plate where it goes horizontal. you can then tension the vertical portion with elastic. I would also suggest shorter guys. The sharper down angle stabilizes the antenna much better. I've used my in cranky winds(20+) with great success. The 80 meter pulls the antenna over some but no prob. I suggest using 14 gauge for everything and don't cut/tune without the 80 installed. All my bands (80-40-20-17-15-12-10) are well under 1.5 swr. 30 is out of the picture as you found out. One last suggestion run two long radials under your 80. I was screwing around and found this trick. The swr on 40 seems to like these radials. Have fun, you'll love the antenna!
Hi Tony. Thanks for the thoughts! 20 is a light breeze up here on the mountain :) I regularly deal with 50-60, so the two sets of guys are pretty much a requirement, and the stakes are optimized for the top set. When I deploy portable, I use just the bottom ones and they're much closer to the pole. The wire gauge actually makes almost no difference, with the exception of buried radials where it simply takes longer for bigger wires to decay.
40 and up my experience has been that you can pretty much tune them all up individually. For instance, I just added 17M to mine the other day and was able to cut it perfectly on the 1st try. It also had no effect on the other elements. 80M is the bugger because of the capacative effects of the inverted L configuration. I have a video coming up about capacitance and all the interesting ways it creeps into antennas. So you're right that the 80M element really should be in place 1st before tuning the others. In the end I decided that 80M was ruining my otherwise perfect DX Commander and took it down. A dipole setup for NVIS is, for my situation anyway, a more practical antenna for 80 and 160 anyway.
@@MattHeere cool beans...I use mine for camping only....so I didn't ever try to bury radials. I have had great success on 80 anywhere I've set up so it's a keeper for me. From Oregon coast dirt to dry high desert sage, my SWR is always great on all bands... no tuner needed. I always deploy 80.... just too easy.. I dont worry about the end of wire the being much above 6-8 ft high.
Good luck!
I don't think the 80mtr addition is adding "linear loading". It is acting as a capacitive "top hat" and so all the other elements (40, 20 etc) are acting as though they are electrically longer than they physically are.
It is a trick we use in Commercial AM Broadcasting to keep the Tower height down a little. We construct a capacitive top hat to make the Tower work at a lower frequency than its physical height would indicate.
Put out at least four radials cut for 80mtrs and watch the SWR come down to something more tolerable :)
Cheers
Roly - ZL1BQD
It's both really. The capacitive "hat" is certainly contributing, but you see the same effect with fan dipoles too without the inverted L setup. It all adds up.
Already have 4, 1/4 wave radials for 80 in the mix, but more copper would likely help the longer band a bit. My next step is to add a common mode choke and see where that leaves things. It should offset the capacitive tendency a bit.
What Antenna analyzer are you using? It looks like it does a great job. Also, good audio!
Put a small piece of abs as a spacer for the turnbuckle clamps to space them away from the guying plates?
Great job , would love to see it in the field. David Byrd KN4BHS
Matt i use TANK tape on my fibre glass verticals here, never once did i or have i had a problem ..............Like your videos !
Thanks Matt great video. I just ordered a DX commander but haven’t received it yet but I have a couple of questions. I thought the hose clamps were supposed to keep the pole from collapsing? I winter in FL so intend to have the antenna up for 7 months in MI. I would like to keep the radials in place year round. Do think it would work to place the aluminum radial plate on a buried pipe stocking out of the ground a foot or so and then remove the cap from the bottom of the fiberglass pole and just drop it over the pipe when erecting the antenna? Also what antenna analyzer do you use? Thanks, Jim WA8MDC
Hi Jim. The hose clamps do prevent collapse, but they only exist at the joints where there is a spreader plate. I added two more clamps at two other joints where there isn't a spreader, but up at the top of the pole things are really too thin for a hose clamp. Taping all of the joints is easy and seems to work well.
A number of people use various "spike" arrangements to deploy these poles, so what you're suggesting should work. The SO239 is mounted on the ground plate, so if you were leaving it in place when removing the rest of the pole all you'd have to unhook is the pigtail for the center of the coax.
Jim, I leave my base out and have a short piece of plastic plumbing pipe to sit the antenna on. The base cap has a removable centre section which allows this. I have some videos on this antenna if you search. Ian.
Matt I forgot to mention
I also added the 75m wire and it works good but a tad high but very usable.
I used 57’ of wire
As far as the 40 meter SWR going up with the adjacent 80 meter element, wouldn't that be somewhat of a false positive? Meaning, similar to the reflected RF you might get from a gutter or bit of pipe near a roof mounted antenna? It's not an actual reading of the radiation efficiency of your antenna, but instead reading reflected RF from another object, which can be discounted because your antenna is still radiating the same percentage of signal traveling through the coax from the transmitter.
Great video!! Are your SWR readings at the antenna or through 250ft of coax?
At the antenna. They don't change as much as you might think back at the radio, but that much coax is definitely noticeable. I have successfully used the DX Commander - 250 feet of coax and all - on 70cm locally.
Matt
Try trimming your 80m wire a bit and check it
My swr is about 1.5ish in the 75 m range.
Taping the joints is critical. My DX Commander 10m fibreglass pole has been up September to June with not one issue.
Ditto. December to July so far...👍🏻
Great videos! I have his antenna and I am just now putting it together. I’ve learned a great deal from your two videos. I plan on making mine permanent. Callum now has better wire than his D10 which he calls DX10. What do you have on your hose clamps? I’ve been searching high and low for something other than the aquarium tubing and yours looks flat. Thank you so much for your videos, and I’m going to subscribe now. I just passed my general ticket, but only had a couple months in the tech category, so I feel like new to the hobby. Which I am. I’ve enjoyed scanners and shortwave since I was about 10 but took me awhile to buckle down and do this. -73- W1KPS
DX10 (Don 10 from early 20th century british phonetic for D was Don, overtime from Don 1 up to Don10 is numbering of different issues and improvements made for use) is Military grade antenna wire with the kit used by the British Army especially Royal Signals, so tried and tested over the years and improved on Each core has 7 strands of wire, 4 of which are plated copper wire and 3 strands of steel wire for toughness. Ex QDG British Cavalry Moto "For King and Country" Greetings 73s
Mike H I bought his DX50 wire! That stuff is real nice!!
Wait where is the Tubing that is supplied with the DX Commander? It is supposed to be placed over the Hose clamps? Cal did you stop supplying that?
I bought the "bare bones" kit, so all I got was the pole and the assorted plates. Call still supplies all the needed parts in the full kit.
@@MattHeere1 meter of 10mm Aquarium tubing is cut to size, read online PDF for relevant sizes for the hose clamps which is in the DX Commander Kit
Hi Matt. Great two part video on the DX Commander. I'm very interested in getting one. Either the classic or the Expedition. Now that you've had more time with it, what are your thoughts on the Classic antenna? Has your opinion changed? Anything you'd do different? When changing the length of a driven element, does it not affect the swr of the other driven elements as well? Is it worth having the 80 as an inverted L, or would it be better to pursue a different antenna for 80? Thanks for your time and 73. Thor , K0TJT
I still love my DX Commanders. The only reason to get an Expedition is that you have a need for the smaller collapsed size of the pole. The classic is the better antenna in every other respect. It even goes up and down a little easier because the pole is fewer sections.
The elements are far more independent than I would have imagined. Start with the 40M element and work your way down to the shortest wire just to give yourself the most wiggle room. Callum gives precise lengths for the elements if you get the wire from him (which I recommend - I did it the hard way...). Odds are that if you follow those directions closely you will have no trimming to do.
I've had the inverted-L for 80 up several times. It works well, but I always end up taking it down. I don't operate later in the day often and so have little use for the band. I also have to run pretty far from the pole to the nearest tree to support the L - and frankly I think it looks silly. If you want 80 and have the ability to tune for 30 (or don't care about 30M) then the L is a solid option.
The one thing I've changed since this install is to replace the ground stakes with screw in anchors. My DX Commander has blown over twice and both times it was a failure of one of the stakes. First time it pulled out so I hammered it in deeper. Next time the stake just broke. My fault for using wood that wasn't treated for outdoor use. I thought I was putting up a temporary install, but the antenna worked so well I never took it down . Good news is that the antenna survived both incidents with no damage.
@@MattHeere Thank you Matt for the reply! Based on your advice, I think I’d go with the classic then. I don’t think I’m ready for the Nebula antenna yet. So far, 30m has not interested me much. I’m mostly on ssb phone. I liked the advice of electrical tape on the pole to prevent it from collapsing! 73.
@@thork0tjt515 I highly recommend it....I love mine and use it over my other antennas most of the time....I also got some different colored cable ties and put one on each element, elastic cords, and on the spreader holes designating each so I can align and install easily...you'll see what I mean the first time you do a build....good luck!
@@kj6155 Thank you for the input and advice. The colored cable ties seems like a great idea!! 73!
@@MattHeere update here Matt! My “long suffering” wife graciously allowed me to order myself a DX Classic ABV for an early birthday gift! So it’s now ordered! I can’t wait to get it. Thanks for your video and advice. 73!
Matt....I’m new to the hobby and trying to figure out which antenna to get so thank you for these videos. It looks like this antenna is way up in your field....how long is the feed line from your radio?
I have 225' of coax made from 4 pieces of different types of coax with a mix of UHF and N connectors. It's Frankenstein's monster of coax, but it's been working since the video for part 1. I really, really need to do my permanent installation!
@@MattHeere I figure the line loss there must be 30% at least, maybe higher.
@@James_Bowie Depends on frequency. At 30MHz it's close to 2dB which is right around your 30% number. At 20M it's only 1/2 that and then at 40M half again and so on. WIth the bands the way they are I'm really not running anything higher than 20M, so my losses are 15% or less as a rule. This only works though because the SWR is so low. If I had to run the tuner - no way would I get away with this much coax.
Hi! Nice video! One comment about having a less than 2 SWR everywhere above 40 MHz: it might be that your coax loss (250 ft, isn't it?) on these frequencies is so high that the SWR you measure in the shack is much better than it you'd measure the antenna at the antenna feed point. 73 de Frank PA4N
I measured the SWR in the first video using a 25 foot piece of RG8X. The antenna really is well under 2:1 across the entirety of all bands 40 and up. The SWR numbers are artificially better back in the shack with all the coax, but it's largely irrelevant since I wasn't going to be running the tuner anyway.
I'd to see a comparison against the GAP Challenger that I believe is 9m folded dipole
Hi Matt. Is that a PC based VNA? Would you kindly give details?
It is the Metro VNA. It can work either connected to a PC or stand alone. Only problem is that while the range of the meter is 250MHz, the PC software only recognizes it as going to 180Hz, so 1.25M band measurements only work stand along.
@@MattHeere Found it - the MetroVNA Deluxe 250MHZ. from www.metropwr.com. Thanks!
I had the same problem with 30m but I just put up a inverted V. I also stuck a DX Engineering 1:1 choke on it and it reduced my noise. Not sure what I did correctly but I'm under 1.3 everywhere but 1.6 on 10 meters. I am using the DX 10 wire. I'm 100' above the Mon river but I get out great with 100 watts. Oh it works great on 6 meters but bad on 2 meters.
Need any help let me know. KA3OAZ
Thanks John. I wound the 1:1 and have it sitting here waiting to be put in a box. Fat lot of good it does like that :)
Do you have link for spreader plate? It looks nice
It comes with the antenna. Pretty easy to replicate if you have either a 3-D printer or access to simple woodworking hand tools. Alternatively you could check out the DX Commander shop and see about ordering it as a spare part.
You know if I had that much space for a ground radial 'Farm' the I would not be bothering with a vertical.
Well to get the same amount of RF radiated at 5 degrees off the horizon on 40M you're going to need about $10K worth of towers. It's not all about the room.
Do you still use the DX Commander, and has it actually stood up against the wind? Hard to belive it stands up. I am thinkabout buying so any updates appreciated! De WO8USA🇺🇸🇺🇸🇺🇸
Yep. Still up and the only issue I had was that one of my guy rope stakes rotted and broke. So it fell over once and still no damage. Replaced the stakes with screw in anchors and no problems since.
@@MattHeere tbe location looked like it would get wind....any big storms? I've got the MFJ1910 33ft pole, I just imagine only guying it like that and it would stand up!!
Where to buy the DX Commander?
Direct from Callums website: www.m0mcx.co.uk/
I have seen a few videos from the commander and he has said to install all the elements before you make your adjustments to your driven lines , the 80 meter L was installed on a different date.
Had you waited until you were able to install the 80 meter to make your adjustments I think you would have gotten close to the first results you had.
There is to many ham operators that talk highly about the DX COMMANDER ANTENNAS. good luck from KG5ZLO
If I was you, since you have so much space I'd probably stick up a separate 160/80m antenna and leave the DX Commander for 40m+ That 80m really seems a bit of a compromise compared to not having it.
Please do go over the parks on the air and using the DX Commander for it I'd like to see it!
I ultimately want to put up a more permanent, self-standing pole and use the basic design of the DX commander for a 40-6 vertical. I'll likely use that same pole as one end of an off-center fed 160M dipole that should work well on 80 too.
I did want to understand how this configuration works though, as 80 is often handy when operating portable in the evenings. I don't think it's so bad. The differences in SWR are measurable, but not big enough to make any difference in real-world performance, even with my long coax run.
@@MattHeere Sure for portable it's a great solution. But you could do a 160 delta loop or a 160m half wave end fed too as an alternative I guess. Having two different types can be nice at home - with spilt VFO's you can have RX on one and TX on the other if it's better.
I’ve used my DX Commander base and a 1/4 wave wire for 160m too 👍🏻
@@MattHeere Have you read the DX Commander PDF for setting up the 80m band.... size of length (19.5m) to the Vertical attaches where the 30m was, and how long the inverted L will be and folding back, longer cut check the fold backs for the Frequency you can match checking SWR at base Radiating Plate and check at Rig, if good do not ATU at your Rig if built in if bad try retune with Rig if ATU is built in, just a thought it is such a great antenna for the price. 73s Greetings from the UK :-)
@@mikeh9446 Read it and tried it. It works well although you need to be prepared to re-tune the rest of the elements if you add it later. It has a "capacitive hat" effect that tunes everything else down. In the end I decided that I like the clean look of the thing as is for 40 and up, so I took the inverted-L down. I might put it back up though as I don't have a better permanent solution for 80M. I have an end-fed 1/2 wave for 80M that works great, but no good way to put it up for long term use.
When you purchase an extendable antenna that is supposed to be designed to be out in the elements for any length of time, and it collapses because of rain...It's a design flaw.
(short and simple)
It's designed to be temporary/portable. If you fully seat the pole the antenna is fine in rain for days, maybe weeks. If you need longer than that you add $0.25 worth of electrical tape to the seams and it'll stay up forever. Mine's now been up through an awful WPA winter with zero problems. A telescoping pole isn't exactly a new design. It has limitations, like all designs. That's hardly a "design flaw". A steel tower has weight and wind load limits, and will eventually rust and collapse. Are those "design flaws"?
As Matt says, it was not designed to be a permanent installation. That said, one of Callum's friends in the UK had it outside for around 12 months and it withstood everything except -- not unexpectedly -- strong winds.
@@MattHeere if you get a bicycle racer tube size 700, cut it and put through the jubilee clip and tighten on the sections, they won't slip down even if water gets in pole
Drill holes and tap or through and through some bolts.Won't collapse then
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