Two Element Vertical Parasitic Array Antenna - Build & Test

This is the full build and test of my vertical ham radio antenna for 40m. According to the modelling, this should deliver around 4-5dB of extra forward gain to USA from England. The reflector is tuned at 6.8MHz and the Driven at 7.05MHz. Ideally, both of these should be higher up the band. I would like to see 6.9Mhz and 7.15MHz but at the time of writing this description, I am yet to do that - however I think it worked well. We will do a live-stream dedicated to this and I will put a link in the description as soon as that is live. See what you think and let me know if you have built a similar system.
Link to the modelling is here:
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[@radiotests]

Plywood doesnt swell much and the harder you pull on a wedging concrete anchor the harder it grips. KZbin critics are dime a dozen and they don't even deserve a dishonorable mention. You rock Cal!

[@DXCommanderHQ]

Yeah, they are full of ideas. 99% of the ideas / suggestions are totally impractical too!

[@m0aze611]

I’m an old BT previously Post Office telecom lad and we had a field of telegraph poles we trained in as apprentices. Cranmore Boulevard in Shirley. Happy memories but my direction, after my apprenticeship, was Radio and Line Transmission and that was my intro to amateur radio. Nearly everyone in transmission stations were hams and I was the odd one out. Thanks for showing. Mike

[@DXCommanderHQ]

Ah!! OK, my Dad was also a linesman (Royal Sigs)

[@NZFarmersGrowersDirectory]

Back in the 80s we ran a 5/8 vertical on 20 meters. (approx 41ft) Ran 20w QRP SSB rig, did New Zealand to UK on occassion. Big fan of verticals.

[@jameski5oeb668]

You've never done a thing that would be considered impractical, that is what matters! Love it when you make things happen. Great video!

[@DXCommanderHQ]

Thank you!

[@Dreamlgider]

Next test I'd like to see is phasing the verticals, see what diffference it is compared to the parasitic array. Great stuff Cal. 73 OY1R

[@michaelpowell782]

Thank you Cal for another excellent video! Per your other videos on parasitic reflectors/directors I have installed the following system which seems to work very well: My homebrew multi band 80-10 wire vertical (DX commander design) is nestled in the middle of pine trees. I have two elements reflector or directors on 40m that I can hoist up and run either as reflector or director and have nice gain NE or S/W with addition/subtraction of a 3 foot element section using Anderson power pole connectors at each end. The kit include two elements at 31' (7.5MHZ6) and two 3' foot elements (when added for 6.84 Mhz). element spacing from the center driven element is close to the 8.5M (28 feet) you use. I have a a nylon horizontal cord with two small pulleys (17M / 68 feet apart) hoisted up approximately 45 feet. Each pulley has about 10' of stretch cord and 80' of paracord for hoisting up the reflector or director. On the ground each reflector/director has 16 x 16' foot radials. I made up two aluminum radial plates with SO239 connector with 4" center conductor with a power pole connector. The radial plates are anchored to the ground with an 18" galvanized nail spike. Each radial plate has a small metal hook for attaching the paracord at full hoist. I quickly check reflector and/or director tune with a NANO VNA. Most of the time I simply use a reflector on 40m as I am not sure if the effort for hoisting up the director provides any substantial TX or RX gain over the reflector. I need to get a ham buddy to hoist up the director per instructions over HTs while I am operational to see if there is any addition RX gain. I also have a similar set up for 20m with four radial plates and radials surrounding the multiband vertical and have two tuned elements (director and reflector) aluminum poles that connect to the radial plates with power pole connections. I typically take down the 40m direct/reflector elements after I am done operating. I coil the elements & paracord and hang them 6' up on nearby tree trunks...we get deer, elk, bears, mountain lions, coyotes, fox, and wolf running around and they can do a fair bit of damage if a guy line or element is snagged or trampled... I am now using your DX10 antenna wire purchased from DX Engineering for my antenna projects...very nice wire! Next project will be a reflector for 80m so I can have gain to the east from NW Montana.

[@DXCommanderHQ]

Great fun! Good work :)

[@thomasperina2990]

Hello Lord Callum: Thank you for this video sir. Love your new antenna experiment in your outdoor antenna farm especially since your trusted & loving sidekick is always with you. I spose you miw your own grass in the field but don't you have to take up all of those radials that are in the grass. God Bless & stay safe dir, TMP, Unit 22, from N.J.

[@DXCommanderHQ]

The radials were hidden a week after installation.. I can't find them now.

[@Stef-in-the-Philippines]

When you do your phased 40m vertical experiment, you'll be able to switch directions. That will give you a positive confirmation of gain. You can test both receiving and have the other station give you two signal reports -- one firing at him, the other pointed away. (Assuming he can hear you when you are pointed away from him!) Great videos, Lord Callum -- blessings from the Philippines

[@DXCommanderHQ]

That will become clear when we go with the triangluar array which as roughly same gain as a 2-element but in three directions.. Should be fun!

[@PenryMMJ]

Well you see Callum, if you get a volcanic eruption like they are having in Iceland, then that set up just won't be strong enough. Just because there hasn't been any volcanoes in the area for a couple of million years, that's no excuse for not being cautious. 😁

[@VE9ASN]

Raced to get a new ocfd up to have a listen for you, good luck!

[@robertmeyer4744]

looks great. for 12V out in field just use small battery. relay does not take much. you can even make up a remote switch . just as long as RF from station does not trip it. if you got extra control lead in your under ground cable just use one. ground outher side or relay. then just send 12V from shack to relay to switch the reflector. love to see you trying things. makes a great video. hope to hear you better in the US. I am in Boston NY . just off the side the station in NY you worked. 73's

[@fasturn-fc2of]

Rock on Tommy ❤

[@MAV8865]

Cracking Video Cal.. looking forward to "Sunday" night if you can. M7MNP

[@shanerorko8076]

I was only just looking at the 4 square setup on your site.

[@AndyAAzeroAM]

Ahhhhhh, so you can leave a DXCS elements as they are and just put a single reflector for the band ya want.. that's a Top Gear Top Tip right there! I don't know why I thought they both had to be single elements. Thanks for the light bulb moment :)

[@DXCommanderHQ]

Yes Sir!

[@radiotests]

Cal, enjoyed this 2 times today to learn how you are able to teach this basic but honestly killer technique to reflect an already great takeoff angle. You should remind folks it's also a parasitic noise reflector too. 2 birds with one stone, or is it birdies? You have done much to advance the hobby and I greatly enjoy your humble but effective authority in the hobby. Great video production too. The bits of pleasant music gave it a high value! But please no balls and vaseline comments, we wouldn't want the censors flagging good content 😅😂 73 KD9UQE

[@DXCommanderHQ]

No censorship yet! :)

[@Dennisjp-8318]

good show

[@DXCommanderHQ]

Thanks!

[@brianfields4479]

That's a great video.

[@DXCommanderHQ]

Thanks!

[@g4lmn-ron401]

The Telco people with their poles, they are not likely to power up the test rig. It is just for their rookies to climb poles and do the health and safety stuff. They might put portable tone generators on the wires to check the continuity but that's audio stuff. I would absolutely nick a pole for a top band doublet.

[@DXCommanderHQ]

Haha.. Yes, I will :)

[@goddlediddles]

Hi Cal. Great video as usual. Did you measure the parasitic's resonance without spreading out the radials - they seem to be coming away from the plate in a bunch? Does that still give an accurate reading? Many thanks, and please keep uploading great videos.

[@DXCommanderHQ]

I just threw them out and they are still all over the place. Dogs keep moving them when they run.. It's like a triup hazard / obstacle course out there! LOL

[@No7Dumb]

I NOW HAVE A FOUNDATION LICENCE !! AND ITS YOUR FAULT MATE !! well partly vk7hh was my local VK hero But you where way up there .. thanks for the channel... VK4 QRM :)

[@godarklight]

Congrats, although hayden obviously got demoted 3 numbers there :)

[@DXCommanderHQ]

Haha Poor Hayden!!

[@No7Dumb]

@@DXCommanderHQ he's Tasmanian ... It's an upgrade haha ..sorry Hayden.. this is what happens when you trust auto pre dicked.. 😂😂

[@morecambeanglersandtrawler1074]

Would be nice to have a pitch marker and make a circumference circle showing the direction of arrays hi hi lol marks at north south east and west just move classics around circle lol prob not see it for snow soon or markers on fence lol anyways great vids antennas and thanks again cal. Mark

[@paulsengupta971]

Create a circular railway line and mount the reflector on that.

[@morecambeanglersandtrawler1074]

Great idea railway rotator lol

[@jakearkinstall5313]

Idea for an A/B test. Run a coax off the parasitic antenna over to a safe, dry place, then fit it into a shelly. When you remotely switch it "on", connect the antenna to the ground plane. When you switch it off, disconnect. This assumes that the parasitic antenna that is not connected to the ground plane will be effectively the same as having no parasitic antenna at all, and unfortunately I know very little about parasitic antennas, but I think it'd be a fun experiment if you think it stands a chance.

[@DXCommanderHQ]

Yes, I could use a Shelly.. I was thinking that...

[@Tore_Lund]

Your neighbour is friendly, put a director on his lawn.

[@user-bd1pk1rc1x]

I would think you could ring the tower at the airport to let them know when you are making a video. Hope you are all well. Regards Chris M1BZN

[@DXCommanderHQ]

HAHA

[@gwlong]

Great fun!

[@MikeDent]

Hhhmmmmmmmm. interesting. Thanks for sharing this.

[@DXCommanderHQ]

Any time!

[@geoffmcwiggan2814]

Hello old mate. Have you ever thought about a twin driven element with the parasitic at the back ? Cheers mate. 👍🥃🇦🇺

[@DXCommanderHQ]

Yes, so that would be effectively the "Trianglular array (although we'll feed all three when we get around to it..!

[@cornbread-KO5RN]

Is this frequency in use

[@ronleblanc9832]

super experiment

[@DXCommanderHQ]

Thank you! Cheers!

[@BrianFields]

Surely the telecom folks could use some practical experience stringing some long wires from the top of those poles..... 😇

[@DXCommanderHQ]

Absolutely!!

[@srinivasnyayapathi9083]

I started wating this video had a bad headace...... at the end of the video it was gone...... the headace was replaced with more more bright ideas based on this video.... Thanks Callum. 7 3's

[@paulsengupta971]

It's the RF. Obviously good for the brain. Either that or Callum has extended his remote operation into healing.

[@DXCommanderHQ]

Remote healing.. Hmmm. There could be a market!

[@paulsengupta971]

@@DXCommanderHQAntenna advice is the way to heal a radio ham.

[@karlwalker9700]

I've been trying a 2 element for 20m using my expedition pole as the driven element. No matter what I do i cant get any directivity, the reflector may as well not be there .....

[@DXCommanderHQ]

From memory.. Spacing on 40m should be 8.5m so on 20m, about 4.3m. Make the reflector 5% longer.

[@ZeroHarry]

Great video Cal. I was wondering if you could use KY Jelly instread of Vasaline but it appears the KY Jelly should only be used in the bed room.

[@DXCommanderHQ]

Apparently.

[@paulsengupta971]

I have my FT-991 on the bedside table, where should I apply the KY? It doesn't get very hot and humid in there.

[@tomstange7762]

Hi Cal...thanks for all Your videos about antennas and s.o.....what do You think about constructing a bobtail beam...I did it in my previousqth and worked perfectly on 40m...I remember a qso with vr6sc shawn from Pitcairn when I came home at around 06:56 utc oct 14th, 1993, talking to her in ssb with that antenna....btw I enjoy Your channel vy much ...greetings to all of You...73s Tom

[@DXCommanderHQ]

Not yet..

[@limanowski1234]

Hello Callum, I am still puzzled how you derived the initial parameters of the element lengths and and spacing of the elements. You stated a 5% increase in length of the reflector over the driven element length Where did you get this factor? Also the spacing for the 40 meters elements was approximately 8.5 meters. How was this derived? I enjoy your videos immensely and look forward to your explanation. John Limanowski N9DNB

[@DXCommanderHQ]

Just go 8.5m and 200kHz difference between the two, it works. Else I would have to write a chapter! My "percentage" notes are approximate..

[@limanowski1234]

Thanks Cal!!@@DXCommanderHQ

[@nrgxpert]

The default Reflector spacing is 0.2 Wavelengths behind the Driven element, so 300/7.1x0.2= 8.5m spacing to put the wavelengths in phase. The passive reflector is 5% longer. I built the same thing for the 12m band for portable use using two V-dipoles on moveable tripods and it worked great.

[@TFuzz58]

Thanks for proving this out Cal. I would love to try this with my classic and signature 9. Do you think the classic would be long enough to be an effective reflector for the Sig 9? On a totally unrelated subject, I made a contact with Jim, W6LG today and I mentioned that the video you did with him was one of my favourites. He said he would love to do another video with you and I hope you guys can do that. It reminds me of some of the videos you did with Roly when you guys were talking about parasitic and phased arrays. Cheers from Moose Jaw. Tim VE5THF

[@DXCommanderHQ]

Yes.. You can use ANY pole for the reflector.. And you can make the wire any length.. As long as it tunes ABOUT 150kHz longer (lower). I need to run the numbers again. I think I should have been 7.20MHz (driven) and 7.00MHz (reflector)

[@paulsengupta971]

@@DXCommanderHQ Won't you be ok with 7.05 driven and 6.8 reflector? Try FT8 or WSPR and look for the spots. Or CW and reverse beacon thingie.

[@stirlingpark6145]

Calum, what is the difference (in gain) between adding a reflector and adding a director element? I am just thinking that on VHF/UHF we add one reflector and then multiple directors. I am not suggesting 12 forward elements on 40m, but what might be theoretically interesting would be a single reflector with say three directors equidistant from the driven element switchable between the three? One would be directly in front of the driven element and the other two a few degrees either side of this central point, like a trident. Late night Saturday madness... Would that even "model"?

[@DXCommanderHQ]

Reflector (according to the books) adds up to 5dB.. The front director, another 2 .. hardly worth it.. But a total of 7 is appealing.

[@Ran-tan-tan]

16:42 I thought that was your knees making that sound... :P I'm some 20 years your junior and my knees do make a sound not dissimilar to that... :D

[@Ran-tan-tan]

20:05 At my work we had a cold storage, like it was not heated but it was mostly covered from the elements... Rainwater had access to it and did get there (under the sliding doors). We had not that different racking there with three levels of pallets and properly heavy stuff on them. The legs of the racks were shimmed with plywood and we never had a problem. I only have about ten years of data from that, as our company just moved premises to bigger and better one, but I'd say you're pretty much golden with your setup. Edit: This is in northern Finland, so we have pretty harsh conditions that that setup had to endure too...

[@DXCommanderHQ]

Yeah.. Not my knees! LOL... OK with the shims.. Same here :)

[@paulsengupta971]

R.I.P. 40m Asia... Question, does this appear to affect any of the other bands at all?

[@DXCommanderHQ]

No it shouldn't..

[@jaimz33]

What's the commander's overall footprint out to its furthest wires?

[@DXCommanderHQ]

Depends.. You *can* go down to about 7 feet diameter.. You could go even lower but then you might be losing out. Will be doing a test on this shortly..

[@jaimz33]

​@@DXCommanderHQdo you sell the parts you have laid out on the table? M6NZP.

[@cuisinartOH1]

For the landed gentry ham, has anyone tried to make the ground-mount vertical equivalent to a 40m-10m log periodic array?

[@DXCommanderHQ]

Woah!

[@michaelpolimer2128]

would be interesting to see the difference between the parasitic element being a reflector or a director? maybe when you put up the phased array you could switch the third element from a reflector to a director...........lengthen and shorten the wire with a relay or switch a little coil in & out? something to model anyway.........cheers from New England to Old England, Mike, K1FNX near Boston

[@DXCommanderHQ]

Hiya Mike.. I am reliably told (modelling suggests also) that a reflector only is better than a director only (similar to a 2-ele yagi).

[@michaelpolimer2128]

QSL cheers MP@@DXCommanderHQ

[@michaelpolimer2128]

with a 2 element driven phased array (Christman) we can switch the radiating direction very easily. If we add a third parasitic element it would be cleaver to be able to electronically make it either a director or a reflector depending on the "driven" direction. We "know" a 2 element yagi is always the driven element and a reflector, the question is how much "worse" would a driven element and a director be? and/or would it be better to put up 4 elements, drive two and make the outer two fixed reflectors and make the odd one out dissapear? ie what do you get with a reflector behind a driven phased pair?

[@foxonem7dfh257]

Who's music did you use Cal

[@DXCommanderHQ]

Oh gosh.. A lot of different stuff. I have a bloomin expensive (sometimes I wonder why!) account with Epidemic SOund.. I could find them all if you need to.

[@foxonem7dfh257]

No worries Cal, was just interested in artists@@DXCommanderHQ

[@foxonem7dfh257]

If it works Cal why change it, we all have little tricks which work for us.

[@2metercrew389]

👍🏽👍🏽👍🏽

[@eazystreet5507]

I wish you would build a multi band that could fit in a tree. You could fit it over a L bracket that had a 3' support pipe that the antenna would slide over. I have a perfect spot on a Fur tree 130' up. Would be fantastic for 40m. good on 80m 12, 11 and 10 would be great! Any thoughts?

[@radiotests]

Take it from experience and 30 years of Army Signal Corps testing. Evergreens like jungle trees will resonate on any vertical in the near field and will affect the far field pattern out several hundred feet. You honestly have to hoist a swivel off a pvc yard arm to use conifers year round and test your antenna tuning for best REACTANCE and good SWR. You can build a resonator coil around said tree and spiking into the sap bark actually tune up a live tree. Its MILSPEC not joking a way to do secure comms without the mast being seen.

[@michaelpowell782]

If you have two trees of similar height you could sling shot over the tree and hoist up a pulley system. One pulley for each tree and using weights to allow for give during wind storms. Use a 4mm diameter paracord to create a horizontal paracord line from tree-to-tree at a height of say 8-100 feet. In the middle of the horizontal hoist line add 6 small pulleys spaced 10-12" apart, one pulley for each element, Each element pulleys will have 10' of UV shock cord and enough para cord to allow an element to be hoisted from the ground. Build yourself a r12"x12" radial plate out of aluminum plate available at just about any hardware store. Drill and tap for stainless bolts/wingnuts for attaching radials. Take some 1" wide aluminum stock, drill hole for SO239 connector and bend into an L shape and fasten to the radial plate with SS hardware or aluminum rivets. Drill 4 holes large to hammer 12-18" steel stakes into the ground to anchor the radial plate or fabricate anchor using 2' threaded rod buried in the ground. Create another plate 6"x6" for the elements with wingnut connection points for element and RF feed connections from the SO239. Use 2"-3"plastic standoffs. Use the element cut lengths per the details in DX Commander manuals on Cal's various antennas. There will be some interaction between the band elements but using a Nano NVA or antennal analyzer will greatly help in tuning the system. Use Cal's info on radial lengths and numbers. On my home brew 80-10M DX commander style antenna I have 32 x16' radials and 16 x 32' and it works great on all bands. I highly reccomend reading Cal's product manuals and watching his videos. The DX10 antenna wire is pretty nice to work with.

[@DXCommanderHQ]

Try it!