This was my first antenna after I got my general class. The antenna was brand new and given to me by a friend. I put it up on a 30’ mast, inverted V, turned on the radio and heard a dude calling CQ on 20m; he was in Northern Ireland, I’m in southeast Texas. I hit him right away and got a great signal report. I used that antenna for a good while until I wanted to go a bit lower in freq. I could get it to tune up on most of the 80m, but not quite all the way down. It was fine on 6m. The one thing I will caution people about is if you use it for going portable, that wire being uncoated is very susceptible to being kinked when you’re pulling it tight or winding it up. Keep that in mind and pay attention when you roll it out and take it down.
Awesome! I’m looking to build similar antennas so thanks for taking it apart and explaining how it was built! And thanks to MFJ. I may buy one at some point for a reference antenna. 73
Hi, today I came to know (from Dave's video) that the BalUn is not the 1:4 Guenella current BalUn but is an autotransformer with 1:1.8 turns ratio to achieve 136-138 ohm at the feed point to be interfaced with the regular 50 ohm coaxial cable; the article was written by K1BQT, Rick in June 2008 qst issue. He had originally used ferrite mix #43 for both the 1:1 CM current choke and the 1:1.8 voltage BalUn. De VU2RZA
nice video on that offset center fed dipole. this is the one I have and appx 3 years old. The only trouble I has is in NY we have bad winters, my copper corroded after 3 years and replaced with THHN wire. Had about the same tune. I shortened appx 3 in on long side and 1 in on short side. this is how you tune offset center fed. I unsoldered and cut re soldered was easier than that crimp . I have ran a sloper for POTA . works great always stays in the tune range of IC 7300 on the 4 bands. now I am re doing with DX commander DX 50 green wire. I have the MFJ end fed 40 meter 800 watt. about same length and that one does not work as well. sometimes needs a counterpoise. had RFI get into my mic on that one. and snow on the ground effects tune on end fed one . not as much on offset center after I shortened a tad. if using portable just swap out that bare wire. use DX commander DX 10 or 50 . or something like that. great for FT8 . some of them small ferrite cores heat up and make SWR rize. FT8 is high duty cycle. and meant to be low power. great review of that MFJ-2012. it is fun trying different antennas' . a dipole is a dipole. the feed point only changes impendences . 73's
@@TheSmokinApe @TheSmokinApe in a HOA now. portable now. POTA ! all year . re doing my collection of dipoles. DX commander 2024 expedition portable soon. saving up. different parks need different setup. 6 meters open in NY today ! going to be trying different unun and balen out. 64:1 . even a type 61 core . want to do 160 meter again. need wire. a lot. still having fun learning ! 73's
I just watched this one. The balun connected to the SO239 is the voltage balun. This takes your unbalanced 50 ohms from the coax and makes it a balanced 200 ohm output. The pair of ferrites that follow it up take it from a balanced 200 ohm impedance to a more lossy 200 ohm output to the antenna. Probably best to just remove those ferrites and connect the dipole directly to the first balun. Use those ferrites for other projects and more power to the antenna. Cheers.
That is a cool exploration of this antenna. Seems pretty cool! Yeah I imagine that if you were making this a permanent solution you could also mess with wire lengths and get things adjusted to where your match is happier still. Sometimes it's just tinkering running back and forth making adjustments and making sweeps with the analyzer. 73 de N2NLQ
Thanks man! A trick I learned along the way is to use a tablet to remote control the NanoVNA Computer setup from the yard to help stop all the back and forth 👍
I am currently studying for my General and will be purchasing the FT-991A in the next couple of months and I am trying to decide on the right antenna. With MFJ not producing as much as it used to will this antenna be available? Also I live in a Ranch house so my roof is only about 12 - 14 feet. That means I would need a 25 foot mast on my house. I would need to attach that to my chimney. My chimney is not in the middle of my house. What should I use to tie down the inverted V ends? Also I already have a Comet CX-333 Triband antenna on the chimney is it ok to mount two masts to one chimney?
Muck of the MFJ stuff is still available if you look hard enough. That VHF/UHF antenna looks like it’s pretty big and could cause some interaction with the HF antenna if mounted close.
@@TheSmokinApe I’m good there it’s a relatively new roof (5 years). It’s plywood, a butyl rubber then heavy fiberglass tarpaper shingle. Also I have a 40’ length but it’s only about 14’ from the ground. I might have to reconsider getting a mast or 40’ tower. Given what I have to work with is there a better antenna for HF that I should consider?
If you want a better antenna than this (quality and coverage) and to save some money just build a 135' OCF. All it takes is 45' of wire on one end and 90' on the other. 4:1balun at the feed with a simple choke (10 coils of coax with 6" diameter) about 10 feet from the feed point. You can work 80 through 6 on it though 15 M can be hard unless you have an external tuner. I have had mine up for 6 years with no issues whatsoever. Probably have made 3000+ contacts and many are DX all on 100w or less. Palomar makes a 4:1 balun with a built in choke just for this use but it is a bit expensive yet it will save you the extra coax for the choke. Nothing against MFJ but quality control is a roll of the dice.
You had me until you mentioned the coax choke or "ugly balun" as it is sometimes called. Those need to be appropriately tuned to work correctly and don't have much in terms of bandwidth which is the point of the OCF. I am glad it's working for you but you could just wind the coax on a t240-31 toroid for about 10$ and be better off...
@@TheSmokinApe Yes you are right that the coil may not work on all bands. I have had no issues but if I were building a new one I would get the Palomar all-in-one balun/choke and call it done. I may yet add a dedicated choke and remove the additional coax.
@@TheSmokinApe Thanks for the reply. I may try the arm mounting. Also, I sent MFJ Customer Support an email asking the same question. I'll let you know if they respond.
Great video Ape! Would you look at doing a video on 100 watt amplifier’s for the G90 beside the Xiegu XPA 125b? I’ve looked at the Radioddity pax100 but a lot of bad reviews. Thanks!
@@TheSmokinApe Thanks so much. After I watched your video I thought I could only mount it inverted V formation. I just ordered one of these the other day and after I saw your video I thought I ordered the wrong thing. I've been out in the yard all afternoon shooting up my wire in the trees at around 70 ft or so. Thanks again my friend 73s
@@TheSmokinApe Okay so I've had the MFJ-2012 up for about 48 hours now and WOW! it it as an outstanding performer. I've made contacts on it on 40,20 and 10 nothing on 6 yet but I've made contacts from Puerto Rico to The island of Bermuda all the way back to the West coast in to California and Arizona I live in Tennessee and I feel this OCFD dipole was well worth the money! Merry Christmas and 73s.
Thanks Brenda’s Husband,JohnBoyUtah KJ7TBR, living at the mouth of parley’s Canyon with 70 mph wind at least three times / year is an Antenna challenge.😎🇺🇸📡🎙73’s
@@TheSmokinApeI like trees 🌳🌳 as well nothing wrong with that - plus they're super handy for holding up antennas in addition to cleaning the air 😀. My big problem wil be getting the antenna high enough in the air. 73
Oh man that unvarnished wire 😳 still makes my blood boil. MF Junk. Only one month and my diepole swr was al over with no change to antenna. But I could already see the copper starting to rot. Good luck. 🍀
Yes, you are right. The multi stranded hard drawn copper wire is somewhat rigid and would kink easily if a good amount of care is not taken. In my 135' double Zeppelin antenna fed with 450 ohm commercial window line I simply put 3 mm heat shrink sleeves (in 6-10' sections) with overlaps of 8-12", and made it into an insulated wire. That prevented it from being oxidized being smeared with green carbonates.
Thanks Ape. I just bought the mfj2012 as my next antenna. The video was very informative. good presentation. 😎👍
Thanks, glad you liked it and good luck with the antenna 👍
This was my first antenna after I got my general class. The antenna was brand new and given to me by a friend. I put it up on a 30’ mast, inverted V, turned on the radio and heard a dude calling CQ on 20m; he was in Northern Ireland, I’m in southeast Texas. I hit him right away and got a great signal report. I used that antenna for a good while until I wanted to go a bit lower in freq. I could get it to tune up on most of the 80m, but not quite all the way down. It was fine on 6m.
The one thing I will caution people about is if you use it for going portable, that wire being uncoated is very susceptible to being kinked when you’re pulling it tight or winding it up. Keep that in mind and pay attention when you roll it out and take it down.
Totally agree. This antenna performs fantastically well but the hard drawn copper elements leave a little to be desired.
I’ve been real happy with mine, tunes up nicely on 40,20, 18, 10, and 6. Have it about 30 feet in tree, inverted V. It’s exceeded my expectations.
That's awesome, thanks for sharing the experience!
Awesome! I’m looking to build similar antennas so thanks for taking it apart and explaining how it was built! And thanks to MFJ. I may buy one at some point for a reference antenna. 73
Thanks Todd, glad you liked the video 👍
Interesting Ape. I like that you got into the box and explained how it works in there. I didn't know any of that stuff.
Thanks Red, glad you liked it! I try to keep them informative and interesting.
Hi, today I came to know (from Dave's video) that the BalUn is not the 1:4 Guenella current BalUn but is an autotransformer with 1:1.8 turns ratio to achieve 136-138 ohm at the feed point to be interfaced with the regular 50 ohm coaxial cable; the article was written by K1BQT, Rick in June 2008 qst issue.
He had originally used ferrite mix #43 for both the 1:1 CM current choke and the 1:1.8 voltage BalUn.
De VU2RZA
Thanks!
nice video on that offset center fed dipole. this is the one I have and appx 3 years old. The only trouble I has is in NY we have bad winters, my copper corroded after 3 years and replaced with THHN wire. Had about the same tune. I shortened appx 3 in on long side and 1 in on short side. this is how you tune offset center fed. I unsoldered and cut re soldered was easier than that crimp . I have ran a sloper for POTA . works great always stays in the tune range of IC 7300 on the 4 bands. now I am re doing with DX commander DX 50 green wire. I have the MFJ end fed 40 meter 800 watt. about same length and that one does not work as well. sometimes needs a counterpoise. had RFI get into my mic on that one. and snow on the ground effects tune on end fed one . not as much on offset center after I shortened a tad. if using portable just swap out that bare wire. use DX commander DX 10 or 50 . or something like that. great for FT8 . some of them small ferrite cores heat up and make SWR rize. FT8 is high duty cycle. and meant to be low power. great review of that MFJ-2012. it is fun trying different antennas' . a dipole is a dipole. the feed point only changes impendences . 73's
Hey Robert, sounds like you're running an antenna farm!
@@TheSmokinApe @TheSmokinApe in a HOA now. portable now. POTA ! all year . re doing my collection of dipoles. DX commander 2024 expedition portable soon. saving up. different parks need different setup. 6 meters open in NY today ! going to be trying different unun and balen out. 64:1 . even a type 61 core . want to do 160 meter again. need wire. a lot. still having fun learning ! 73's
I use the mfj-2010 almost daily on Ft8 and am completely satisfied with its performance. 73 de KE8NQL.
Awesome! Thanks for letting us know 👍
Man I was just looking at picking up a 2012, you really do have a vid for everything lmao
I really liked this antenna, I know a few folks who have them and are happy with them as well. Thanks for watching RO 👍
MFJ makes some good stuff.
I like them 👍
great vid, i'm not keen on the design(shape) of the main box, how do they propose it should be mounted?
I use the holes on the plate to mount it to a mast or an anchor in a tree.
Thanks Ape!
Glad you liked it 👍
I just watched this one. The balun connected to the SO239 is the voltage balun. This takes your unbalanced 50 ohms from the coax and makes it a balanced 200 ohm output. The pair of ferrites that follow it up take it from a balanced 200 ohm impedance to a more lossy 200 ohm output to the antenna. Probably best to just remove those ferrites and connect the dipole directly to the first balun. Use those ferrites for other projects and more power to the antenna. Cheers.
Great info, thanks for the comment Jerry!
That is a cool exploration of this antenna. Seems pretty cool!
Yeah I imagine that if you were making this a permanent solution you could also mess with wire lengths and get things adjusted to where your match is happier still. Sometimes it's just tinkering running back and forth making adjustments and making sweeps with the analyzer.
73 de N2NLQ
Thanks man! A trick I learned along the way is to use a tablet to remote control the NanoVNA Computer setup from the yard to help stop all the back and forth 👍
@@TheSmokinApe bloody brilliant
This is Why I use a Tuner with These Antennas!
I pretty much always use a tuner 👍
I am currently studying for my General and will be purchasing the FT-991A in the next couple of months and I am trying to decide on the right antenna. With MFJ not producing as much as it used to will this antenna be available? Also I live in a Ranch house so my roof is only about 12 - 14 feet. That means I would need a 25 foot mast on my house. I would need to attach that to my chimney. My chimney is not in the middle of my house. What should I use to tie down the inverted V ends? Also I already have a Comet CX-333 Triband antenna on the chimney is it ok to mount two masts to one chimney?
Muck of the MFJ stuff is still available if you look hard enough. That VHF/UHF antenna looks like it’s pretty big and could cause some interaction with the HF antenna if mounted close.
@@TheSmokinApe what’s your take on attic antennas?
@@JoeKrol people use them with success all the time. Just make sure you don’t have metal lining the roof as it will block RF 👍
@@TheSmokinApe I’m good there it’s a relatively new roof (5 years). It’s plywood, a butyl rubber then heavy fiberglass tarpaper shingle. Also I have a 40’ length but it’s only about 14’ from the ground. I might have to reconsider getting a mast or 40’ tower. Given what I have to work with is there a better antenna for HF that I should consider?
@@JoeKrol maybe a vertical in the back yard? Or an endfed as a sloper?
Ape, how high were the endpoints of the dipole in your test configuration? Thanks for the video.
About 8'
If you want a better antenna than this (quality and coverage) and to save some money just build a 135' OCF. All it takes is 45' of wire on one end and 90' on the other. 4:1balun at the feed with a simple choke (10 coils of coax with 6" diameter) about 10 feet from the feed point. You can work 80 through 6 on it though 15 M can be hard unless you have an external tuner. I have had mine up for 6 years with no issues whatsoever. Probably have made 3000+ contacts and many are DX all on 100w or less. Palomar makes a 4:1 balun with a built in choke just for this use but it is a bit expensive yet it will save you the extra coax for the choke. Nothing against MFJ but quality control is a roll of the dice.
You had me until you mentioned the coax choke or "ugly balun" as it is sometimes called. Those need to be appropriately tuned to work correctly and don't have much in terms of bandwidth which is the point of the OCF. I am glad it's working for you but you could just wind the coax on a t240-31 toroid for about 10$ and be better off...
@@TheSmokinApe Yes you are right that the coil may not work on all bands. I have had no issues but if I were building a new one I would get the Palomar all-in-one balun/choke and call it done. I may yet add a dedicated choke and remove the additional coax.
Would the mounting of the feed-point onto a leg of a metal tower be acceptable, or would the metal structure affect the height above ground impedance?
The metal might interfere, some folks will mount an arm off the tower and then use that 👍
@@TheSmokinApe Thanks for the reply. I may try the arm mounting. Also, I sent MFJ Customer Support an email asking the same question. I'll let you know if they respond.
From MFJ Customer Service: i believe this installation to be sound. the tower leg should not
interfere with the coax lead. thanks for your business.
Great video Ape! Would you look at doing a video on 100 watt amplifier’s for the G90 beside the Xiegu XPA 125b? I’ve looked at the Radioddity pax100 but a lot of bad reviews. Thanks!
Glad you liked it. Goodgame is planning to review that amp, I might see what I can do. Thanks for the comment 👍
what are those white insulators in the package? (what are they called). and where would a person get those?. thanks
People call them "dog bones" they are use with a cable or a cord to keep the elements under tension. I'm pretty sure DXEngineering has them.
@@TheSmokinApe thanks for your time.. have a good one
@@TheSmokinApe thanks for the reply. ordered and recieved my ten pack.
Any downside to getting the 2012 over the 2010 if I’m starting out at 100W station today? It’s not much more $$.
The 2012 is a bit bigger / heavier but no showstopper 👍
Do these have to be mounted an a inverted V formation or can you just put it up it the air between two 100 ft trees?
You can mount them as an inverted V or a flat top 👍
@@TheSmokinApe Thanks so much. After I watched your video I thought I could only mount it inverted V formation. I just ordered one of these the other day and after I saw your video I thought I ordered the wrong thing. I've been out in the yard all afternoon shooting up my wire in the trees at around 70 ft or so. Thanks again my friend 73s
@@TheSmokinApe Okay so I've had the MFJ-2012 up for about 48 hours now and WOW! it it as an outstanding performer. I've made contacts on it on 40,20 and 10 nothing on 6 yet but I've made contacts from Puerto Rico to The island of Bermuda all the way back to the West coast in to California and Arizona I live in Tennessee and I feel this OCFD dipole was well worth the money! Merry Christmas and 73s.
Looking for a ht radio with gps duel band fm am is this possible for about 200 dollars ?
Check out the BTECH DMR 6x2, it’s has all that plus DMR for about 210$
@Temporarily Offline
i need the antenna files and the jucebox file.
www.thingiverse.com/thing:4598906
www.thingiverse.com/thing:2804993
Not that cheap in 2022 , more expensive. Balum Designs has some great Baluns for OCFDP hybrids, no building interference!
Hey Brenda, I am sure it's gone up... And you are right, Balun Designs has great stuff!
Thanks Brenda’s Husband,JohnBoyUtah KJ7TBR, living at the mouth of parley’s Canyon with 70 mph wind at least three times / year is an Antenna challenge.😎🇺🇸📡🎙73’s
@@Brenda-jf2pe hey John, I bet that wind takes a toll!
Did you end up using this or gave up?
Yeah, it works really well.
You are an excellent instructor however you can keep the “save the trees” comment(s) to yourself. I’m here for the knowledge, not the politics.
Hey man, I just like trees 🌲
@@TheSmokinApeI like trees 🌳🌳 as well nothing wrong with that - plus they're super handy for holding up antennas in addition to cleaning the air 😀. My big problem wil be getting the antenna high enough in the air. 73
Oh man that unvarnished wire 😳 still makes my blood boil. MF Junk. Only one month and my diepole swr was al over with no change to antenna. But I could already see the copper starting to rot. Good luck. 🍀
The wire could be a bit better 👍
I have to agree with your point about wire, mine did rot pretty quickly over the winter.
Yes, you are right. The multi stranded hard drawn copper wire is somewhat rigid and would kink easily if a good amount of care is not taken. In my 135' double Zeppelin antenna fed with 450 ohm commercial window line
I simply put 3 mm heat shrink sleeves (in 6-10' sections) with overlaps of 8-12", and made it into an insulated wire. That prevented it from being oxidized being smeared with green carbonates.