End Fed Multiband Not So Long or Random Wire Moonraker's LWHF
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- čas přidán 21. 08. 2024
- #ThNHR
I have heard many misleading comments given about the end fed long wire/random wire eg. "You can't make DX contacts using a long wire", "a long wire is too long to be usable", "the length of a long wire must not be resonant on any ham band to be usable". With comments like these it is not surprising that new amateurs shy away from them despite their major benefit of being usable on a wide range of bands.
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The "Best" Random Wire Antenna Lengths
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LWHF MULTIBAND END FED LONG WIRE ANTENNA
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Well I installed that wire yesterday. Didn't expect to much from it. First thing: The SWR is not good and mostly around 3 on all bands, on 20 meters even worse...on 15 mts the antenna is 1 to 1.5 without an antenna tuner. You can tune all the other bands with a Manual Antenna Tuner, I used the AT 230 by Kenwood. Tried some contacts yesterday and today on 10 15 20 and 40 meters. Surprising....on 10 Meters I reached India, Brazil and the USA among the usual Russians and South European Stations. On 20 Meters only Europe. On 15 Meters North Africa. On 40 Meters only Europe. But this simple lowcoast wire works...it is installed about 7 Meters high, fixed between two trees. For that small money an absolutely amazing antenna. QTH is JN 39 AM. I recommand for portable use and if you need a fast installation done by yourself to be on air. Rig was an old Kenwood TS 690SAT and 100 Watts, all contacts made in J3E
I built one a few weeks ago, 133ft wire to a 9:1 balun, with about a 17ft wire on the, we'll call it the "negative" side of the balun, & a 50ft coax with a ferrite choke wrapped up in the coax near the radio end. Xiegu g90 tuned it on every band from 160m to 6m. I set it up once as a sloper, & once as an inverted L & made contacts both times. It's long but I wanted to give my radio an opportunity to work on all the possible frequencies. Nano vna showed no resonance anywhere along the frequency range. I'm pretty happy with it.
Counterpoise was the word I was looking for.
I also get 160m-10m on my G90 and 80m-6m on my FT-991a. If I wanted 160m on the FT-991a I would require an external tuner but as I have a G90 I don't really see any benefit there for me.
Thank you for showing and telling other hams about this family of antennas. I agree that what others say about this antenna is very confusing mainly because of the words used like random. Random is a bad word when it comes to this antenna. Just buy one put together and don't worry about the length. Your advice about needing a choke before going into the shack is very important.
Thank you John for a very useful video. I’m a newcomer and I have been looking for something relatively discrete so the 10m version looks to be ideal. I really appreciated your methodical commentary too as some people are so glib they leave me feeing lost. Nick.
Thank you I'm glad it helped.
If you are looking for a great antenna (also a 10m version) you should also see this video:- czcams.com/video/td_hqSn_c94/video.html
That is the whole idea of these "random" antenna lengths. These lengths are resonant on a frequency, but not on any amateur radio frequency. Therefore, they are not for any particular band. Just put one up and see where it tunes. If your tuner cannot handle the mismatch, use a 9:1 Unun between the antenna and your tuner. For 80m- 10m, try the 71 ft length, it is close to a 1/2 wave on 40m and a 1/4 wave on 80m. Tthis can be deployed as a sloper, inverted V, an L or inverted L, a vertical . . . it is very versatile.
Interesting video and great results 👍🏼
Might try one of these. I made my own EFW antenna last week, I used one of those ‘green’ numbers on the link you looked at (41feet) that fits nicely into the garden. The 9:1 balun was something I previously had for shortwave listening and I took a ground to a copper rod in the soil. Had some good results in Europe on SSB but nothing further and it tunes down to 40m with the transceiver ATU. Best results on 15m.
I’d like to try a dipole but too inconvenient getting a centre support up in the middle of the garden.
Anyway, if I try this Moonraker version I’ll report back if there is any improvement on what I am using.
Nice to have you back John hope your well.
I'm getting there.
Hi John, thanks for the video, just wondering if you have done any simplex at all on the Moonraker LWHF ? I've just got the 20m version & hoping to be put up in the next few weeks, as opposed to being on a fence mine is going to be mounted between the house & rear of garage. M7JTF
Unfortunately due to my location (in a valley) I have not been able to do any significant simplex testing however I have used it on a few occasions to good effect for working NVIS.
Hello john ,just came across your YT channel. Am i right in thinking your contacts DX are on digital modes ? Because to work across the pond on 80 m on a 20m end fed is very difficult on 10watts even using morse code? But you managed loads of contacts, well done !
I don't do digital, so I'm not familiar.
As for ant length the idea of the 84 feet on your first chart is to find a happy compromise.
84/ 85feet with a 17feet tail as counterpoise ( same lengh as G5RV ) .
The idea of 9/1 un-un is to transform a impedance of 450 ohms to 50 ohms . A half wave end fed will be very high ohms hence 49/1 un-un is needed .
Try different lengths, if you can get the feed point a bit higher will also help keep the current higher about ground . 73
I use FT8 for ease of generating a range report on the fly. Unfortunately my Morse isn't good. FT8 will get slightly further than Morse and considerably further than SSB/FM/AM. The version I am using in this video is the 10m end fed and 80m to USA is sporadic at best and mainly reliant on current conditions. I would expect better results from the longer versions that Moonraker do but I am limited by the size of my current property. Height is also something that should benefit this antenna.
@@A.R.O.T.A. No prob , tks for responding. Enjoy your ft8 .
The power rating is 400w....it was the last item listed, a little below the wire length
The 400w rating is also known as UK Max for full licence holders and in this case refers to ssb. CW & Data modes are normally a lot less so be sure to ask for a rating specific to these modes if you intend using them.
I only have a UK foundation class licence and can only test upto 10w (far bellow the max rating for this antenna).
@@A.R.O.T.A. Ahh, gotcha....I wasn't aware of the UK limitations, just assumed that was the max for the antenna. As for the CW and Data modes, I've never understood why anyone would use more than a few watts (20 or so).....actually even seems a bit rude when 5-10 watts will do the job...
Amazing - I might get one if it really is that easy. Purely for RX. Have you tried it on 27mhz and how does it perform?
The short version of this antenna has a VSWR on 27mhz is 1.5 without a tuner so should work perfectly well but I have not tried TX on that frequency.
@@A.R.O.T.A.Thanks. I'll be getting one and putting it in ready for when I've done my Foundation license. Question: I want to run it off the top of a Spiderbeam telescopic pole and then down the side of a very old 60ft long outbuilding made of stone. Using plastic cable clips presumably. I'm assuming it's ok to run it down the side of masonry?? I've only get experience with vertical 11m antennas. TIA
Should work pretty good with that setup. Just remember that the feedline or the counterpoise should be kept at least 90 degs from the main radiating element.
counterpoise as in earth?? Feedline as in coax??
Counterpoise as in an extra piece of wire sometimes added to the earth side for better performance (not to be confused with a coper rod imbedded in the earth).
Feedline as in coax yes.
i have just installed the 160m version i have yet to use it for tx but it seems to tune well right up to 6 and it hears well mine is mounted via poles and a tree at 10 meters agl with a 20 ish meter counterpoise on the earth terminal. might i suggest if you are going to keep it up to loop it through to another dogbone insulator at the ba8un end seeing it tensioned straight to the ring terminal made me cringe as the first decent gust of wind its going to ping off.
It is not "tensioned straight to the ring" the 9:1 Un-Un is 5 meters from the shack (as far as I could get it from surrounding buildings) the coax then goes to a 1:1 choke Bal-Un outside the shack with a short jumper to a through window lead and then another 1 meter lead on the inside of the shack.
While The setup is not perfect, it does work.
After I move I will be hoping to be able to improve the setup and add height of the main wire and if I'm lucky I may be able to setup the 160m version.
Thanks for the video, I be interested in a js8call qso on 20m greyline sometime. vk5cz ..
While sj8call should work as well as FT8 I have not as yet tried it. Perhaps soon though.