G7FEK Limited space antenna comes of age.

Posted by Mike G7FEK on Thu, 05 Feb 2009 01:15:10 +0000

A small antenna for all amateur bands, including 80 meters, and in a small garden without the compromise. This is the latest version.

This year it will be 21 years since the very first application of my limited space quad band antenna idea - doesn't time fly by!!. During 2008, a revised version was born.

An Ideal replacement for your 1/2 sized G5RV or Windom 40

Designed specifically for small gardens, it is an ideal replacement for those half size antennas such as the 1/2 size G5RV and Windom 40 (51 ft and 66 ft long respectively). This smaller antenna will give six bands, including 80 meters as a resonant band with a full size 1/4 wave element. On this antenna, tuning on 80 is not an issue and it will easily outperform the 1/2 sized antennas by 10's of dB on this band.

Only 46 ft long x 24 ft high
Multiband operation including 80 meters without traps
Low angle of radiation is dominant on most bands (ideal for DX)
Enough High angle for short skip on 80m (local contacts)
Coax fed for convenience
Low visual impact
Ideal DX antenna for portable working

Tested under the most difficult conditions

Taking advantage of Sunspot minimum throughout 2008 I was able to gather feedback from users and more technical data in order to improve the design further. Combined with data from blind testing on various regular 80m nets in 2007, this has led to the conclusion that, on 80 meters, this modest 46ft antenna performs slightly better than full size dipole for DX, and almost as good for local (short skip) contacts, when installed at the same height (24 ft) with a reasonable ground. It's low angle of radiation and full size elements means that, although it is small, it's definitely no compromise.

More Bands

EZNEC VSWR Plot for the antenna with a typical ground.

Originally designed as a quad band, the antenna now works on six (seven with the 20m element added) bands at an easy to match low impedance, and its dimensions mean that most bands have a low angle of radiation ideal for DX.

Ideal home brew project

The antenna is incredibly easy to build and will seriously surprise you with its performance on 80m in such a small space. The design is quite flexible and there is good scope for experimentation.

What users are saying

Scott, VE3SCP has recently (Dec 2008) switched from a 1/2 sized G5RV to this antenna. He says: "My first contact was G0EVY on 80m and he gave me a 59 report. I was impressed already. My second contact on 80m was to Cuba, again another good haul." ...." I love antenna design and I am intrigued by this one. For a limited space antenna, this is by far the best I have used." - Note that Scott is in Canada, and running only 100W and at sunspot minimum.

My latest easy to read technical document is available for free download here:

G7FEK 80m Multiband Restricted Space Antenna

Please enjoy building this antenna and adding more bands in your small garden. Please feel free to contact me with your feedback and details of the DX contacts you are making.

LATEST NEWS: G7FEK Antenna Tested at Sidmouth Observatory

Home | Permalink | Archive | RSS | Add Your Comment

Comment by 'Chris DL4FO' on 19 Aug 2024 - comment

“Just worked ZL4GW on 17m in CW. Greg was using your antenna (up 10m) and only 3 watts from his QMX-transceiver. I received hin RST 429 here in Frankfurt/Germany. The antenna really did a great job!”

Comment by 'gary wb8icu' on 10 May 2020 - comment

“i run cw only. would like 3.525 min swr. I am thinking 42 ft and 9 ft for length,would it work? also if i use a tuner would it be best to go to the twinlead,or is the 24 ft coax needed? ”

Comment by 'Eduardo' on 6 Oct 2019 - comment

“Dear friend My name is Eduardo and call letters CO8LY I write to you because I am looking for the diagram of a multiband wire antenna with gain for DX, I built the G5RV and then I turned it into the version ZS6BKW which is the use at the moment. I have read on the internet about the Marconi G7FEK version that you have built and would like Know your opinion and criteria on that multiband antenna. I would like to know if you have better gain in reception and transmission than the ZS6BKW. Your opinion is very important to me. I await your response and a million thanks in advance. Forgive my boldness in writing to you. greetings to your family and a big hug for you Best 73.- Eduardo CO8LY”

Comment by 'John' on 22 Apr 2019 - comment

“I'm wondering if the design scales easily, to cover say, 160m. I'm considering literally doubling the dimensions (76'/16'/48'), instead of cobbling a loading coil into the mix, and playing with additional elements (a la the 20m/15m add-ons). If there's a MMANA-GAL file for the current size, I'd like to remodel it, before trying to build. Thoughts? Thanks! John, W2JF NE USA”

Comment by 'David' on 10 Mar 2019 - comment

“Hi been playing about with this aerial for a year or 2 on 80m it is 1.1 to 1 on 40m 1.3 and partof the 40m element is at right angles which should not work but it does. Had to shorten the ladder line so lengthened the top elements Great aerial on 80m when you look at the size try to tell other guys about it but not easy to explained how well it works . David M0TLX NE England”

Comment by 'David' on 10 Mar 2019 - comment

“Hi been playing about with this aerial for a year or 2 sir on 80m is 1.1 to 1 on 40m 1.3 and pert of the 40m element is at right angles which should not work but it does. Had to shorten the ladder line so lengthened the top elements Great aerial on 80m when you look at the size try to tell other guys about it but not easy to explained how well it works . David M0TLX NE England”

Comment by 'Al' on 5 Aug 2018 - comment

“I would like to make one just for 10 meters! What would the dimensions be for it? Thanks! Al”

Comment by 'G7FEK' on 4 Mar 2018 - comment

“Hi Mike,If you still need help, drop me an email (see contact page).”

Comment by 'Mike' on 4 Oct 2017 - comment

“I just installed the antenna. Followed the directions added extra on the lengths. The ground I put one 65 and one 30 foot. The 65 under the 80 meter leg and 30 under the 40 mtr. My nulls are way too high. Like 4.2 mhz and 7.6 mhz. Any suggestions on changes to the ground?? I did as about a 20 foot section to either side with little change. I'm using 16 gauge insulated wire for ground. As well as the elements.. ”

Comment by 'Mark' on 16 Aug 2017 - comment

“My first antenna was this antenna. Very limited space in my back yard (garden) in the northwest US. I opted to add the second ground wire that I had woven into the bottom portion of my chain link fence. Once I got the hang of my manual tuner, I was working the world. Good local coverage on 80m, good regional coverage on 40m plus the occasional Japan phone contact. Once I got into digital modes, I was working Japan, Australia and New Zealand. I even got an opening in 15m one afternoon and worked the Azores! Moved to new QTH, bought a hexbeam and have up a horizontal loop, but I am going to do another on Mike's antenna. It just seems to be what works for me. Plus Mike answers emails promptly! :-)”

Comment by 'Richard' on 26 Jan 2017 - comment

“hi guys have small garden (55ft)built this antenna solely for 80m with excellent results when I got the the earthing right, worked US and Canada at the appropriate time of day with good reports many thanks G7FEK 73 From Richard G8RAU”

Comment by 'Clive' on 21 Feb 2016 - comment

“Hello. I have put together this antenna and it work very well, vswr low on 80 40 and 15. I recommend it for small spaces. 73 G0fbo”

Comment by 'Bill' on 2 Sep 2015 - comment

“1 meter = 3.28 feet https://www.google.com/search?q=meters+to+feet+conversion&ie=utf-8&oe=utf-8 ”

Comment by 'Tony Keough' on 28 Nov 2014 - comment

“Hi Mike, built the antenna to the construction spec's SWR a bit high shortened both legs bt 150mm. Brought SWR down to a very good reading a little high at the very top of the band could of trimmed a little further but decided to use ATU. Getting absolutely brilliant reports stations asking what type of antenna I'm using I tell them so and they are very intrigued with it. I only use it on 80m. Tnx Mike, Cheers Tony”

Comment by 'Mike, G7FEK' on 12 Apr 2012 - comment

“Hi Dov, 1 foot = 0.3048 metres if you want absolute precision, not 0.33 as you have suggested. So the dimensions are correct: The vertical = 7.4m / The 80m element = 11.7m / The 40m element = 2.5m. In any case, each installation will vary so you should always start with a 1m extra wire to each for end to allow for adjustment to your own installation environment and earth conductivity. Good luck with your antenna. Regards Mike, G7FEK.”

Comment by 'Dov 4Z5DZ' on 11 Apr 2012 - comment

“I built this antenna today. Unfortunately the length in meters as described in the article is wrong!! so the antenna is too short and requires a tuner..... The conversion from feet to meters should be multiplied by 0.33 Good Luck”

Comment by 'Mike,G7FEK.' on 25 Nov 2010 - comment

“Hi Lancelot, The antenna can work 4 bands for me without ATU - They are 80m, 40m, 20m (with 1/4 wave tuning element) and 15m. I can also work upper 27MHz and low end of 28 MHz without ATU. Each persons installation will vary a little depending on your location and earthing arrangements etc.”

Comment by 'Lancelot ' on 25 Nov 2010 - comment

“Hi the dimenssion given is for amultiband or it will also work on other bands without a tuner,i have very limited space,i hope i am not jumping the gun here,as i made my baseplate out of a 10inch round aluminium plate i have.I also made a magnetic loop 5ftby5ft,i can tune it from 14mhz to 2mhz very high Q but i use it to my advantage.Thanks for Mates like you.73's ----VE2SW. ”

Comment by 'Chris G4LDS' on 3 Oct 2010 - comment

“Helo, Been watching and reading up on this aerial. Thinking of trying it as have a small patch surronded by 3 storey buildings!! Have you had any feedback on the horizintal lenghts being slopers as thats the only way I can put it up. Having to use the house as the vertical support (pulley under eves and a rope). ”

Comment by 'Craig' on 22 Nov 2009 - comment

“I'm intrigued with your design and would like to try it. Is the EZNEC or MMANA-GAL modeling file for this antenna available somewhere for download?”

Comment by 'Mike G7FEK' on 20 Apr 2009 - comment

“What did you use for radials? What length, are they on the ground or raised? Have you made the elements longer than specified?. Is there insulation between the end of the elements and the support tree / gutter?”

Comment by 'Andre\' 2E0SKI' on 20 Apr 2009 - comment

“Hi Mike, I finally got round to erecting the antenna this Sunday. I have had to "fold" it so it can fit in my tiny garden though. From above it would look like an "L" and connected to the gutter at one end and a tree at the other, with a fibre-glass pole in the middle. I have only got to the point in the doc were you tune the radials, and I have a question here. Using the MFJ antenna analyser, I am able to tune the lowest VSWR at 3.1 MHz of 1.4, and when around 7.1 I can't get lower then 3. In you docs you say we need to find the lowest VSWR between 3.7 and 7.1, but I seem to be abit out. I tried moving the radials a bit and changing the length but the VSWR just gets worse, so I left were I get 1.4 @ 3.1 MHz. It was getting late so I left the element tuning for another day. Early indications looks as I should be able to tune the longer element easily by making it shorter, but the 7.1 Mhz seems to be way out or influenced by the trees it is attached too? ”

Comment by 'Mike G7FEK' on 6 Mar 2009 - comment

“Hi Andre. Yes you can put the vertical section in the corner of the garden. That should not cause any significant problem. I guess your radials will be following the same line. You could have the longer radial along the back and round the corner, with your short radial under the 38ft section if it is more convenient. Make sure you start with the element wires longer than specified so that you have some room for adjustment.”

Comment by 'André 2E0SKI' on 6 Mar 2009 - comment

“I have been following your updates, and it was great to see you have now done a "live" test from scratch. I do have another question. If I needed to, can I have the radiators at right angles to each other? What I mean is instead of running in a straight line, the feeder is in a "corner" so to speak. I hope I am clear (Friday afternoon syndrome)”

Comment by 'Mike G7FEK' on 18 Feb 2009 - comment

“I have updated the PDF with some pictures and performance information. Please feel free to download it.”

Comment by 'Mike G7FEK' on 8 Feb 2009 - comment

“Hi Andre, I use standard 2.5mm cable in black, plus a standard ribbon type dipole centre at the top. At the bottom I use a Coaxial dipole centre on its side, making sure the coaxial centre connector is joined to the vertical section, and the outer to the counterpoise!!. Another Ham is using two counterpoise lengths. One is 62 feet and the other 35 feet.”

Comment by 'André M6ABS' on 8 Feb 2009 - comment

“I have had an eye on your design for some time. I still have a copy of the article that was on a packet BBS. Now that my doublet broke in the recent snow storm, and seeing I have a small garden, I am going to give your new design a go. What antenna wire do you recommend for your design?”