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Emergency Amateur Radio Club Hawaii = END FED 6–40 Meter Multibander

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G0BVZ:
By happy accident, I found this design and I'm glad I did:

http://www.earchi.org/92011endfedfiles/Endfed6_40.pdf


I made one using stuff I had in the junk box and it works fb. There are no new ideas here but the design is a great combination of known principles
Disadvantages
(1) It needs around 5m of coax feed.
(2) It needs a small atu.
Advantages
(1) Fairly compact & stealthy.
(2) Multiband.
(3) Easily configurable in the field.
(4) Light hookup wire works fb at qrp, easy to have different colour coded lengths for various situations.

There is customer feedback, from those who purchased the antenna from the club, at the bottom of the link above which is well worth reading. It is great that the club encourages folk to build the antenna.

'Experts' may grouch that it is not the most efficient antenna and design XYZ... is better: I say that for simplicity and effectiveness it is hard to beat; the best antenna is the one you have when you want to get on the air!!!

Vic

PG4I:
I know of a dutch company that sell these as a commercial product, see http://www.hyendcompany.com/antenna
Price is around 100 euro. They are very popular over here.

G0BVZ:

--- Quote from: PG4I on January 13, 2014, 11:09:50 UTC ---I know of a dutch company that sell these as a commercial product, see http://www.hyendcompany.com/antenna
Price is around 100 euro. They are very popular over here.

--- End quote ---


Good morning Joop!!

I checked the link you gave and I see their version is made using absolutely first rate materials but there are some differences. They do not claim such a wide frequency range, probably because they also claim that no tuner is needed.  This Dutch company has an equivalent here in UK: http://www.gwhip.co.uk/widebander.htm but this widebander needs an atu.  You pay your money and you take your choice....    :)

My version probably took 90 minutes to make from junk and a small plastic box.  I find light hookup wire pretty durable.  (In summer 2013 I put up a low 40m horizontal loop of hookup wire for NVIS work and it has survived a VERY windy winter so far.)  I'm MUCH more inclined to experiment with wire antennas when the wire does not cost Euros 1.20/metre!!!  Also, for rigging antennae I use green paracord produced by WebTex and sold on Ebay. It costs around Euro12 for a 100m reel. Lots of experiment potential!! It is fairly hard to see and it lasts well.  I guess I must be cheap: but I'm happy to keep things basic. As many folk say, there is merit in simplicity.  ;D

Vic  / off to make coffee

PD7MAA:
Hello OM´s

The Hawaiian enfed has nothing more than a 1/9 UNUN transformer . I build several of these antenna´s but the efficiency is pitiable and can not  be compared with the Dutch antenna´s for a unun type antenna is never resonant  on ham bands and gives a lot of stress at your qrp receiver frontend.

BTW a unun should be build on a FT140- 43 type toroid......
Have fun

73 John

G0BVZ:

--- Quote from: PD7MAA on January 13, 2014, 14:40:06 UTC ---The Hawaiian enfed has nothing more than a 1/9 UNUN transformer . I build several of these antenna´s but the efficiency is pitiable and can not  be compared with the Dutch antenna´s for a unun type antenna is never resonant  on ham bands and gives a lot of stress at your qrp receiver frontend.

BTW a unun should be build on a FT140- 43 type toroid......
Have fun

73 John

--- End quote ---

Hi John,
I guess the best toroid is the one which does the job.
Amidon spec for FT140- 43 "43 Material is used for EMI/RFI suppression in the 20 MHz to 250 MHz range"
Amidon spec for T130-2 is "Frequency Range 2 Mhz - 30 Mhz"

For general QRP HF purposes I'd probably specify T130-2 (That's what I used -Overkill!!); the EARC Hawaii group specifies the smaller T106-2 .  The type 43 material you advise  might be the better choice for upper bands + 6m. I guess it all depends on what you want to achieve, where you want best response to be.

As to resonance, I think maybe it is over rated.  A resonant antenna is only resonant on one frequency. Stray far from that QRG and the antenna is no longer resonant. -But that doesn't make it a bad antenna.  ;D

My wonderful doublet with open feeders isn't resonant on any frequency I can legally transmit on but it really does the business when coupled to a good antenna matcher.  There is great merit in simplicity....

In the days before the military used frequency agile radio systems, they regularly used resonant antennas, but in those days they were also using fixed frequency links!

It was very nice to exchange ideas with you.

Vic

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