EFHW from ARRL


Jim Strohm
 

The ARRL just announced an EFHW antenna that they are marketing. They claim coverage from 10 to 40 on the traditional ham bands, but not 30, 17, or 12.

Their pix show that it looks pretty robust, but at USD$70 plus shipping, it’s a little spendy for many of us.

ARRL dot org. I have no financial interest, but I am a life member of ARRL.
73
Jim N6OTQ



Sent from my quenched-gap spark transmitter.


Russ AB6MU
 

The kit is made by HF Kits:https://www.hfkits.com/build-instruction-impedance-transformer-250w-for-end-fed-antennas/

$69.95 is not an unreasonable price, especially these days. It is also not that hard to make your own EFHW following the same design. There is plenty of information on the internet.


ken WA2MZE
 

Due to the way the maths work out, an 80 meter EFHW antenna WILL cover the 30,17,12, and 24 mhz bands, but  a 40 meter EFHW won't, at least not without a tuner.

On 5/6/22 15:48, Jim Strohm wrote:
The ARRL just announced an EFHW antenna that they are marketing. They claim coverage from 10 to 40 on the traditional ham bands, but not 30, 17, or 12.

Their pix show that it looks pretty robust, but at USD$70 plus shipping, it’s a little spendy for many of us.

ARRL dot org. I have no financial interest, but I am a life member of ARRL.
73
Jim N6OTQ



Sent from my quenched-gap spark transmitter.



Shirley Dulcey KE1L
 

It includes antenna wire and a good enclosure for the unun, and it's rated for 250W which means a larger and more expensive toroid. For us QRP operators it means a bit less loss in the transformer, but also a heavier antenna than one designed strictly for QRP. The price is in line with other similar antennas, and less costly than completely assembled ones like the PAR End-Fedz.

People outside the US who are interested may do better if they order directly from ARRL's supplier, HF Kits.

On Fri, May 6, 2022 at 3:48 PM Jim Strohm <jim.strohm@...> wrote:
The ARRL just announced an EFHW antenna that they are marketing.  They claim coverage from 10 to 40 on the traditional ham bands, but not 30, 17, or 12. 

Their pix show that it looks pretty robust, but at USD$70 plus shipping, it’s a little spendy for many of us.   

ARRL dot org.   I have no financial interest, but I am a life member of ARRL. 
73
Jim N6OTQ



Sent from my quenched-gap spark transmitter.





ajparent1/kb1gmx
 

The poster didn't say 80 and warc or 40 and warc.

His words on bands...
>>>They claim coverage from 10 to 40 on the traditional ham bands, but not 30, 17, or 12. <<<

Look up the antenna and they say harmonic bands from 40M and up, no warc.

I built one for fun and it does exactly what it says.  If cut properly it does 40/20/15/10.
Some have said with a tuner you can "force"  30, 17, 12m and you can to a point
as it will be inefficient and with 100W likely cook the transformer.

You can however cut a wire for any single warc band.

Allison
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due to address harvesting


Russ AB6MU
 

On Fri, May 6, 2022 at 02:37 PM, ajparent1/KB1GMX wrote:
I built one for fun and it does exactly what it says.  If cut properly it does 40/20/15/10.
Some have said with a tuner you can "force"  30, 17, 12m and you can to a point
as it will be inefficient and with 100W likely cook the transformer.

You can however cut a wire for any single warc band.
You could cut the wire for 80 meters instead of 40 meters and it may then work on the WARC bands.


Steven Dick, K1RF
 

If you want to make the kit into an 80 meter EFHW, add a second
FT240-43, glue the two together with a few dots of crazy glue, and wind
the turns as specified. Use your own longer length wire for the antenna
itself. Not a bad price when you add up the cost of all the bits and
pieces and their individual shipping costs in one convenient package
compared to if you making one yourself.
-Steve K1RF

------ Original Message ------
From: "ken WA2MZE" <wa2mze@...>
To: QRPLabs@groups.io
Sent: 5/6/2022 4:34:06 PM
Subject: Re: [QRPLabs] EFHW from ARRL

Due to the way the maths work out, an 80 meter EFHW antenna WILL cover the 30,17,12, and 24 mhz bands, but a 40 meter EFHW won't, at least not without a tuner.


On 5/6/22 15:48, Jim Strohm wrote:
The ARRL just announced an EFHW antenna that they are marketing. They claim coverage from 10 to 40 on the traditional ham bands, but not 30, 17, or 12.

Their pix show that it looks pretty robust, but at USD$70 plus shipping, it’s a little spendy for many of us.

ARRL dot org. I have no financial interest, but I am a life member of ARRL.
73
Jim N6OTQ



Sent from my quenched-gap spark transmitter.








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Pat - N0SHU
 

I built the Steve Ellington EFHW (N4LQ) Special with three 240-52 toroids and 12g wire.  I don't mean that Steve has his own design or anything or that he did anything special, just that he has a couple of great videos on the history of the EFHW and many on building his version of the EFHW.  He uses a beefy enclosure like the one Jim and Russ refer to.  

During the build, my poor old hands could barely get the 12g wire around the toroids.  The only reason I bring this up is that this build, was way over $100, and maybe closer to $175.  I could probably build another for for less than $50 with the parts left over of those I had to buy in bulk, like the vents for the enclosure, stainless hardware, etc.  It's been a great antenna for my shack use, mirroring the performance of my My Antennas 10m-80m version.  I laugh about this a lot, but I built it for kilowatts of power and I doubt I have anything that makes over 15w in the shack.  It was just a fun exercise, and it was nice to build it myself rather than buy another antenna.  

I've enjoyed testing K6ARK's EFHW (a BNC-based EFHW) and KM4ACK's EFHW kit with a winder, as well.  




tmmlrd
 

Should I want to realize a more compact version for QRP only (10-20-40m with total radiator length of 12 m, not so much interested in 80m), may I use a 140-43 toroid instead of 240-43? Would the same number of turns work to obtain the same impedance ratio of 49:1?
Thanks.


Martin DK3UW
 

I use a 41 m EFHW for my station and it works great. About 12 m above ground. I was lucky to get a roll of army twin field phone cable. 800 m makes a lot of material to build antennas from.

Important is to have a pig tail or place the RF choke at ,05 wave length of the lowest QRG.  Works indeed from 80 to 10 m incl. WARC. I don't have 10 m so no experience there and 15 is rare to be really open unfortunately.

For the field day we run an EFHW for 160 m which works on 80 and 40 too.


Steven Dick, K1RF
 

At the risk of extending the off-topic thread, but since you asked, an FT140-43 is fine for QRP but use 3T/21T instead of 2T/14T.  Same turns ratio but better primary inductance for the smaller core. You can also build it as an autotransformer for easier winding (I.E use 21 turns tapped at 3 turns).  Crossover not necessary. -Steve K1RF

------ Original Message ------
From: "tmmlrd" <leo.tommasi@...>
Sent: 5/7/2022 4:40:53 AM
Subject: Re: [QRPLabs] EFHW from ARRL

Should I want to realize a more compact version for QRP only (10-20-40m with total radiator length of 12 m, not so much interested in 80m), may I use a 140-43 toroid instead of 240-43? Would the same number of turns work to obtain the same impedance ratio of 49:1?
Thanks.

Virus-free. www.avast.com


Dave VE3GSO
 

Short answer, yes indeed.  For QRP the toroid core can be quite small, one inch or even smaller.  For example, the output transformer in the QDX is handling 5W, and it is magnetically equivalent to a half inch core.

Dave

On May 7, 2022, at 04:40, tmmlrd <leo.tommasi@...> wrote:

Should I want to realize a more compact version for QRP only (10-20-40m with total radiator length of 12 m, not so much interested in 80m), may I use a 140-43 toroid instead of 240-43? Would the same number of turns work to obtain the same impedance ratio of 49:1?
Thanks.


ajparent1/kb1gmx
 

Steven Dick
4:21am   
,

Your posit on turns vs core size is valid to a point.  IF your doing 20M and up 2/14 might
actually be better but for 80M 3/21 or greater might be the winner.

The problem is its a generalized wide band transformer and for 80 to 10M you have
conflicting requirements of primeary impedance, sore saturation (power) and leakage
inductance.

Then add to that 1:49 may not be optimal for a given antenna as installed.  I've
used 1:36 with success for antennas that are electrically low (like 75M at 40ft).

One last item, end point impedance is at often a guess and rarely measured.
Also like the common center fed half wave dipole  Feed point impedance is 
relative to its electrical height.  

Allison
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due to address harvesting


Jim Strohm
 

Yes and yes. Steven’s answer is very wise and useful too.

If money and physical space were no object, buying the ARRL kit might be a better option, because it comes with everything in the same box. Nowadays, sourcing parts can be problematic — just ask Hans. 😋

73
Jim N6OTQ


Sent from my quenched-gap spark transmitter.


Roger N5RWK
 

One of the better presentations I've seen about EFHW antenna design is here:

http://hamfest.w7yrc.org/wp-content/uploads/2019/06/EFHWslides.pdf

The author shows how adding a compensating coil can enable improved resonance on the various bands.  Myantennas.com sells EFHW antennas using this design, and it works quite well.  It would be easy to add this to the ARRL kit.


Michael.2E0IHW
 


I get a "not found" on this link.

Michael 2E0IHW

On 07/05/2022 15:28, Roger N5RWK wrote:

One of the better presentations I've seen about EFHW antenna design is here:

http://hamfest.w7yrc.org/wp-content/uploads/2019/06/EFHWslides.pdf




jjpurdum
 

Michael:

I dug around and I think the attached paper is the one of interest. FWIW, the EFHW antenna discussed is the one I use here and I'm very happy with it.

Jack, W8TEE

On Saturday, May 7, 2022, 10:31:43 AM EDT, Michael.2E0IHW via groups.io <blumu@...> wrote:



I get a "not found" on this link.

Michael 2E0IHW

On 07/05/2022 15:28, Roger N5RWK wrote:
One of the better presentations I've seen about EFHW antenna design is here:

http://hamfest.w7yrc.org/wp-content/uploads/2019/06/EFHWslides.pdf




D. Daniel McGlothin KB3MUN
 

Pick the 2 EFHW links from this page: https://hamfest.w7yrc.org/2019-prescott-hamfest-presentations/

73 de Daniel KB3MUN
On 5/7/2022 10:31, Michael.2E0IHW via groups.io wrote:


I get a "not found" on this link.

Michael 2E0IHW

On 07/05/2022 15:28, Roger N5RWK wrote:
One of the better presentations I've seen about EFHW antenna design is here:

http://hamfest.w7yrc.org/wp-content/uploads/2019/06/EFHWslides.pdf




jjpurdum
 

You don't suppose it's the same Robert Redford, do you??

Jack, W8TEE

On Saturday, May 7, 2022, 10:55:46 AM EDT, D. Daniel McGlothin KB3MUN <kb3mun@...> wrote:


Pick the 2 EFHW links from this page: https://hamfest.w7yrc.org/2019-prescott-hamfest-presentations/

73 de Daniel KB3MUN
On 5/7/2022 10:31, Michael.2E0IHW via groups.io wrote:

I get a "not found" on this link.

Michael 2E0IHW

On 07/05/2022 15:28, Roger N5RWK wrote:
One of the better presentations I've seen about EFHW antenna design is here:

http://hamfest.w7yrc.org/wp-content/uploads/2019/06/EFHWslides.pdf




Gerald Wolczanski
 

Fellow from the QRZ antenna forum suggests a better version:
https://forums.qrz.com/index.php?threads/the-arrl-end-fed-half-wave-antenna-kit-and-doing-it-cheaper-and-better.770104/

TMMV

Jerry
KI4IO
Warrenton, VA