Nigel Coleman (G7CNF's) 4m Band First to Italy

IW0FFK QSO

England - Italy 4m First; MS - with a Hentenna?

During the day on July 13th 2007, I chatted with Marco, IW0FFK on KST chat. Four meters was again on the radar because the day before, news was leaked and then subsequently confirmed that Italy had been granted temporary experimental access to the band. We agreed that at some point the following day we would conduct a JT6m test but no fixed plans were made.

The propagation had been notably poor and indeed for several days 4m had been quite inactive (here at least). There is a hard-core group of us with 4m that have digital 4m MS capability and for us sporadic E propagation is irrelevant. The opportunity to grab a Country First is more-or-less determined by whether the operators in a new country have the same capability themselves; anything up to 1600km on 4m can be done without even breaking a sweat... More with a little effort.

I did not give a moment's thought to Marco's equipment, rather I presumed that he would be running something like the ERP that the Italian authorities had specified - 25w. Several Italian stations had suggested that they would initially be operational with around 5w to 8w and three to four element Yagis. These conditions unconsciously fixed themselves in my mind and I considered the matter no further.

The following day was a cold and very damp July morning. I hobbled down to the shack with a degree of apprehension; such that I would lose a potential First! Very aware that there might be a posse of MS enthusiasts gathered like a colony of vultures waiting for their pickings, I tentatively powered up the shack and logged in to KST.

To my surprise Marco was already logged in and appeared to be waiting for an S5 station for what looked like a sked but with only one partner ready to go. Not wanting to lose an opportunity I offered myself up as potentially the next person in the queue. Moments later Marco asked if I would like to run with him and I graciously accepted.

Filled with excitement and sense of foreboding (I have been in this position before) we commenced a JT6m MS correspondence. Initially all I could hear were pings and bursts which I am certain were only in my head; I could hear them but the decoder could not, so I guess they were simply constructs of an overactive imagination! Then the signals started to appear in the same reality as me and the QSO was in progress...

The first message I decoded in the QSO was one that I was not expecting to see, now that I was in a sked:-

I responded by convention, sending a report.

It was only a matter of minutes before I saw a reflection with a response:-

A string of RRRR was summarily dispatched :o)

By now you may be thinking, "So what was so impressive about that?" Well, what was remarkable was the equipment Marco was using, let me explain. I am no stranger to MS on 4m and 6m. I have conducted tests over the years in various modes and with differing levels of equipment. In May 2007, IW3SNU and myself conducted a series of MS tests on 6m, each time decreasing power incrementally. This culminated in a successful MS QSO at an output power of 200mW/250mW (not ERP) - yes, milliwatts and MS, no Sporadic E was evident. Granted we were both using 6 element beams at good mounting heights but still an accomplishment nonetheless.

Once the QSO between Marco and myself was completed, he informed me of his condx. I already knew he only had 8w from our chat the day before; his attempts to modify a PA were not completed. What I did not know about was his antenna. I presumed (yes, dangerous) that he had at least some kind of modded TV yagi. I was quite wrong. He informed me he was using a Hentenna which is a type of loop. Marco kindly pointed me to his web page which explained about this quirky antenna. I reproduce the details here to save the opening of another window as I feel it lends well to the continuity of this tale!

Before I elucidate on the Hentenna however, one final note about the day we made this First. Life it seems is never without a sense of irony and later that day the band opened up most spectacularly to Italy. Among the many stations worked that afternoon in SSB and CW was (yes, you've guessed it) - IW0FFK!

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The Hentenna

The following information is provided "as is" for interest only and I do not have any further details. I do not operate such an antenna and I do not support or oppose any claims made by its designers. I can confirm IW0FFK worked me with 8w by Meteor Scatter using this antenna (1550km) :-S

"Hentenna" was developed by Japanese 6m Hams (JE1DEU / JH1FCZ/ JH1YST members) in 1970s.

Finally they got new antenna with good performance, however, it was difficult to explain why the performance is so good, or how it work basically at that time, besides there are many unusual properties. So they named it Hentenna, because, "Hen" means "strange" in Japanese. Anyway, the antenna has good performance and many advantages, it was becoming very popular in Japan. Many of JA stations make it and enjoy their Ham life at Home or in a field. Some Japanese 6m beacon stations are using Hentenna based antenna actually.

I got more than 400 hits using keyword by "Hentenna" on Japanese search engine, but, not many Hentenna information is available in English. I am very happy if we could share the good antenna with many people on the web.

1. Easy to make

It is possible to adjust impedance and SWR perfectly, This means, not so sensitive to make.

No special parts are required. You can use any electric conductor for making the main rectangle

Easy adjustment 2. Easy to build up

If you use thin aluminium pipe and thin wire, you can make this antenna for 6m less than 500g

This means, it is easy to put it higher position in the air. You can also use light mast for it.

As this vertically long antenna, it is easy to install the antenna on a veranda or small space.

Vertical long physically but mainly Horizontal radiation: This is one of the reason this antenna is "Hen".

3. Good performance

Low angle radiation
3-3.5 dBd gain

* Total performance is equivalent to 2-3 element Yagi-uda antenna,

Wide band width

(MMANA Antenna Simulation Software by JE3HHT)

How to make Hentenna

General Formula	Length For 6m
W =1/6 WL	1.0m
H = 1/2 WL	3.0m
S : about 1/10 WL Need to adjust (Points "a" and"b")	0.6m
F : Feeding point	50 or 75 Ohm Feed here by coax cable direct (Balancer feed is preferable)
WL : Wave Length

Above formula is applicable from HF to UHF
W also applicable from 1/10 - 1/5 WL W:1/6 is the standard

Hentenna Basics 1. Basically 1 WL Loop antenna 2. L1 works as 1 loop antenna 3. L2 works as matching section 4. Vertical long rectangle make more gain than ordinal square loop and less impedance. L2 helps the matching and low angle radiation. 5. 3D pattern is like shell of peanut

How to Adjust 1. Move "a" and "b" point to adjust S1 >S Matching Frequency UP S1 <S Frq DOWN ) 2. Even matching point is fixed, SWR may higher than 1:1.5, Try to move points "a": S1 + little / "b": S1 - little to find best position for SWR . (This action makes balancer into hentenna !)

* S1: Adjusted "S" Length

6m Hentenna parts example

1. Horizontal element	12mm diameter Aluminum pipe 1000mm x 2
2. Vertical element	2mm diameter Stainless steel wire 3000mm x2
3. Feeding element	2mm diameter Copper wire 480 mm x2
4. Bite clip for "a" and "b" points	To make adjustment easier

Assembly work Make rectangular using parts 1, 2 and appropriate bolts, press connection terminals. Make feeder elements using 3 and 4 and coax cable. (You can use coax connector at "F" point) Adjust Frequency and impedance moving point "a" and "b"

Remarks : You may use electric conduct materials for the antenna mast, as far as connecting center of horizontal elements. There is no problem to use none electric conduct mast, like FRP, or using isolator for the joint points.