Monday, 17 June 2013

The secret of the Hately Cross Field Loop antenna revealed

Now it can be told – how were they built and what was Maurice working on before he died?

Maurice Hately G3HAT (SK)
It was with regret that I learned that Maurice Hately GM3HAT (and latterly G3HAT) had passed away. It appears that he actually died in the spring of 2012, but there was no mention of it in the radio press.

My interest in Maurice's work stems from my enthusiasm for small and stealthy HF antennas. As one of the pioneers of the very controversial crossed field antenna (CFA) theory, Maurice used to make and sell small loops for everything from Top Band to 6m.

His adverts regularly appeared in RadCom and I was lucky enough back in 2002 to review some of them for the RSGB.

BUT! This was on the strict understanding that I didn't reveal how he had configured the matching circuitry. I even had to promise not to break the seals on the boxes.

This I duly did and the review was written and published.

But now that Maurice has died I feel I should reveal how the antenna was constructed and also release details of what he had been working on before his death -  a new form of crossed field antenna that used two loops.

All this information may be too important to be lost and it is presented here so that amateurs can continue experimenting with his ideas. Was he on to something? Did his antennas work as as he said and can we continue developing them?

Steve G0KYA
June 2013

Download a PDF with the details of how the CFLs were built and also Maurice's last secret antenna design.

11 comments:

  1. Hi Steve, The matching/phasing is close to that which i mentioned on the other forum, but your version shows 2x 2turn links from the inner to outer on the input feed ?? is this a typo ? Thanks for the info about the other version, will twiddle when i get some free time. Me, I think he was onto something. My 7 Mhz Job went like a bomb. Paul G4HDS

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  2. As I said in the article, I never actually pulled one apart as Maurice didn't want me to. The diagram came from another ham who bought one and did pull it apart, so I have no idea if it is right or not. There must be one of these laying in a cupboard somewhere that we could inspect - I'll put an ad out there and see if we can't dig one out!

    Steve G0KYA

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    1. Hi Steve, looks like my last attempt at a reply here has gone AWOL. so here goes again.

      I doubt that I would have been able to resist the temptation to go inside... the label would have been steamed off HI. I like your idea of seeing if there's a unit kicking about in a garage or such likes. I have no doubt the the Prof was genuine and the CFA works, its just getting the physical implementation of the CFA built that's the problem. I truly belive the Prof did infact get the FIRST poynting vector aerial working and well predates the EH and such young pretenders. Please keep me in the loop (Pun) if and when any extra info comes to light. P.S. was the MOLE Bob H ?. I was a member of his yahoo group prior to his death, it's unfortunate that when he died so di his group.
      Regards Paul g4hds@ronaunwin.plus.com

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  3. Hi Steve,
    Just put a copy of the HATLEY 7 mhz loop together. The analyser shows an swr at 7.100 of approx 3 to1 at ground level, lift it to about 10 feet and it drops to about 1.2 to 1 looks promising, will try it on a rig tomorrow
    Regards Paul G4HDS

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    1. Excellent - yes, it is a shame about the Yahoo Group. I understand that if three existing members can get together, Yahoo can be persuaded to move ownership to another person. Might be worth a try.

      http://groups.yahoo.com/group/x-field/

      Steve G0KYA

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  4. Hi Steve..

    I am going to be running my WSPR setup during September at 500 mW on 7Mhz with my homebrew CFA. I have updated my matching network with the design with info you released. Should be fun.

    Regards Paul G4HDS

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    1. I'm thinking of buliding a 40m version Paul, so I'll be interested in your results !

      Cheers Chris G0BHX

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  5. Hi Steve and gang, my 7Mhz 500mW beacon goes live with the CFL Sat 31st August going to run it 24/7 for approx 28 days. It will be interesting to get some real world results for the CFL both on RX and TX.
    Regards Paul G4HDS

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  6. Hi Paul - don't forget to tell us the frequency! By the way, I will be on the Propagation Studies Committee stand at the Newark Hamfest on both 27th and 28th September if anyone is attending. Steve G0KYA

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  7. Hi Steve, it's in the WSPR allocation at 7.040 Mhz within the 200 Hz bandwidth used by the system Last night the CFL heard VK7FI at 10700 Miles and DU1MGA at approx. 6600 Miles + HS0,K5,W4,KK4, Not bad for a "15 inch loop at 25 feet agl" Watching the Map at http://wsprnet.org/drupal/wsprnet/map you can almost see the propagation changing in real time.

    Regards Paul G4HDS

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