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Author Topic: Just got in some new deviecs for my Johnson 500 finals to try out  (Read 279 times)

N4MQ

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One of my old ham buddies [W0boy] put me on to an interesting new development.  Seems that he works on maintaining Lithotripsy and other medical equipment and they have two pairs of 4-400 type tubes in their acoustic mass driver “finals”. Using focused HIGH POWER audio shock waves in a water tank evidently breaks up kidney type of stones internally without the patient needing surgery. Please see: https://en.wikipedia.org/wiki/Extracorporeal_shockwave_therapy

Whats cool about this is that as a ham he wanted to pass along the info that Fujitsu has produced and is releasing a solid state drop to do away with the tubes. He kids me about the boat anchors that I have been restoring / using these tubes: my Thunderbolt, 500, and Invader so he thought of me.  This SIT* upgrade eliminates the filament and its heat and improves efficiency overall. I was able to order one thru him for my Johnson 500 for only $401, to try it out on the ham bands. 
* See:     https://en.wikipedia.org/wiki/Static_induction_transistor


Its more of a pulse device and not for AM operation but seems at home on SSB with my Johnson 500 & SSB adapter. My Johnson 500 only applies 2300 volts on the 'plate', well below the 3300 volt rating of the AF1-2023.  In the AM mode 'plate' voltage would have exceeded that rating on voice peaks and the resting current would likely have also caused thermal over dissipation.

An 1.3 cu meters/minute flow (35.1 CFM) is needed to ensure proper forced air cooling, Iam just re-using the existing emiac glass chimney and so far have not seen any operational issues. The physical dimensions are very similar to the old 4-400, so the “plate lead” connects without issue, see photos.  An added benefit is that the old screen voltage supply is not needed, so pulling the old OD3 voltage regulator tubes is recommended.   Thought you might want to know about this **Static Induction Transistor (SIT) develop.  I feel that having a HYBRID 1950 era transmitter is kinda cool and Ill be considering adding a pair of the SIT devices to my lnvader 2000 when I can save up the ca$h.

Enjoy Woody N4MQ














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WA2EIO

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Re: Just got in some new deviecs for my Johnson 500 finals to try out
« Reply #1 on: April 01, 2023, 04:39:05 AM »

It is great that they even kept the 'look' of the original tube as much as possible!

 :o
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W3SLK

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Re: Just got in some new deviecs for my Johnson 500 finals to try out
« Reply #2 on: April 01, 2023, 05:29:13 AM »

That's something Woody! I used to work for Dornier Medical Systems years ago. I serviced their HM-3 and HM-4 machines at the time. The home company, Dornier Medzine Technique, kept the internal workings of the shockwave generator a closely guarded secret. I would replace one and send it to Marrietta, GA and then it would be sent to Germany for overhaul. I wish I would have known if that was in there. We were always told it was a bank of caps and would fire anywhere from 18Kv~25Kv on a brass spark plug while submerged in water. Of course at the time I wasn't involved in AM or radio at all. I got my license at a rather late age. Not because of want but because of circumstance.
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KB7TT

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Re: Just got in some new deviecs for my Johnson 500 finals to try out
« Reply #3 on: April 01, 2023, 08:57:42 AM »

Has anyone bothered to look at the calendar today????
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WA3SKN

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Re: Just got in some new deviecs for my Johnson 500 finals to try out
« Reply #4 on: April 01, 2023, 10:02:42 AM »

I have decided to bring back "spark"!  No silly filaments to worry about, no plate current, etc... Just a power cord, a key, and one transformer... ONE!
Think of the simplicity!

-Mike.
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W3RU

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  • Posts: 75
Re: Just got in some new deviecs for my Johnson 500 finals to try out
« Reply #5 on: April 01, 2023, 10:12:25 AM »

One of my old ham buddies [W0boy] put me on to an interesting new development.  Seems that he works on maintaining Lithotripsy and other medical equipment and they have two pairs of 4-400 type tubes in their acoustic mass driver “finals”. Using focused HIGH POWER audio shock waves in a water tank evidently breaks up kidney type of stones internally without the patient needing surgery. Please see: https://en.wikipedia.org/wiki/Extracorporeal_shockwave_therapy

Whats cool about this is that as a ham he wanted to pass along the info that Fujitsu has produced and is releasing a solid state drop to do away with the tubes. He kids me about the boat anchors that I have been restoring / using these tubes: my Thunderbolt, 500, and Invader so he thought of me.  This SIT* upgrade eliminates the filament and its heat and improves efficiency overall. I was able to order one thru him for my Johnson 500 for only $401, to try it out on the ham bands. 
* See:     https://en.wikipedia.org/wiki/Static_induction_transistor


Its more of a pulse device and not for AM operation but seems at home on SSB with my Johnson 500 & SSB adapter. My Johnson 500 only applies 2300 volts on the 'plate', well below the 3300 volt rating of the AF1-2023.  In the AM mode 'plate' voltage would have exceeded that rating on voice peaks and the resting current would likely have also caused thermal over dissipation.

An 1.3 cu meters/minute flow (35.1 CFM) is needed to ensure proper forced air cooling, Iam just re-using the existing emiac glass chimney and so far have not seen any operational issues. The physical dimensions are very similar to the old 4-400, so the “plate lead” connects without issue, see photos.  An added benefit is that the old screen voltage supply is not needed, so pulling the old OD3 voltage regulator tubes is recommended.   Thought you might want to know about this **Static Induction Transistor (SIT) develop.  I feel that having a HYBRID 1950 era transmitter is kinda cool and Ill be considering adding a pair of the SIT devices to my lnvader 2000 when I can save up the ca$h.

Enjoy Woody N4MQ










Part number "AF1-2023"?  Next year part number would be AF1-2024?
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W3SLK

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Re: Just got in some new deviecs for my Johnson 500 finals to try out
« Reply #6 on: April 02, 2023, 05:48:06 AM »

Got me! Hook, line and sinker! Thanks for the laugh, even though it was at own expense! :D
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K8AXW

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Re: Just got in some new deviecs for my Johnson 500 finals to try out
« Reply #7 on: April 02, 2023, 09:57:26 AM »

Too bad this wasn't in QST.  I miss the April edition levity.  We need more of this. 

 I remember getting embarrassed and pissed (not necessarily in that order) when I started searching for parts to build the first April 1 "project."

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A Pessimist is Never Disappointed!

N4MQ

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Re: Just got in some new deviecs for my Johnson 500 finals to try out
« Reply #8 on: April 03, 2023, 03:34:14 AM »

I am glad to have spread some fun - grins.  Hope to keep ;) :) spreading the smiles. 73. Woody
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W3RU

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Re: Just got in some new deviecs for my Johnson 500 finals to try out
« Reply #9 on: April 03, 2023, 06:32:31 AM »

This posting obviously required a substantial amount of time and creative thought to compose.  Woody is to be commended for his efforts and contribution which has made all of us smile!

Jack  W3RU
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K8AXW

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Re: Just got in some new deviecs for my Johnson 500 finals to try out
« Reply #10 on: April 03, 2023, 07:37:32 AM »

Thank you Woody.  Next one, try to get it published in QST.  Well done!
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A Pessimist is Never Disappointed!

KD0REQ

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-SKM, WAB, WAC, Worked All FCC in one contact on spark. Genius!
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