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[Articles Home]  [Add Article]  

A Transmitting Tube Lamp

from Web Williams, WY3X on October 30, 2011
View comments about this article!

I had been wanting a unique lamp for some time, and remembered seeing some for sale (I believe on eBay) several years ago that utilized a radio tube mounted on the base as a decorative accent. I took the concept one step further so that it could be used as a night light, or serve some other purpose where there is a need for a very dim light.

First I had to choose what type of tube I wanted to use. The design of a transmitting triode, in my eyes, is a very elegant design. Nothing says "ham radio" like the dull red glow of a properly operating 3-500Z tube which is visible from the outside of an amplifier! Others may have their favorite tubes for this project, but for me, the 3-500Z was the perfect size, and could probably be had in "burned out" condition either free or cheap. After all, this project will ruin a good tube, so free or cheap is good in this case! The key element being that the glass envelope is intact, and the elements inside are pleasing to the eye. After a few inquiries looking for a candidate tube, I found none. I finally stumbled on one at the Shelby, NC hamfest. As it turns out, the box was labeled 5-500, but there are no markings on the tube. It "looks" like a 3-500Z. Close enough to work. And the price was right.

Tube found at the
      Shelby hamfest

Found this old tube at the Shelby Hamfest. Seller stated it was used in a broadcast transmitter, and had exceeded the number of allotted hours. The silvering on the inside made it look better in my eyes!

The first thing to do after you have selected your tube is to find a location you can drill the glass envelope that will be hidden during operation. With a 3-500Z,
there is a metal cup upside down in the bottom of the tube. It is welded to the electrodes which pass through the glass on the bottom of the tube, and these electrodes appear to be copper plated steel, i.e. nice and strong, providing lots of support for the elements inside the tube.

I made a post in the forums here on eHam.net asking if anyone had ever drilled a 3-500Z before, and got all sorts of answers. "Don't do it- the glass is tempered and will shatter", and "keep it cool or the glass will crack". I even e-mailed Eimac, and the answer that I got from them was "I think it's tempered glass, but I don't really know". How kind and helpful! I didn't really get any answers from -anyone- telling me "I did it before, and this is how it's done". So I was left on my own to determine IF and HOW it could be accomplished. I don't mean this to insult anyone, I'm merely pointing out that I believe others probably have done this, and these people probably did not see my inquiry.

Knowing that the usual carbide-tipped tile drill bit was pointy, I made the mental connection that it would force the glass outward as pressure was applied during drilling, and it probably would crack the envelope. What was required was some type of hole saw that would only apply pressure in one plane, i.e. inwards, not to any side. A trip to the local hardware store helped me locate a diamond-tipped hole saw.
I knew that the glass had to remain cool during drilling from talking to a local glass shop. The only way I could do this at home was to drill the tube in a sink under running water, and run the drill at very low speed while doing it. Naturally, this precludes using an AC wall-outlet powered drill! I happen to own a battery powered variable speed cordless drill, and it was perfect for this application.

Let's get started

First things first- there was a ceramic bottom on the exterior of the tube that held the pins in place. The pins on the bottom of the tube must be unsoldered and the ceramic base removed to get at the glass underneath it. A solder-sucker and a heavy-duty soldering gun is required. After all, you're not going to use the tube to transmit with ever again once you punch a hole in it, so don't worry about getting the pins overheated. Just get the solder out from around the pins as best you can. Once all the solder is removed, start pulling the ceramic base away from the tube while working the pins with the soldering iron. There may be a better way, but that's how I did it. Eventually it will give way and come off. It won't need to be soldered back on. You'll want to leave it loose so you can change the bulb you're going to put inside (if it ever burns out).


Tools required to remove the tube base

After unsoldering
      the base, it is pulled off.

The drilling operation

Turning the water on, and running the drill very slowly, I began to drill in the center of the bottom of the tube in between the pins. There is a seal on the bottom of the tube where the factory closed off the glass after pulling a vacuum. I centered the hole on this little protrusion of glass. It went right up inside the hole saw. I let the drill operate a few dozen turns, then pulled it out and examined what progress occurred, if any. Sure enough, there was some white dust in a circle around the pin! The diamond-tipped hole saw was working! I proceeded to drill under the water, proceeding very slowly and methodically, wearing a heavy leather glove on the hand holding the tube (in case it broke), and stopping to rotate the tube about every 15 seconds to keep the hole concentric. The drill DID want to walk around a bit, but eventually created a track which held it in one place. You MUST drill VERY SLOWLY, and pause to rinse away the debris from drilling! The vacuum broke about 10 minutes into the process, which relieved me because that was one less factor to worry about. Obviously, because the tube was under running water, it sucked some water inside the tube. I continued to drill slowly and carefully under running water until the hole saw cut the plug from the tube. I rinsed the inside of the tube to remove any stray glass shards. Conventional thinking will lead you to believe that water will leave spots and residue inside. There is a trick to removing the water completely, which will not leave a chance for any spots to form.

After making absolutely sure there is no remaining glass inside, give the tube three rinses, each with a couple of ounces of denatured alcohol (available from most paint stores). The water will bind with the alcohol, which will remove the water when poured out. Lastly, you'll need to VERY lightly blow dry the inside of the tube with compressed air to completely dry the alcohol. Look Ma, NO SPOTS!!! DO NOT USE A HAIR DRYER FOR THIS OPERATION!!!
The heat COULD ignite the fumes from the alcohol!!! And do not use the full force of an air compressor, as it may damage the internal structures of the tube!

Hole saw used to
      open tube envelope.
Drilling the tube.
Hole saw used to put hole in bottom of tube. The drilling operation.
View of drilled
      hole Bulb soldered to leads.
The completed hole. Leads soldered to Type 44 pilot lamp. No room for a socket inside the tube!

Type 44 bulb in place
Type 44 pilot light inserted into the grid element inside the tube. It's a snug fit, bulb must be pushed in with
a small flat screwdriver. Since there are no other connections to the bulb, and the entire assembly is intended
to be mounted on an insulator, there is no reason to insulate the connections further. There is more than
adequate clearance between the leads so they won't short together.

Let's light 'er up!

Originally, I had planned to use LEDs to light the tube. I purchased one of the "grab bags" of LEDs from Radio Shack, as well as one each of all the others they had in stock. Some purported to be very bright. None matched the beautiful color of a radio tube's filament glow, but I did try them. I took some long forceps and removed some of the structure from the center of the tube, leaving a cavity inside the plate to place my bulb choices in. All LEDs failed miserably at being either bright enough or emitting a pleasing color of light. A red one looked pretty cool, but in the normal daylight coming in through the window, you couldn't tell it was on. In the pitch black dark of a closet, it did look great! But- that wouldn't accomplish what I wanted. I was looking for as much light as an ordinary night-light so it could be left on to light the way to the "water closet" at night. I happened to be working on another project, an antique Westinghouse radio, which used type 44 pilot lights. These bulbs are fairly bright, and operate from 6.3 volts AC. Of course, a bulb doesn't necessarily know the difference between AC and DC (technically, an AC bulb operated from DC will fail quicker by a few hours, but when you're talking about a 3000 hour bulb, 2995 hours isn't that much shorter!). And I won't get into the mechanics of why this is so, as it's beyond the scope of this article. The current draw on a type 44 bulb is pretty low, so it can be operated from many "wall-wart" type power supplies. And, the piece-de-resistance, the type 44 bulb fit PERFECTLY inside the grid element like it was made for it! And the color, brightness (when operated at 5VDC), are a near PERFECT SIMULATION of the tube being lit in use!

Tell me this isn't
      beautiful!



Why?

I think radio tubes are beautiful. I want my grandkids to know about them. I want them to ask me questions so I can explain how they work, and why they're so much more aesthetically pleasing than some dumb ol' transistor. I want them to experience the same joy I did when sitting and listening to old radio programs as a teenager, like Jerry and Dodie on Radio Nederland. I want them to know the warm fuzzy feeling of curling up near an old tube radio, and the comfort of smelling the wax caps heating up, and coming to the realization that all is not evil in the world. The inevitable questions I will field the next time they come for a visit, and seeing them looking with wonder at this glowing glass bulb emanating it's warm ambiance will make it all worth it!

Epilogue

Now I just need to build a nice decorative figured-hardwood base for it and install an ordinary lamp on top so it will have full function. The photos are not necessarily in order with the article text, but are in order of dis-assembly and re-assembly.

Member Comments:
This article has expired. No more comments may be added.
 
A Transmitting Tube Lamp  
by KX5JT on October 30, 2011 Mail this to a friend!
That's a pretty sweet little project and a neat idea. Now hook that up to your vintage boat anchor transmitter as a dummy load and watch it glow with RF!
 
A Transmitting Tube Lamp  
by W5LZ on October 30, 2011 Mail this to a friend!
I'm of two minds about this.
1st, I really like it!
2nd, I think it's a terrible, silly idea and you should send the finished lamp to me to keep you from being embarrassed!

...that's not gonna work, is it? Oh well. I still think it's nice.
Paul
 
RE: A Transmitting Tube Lamp  
by AH6RR on October 30, 2011 Mail this to a friend!
Very very nice now I know what to do with my dead 3-500Z
tube.
Thanks for the great effort and article.

Roland AH6RR
 
RE: A Transmitting Tube Lamp  
by K1CJS on October 30, 2011 Mail this to a friend!
Careful! You just increased the worth of old, failed transmitter tubes! Now there is going to be a market for them.

A nicely done and well thought out project. Thanks for sharing!
 
RE: A Transmitting Tube Lamp  
by W9PMZ on October 30, 2011 Mail this to a friend!
Neat idea, have seen before; but good how to
Do it article...

Missing key ingredient though... That cherry
red glow on the plate and the soothing warm
heat...

73,

Carl - W9PMZ
 
A Transmitting Tube Lamp  
by KB2DHG on October 30, 2011 Mail this to a friend!
VERY NICE! Now I got another winter project to do! I love it!
 
A Transmitting Tube Lamp  
by N6XJP on October 30, 2011 Mail this to a friend!
Quite possibly one of the coolest things I have seen. I hereby wish to commission you to do one for me! I would love to have that on my desk.

Wonderful imagination. Great hands!

Dave
N6XJP
 
A Transmitting Tube Lamp  
by KC4IWI on October 30, 2011 Mail this to a friend!
Very nice job based upon a great idea. I agree with N6XJP. You Really should consider making a few of these because it is real art. If you consider the offer, let me know.

73,

Steve
KC4IWI
 
A Transmitting Tube Lamp  
by K2LGO on October 30, 2011 Mail this to a friend!
Some years back I did the same with a bad 833A I had, and made a lamp for a very good ham friend of mine. But I must admit yours is 100% better, as I lit mine from behind and although it was attractive, it can't match the effect your inserting of the #44 bulb gives...Five stars...Thumbs up..
 
A Transmitting Tube Lamp  
by N0TW on October 30, 2011 Mail this to a friend!
A good example of Ham Ingenuity. This will make a good topic of discussion for anyone visiting the hamshack. Congratulations for an article well done.

73 Terry, N0TW
 
A Transmitting Tube Lamp  
by KE4DRN on October 30, 2011 Mail this to a friend!
Hi,

Nice project!

Back in shop class we made lots of lamps
by using brass tube in the drill and
valve grinding compound as the abrasive.

73 James
 
A Transmitting Tube Lamp  
by DL9LH on October 30, 2011 Mail this to a friend!
Nice work and idea but one caveat: What about the unhealthy stuff in the old electron tube which can escape now like led,mecury, arsenic components and other stuff which likes to vapor away with heat (if allowed to by drilling the glas) ?
 
RE: A Transmitting Tube Lamp  
by KB4XV on October 30, 2011 Mail this to a friend!
Re DL9LH - Easy fix for that would be to seal the hole up with Silicone sealent.It can handle temps up to 500 degrees F.
 
A Transmitting Tube Lamp  
by N6JSX on October 30, 2011 Mail this to a friend!
I've been looking for years to find dead/flat 3-500/400 to do a similar project(s).

My similar project is to make bookend shade lamp stands in wood with these tubes as the base center piece having glowing filament/nite-light.

I've yet to find any sellers of these dead/flat tubes.

Another variation of this tube project is to RF detect shack TX RF (much like the ON AIR indicator) and allow the RF to modulate the filament lights inside a pair of these tubes making them look like they are working. The tube lamps would be placed on the shelf above my station.
 
RE: A Transmitting Tube Lamp  
by CBISBACK on October 30, 2011 Mail this to a friend!
by DL9LH on October 30, 2011
What about the unhealthy stuff in the old electron tube which can escape now like led,mecury, arsenic components and other stuff which likes to vapor away with heat (if allowed to by drilling the glas) ?
-----------------------------------------------

You breath worse things walking down the street than will be emitted from the tube.

If you were processing 1,000,000 of these a day it might be a problem.

But one tube isn't going to kill anyone.

 
A Transmitting Tube Lamp  
by DL9LH on October 30, 2011 Mail this to a friend!
Well sealing the tube hole with silicon as suggested will do the trick needed to keep the bad stuff in, regardless how unhealthy it really is. Nice idea and article tnx !!!
 
RE: A Transmitting Tube Lamp  
by N3CSA on October 30, 2011 Mail this to a friend!
I LOVE this idea!! Isn't there a way to just light up the tube and let it emit it's normal glow?
 
RE: A Transmitting Tube Lamp  
by K2LGO on October 30, 2011 Mail this to a friend!
In answer to N3CSA "I LOVE this idea!! Isn't there a way to just light up the tube and let it emit it's normal glow?"
Indeed there is, if you have a 5v 10 some odd amp transformer...Then of course you would need a fan to keep it cool, as if it was in an amp, and lastly you would not leave it on too much, if your electric was as expensive as here on L.I. NY
 
RE: A Transmitting Tube Lamp  
by AL7B on October 30, 2011 Mail this to a friend!
I have been giving this sort of projects consideration for years. WY3X solved the problem of access to the tube. I followed the eHam thread on this with great interest.

Thanks for sharing your findings with us.

As for sealing the base I would want to do so to keep the dust out of the inside of the tube. As for nasty stuff coming out I am more worried about the CFLs being forced on us.

 
RE: A Transmitting Tube Lamp  
by KA4NMA on October 30, 2011 Mail this to a friend!
Nice. If you have any extra's let me know!

Randy ka4nma
 
A Transmitting Tube Lamp  
by K1CJS on October 31, 2011 Mail this to a friend!
There is way too little of the "bad stuff" in one tube to worry about, and little in the way of heat that would boil that stuff off while the bulb is lit. You get exposed to more dangerous elements and compounds every day of your life. Sealing the tube can be done so that the worry warts have peace of mind, but I would leave it open so bulb replacement can be done if needed without the fear of breaking the tube envelope. If you're really worried, you can use a bit of duct sealant to seal the base up to keep the traces of 'bad stuff' in and dust out.
____________________

Carl, W9PMZ, mentioned the lack of the 'cherry red plate' that a tube in service would have. A thought about that--maybe with the use of a smaller bulb, there would be room for one or two red LEDS in the center. In addition, for someone who wanted to take the time and the trouble, an idea mentioned by Dale, N6JSX--to build an RF detector and wire that to the red LEDs may give the approximation of how an in-sevice tube may look while its working.

Then you would have an even better display piece and conversation starter!
 
RE: A Transmitting Tube Lamp  
by CBISBACK on October 31, 2011 Mail this to a friend!
by K1CJS
<snip>
Then you would have an even better display piece and conversation starter!
==========================================

It would be a conversation starter alright, GET THAT UGLY THING OUT OF MY LIVING ROOM.

 
RE: A Transmitting Tube Lamp  
by K2LGO on October 31, 2011 Mail this to a friend!
I believe somewhere I have one that I would not use in an amp, and would sell it for $10.00 + shp...If interested email me at my QRZ email...and then I'll see if I can find it...
 
A Transmitting Tube Lamp  
by N1DVJ on October 31, 2011 Mail this to a friend!
What would be REALLY neat is to have the tube as the 'base' of a lamp. Then take the box with the logo and have that silkscreened onto a lampshade.

Then configure it for a 3-way lamp. It can be off, or just the base lamp on as a nite-light, or just the top lamp on (with a standard 40W or so behind the lampshade with the logo, or both on.

 
A Transmitting Tube Lamp  
by W3HKK on October 31, 2011 Mail this to a friend!
It IS beautiful! Thanks for such a top notch and well documented article!

PS Im jealous.
 
RE: A Transmitting Tube Lamp  
by W6SDM on October 31, 2011 Mail this to a friend!
Thanks for a great, detailed, illustrated article. Now I know what to give myself for Christmas.
 
RE: A Transmitting Tube Lamp  
by N4NYY on October 31, 2011 Mail this to a friend!
That is simply fantastic. You have to make that a PDF and post it on a website. I am very interested in that.
 
A Transmitting Tube Lamp  
by KC2VDM on October 31, 2011 Mail this to a friend!
I like it!

I've got millions of 12au7's, maybe I'll try a christmas light version.

-Alex
KC2VDM
 
A Transmitting Tube Lamp  
by KU2US on October 31, 2011 Mail this to a friend!
Yes: Im going to try it with a big ole' 572B. Nice article..
 
RE: A Transmitting Tube Lamp  
by KG4YMC on November 1, 2011 Mail this to a friend!
Cool idea, I was curious about what camera you used for the photos/ nice job all the way around . Probably better than a leg lamp in the shack . Had a burned out old security light sodium vapor lamp , looked cool but with presserized bulb would have not worked for this type project, bu this looks cool . great job.kg4ymc
 
A Transmitting Tube Lamp  
by K4SSS on November 1, 2011 Mail this to a friend!
Hi Web.

I'm torn between either loving you or hating you right now, hi! That's because I love your new lamp and hope to build one oneself, but hate the fact that you've just increased the price of dead tubes at hamfests!

Thanks for sharing!

Bob -- K4SSS
 
RE: A Transmitting Tube Lamp  
by WY3X on November 1, 2011 Mail this to a friend!
W9PMZ: Missing key ingredient though... That cherry
red glow on the plate and the soothing warm
heat...

Can't do that without making the tube hot. VERY hot, in fact. That wouldn't work for my application.

N6XJP and KC4IWI: Make one for me.

I wouldn't mind, but you'd have to send me two tubes and I get to keep one for my own use. Also, I can't warranty that they won't break when I drill them. If they break, it's your nickle. But I do promise that I'll do my best NOT to break them! My callbook address is valid. You pay shipping both ways. I won't charge you for drilling other than sending me an extra dud tube so I can make more for myself, friends, and family. Two dud tubes buys you one drill job and one tube will be returned drilled (you also pay return shipping) and a type 44 lamp with pigtails soldered to it.

N3CSA: Isn't there a way to just light up the tube and let it emit it's normal glow?

It would require a honkin' big transformer which is better suited to amplifiers, not table lamps. 5VDC at 10 amps. Then there's heat to get rid of too.

KA4NMA: Nice. If you have any extra's let me know!

I don't have any extras, but see above note to N6XJP and KC4IWI. I don't mind doing 1/2 a dozen for folks, I just don't want it to turn into a full time job. After all, I'm retired!

K1CJS: the red LEDs may give the approximation of how an in-sevice tube may look while its working.

I tried dozens of LEDs. None were bright enough in the daytime. Only the bulb mentioned in the article put off enough light to be seen in a room with windows open to sunlight. If the purpose is to make one only used in the dark, LEDs may work well enough.

KG4YMC: I was curious about what camera you used for the photos.

A Fuji Finepix S-1000fd from Wal-Mart. It has a honkin' big lens for a cheapie camera. It impressed me as well, and I'm an old film guy who usually uses a Canon A-1 with lots of lenses. When I know I'm going to put the photos on the internet or send them via e-mail, I always do digital. If they're for my photo album, I always use film and the A-1. Some day I hope to buy a digital SLR with interchangeable lenses when the prices drop below $300.00.

K4SSS: you've just increased the price of dead tubes at hamfests!

I'm almost ashamed to say what I had to pay for this one. After looking for a few months for a $10.00 dead tube, I found this one, a used broadcast tube, for $25.00. It was the cheapest one at the Shelby hamfest. Apparently, nobody sells their old duds these days! Somewhere, I know somebody has a closet full they won't part with!

If anyone has any oddball large dud glass tubes, please don't throw them away. Keep me in mind!

Thanks, -Web (WY3X)
 
RE: A Transmitting Tube Lamp  
by N1DVJ on November 2, 2011 Mail this to a friend!
Hmm... For the glow, couldn't you use a higher voltage light bulb and drive it with a lower voltage?

Or how about colored LEDs?
 
A Transmitting Tube Lamp  
by K4MLB on November 2, 2011 Mail this to a friend!
Years ago I was taught to drill glass by making a clay dike around the area you wanted to drill and filling it with kerosene as a coolant/lubricant, of course you need a carbide drill.
 
RE: A Transmitting Tube Lamp  
by KG4YMC on November 3, 2011 Mail this to a friend!
Web, thanks for the feedback on the camera.have pentex system . I'm an old film man also. Have collection of some old kodak and pullout bellows cameraas . Anway , don't mean to get off topic , but cannon has a digit al with quite a zoom range. Almost won't need interchangble lens the way they keep going on this . I will also keep eye out for old tubes, mabey at ham fest, but sadly local flea markets are being taken over by made in china dollar junk sellers . Don't see anything good anymore. enjoy fillm while can , anyt hing with kodak name will be collectable also ,when not if , company goes under.Old flashbulbs, kodachrome film . Sorry to get off topic , if see new digital that doesn't look or feel like cheap plastic compared to old film cameras will consider ,will check out one you got , thanks kg4ymc
 
A Transmitting Tube Lamp  
by NQ4A on November 5, 2011 Mail this to a friend!
I am an old timer that loves the warm glow of these and other tubes in the broadcast transmitters of the past. Nothing like it. Now by the time a transistor glows like that, it is all over... Wonderful article and it brings back the warm glow of my 51 years in broadcast engineering! Thank you. Jon NQ4A
 
A Transmitting Tube Lamp  
by WC6W on November 6, 2011 Mail this to a friend!
Tube lamps in the old way ...

http://qsl.net/wc6w/wc6waccy/index.html?fr60.html







*
 
A Transmitting Tube Lamp  
by N3QH on November 6, 2011 Mail this to a friend!
Great idea and well written. Let see if I put one on a red oak wooden base and built a straight key from red oak with a shorting bar I can have a lamp and also send visually CW with that beautiful glow Love it
 
A Transmitting Tube Lamp  
by K3LUE on November 9, 2011 Mail this to a friend!
I remember a very old issue of CQ had a funny story about a guy that got a 304TL bottle at a hamfest and turned it into a lamp. It's not A Christmas Story leg lamp but it ain't bad! :-)
 
A Transmitting Tube Lamp  
by K3LUE on November 9, 2011 Mail this to a friend!
I remember a very old issue of CQ had a funny story about a guy that got a 304TL bottle at a hamfest and turned it into a lamp. It's not A Christmas Story leg lamp but it ain't bad! :-)
 
A Transmitting Tube Lamp  
by W4CP on November 18, 2011 Mail this to a friend!
A great idea and a good article.
 
A Transmitting Tube Lamp  
by K4DES on November 21, 2011 Mail this to a friend!
Why not just use the filament to provide the lighting, or was the filament not working? Seems to me an alternative would have been to also have acquired a filament transformer and a tube socket, and then mounting everything on some sort of decorative stand.
 
RE: A Transmitting Tube Lamp  
by N1DVJ on November 21, 2011 Mail this to a friend!
Well, isn't it the filiments that usually burn out on these things?

Besides, I can't imagine you'd want the space heater that running the filiments would turn it into.
 
RE: A Transmitting Tube Lamp  
by W7ETA on November 22, 2011 Mail this to a friend!
What a fantastic article!! great easy to read prose peppered with important pictures.

Nice job.

Way to go!

73
Bob
 
A Transmitting Tube Lamp  
by K2LGO on November 26, 2011 Mail this to a friend!
Found a 4-400A in my stuff that might be just about the same...Its marked good filament on it, so it actually might have some life in it...Not sure...$20.00 to your door ...
 
A Transmitting Tube Lamp  
by WA0SBU on November 27, 2011 Mail this to a friend!
Great Article and really well written instructions. I am a little bit scared to start drilling on tempered glass. When I was in School, (Yes many years ago), I took a tour of a company the rebuilt TV picture tubes. They used a "hot wire" to cut the neck of the CRT. Remove the gun and then remount a new gun, using heat to melt the glass. So maybe a small torch, and just burn a hole in the bottom?
 
RE: A Transmitting Tube Lamp  
by N8IL on December 1, 2011 Mail this to a friend!
I found spent transmiting tubes here:
http://www.mgs4u.com/RF-Microwave/transmittingtubes.htm

-Neil
N8IL
 
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