[Amps] YU-158 still being made?

[Roger (sub1)]

On 7/13/2011 4:03 PM, Dr. David Kirkby wrote:
> On 07/13/11 07:39 PM, ED MCKIE wrote:
>>    I built a twenty meter monobander in1997 using a new YU-158 I got from a
>> friend who had a friend that worked for GE Medical Systems. I found when
>> trying to get info from Eimac that it was a proprietary tube made for ETO.
>> About all I could get out of CPI / Eimac was that is was a more rugged 8877
>> and ran lower grid current for a given output.
>> Well, there is a new YU-158 for sale on Ebay with a date code 1039. My
>> question is this: if it was a proprietary tube made for ETO, do they still
>> make them or could it be a counterfit. The 1 on the datecode is taller than
>> the rest of the numbers in the date code.
>>    I read something a few days ago about people putting CPI / Eimac silkscreen
>> on import tubes.
>> TNX, Ed
> Assuming you are talking about this auction
>
> http://cgi.ebay.com/Eimac-YU-158-8877-3CX1500A7-Power-Triode-/350477144083?pt=LH_DefaultDomain_0&hash=item519a10d013
>
> it's possible the "1" looks bigger due distortion caused by the perspective
> and/or the use of a lens not suited to close up work. The anode appears to be
> much deeper at the front than at the back.

There is definately distortion due to lens focal length and distance to 
the subject, *but* if you look at the large "1" look at the sting of 
characters starting above it. The H in Hazardous is directly above the 
"1" and it is not distorted.  Also if the "1" were distorted due to the 
focal lenght/distance the string of numbers should get larger as a 
function of distance. IOW the 0 would only be slightly smaller and the 3 
would be slightly smaller than the 0 with the difference rapidly 
diminishing with distance. Also you do not see the same distortion with 
the numbers under the Eimac Logo to the left.  If you look at the anode 
size Vs distance that same change should apply to the lettering and 
numbers.  The "1"  is the only thing out of character for size.

Would this indicate some one had made a change? I don't know, but I've 
seen date codes with the first digit larger before.

73

Roger (K8RI)
>
> Many cameras have a "macro mode" which can do close-ups, but the lenses do a
> pretty poor job, as they are optimised for focus at much longer distances.
>
> I've got a 105 mm macro lens for my Nikon D3 and the lens cost about 4 x that of
> a typical 12 Mpixel camera with inbuilt lens which has a macro mode.
>
> Someone recently made me some clips to hold an Eimac SK-810B base in place. He
> sent me a photo of the completed clips.
>
> http://boxen.math.washington.edu/home/kirkby/base-clamps.jpg
>
> Note how the clip at the top appears to be quite a different shape to the other
> two. The piece of metal on the side which is not drilled looks to be much larger
> than the corresponding parts on the other two clips. This is just a problem with
> the image. I'm told they are the same and whilst I've not put a micrometer on
> them, they look approximately the same when viewed with the eye.
>
> If someone was going to go to the bother of badging conterfeit tubes with an
> Eimac label, I'm sure they would have the ability to print the numbers straight.
> As such, I suspect that's an optical illusion.
>
> As to whether its a fake or not is another matter. It would seem suspicious.
>
> A friend of mine bought a handbag for about $1000 through eBay. It was a fake so
> she reported this to eBay and Paypal. Then Paypal wanted an expert to determine
> if it was a fake or not, so my friend had to appoint one. The expert found
> endless signs to indicate it was a fake and submitted a report.
>
> Paypal made life very difficult for her. She had to fax documents - despite one
> can sign up and move money with Paypal with a computer, for the document it has
> to be faxed.
>
> The end result was Paypal agreed it was a fake, so refunded her the money.
>
> Since it was a fake, Paypal insisted that the handbag was not returned to the
> seller, but must be destroyed. So she got her money back and kept the bag!
> Needless to say she did not destroy it! So the seller lost not only his bag, but
> his money too. (I'm told its quite a nice bag, though it is indeed a fake).
>
>