[GreenKeys] RK-65 RF Amp Questions

Roy Morgan [email protected]
Thu, 11 Dec 2003 12:46:37 -0500


At 10:26 AM 12/11/03 -0500, Merz Donald S wrote:
>I have this RF amp here that is making its way up the to-do list. It uses 
>push-pull RK-65 tubes and a large B&W "CX" type tank assembly.  ...
>
>This is my first encounter with a piece of gear using RK-anything tubes. 
>Has anyone seen any published circuits using RK-65s?


I did find specs for the tube at:
http://www.mgte.com/rk-65-schm.pdf
and he has a nice picture at:
http://www.mgte.com/jpg/rk-65c.jpg

It appears that at 3,000 volts on the plate, a pair of them will deliver an 
output of one kilowatt in CW service.

For published circuits, see any ARRL handbook prior to about 1950, and 
especially the very early west coast handbooks for transmitters using the 
250 TL  or TH.

>Does that tube have any equivalent types by other manufacturers?

As I understand it, the RK-65 is similar to the 250 TH used in the 
Hallicrafters HT-4 and BC-610.  The fellows on the T-368/BC-610 list would 
have more information on that.

>   Has anyone seen a good summary anywhere of the Raytheon line of 
> RK-series tubes?

The 1944 ARRL Handbook lists a number of Raytheon transmitting tubes in the 
context of other similar types.

>  I can't see any rhyme or reason in their numbering system.

They may have simply started with  a low number and just used the next one 
for a new tube type.

>  And finally, does anyone have any RK-65's for sale or trade? I'd be 
> interested in picking up a couple for spares.

The owner of the website below seems to have three for $55 each.  I say buy 
them all.
http://www.mgte.com/h_tesla.htm

I found info below with a google search for "Raytheon RK-65"  There seemed 
to be some confusion comparing the 833 and the RK-65.  I have an example of 
each and I assure you they are not at all the same tube and the 833 is a 
far bigger tube.  The owner of the website replied to someone on the 
TESLA  list that the RK-65 has "twice the capacity of the 833.  This is 
just plain wrong.

from: http://www.pupman.com/listarchives/2001/November/msg00702.html
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>
>RE: 833's
>
>
>
>      To: tesla-at-pupman-dot-com
>      Subject: RE: 833's
>      From: "Tesla list" <tesla-at-pupman-dot-com>
>      Date: Wed, 21 Nov 2001 18:46:43 -0700
>      Resent-Date: Wed, 21 Nov 2001 19:11:33 -0700
>      Resent-From: tesla-at-pupman-dot-com
>      Resent-Message-ID: <1W6y7B.A.VHB.U7F_7-at-poodle>
>      Resent-Sender: tesla-request-at-pupman-dot-com
>
>
>
>Original poster: "John H. Couture by way of Terry Fritz 
><twftesla-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>
>
>
>Dave -
>
>You are correct. The specs for the RK-65 are shown at
>      http://www.mgte-dot-com/rk-65-schm.pdf
>
>These specs show the output for the RK-65 as 510 watts. This is less than
>the 635 watts for the 833a tube. I was guessing at the 833a tube output but
>incorrectly used the 811 output which is about 200 watts. It is obvious I am
>not a tube expert. I am sorry if this has caused any inconvenience.
>
>John Couture
>
>-----------------------------
>
>-----Original Message-----
>From: Tesla list [mailto:tesla-at-pupman-dot-com]
>Sent: Wednesday, November 21, 2001 9:51 AM
>To: tesla-at-pupman-dot-com
>Subject: Re: 833's
>
>
>Original poster: "David Speck by way of Terry Fritz 
><twftesla-at-qwest-dot-net>"
><dspeck-at-relex-dot-com>
>
>John,
>I checked the specs for the RK 65 tubes, vs. the 833a's
>
>Parameter 833A RK-65
>Plate current, Class C 400 mA 200 mA
>Power output, watts 635 watts 380 watts
>Plate voltage 2500 2500
>
>Unless I'm reading the data wrong, it seems that an 833a is worth about two
>RK-65s.  Any comments?
>Dave
>
>Tesla list wrote:
> >
> > Original poster: "John H. Couture by way of Terry Fritz
><twftesla-at-qwest-dot-net>"
> > <couturejh-at-mgte-dot-com>
> >
> > Ben -
> >
> > Click on      www.mgte-dot-com
> >
> > Click on "TESLA"
> >
> > The Raytheon RK 65 tubes shown here have twice the capacity of the 833's
>and
> > they are brand new for only $55 plus shipping. You do not need a socket
> > because only 2 of the socket prongs are used (for the filament). The grid
> > connections are on the sides of the tube. The plate connection on the top.
> > Click on "Raytheon" for a photo. There is also plenty of test equipment
> > available at this web site.
> >
> > You can find my Tesla books and the on-line JHCTES Ver 3.3 computer
>program
> > by clicking on the JHCTES box.
> >
> > John Couture


- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
7130 Panorama Drive, Derwood MD 20855
Home: 301-330-8828 Work: Voice: 301-975-3254,  Fax: 301-948-6213
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