Yes Steve, it is important. One signal generator coupling into another can create IM in the output amp of the signal generator. An attenuator should be used on each generator. Some generators are rat
Hi Tom, In answer to a couple notes: 20 feet of coax should pose no problem as long as both ends are 50 ohms. There may be some modern devices that perform better than those ancient TRW things I sugg
Thank you Marv. You da man! That answers a lot. I'll ask you just a few more, please, and then let you be... :-) I've got a few of 4-400A's, sockets and chimneys here. I was hoping to substitute one
Hi Tom, The wideband RF-preamplifier in the TA1800 by Racal uses 4 parallel 2N3553 in common base, transformer coupled in and out, it does 10db, but standard level of that stage is 50mW in 250mW out.
In the data I have, only the FJ has IMD data in the specs - but it's at either 100 or 250W out, even if that's average power it's less than the tube is capable of. It reminds me a lot of the ratings
OK then here it comes Steve. :-) First let's start with an excerpt from Care and Feeding of Power grid Tubes which is posted on Eimac's Website page 96: [I]It is possible by clever manipulation of el
Hi Tom, First, let me reiterate that to end up with -55dB you'll need to budget your distortion carefully. Consider your project has 3 stages: The FT-1K, the preamp (10mW to a watt or so), & the main
< snip, snip > I believe that IMD on the 4cx3000a is actually tested before shipping to guarantee -32db and -37db, and "typical operation" says -35db and - 40db at 5300W out! So Marv's estimate of -4
Hi Marv, Well, you've given me a lot to think about. I'll look for cleaner drivers than the 6146 and 4-400A. You make a good point about not giving up IMD in that lower level area, if there is an eas
Hi Tom, Just checked the www.qrz.com/callsign/k1jj and must admit you look damn good for 103 year old man! 73! bp (wf3j) chain _______________________________________________ Amps mailing list Amps@c
LMAO! Sure couldn't of picked a better pic of Buckwheat! Will ** REPLY SEPARATOR ** _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/m
Hi Tom, Low distortion -- An low effort alternative. If the low level section of the FT-1K is clean enough (-75 dB distortion)... then: Apply feed-forward correction to your FT-1K amplifier. This wil
Aw, you guys are brutal! Here's what I REALLY look like: http://home.comcast.net/~k1jj/wsb/media/254120/site1050.jpg Marv, OK on the FT-1000D feed forward info. Interesting alternative. Though, chang
Hi Tom, I put diagrams of the Harris linear and the Racal widebanddriver on the following website: http://www.pbase.com/df3kv/gallery/linear By the way, the TA1800 also uses 10db of negative feedback
Hi Tom, Here is some more info for you to look at. Qst July 1967 page 34 is an article by Orr on super cathode driven amps. He shows the difference in IM performance on the 4CX350 in this configurati
Hi Peter, Yes, that's an interesting tube line up. I'm kinda leaning that way. That's a great way to provide voltage for both the final's screen and driver's plates. One regulated supply - I like it.
Just looked at the article. Seems to be what I suggested earlier. Low mu triode in grounded grid. The advantage of a 4CX tube with control grid connected to the cathode requires no bias voltage and i
Hi Tom, The FF system would be entirely external to your FT-1KD -- It just connects between the rig's output the outboard linear, plus an input from the low level tap. Therefore, transportable to a n
WOW! That's a bad case of RF BURN. Larry LMAO! Sure couldn't of picked a better pic of Buckwheat! Will ** REPLY SEPARATOR ** _______________________________________________ Amps mailing list Amps@con