The Selectoject

[KB3NOV]

Hi,
   Yes Now that I have the story straight. I have been collecting parts at hamfests. I just got at a fleamarket old knight kit test equipment. The cases will be nice for a B+ supply, A+, and the selectoject.

I'm going make in the one 2 stages of pre amp - the selectoject - 2 stages of amp after it and go to a 6v6gt for final power. I may also build a ANL circuit
in as well. I figure why keep building audio stages for every receiver. Less parts and cost. I could use the money to build more.

                         73,

                         Jennifer

[AE6RO]

So Jennifer, are you building a receiver to go with your Selectoject?
  Not to Muddy(the)Waters more but the 1967 Handbook features the transistorized Selectoject. The doubleganged pot would be 250 Kohms for that one.
  I'm kind of curious why you like Vacuum Tubes. I like them even though they always drive me crazy. Like today I was trying to modify a coil for an old Heathkit. Trying to put this one on 60 meter ham band.
   Anyway, I don't know what happened but the inductance is way too small now. It's a one-of-a-kind part so I'm kind of stuck. Can't exactly order a new one from Heathkit anymore.
  That Knight-kit test gear is junky, alright.

[KB3NOV]

Hi,
   I like tubes because.....my age is showing.
Solid state is amazing, and all my test equipt is "SS".
Many years ago I played around with stuff, and did SWL.
Had a HQ-129X, BC-603 and some big navy RX that went from something like 150KC 2.0MC. Ohh and a S-38D.
Got away from it till this year and got my ticket, just need the code to be a general.
I never owned a multimeter with a needle !. My first was...remember the heathkit one with the nixie tubes.
My fond thrill was the one tube regen I made. Amazing.
I have a DX-394 not too bad, but my station will be low
power and look circa 1940's. Except for the new fangled test equipt. I love this BK-LCR meter !.

History lesson over...


I found...here we go, the schematic for the selectoject
National made. They used a (2.5)meg pot and another one
(.5)meg for BOOST. This gets better every day....

I am planing to build REGEN's. And a little of "SS" for fun.

                   73,

                     Jennifer
 

[AE6RO]

You never had a multimeter with a needle? I remember how my father was so picky about loaning me his Midland multimeter. A pretty basic analog VOM. This was around 1970.
  Solid state test gear is probably a good idea but I use whatever I have handy. An inductance meter would be nice.
  I checked out the website with the regen and selectoject. (SOJ). I built a 6C4 regen in 1992 and it is a very good detector tube. I like fooling with regens and doing SWLing with them. But no transistors. And use plugin coils.
  Used to have an RBM receiver which covered the range you mentioned. Kind of wish I kept it.
73, AE6RO John

[KB3NOV]

Hi,
    Yes regens are nice. Yup, never had a meter with a needle. I know, like old stuff, and not opposed to them, but digital readout can spoil you. I built the nixie heath around 1974-75. It was the first digital meter a regular person could afford. Or should I say Dad could. I think it was about $80.00, and thats all I got for Christmas that year.
It worked pretty good till someone tried to measure AMPS on the OHM setting. Don't know who would do that.
Got another one at a hamfest, and darn it, same mistake . I've had my trusty beckman DM15XL for quite a long time now. I had to use a meter the other day with a needle, and had to stare at it for a few min to read the scale.

I can recommend a cheap digital CAP only meter. The ELENCO CM-1555. $30.00 and it is accurate.
My BK-875B LCR wasn't cheap, but it sure makes life real nice. Got some cheap rf chokes at hamfests. No clue on the value, but my BK sure told me .

Well I have no Ideal what all this has to do with the selectoject...

I'll have to do some more digging on the SOJ.

                      73,

                     Jennifer
 

[AE6RO]

That happened to me once. Back in the day (1973 or so) I saved up my pennies and bought a Lafayette VOM. One day it quit working. I opened it up and all the standards resistors were smoked. Must have been a gremlin checking the mains.  So I saved up more pennies and bought a better meter from Olsen Electronics.
  Man, I used to love Heathkits. The last one I built was an HW-9 plus the SWR meter and transmatch. But it was hard going and I didn't like it as much building my HW-16 and HW101. The HW101 went back to the factory tech because the wiring harness got messed up. But the HW-16 (and the HW-9) worked right off the batt. I also built an HW-30 but that also had to go to the tech.
   Nixie tubes are cool-looking. Think I saw a project that used one. I used to work at a place in the '80s that stuff with Nixies in them.
  It's more fun to build stuff from scratch. I might just give that Selectoject a try. Probably the vacuum tube version. The solid state one could be used right at the headphone jack.
  Isn't SOJ an airport? 73, AE6RO

[AE6RO]

I was thinking today I should get an inductance meter. Just thought I'd learn more by doing it the hard way.
 "WILEY COYOTE! SUPER GENIUS! I LOVE the way that rolls off the tongue! "WILEEY COYOTE SUPER GENIUS!"
That oughta date me! 73, AE6RO

[KC9KEP]

Hello all ..

Just a comment about the ubiquitous Selectojet :-)

It had been mentioned that a certain value pot caused
a too-sensitive condition.  I quote:

"I also found that another person built one using the FIVE meg pot, and it
was very touchy to tune. He measured the pot and only had used 78K
on a cw signal."

Here's a thought .. Should one be sure to use a Linear, not Audio taper
pot for the frequency sweep?

An audio pot could potentially bunch-up the control’s effectiveness to a small
region of the control's travel?

--Tom Nickel

KC9KEP