Early homebrew set

[radio nut]

I recently acquired a home made 1 tube regenerative radio. It has a number 12 vacuum tube with a good heater and I am hoping it has good emissions.
The grid cap/resistor assembly is a freshman part that according to radio museum. Org is from 1923. One thing I am curious about is the tube, the base is large like a 201a and so far the pictures I have found of a 12 show a small base. But at the same time the socket it sits on doesn't seem to match a 12 tube. The socket shows pin 1 being heater minus,2 being grid,3 plate, and 4 heater plus. This matches how its wired compared to an online 1 tube regen set. However a 12 tube base is pin 2 plate and pin 3 grid . So far I can't figure out which tube matches this socket. So I am unsure if the 12 tube has been put on a different base or what.

[radio nut]

I tried looking through tube base pics and I have no idea what the correct tube would be for the socket.
I tried uploading pics but once pics uploaded on the manage attachments page my screen just sat there and Iit never took me to the original screen in order to submit!

[radio nut]

Well, I missed the basics and forgot to look at the tube pins from below.! I powered it up and it works.... ya!
I am curious though, with 60 feet of wire all I can get is the 2 local stations. Here in Lima ohio that is 940 and 1150. They do come in very well with an earphone and I kinda have to detune the tickler coil inorder to keep from over driving the earphone, shouldn't I be able to get more stations then that?

[radio nut]

Does anyone have experience with a 1 tube regenerative set that can maybe explain what I need to do inorder to pick up more?

[init4fun]

Originally Posted by radio nut

Does anyone have experience with a 1 tube regenerative set that can maybe explain what I need to do inorder to pick up more?

Is your 60 foot wire antenna inside or out ? (gotta be outside) . Any way to get it up into the 200 or so foot range ? With not much amplification (due to only one tube) a long antenna is your friend , the longer the better . How's your ground ? Connected to a copper pipe driven a good 6 or 7 feet into somewhat moist soil , or are we connected to the wall outlet's ground (the worst ground connection one can possibly have) ? Things like that become extremely important when you don't have several tubes worth of amplification to mitigate the effects of a marginal antenna or ground .

[Titan1a]

Congrats. Would headphones help? Wish I were you.

[radio nut]

Headphones or a horn speaker would be great!
My antenna is outside and I will add more this weekend.
My ground wire runs to the actual house ground right outside my garage where my workshop is.
So it should be ok.

[init4fun]

Originally Posted by radio nut

My ground wire runs to the actual house ground right outside my garage where my workshop is.So it should be ok.

Nope , it ain't OK for your ground to be connected to a ground shared by any other (especially AC) circuit . Period . That's why I specifically mentioned using a grounded outlet in the hose as being unacceptable , well that ground is one and the same with the rest of your garage's (and house's) circuit grounds , isn't it ? The optimal ground for a any receiver and especially a one tube receiver such as yours is a copper grounding rod driven 6 to 8 feet into moist soil with a copper wire leading from that rod to your receiver in the shortest possible distance , and with NO sharing of any other grounding circuits with it whatsoever .

A compromised ground . A relatively short 60 feet of antenna . Your lucky you got the two stations you did , and I really believe a proper antenna and ground will get you more than the two your getting now .

[radio nut]

A friend of mine is an electrician and I have him bringing his supplies over for the ground, the antenna will be done Saturday . So lets see what happens!

[Reece]

Sometimes a regenerative set won't like a long antenna connected directly: the capacitance of the antenna can keep the set from regenerating. If that happens, you can just twist two pieces of insulated wire together as a gimmick capacitor and use that to couple to the set. Have you operated regen sets before? The set was designed to use a 2000 ohm traditional headset. The regen control is advanced slowly until a rushing noise is heard and then backed off just until the rushing stops. That is the most sensitive point. It will be very sensitive but very touchy. As you tune, this point will change also and you'll have to readjust the regen control up or down to maintain sensitivity. Try the set after 8:00 PM. I have used regens that can pick up stations all over the eastern half of the country after dark. This set did not like my outdoor antenna but picked up all these stations with about 20 feet of wire strung in the rafters of the garage.

This shows the idea of a gimmick cap. One wire would connect to the antenna, the other to the set. Does not have to be tightly twisted as shown. Can be loosely done, adjust number of twists to suit operation.
http://213.114.137.49/begin/gimmik-0.htm

[old_coot88]

I scratch brewed regen sets back in the day that worked fine with just a random length wire strung across the room and NO ground, and DXed plenty of stations. (Well, one was AC operated and thus had a RF ground via the powerline.) But the tickler adustment is always super critical and you have to 'ride' it as you tune.

[radio nut]

Lets see, new copper pipe ground made zero difference.
I tried a lot more wire and all that did was kill the tickler, meaning it acted like a volume control and the strongest lima station stayed in no matter where I tuned the tuning cap. I added a homemade wire cap and I ended up with basically what I started with. I tried subbing with jumpers a very strong 864 tube and had similar results. A diagram online for an Armstrong 1 tube regenerative set shows a rf bypass cap in parallel with the headphones. I just tried a .022 cause that's all I can find and if you aren't perfectly on a station this set will squeal loudly. I am sure that it should be a lower value .

[radio nut]

Homemade wire cap in series with antenna is what I meant.
Could I be sitting in a dead spot for signal?
I did try this radio at night and it did grab a couple more stations but extremely weak.

[old_tv_nut]

I'm thinking the .022 might not be a RF bypass at all, due to self-resonance. I would try putting a small ceramic disc, say 100 pf, across it.

[Reece]

Are you using a 2000 ohm traditional headset? A one-tube regen should be picking up a bandful of signals at night. You advance the regen control until it oscillates and then back off until it just stops. Maintain that condition as you tune.