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 Post subject: Transistor regenerative radio?
PostPosted: Dec Thu 08, 2005 4:11 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Willington, CT USA
I wasn't sure where to post this as it's not a restoration issue so pardon me if it's off-topic.<P>I was looking at building a regenerative radio with my Nephew. My question is, can you build one of these sets using a FET (GASP!) instead of a tube? My reason for asking this is that I don't really want a 12 year old working with a high voltage power supply. Plus I don't want the added expense of building one either.<P>I was looking at Dave Schmarder's design here: <A HREF="http://www.schmarder.com/radios/tube/images/6418-schematic.gif" TARGET=_blank>http://www.schmarder.com/radios/tube/images/6418-schematic.gif</A> <BR>It looks simple enough to use a FET in place of the tube, but I'm no expert at this, so I thought I'd ask (the experts) <IMG SRC="http://antiqueradios.com/forums/smile.gif"><P>I'm open to other designs if anyone has built one using a transistor.<P>Thanks<BR>Glenn<P>------------------<BR>


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 Post subject: Transistor regenerative radio?
PostPosted: Dec Thu 08, 2005 4:27 pm 
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Location: Nova Scotia, Canada
Hi,<P>Just a suggestion here. But since you're looking for a solid state regen, Radio Shack some years ago had 2 regen kits out there. A tube one as well as a solid state one. Rather than try and find the kit, just use the schematic and try to get the parts and build yours from scratch.<P>I have both sets here and I'm pretty sure I have the schematic for the solid state one. If you want, I'll dig it up and send it.<P>Bob<P>------------------<BR>


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 Post subject: Transistor regenerative radio?
PostPosted: Dec Thu 08, 2005 4:32 pm 
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Location: Willington, CT USA
Thanks Bob!<BR>That's a good suggestion. I didn't know Radio Shack made such kits.<BR>Is this it? <A HREF="http://oak.cats.ohiou.edu/~postr/bapix/RSglobeP.htm" TARGET=_blank>http://oak.cats.ohiou.edu/~postr/bapix/RSglobeP.htm</A> <BR>Glenn<P>------------------<BR>


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 Post subject: Transistor regenerative radio?
PostPosted: Dec Thu 08, 2005 9:09 pm 
Silent Key

Joined: Jan Thu 01, 1970 1:00 am
Posts: 34328
Location: Sandpoint, IDAHO 83864
Yes you can! Simplyuse an enhancement mode FET as you would a triode tube.<BR>Source= filament or cathode of tube<BR>Gate= control grid of tube<BR>Drain= plate of tube.<P>An MPF-102 or el cheapo equivalent should work fine. Use a transistor radio 9 volt battery for power and away you go. I would start with the same circuit values for a tube and once you get going, the values can be adjusted for best performance. Make sure your headphones are of the high impedance (2000 ohms or more) to protect the FET from excessive current.<BR>Curt<P>------------------<BR>Curt, N7AH<BR>(Connoisseur of the cold 807)<BR>QCWA# 25085 AMI# 242<BR>CW forever


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 Post subject: Transistor regenerative radio?
PostPosted: Dec Fri 09, 2005 1:33 am 
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ve1arn wrote:
<font>quote:</font><HR>Originally posted by Glenn B:<BR><B>Thanks Bob!<BR>That's a good suggestion. I didn't know Radio Shack made such kits.<BR>Is this it? <A HREF="http://oak.cats.ohiou.edu/~postr/bapix/RSglobeP.htm" TARGET=_blank>http://oak.cats.ohiou.edu/~postr/bapix/RSglobeP.htm</A> <BR>Glenn</B><HR>
<P>Hi Glenn......... yep that's the one. RAdio Shack had a 3 tube model. That's the first kit I ever built. I bought the solid state one at a flea market for $10 2 years ago. <P>And I did find a copy of the manual on one of my CD's I have. pdf as well as djvu format. So if you're interested, let me know.<P>djvu ...... 652 kb<BR>pdf........ 3.9 mb<BR>gif........ 807 kb (schematic only)<P><P>------------------<BR>


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 Post subject: Transistor regenerative radio?
PostPosted: Dec Sat 10, 2005 1:44 am 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Watsonville, CA, US
I have found solid state regens to be poor performers. I have tried several. A simple one will not work for beans. The one you cited looks very good. It also highly reccomends a printed cirgut board. <P>You could go with a 1T4 or 1S4 tube. You can run them on 27v and get good results. Either a triode hook up or controlling the screen grid will be fine. 27-volts wont hurt you. Peebles Originals makes two kits. A 1-Tuber and a 2-tuber. The 2-tube set was my first try at making a regen. It worked OK. The antenna is overcoupled so you will need to deal with that. The 1-tuber is very simple and should work fine too. I think that one would be good for a first try. <P>If you want to go it on your own most any triode will work. I would start with a triode. The optimal voltage to run a triode regen detector is about 20-volts. A 6J5 or 6C5 will make a great regen. The old '76 is even better. Any of the miniature triodes, 6C4 and such will be dandy. You can hook a pentode as a triode by tyingn the screen grid to the plate. Find something in the junk boy and go with it. Run the heaters off a 6-volt lantern battery. Use two or three 9V batteris for the B+. IF you get the glass version of the tube it will even glow ! <P>You can use a set of amplified computer speakers for your audio section. Alternatly a pair of tin cans or high-Z phone will work. Either way you will have no high voltages at all. <P>------------------<BR>


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 Post subject: Transistor regenerative radio?
PostPosted: Dec Sat 10, 2005 4:30 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Willington, CT USA
Thanks everyone for the responses!<BR>I think I'm going to try the circuit here: <A HREF="http://www.webex.net/~skywaves/homebrew/12Vregen.htm" TARGET=_blank>http://www.webex.net/~skywaves/homebrew/12Vregen.htm</A> <BR>It uses the 12v tube family 12AC6, 12AF6, 12BL6, 12CX6, 12DZ6, 12EA6, etc.<P>I've seen someone making and selling this type of radio on Ebay, and they look very well built. His/hers has a bandswitch, and a very heavy gauge coil: <A HREF="http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5838293022&rd=1&sspagename=STRK%3AMEWA%3AIT&rd=1" TARGET=_blank>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5838293022&rd=1&sspagename=STRK%3AMEWA%3AIT&rd=1</A> <P>My only question on this circuit is how do I add a bandswitch? Is the coil just tapped with a switch(es)?<BR>I'll probably also add a bandspread capacitor to the main tuning cap in parallel.<BR>I can then run this set from a Wal-wart or the car battery.<BR>Glenn<P>------------------<BR>


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 Post subject: Transistor regenerative radio?
PostPosted: Dec Sat 10, 2005 5:07 pm 
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Location: Willington, CT USA
Speaking of this type of radio, does anyone have a scan of "Shortwave Coil Data Book" 1937 Gernsback? I'm looking for coil winding information to make a few plug-in type coils for this radio.<BR>Thanks<BR>Glenn<BR><P>------------------<BR>


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 Post subject: Transistor regenerative radio?
PostPosted: Dec Sun 11, 2005 5:42 pm 
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ve1arn wrote:
<font>quote:</font><HR>Originally posted by Glenn B:<BR><B>Speaking of this type of radio, does anyone have a scan of "Shortwave Coil Data Book" 1937 Gernsback? I'm looking for coil winding information to make a few plug-in type coils for this radio.<BR>Thanks Glenn</B><HR>
<P>I have the Lindsay Publications reprint of the Shortwave Coil Data Book, by Radio Publications, Hudson Street, NY.<P>Is that the one you're talking about?<P>Bob<P><P>------------------<BR>


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 Post subject: Transistor regenerative radio?
PostPosted: Dec Sun 11, 2005 5:59 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1175
Location: Willington, CT USA
I'm not sure if that's the same book, but It's not important. I'm just looking for information on coil winding to make a few plug-in coils to cover various bands. I have made a few coil forms using bad tube bases with pvc tubing glued onto them.<P>I really don't know where to start with # of turns on the main coil & # of turns on the tickler (with spacing between the two).<BR>The antenna is going to be coupled with a trimmer capacitor, so I don't need a winding for that. <P>The main tuning capacitor is going to be the standard 365pf, not the 150pf on the schematic, with a 10pf bandspread capacitor in parallel.<P>Glenn<P>------------------<BR>


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 Post subject: Transistor regenerative radio?
PostPosted: Dec Sun 11, 2005 8:08 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Florence, Al. U.S.A.
A good source for plug in coil data is in older ARRL Handbooks, 1940 and earlier.<P>------------------<BR>


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 Post subject: Transistor regenerative radio?
PostPosted: Dec Mon 12, 2005 1:38 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 991
Location: NW WA
Glenn-<P>If you're still interested in trying a transistor circuit, I have a little book called "Make and Use Series Modern Transistor Radios". It has circuits and construction details for several regenerative and reflex receivers along with some audio stages. These use bipolar transistors, not FETs. It looks like a good book for a kid to learn from. Let me know if you're interested and I'll send it to you.<P>-Steve W.<P>------------------<BR>


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 Post subject: Transistor regenerative radio?
PostPosted: Dec Mon 12, 2005 8:31 pm 
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Location: Willington, CT USA
Glenn B wrote:
<font>quote:</font><HR>Originally posted by Carl Neidert:<BR><B>A good source for plug in coil data is in older ARRL Handbooks, 1940 and earlier.<P></B><HR>
<P>Thanks Carl, now to just find a 1940 AARL handbook <IMG SRC="http://antiqueradios.com/forums/smile.gif"> EBAY probably right?<P>Steve-<BR>Thank you very much for the offer but I think I've settled on a low voltage tube like the 12AF6. I'd like to get him started on something with glass in it <IMG SRC="http://antiqueradios.com/forums/smile.gif"> 12VDC seems low risk, and he can run it on the car battery or a wall-wart.<BR>Glenn<P><P>------------------<BR>


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