3 Band Homebrew rx.

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M0JSW
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3 Band Homebrew rx.

Post by M0JSW » 10 Jan 2013, 22:10

Found a nice little,3 band,regenerative rx circuit.No IC`s,no trimmers to adjust,just solder together and it should work.20,30 and 40m on a 3 position switch.I had most bits in,just needed 4 transistors that cost 39p each from maplins.Amazingly it worked on the first test,but it`ll be interesting to get the frequency counter on it to see where its band edges are and perhaps adjust the coils by a turn or two if needed.Its very sensitive and needs a steady hand to tune,but its fun to play with.Mounted it in a grotty old tobacco tin.
Nice project for a novice like me,plus I now have an rx for 30m.
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Re: 3 Band Homebrew rx.

Post by MonkeyWorks » 07 Apr 2013, 20:13

Very nice :) I also made a regenerative receiver for 80m band and one super regenerative for FM, using vacuum tubes. It is possible to measure the frequency. I made a high impedance probe with a fet and for the first radio it was enough to move this probe close to the radio to get a stable reading on the frequency counter :)

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Re: 3 Band Homebrew rx.

Post by pentode » 09 Apr 2013, 11:58

Looks a nice little project, any chance of a link to the web page / schematic,
Andy

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Re: 3 Band Homebrew rx.

Post by M0JSW » 11 Apr 2013, 11:17

I no longer have the link but I do still have the schem.
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Re: 3 Band Homebrew rx.

Post by normal » 11 Apr 2013, 14:57

PA2OHH's page about his receiver design

http://www.qsl.net/pa2ohh/03rega.htm


A short blog entry by OK1CDJ who has built one

http://blog.ok1cdj.com/2013/01/jednoduc ... c-40m.html

Translated from Czech to english.

http://translate.google.co.uk/translate ... c-40m.html

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Re: 3 Band Homebrew rx.

Post by Buick Mackane » 06 Aug 2015, 18:58

M0JSW wrote:I no longer have the link but I do still have the schem.
Dragging up an old thread. But fancy having a stab at this. Built a few regens in the past. But they never quite worked the way i wanted them too.

Am i right in thinking that L2a & L2b consist of 2 x 3 turn coils joined in the centre? As per the pic below
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Re: 3 Band Homebrew rx.

Post by crusty » 07 Aug 2015, 16:30

You are spot on. Have fun.

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Re: 3 Band Homebrew rx.

Post by normal » 07 Aug 2015, 19:29

I think the whole of L2 needs to spiral the same way, not change direction in the middle

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Re: 3 Band Homebrew rx.

Post by Buick Mackane » 07 Aug 2015, 19:35

think iv'e got it sussed now, cheers gents
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Re: 3 Band Homebrew rx.

Post by Buick Mackane » 03 Sep 2015, 17:05

Heres my attempt at this receiver. Built into a tobacco tin. The original design was a tri bander. But the only toroid i had in the junk box was a T-50-2 And thats only good up to 10 mhz. So iv'e set it up for 40m :)
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Re: 3 Band Homebrew rx.

Post by Andy » 06 Sep 2015, 14:44

It's amazing just how much 'back to basics' fun you can have with these simple RX desgns, and with careful operation you can hear pretty much anything you can hear on a shop-bought radio. Back in the 60's (watch out now, the 'when I were a lad' switch has been thrown) I used to build two or three transistor radios with regeneration or reflex (or both) and the performance could be astonishingly good. The pop pirate ships* which were weakish signals here in Manchester were easily audible.

*Note for youngsters - these were ships anchored off the coast, broadcasting popular teen-beat tunes to a young and groovy audience.
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Re: 3 Band Homebrew rx.

Post by Admiral » 06 Sep 2015, 18:03

Nice work PLL02A, I like it.

Believe it or not, I made a 'dead bug' civil airband RX just for S&G a few months back, and it actually worked, it was someone elses cleverness, I just followed the idiot guide, but when something works, and costs less than £4 (would cost virtually nothing to those with tins of old bits), it brings a big old grin to your chops.
Winner of the 2017 IBTL 'Summer Sizzler' competition

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Re: 3 Band Homebrew rx.

Post by Buick Mackane » 09 Sep 2015, 21:20

Just noticed your comments, Yeah you defo cant beat tuning round the bands on something you've built yourself. For such a simple design its quite stable with minimum drift, Any drift is easy to correct with a slight adjustment of the regen control. Ive decided to rebuild it as i wasnt happy with the messy component layout, Plus i want to make it more compact so i can get the battery in the tin as well, Having an external battery only leads to noise pickup etc, Watch this space for more crap quality pics from my crap quality camera phone :x

Just a bit of extra info, The original design uses BF494 Transistors for the RF amp & mixer, I didn't have any so i used 3904 ''popcorn'' transistors. Almost any low gain NPN could be used i suppose, the 3904 is around 200 hfe. For the audio amp i used BC548 Which are medium gain (400 hfe) and they produce plenty of volume, the original uses BC547 Which are rated around 800 hfe that would blow yer lugs off :shock:

Heres a diagram of how i wound the coil. Happy soldering troops :)
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Re: 3 Band Homebrew rx.

Post by Buick Mackane » 13 Sep 2015, 17:16

new and improved
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Re: 3 Band Homebrew rx.

Post by Buick Mackane » 04 Apr 2016, 20:25

Dragging up an old thread, But wanted to show off my new camera :D
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Some days will stay a thousand years, Some pass like the flash of a spark, Who knows where all our days go ~ Stuart Adamson.

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