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Author Topic: Foxhole Radio detector variants (updated)  (Read 1075 times)
VU2NAN
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Posts: 214




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« on: March 02, 2014, 11:35:11 AM »

Please do check this out.

http://nandustips.blogspot.in/2013/05/foxhole-radio-detector-variant.html

73,

Nandu.
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N1NQC
Member

Posts: 48




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« Reply #1 on: March 13, 2014, 07:23:09 AM »

Hi,

Using just a detector (be it Razor or diode) and headphones without a coil isn't really going to work very well.My suggestion would be to wind a 330uH  coil (with taps)  on a salt or oatmeal box (search oatmeal box radio) .This should "boost" things  considerably. An optimal antenna ( single  wire end  fed, hopefully, 75 ft + ,  up as high and clear  as possible) and good ground are also very important for this type  of experimentation.

Find the  best tap settings  with a diode FIRST(preferably a 1n34 type ), THEN swap to any dissimilar detector you want (new  razor, old blue razor, rusty  razor or any thing else  you care to try).

I found that a pencil actually makes a blue razor MUCH easier to adjust. But even WITH a pencil, these type  of detectors are VERY,VERY  touchy and require  a LOT of signal to "motivate" them into working.They are much harder to get working compared to mineral detectors (galena, pyrite, etc).

Hopefully your headphones are  in good working order (not weak)

More  crystal  radio help on Schmarder radio  board chat.



de N1NQC



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VU2NAN
Member

Posts: 214




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« Reply #2 on: March 13, 2014, 08:25:08 AM »

Hi OM Kevin,

1. My headset (WWII 'Balanced armature' type) is in excellent shape and quite sensitive.

2. My shack is only 20km (as the crow flies) from the local 200kW broadcast station on 612 kHz.

3. No selectivity is required as all nearby stations are on 88-108 MHz FM.

So just a diode-shunted headset is good enough at my location!

The signal strength is not as good with the razor blade or oxidized-brass detector, of course.

Thank you very much for your kind response and real useful tips.

73,

Nandu.
« Last Edit: March 13, 2014, 08:30:38 AM by VU2NAN » Logged
N1NQC
Member

Posts: 48




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« Reply #3 on: March 18, 2014, 05:22:22 AM »

Sounds  cool , Nandu.

Enjoy.

de N1NQC
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VU2NAN
Member

Posts: 214




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« Reply #4 on: March 18, 2014, 09:06:11 PM »

Thank you, Kevin!
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