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Thursday, November 21, 2013

BITX Build Update #20 -- Switchable Crystals, South Africa QSO


I got tired of popping the hood and manually changing my VXO crystals.  First I tried to switch the rocks using a rotary switch on the front panel, but I think the leads were too long and the output was kind of squirrely.   So I dug around in the junk box and found a 12 volt double pole double throw relay.  I put the crystal sockets across the two poles and ran leads from the armature terminals to the crystal terminals. I use the rotary switch to activate the relay.  I cover about 41 kHz of the 17 meter band with the two crystals. 

17 meters has been in great shape.  On November 16 I had a very nice contact with Syd, ZS1TMJ in Glenwilliam, South Africa.  That's about 8000 miles on 5 watts SSB.   

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4 comments:

  1. Nice! What kind of antenna did you use for the South African contact?

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  2. Nice QSO Bill!

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  3. The antenna was an ordinary half-wave dipole, about one half wavelength up, in the trees, fed with RG-58 coax.

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  4. Good QRP DX OM. Whatabout 2N7000s or ordinary transistors for switching those crystals?

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