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Author Topic: 40-meter QRP tuner ideas?  (Read 3560 times)
SM0MDG
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Posts: 3




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« on: October 11, 2000, 02:57:21 PM »

I am looking for ideas to build a 40-meter QRP tuner. It should handle 5 watts and be able to tune a wire. Ideas anyone?


72 de SM0MDG
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K7ZOV
Member

Posts: 11




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« Reply #1 on: October 17, 2000, 05:19:00 PM »

I found a great one presented by G3VGR.  Go to http://www.qsl.net/g3vgr/hw_ant.html.  He has a 20 meter
and 40 meter version and it's simple and really works.  Have fun
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VK3YE
Member

Posts: 8




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« Reply #2 on: October 18, 2000, 04:39:42 PM »

If you're using a wire about 20 metres long, it's hard to
go past an L-match. Just a variable capacitor and coil, wound on a toroid if you want to keep it small.
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WB6BYU
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Posts: 13026




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« Reply #3 on: October 24, 2000, 04:11:30 PM »

If you can standardize the length of your wire, you won't need as
much tuning range on the tuner.  For example, the 20m wire
mentioned earlier used for portable operation will not change
impedance much even when it is installed in different configurations
characteristic of backpacking or other temporary use.  You can
breadboard an "L" tuner to find the desired L and C values, then
wind a toroid core for the coil and use a small compression mica
trimmer for the cap. You may want to have a couple coil taps,
perhaps + and - 10% from nominal.  For a wider matching range
you can tap the coil with a clip lead or multi-position switch.
Using a T-50 or T-68 size core (#2 or #6 material) with a 200pf
mica trimmer should take less than 1 inch square and handle 5
watts with no problem.

Good luck!   - Dale WB6BYU
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OZ1GIY
Member

Posts: 3




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« Reply #4 on: November 02, 2000, 02:36:02 PM »

LDG Z-11 in connection with a homebrew 4:1 balun has worked very good for me. A 33 ft (10 m) longwire tunes ok from 160 m to 6 m.

Erik
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N4EJG
Member

Posts: 2




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« Reply #5 on: March 06, 2001, 02:28:48 PM »

I would recommend a Z-match...it can be made light, compact and tunes faster than any other type of tuner I have used. It also tunes more bands than my conventional tuners.

Check out the BLT on the Norcal QRP Club website. Also, Emtech has a ZM-2 which is what I use and highly recommend. Both of them have a built-in SWR indicator that uses an LED. When you have a match, the light goes out!

Good luck,
73
Ed
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