A GREAT LITTLE KIT!
The QRPGUYS call this their "LED Tuning Indicator" but most other people would call it an SWR Bridge. I purchased it because I was just a little concerned that I might harm the finals in my QRP-Labs QDX while tuning-up.
I use an Elecraft AT1 tuner which is remarkably fast at finding a match, but for the sake of $20, it's just not worth the risk. With this bridge fitted inline, the QDX will never see more than a 2:1 mismatch. It's rated at 10W PEP or 5W CW which is perfect for the QDX.
All you need to do is fit it between your transceiver and ATU and flick the switch to the TUNE position before tuning up as normal. As the tuner gets closer to a good match, you'll see the onboard LED glow dimmer and dimmer. When your tuner finds a 1:1 match, the LED should extinguish (although it may actually stay on VERY dimly).
So once you've found your match, just flick the switch back to OPERate and away you go. Leaving the switch in the TUNE position will result in your transmitted power being reduced by a factor of 4 (approximately). This can be handy for when you wish to reduce the transmitted power of your QDX for WSPR tests.
When I'd built the little kit, I attached it to the QDX and gave it a go. It worked perfectly on all bands and had ZERO impact when in the bypassed mode for normal operation. Very pleased with this little device and I look forward to playing around with some more QRPGUYS kits in the future.
Kit available >> here <<
73, Tom, M7MCQ.
#qrpguys #qrp-labs qdx #swr-bridge
5 comments:
Where can I buy this kit?
Good article! You might add one thing, a link to the QRPGuys product page. Roy WA0YMH
Hi Tom, might seem like a silly question but if I've got this right its for use with a manual ATU and you tune up without any power until the LED goes out/dims? You then go to the operate position which bypasses the bridge and tune if need be as normal. Is this correct?
D'oh!! Sorted Roy. Thanks for visiting the Blog.
Merry Xmas!
Link is now in the article Larry :-)
Merry Xmas.
Post a Comment