Radio Preppers

General Category => Technical Corner => Topic started by: vwflyer on October 23, 2015, 04:04:40 PM

Title: BangGood QRP tuner
Post by: vwflyer on October 23, 2015, 04:04:40 PM
Hi guys,
Does anybody have experience with this inexpensive tuner? I have ordered a few kits and things from this outfit before and so far I've been pleased with what I've gotten but I figured I'd ask first.
http://www.banggood.com/QRP-1-30-Mhz-Manual-Antenna-Tuner-Tune-Kit-p-914663.html
Title: Re: BangGood QRP tuner
Post by: KK0G on October 23, 2015, 04:23:49 PM
I have no experience with that particular tuner but it looks to me like it's pretty much the same design as the SOTA tuner in a slightly different package. For only $14 you don't have much to lose, I'd go for it.
Title: Re: BangGood QRP tuner
Post by: vwflyer on October 23, 2015, 04:34:23 PM
That's kind of what I was thinking. BangGood often times puts a link to the assembly manual right there on their site but I don't see one in this case. It looks like there are two variable caps in this kit and a potentiometer. I have no idea what the potentiometer would be for. And without the manual I don't know how to tell if this will tune end feds or center feds or what. I'm wanting it to tune center fed dipoles as I already have a sota tuner for end feds.
Title: Re: BangGood QRP tuner
Post by: vwflyer on October 23, 2015, 05:18:22 PM
I found the instructions here.
https://app.box.com/s/mz1zmg9o2sret4lyl4pt
This is the same tuner, it appears, that showed up on these forums many many months ago. The one where everybody made fun of the english translation. I'll have to go back to those threads and see what was said about it. I only remember the comments about the manual's interesting english.
Title: Re: BangGood QRP tuner
Post by: cockpitbob on October 23, 2015, 05:29:27 PM
Vwflyer, you are right about it being the same tuner who's instructions we made fun of.  I've built 2.  The first was over a year ago and the kit had problems.  6 months ago I got another and it's pretty good.  The only weak point might be the 2 variable caps.  In the first kit I replaced them with polyvaricons, but in the newer kit they seem OK.

It's a standard pi-tuner and tunes a random long wire well.  Add a balun and I'm sure it will do well with a G5RV.
Title: Re: BangGood QRP tuner
Post by: vwflyer on October 23, 2015, 06:00:21 PM
Thanks for the confirmation Bob. After looking at the manual I realized that what looked like a potentiometer is the multi-tap switch for the inductor. I don't know what I was thinking. Sounds like it's not a bad deal for what it is.
Title: Re: BangGood QRP tuner
Post by: cockpitbob on October 24, 2015, 07:59:58 PM
It's a good deal.  It's worth it just for the parts.

Verify hole locations before drilling.  I think I lowered the BNC's holes a little because they would have interfered with the variable caps.

For me, the worst part was the multi-tap inductor.  The magnet wire in the kit is good quality with high temperature kapton insulation.  It's good, tough stuff.  The down side is it won't melt-back with the soldering iron.  You have to scrape off the insulation at each of the 12 taps while you wind it.
Title: Re: BangGood QRP tuner
Post by: vwflyer on October 24, 2015, 08:38:23 PM
QuoteFor me, the worst part was the multi-tap inductor.

That was my thoughts when I looked at that inductor. I don't mind winding toroids but that one looks like a real bear. I think I'll go ahead and put it on my Christmas list though. It will give me something to do on the cold winter nights while I huddle close to the glowing tubes my Collins KWM-2.