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Reviews For: NS-40 Class E Transmitter by NM0S

Category: QRP Radios (5 watts or less)

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Review Summary For : NS-40 Class E Transmitter by NM0S
Reviews: 12MSRP: 30 (DX $33)
Description:
Kit designed by David Cripe NM0S, and made available by 4SQRP Group. The NS-40 Transmitter is an upgraded version of the overall winner in the FDIM 2008 Homebrew Contest. It is a truly unique QRP transmitter design. NS stands for No Simpler, so this is the No Simpler 40 Meter Transmiter.
Product is in production
More Info: http://www.wa0dx.org/wa0itp/ns40.html
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
00125
KB7PWJ Rating: 2022-09-10
Amazing performance from cheap and simple kit. Time Owned: more than 12 months.
Got mine from the NM0S store on eBay (search "NS-40+ 40M 5 watt QRP CW Transmitter") for 24$ shipped. Just adding my verification that it goes together fast (there's almost nothing there!), and if you build mindfully and pay attention to the instructions, works immediately. And I get 5-7 watts at 11.9 - 12.2 volts from a battery, and 8-9 on my bench supply, which for such a simple and cheap kit is miraculous.

Have had several enjoyable QSOs with it to date, and really love being XTALC and RX/TX again after all these years. I'm running it to the Easy TR Switch kit from QRPKITS.com, which switches the antenna automatically from RX (my old TenTec 580D) to TX on key-down. Soon I'll add their bandpass filtre kit as well to clean things up.

Recently a WebSDR in DC fed this station back to me loud and clear, which when you figure I was transmitting to a longwire in a tree in the real Washington, is terrific performance by any measure.

Anyway, that's my thumbs-up. For those who want to build this, I recommend reading through the reviews here to avoid common mistakes. The biggest one seems to be trying to enclose the board in a metal case, or otherwise operating it near metal, which spoils signal stability. Also, remember to clean the contacts on your key. If they're dirty, the NS-40 will pump less power forward and it'll chirp. (Learned that the hard way.)

You could build a QCX for less money than a complete scratch-built NS-40 station, but I'd argue the two accomplish different goals.

In my case, it's a way to relive my Novice days.
WB0FDJ Rating: 2019-01-31
Great QRP transmitter Time Owned: 0 to 3 months.
Wow. For less money than I'd pay for dinner with my SO I ordered this kit from NM0S. When it showed up I thought, "wheres the rest of it"? Well I had an hour or so and decided to fire up the iron.

Very simple to put together. Directions are clear. Everything in the bag. Two minutes after assembly it worked without any drama or surprise. Nice clean signal and no chirp. (I have other rigs for that!) :)

I get about 6 watts out. If you want to build something simple and actually useful, this is the ticket. 5-6 watts is plenty for easy QRP contacts. Oh instead of soldering the crystal to the board use DIP pins so that the crystal can be easily switched out. I bought a "Pixie board" that allows switching between 4 separate crystals: we'll have to see how that works. Recommended!!
KD8IIC Rating: 2017-08-21
Great Little Powerhouse. Time Owned: 0 to 3 months.
Got mine in the mail today and it went together quickly.
The smaller transistor orientation is the flat side facing towards the BNC connector.
The pix of it is blurry, other than that it is a lotta fun and mine is putting up 6 watts with no heating the output. Loading a full wave open wired doublet.
1st CQ answered 850 miles was away with QSB/QRN 479 RST.No chirp and no drift.

Hope he makes more of these. I got last one!
W2DLC Rating: 2017-03-07
Clean Signal From Mine Time Owned: 0 to 3 months.
NM0S is selling a few kits on eBay, and I was intrigued. I sent for one and it came in about three days. It took me about an hour to carefully put together. I tested it several times while listening on my receiver, and the signal is clean. I sent a couple of CQs at about 1800hrs, and K2QU in New Jersey came back and gave me a 589. I'm looking for a box to house it to make it look a little nicer now, but otherwise, I'm very happy.
KD7RDZI2 Rating: 2015-01-05
powerful Time Owned: 0 to 3 months.
Is this a qrp? I get about 7W at something 13Vdc. Others have reported over 10w!! To protect the keyer I used the simplest interface with a single TIP42G. My first qso was a bit chirpy, I could hear it on my receiver. Then I moved the plastic case in such a way that spirals were not too close to metal surfaces. The note is now a good one. It's really incredible how cold the final is! Building this kit is just a pleasure. No toroids to wind just a few components. A really well designed transmitter. I wish they could offer a 20m and 30m versions.
KU4UV Rating: 2012-12-04
Fun and easy kit that actually works! Time Owned: 0 to 3 months.
I ordered my NS-40 last Tuesday, and it arrived on the following Monday. The whole kit, short of the needed wires for the antenna, key, and power hookups, took about 30 minutes to complete. When I powered up the transmitter, it showed around 10 Watts output power. I played around with the kit last night, but wasn't able to make a contact just yet. Overall, I give the kit a 5. One thing I noticed that concerned me though was that the kit was mailed in a padded mailing envelope that had a nice 1 inch gash in the side of it. Luckily, all the parts were still there, but I wish that the kits could be packaged a little better. I know the kits are shipped by volunteers, but I would gladly pay the extra cost to have the kit shipped in a little better packaging.
One other thing, one of the the capacitors was much larger than the other components, and the leads were not able to go through the tiny holes on the circuit board. I ended up just tack soldering the capacitor to the board, and so far everything works fine. I don't know why this particular part was so much larger than the others, unless they ran out of that particular item. I may change the part to a smaller capacitor sometime. Also, the components were shipped in a Ziplock bag. There is a note in the instructions (which you have to view online) that warns about the danger of static discharge to the MOSFET transistors. Not sure why the Ziplock bag was used, but no problems so far. Other than these few minor gripes, I recommend this kit.

73,
KU4UV
DAVER Rating: 2011-09-29
Great Kit Time Owned: 3 to 6 months.
Not much to say that hasn't been said... Simple isn't the word for it, only a few parts. Performs great (just over true qrp with my gell cell at full charge). Has taken plenty of abuse as well regarding pushing into bad loads and no damage to the final at all. Only tricky part is you may need to whip up something to use a paddle with a keyer b/c it has a high current on the keyline.

I use it with the Magicbox (nicest designed kit I've ever seen) and the SS-40 receiver and am very happy with the station. If I get overly ambitous I may pursue getting a VFO dds hooked to the station for expanded coverage.

With the NS-40 it comes with just a crystal (around 7030) but also has some thru-wholes you can use to add C/L combos for a simple VFO of sorts. Or you can ake the crystal out and just add your own VFO utilizing multiple crystals and whatnot.

I love the 4states kits and like I said before, it is my 40m CW station.

73,
Dave KD2AKC
WD9F Rating: 2011-09-11
Amazing QRP Xmtr Time Owned: 3 to 6 months.
This is a simple to build project with about 15 parts. The build directions were perfect and all parts were provided. I finished mine in about 45 minutes and it worked FB. I did have a chirping problem with a 13.8V AC supply but when I backed off and used a 12V battery, no problem at all. I get great reports, it cranks out a solid 7W at 12V and I've worked 16 states with it. I'd recommend it to anyone. It's really fun.
AE4GM Rating: 2011-06-14
VFO for NS-40 Time Owned: more than 12 months.
I finally got VFO control of my NS-40. I had tried my Heathkit HG-10 before with no luck. This time I tried keying it in SPOT position. It worked!!! I'm getting about 5 or 6 watts of great sounding CW out of it. Eureka!!!!!!! To go back to receive you have to put the VFO back in the normal vfo position off of spot so the tone does not interfere with the receiver.

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Earlier 5-star review posted by AE4GM on 2011-01-29

I had an initial problem with good contact on the crystal through hole soldering connection. If you are only getting 5 watts and it's chirpy you should look at that and other solder joints. I get just over 9 watts out of mine and it works very well.
KF7DMY Rating: 2011-01-31
It WORKS!!! but I still wish it'd be plug-n-play.. Time Owned: 0 to 3 months.
My NS-40 works as it should now. Initial problem of chirping was not because of poor soldering job but has something to do with voltage regulation. The circuit works even with 9 volts power supply. I am using a regulated 13.5 volts and was extremely chirpy until I added a higher value to C2 2.2uF to be exact since that was all I have in my junk box. I'm pretty sure the value I used could be a bit smaller.
I am happy with my NS-40. I gave it 5 for its simplicity.

Thanks to AE4GM for the quick help.

73.

al






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Earlier 3-star review posted by KF7DMY on 2011-01-29

This is my first QRP project and I'm not very happy with the performance. It is very chirpy. I was able to get 5 watts out. But the quality of the cw is so ugly. I would hold on to the NS40 until I can find some help. If the other hams like it, then there must be something good about it. Al, KF7DMY