Harry. Very helpful as usual. Thanks so much.

Good stuff. Besides Eu for me, Antartica, Iceland, Hawaii, New Zealand. (Also South America and South Africa) Just with 250mW from North America! This transmitter is great isn't it?

@Harry Zachrisson At first I was thinking, based on the second image, one of your transmitters was taped to a rabbit cage instead of a window. Maybe a name like QRP Carrot Beacon Transmitter or similar.

@Harry Zachrisson Yes, after I posted, I thought about it, and the current SMT ATMEGA328P is as high as they go in terms of flash, eeprom and ram. So an alternate Arduino platform. So your transmitter would expose it's own access point... Interesting. I think that would be a great capability, but it's the memory that is evidently critical. I personally do not mind using a USB port to configure. There is something re-assuring about that, although having WiFi means the device could comm in real-time to another device on one's network to have crazy flexibility. Fun stuff.

Sounds good. Don't let these ideas take you off task. Just thought people could brainstorm and record ideas somewhere. Silly question, is there a version of the Arduino module that has more non volatile memory?

Harry. I don't know if possible, but an alternate SW firmware load that allows the WSPR Transmitter to do slow speed CW, QRSS? Is the hardware capable?

That is wonderful. Go for your Extra and get access to all bands. If someone is on the fence about going QRP, jump in... You won't regret it.

Sure, I hope others put in a product review, and then so many people will want your transmitter and other products that you'll have to hire someone full time to do assembly. Perfect job for the whole family. But seriously, I think what you are doing with the Balloon transmitter would make a great article for QST Magazine, QRP Quarterly: https://www.qrparci.org/ or other. You've got a great product, and I think more people should know about it. :)

Ron, I don't know if Harry goes by the nickname Zack, but I made the same mistake initially. What frequencies have you been transmitting on? I'm using the MID+ and on all 5 bands, have seen entries on www.wspr.net. Sam

My thoughts and initial plan: the power output of the WSPR-Desktop is fixed based on the line-driver IC used for power amplification (74AC244), So you find an HF amp that has a relatively flat response down at the frequencies you are transmitting, and observe the nominal input power level specified for the amp. To exceed that would probably result in distortion. I plan to add a SMA attenuator on the output of the transmitter, run that into a small 10W amp purchased from eBAY, then examine the performance of the amp (I'll use the signal generator capability of the transmitter) and attenuate the output of the amp with another SMA attenuator rated for 10W or better running into a dummy load of 50ohm. I can probably purchase the SMA attenuator for the input to the amp, and most likely will build the dummy load and attenuator and verify output using an oscilloscope, or a small ckt to use with a digital voltage meter..

Wow - this is *exactly* what I needed. Thank you. What role does the feedline play? Does it help at all with the radiation of the signal? What would happen say if I had a WSPR transmitter in a water-tight enclosure with a short run of coax to the TX/GND connection (SO-239 likely)? Wouldn't I have less feed-line losses (although I wouldn't expect much in 25' of 400MAX... I'd likely be using a short run of 8X).

Hi, this is great. Can you provide a simple schematic of the antenna, toriods, and the feedline. I'm not immediately understanding the arrangement. Thank you.

@Harry Zachrisson After using this a bit, I plan on writing a review on eham.net. I'm fortunate to have seen the review of your WSPR Desktop on YouTube. Lucked out with the new hardware and software update. Kudos.

@Daryl Hooke Daryl can you tell me what sort of vertical? I've got a small property that sits low in the sub division... Options for the Beacon would be good and free up my current antenna for my transceiver.

Harry, your getting started directions - perfect. Within 5min of downloading the config software and hooking up the transmit and GPS antennas, the unit I received today was on the air! First impressions: build very nice. Instructions clear, straight-forward. Software for configuring - quite good. Performance: I'm blown away. GPS acquired numerous satellites, and the antenna no where near a window, infact in the basement and below grade. I'm running 100ft of 8x into a G5RV jr T/R antenna. The WSPR Desktop transmitter quickly heard on 20, 30, 40 and 80M. One word: WOW.

@Bruce Johnson Incredible. A 10th of a mW? Wow. USPS predicts delivery today. Again, thank you for the clarification w.r.t. dBm levels supported and reported by the protocol.

@Bruce Johnson Bruce. Thanks for the clarification! Aha. WSPR senders send their set power level setting? OK, I get it now. Can you use one of those inexpensive sma to sma resistor attenuators to do the job on the back-end of the WSPR Desktop? I see on ebay, they are sort of cheap. Did you roll your own? BTW - how low in power have you gone? Interested in your reply. Getting excited... My transmitter got to the US on the 16th and processed through Chicago... I would have expected to receive it already. The wait is more excruciating than when I saved up for my first Kenwood transceiver! Ha ha to me.

The screenshot of the control software seems to suggest it's possible to set a custom output power level. Does that feature work? Could it be used to properly drive a small RF power amp with output of 10-20W? What kind of attentuator could be used to drop the output to under the accepted QRP limit of 5W?

Daryl, you mean wsprnet.org right? :) Can you tell me what antenna you are using? Thanks. 73 de KJ4VPI