Sunday, September 28, 2008

80m QRP Beacon on the air

After biting off more than I could chew a few times recently, I've successfully built a QRP (low power) beacon for 80m.

beacon.jpg


It's on air at the moment on 3.686Mhz sending a morse ident with my email address so I'm hoping to get a few signal reports.

I think it's putting out about 250mW.

There are some obvious faults, I can hear chirp, clicks and when it's off carrier from the oscillator leaks out to some extent.

The keyer is an Atmel AVR ATMega816 which is complete overkill in this case.

The circuit is very closely based on Alan VK2ZAY's design except that I didn't have any 2N7000s so I've used a single IRF510 with a bit of bias.

I used perforated board with just a copper spot under each hole and it went together rather well (for me).

beacon board.jpg


I don't speak morse yet, but here's what I'm sending:

morse.png


Anyhow, please tune in to 3.686Mhz and let me know if you can hear my slow morse.

Update

Hi Peter,

Read about your 80m QRP beacon mentioned on hamnews and had a listen.

It’s peaking about S5 in Canberra. I’m using a TS-480SAT with a 40/80m trapped dipole. Here is some of what I decoded using Ham Radio Deluxe DM780 software:

LE EK*E PM VK2TPM VK2TPM PLS EMAIL RPT PETER DOT WARKS AT OBOX COM THIS ISE A QRP BEANION TRANSMISSIOLE VK2TPM VK2TPM VK2TPM PLS EMAIL RPI PETER DOT MARKS AT POBOX COME THIS IS A QRP BEACON TRANSMISSION DE VK2TPM VK2TPM VK2TPM PLS EMAIL LPT PETER DOT MARKS AT POBOX CON THIS IS T *RP DEACON N E IS E UK2TPM VK2TPM VK2TPM PLS EMAIL RPT PETER DOT MARKS AT POBOX COM THIS IS A EQRP BEACON ARANSMISSIXD DE VK2TPM VK2TM VK2TPM PLS EMAIL RPT AIETER DOT MARKS AI POBOX /OM THIS IS A QRP BE P EHANSN ESSIO N DE VK2TPM I ERM VK2TPM PLS EMAI D RP E NETER DOT MARKS AT POB3X COM E I IS A QRP BEAON TRANSMISSION DE VK2TPM

As you can see I’m missing/badly reading some characters and have interference but the message is coming through, probably be better received by a human than a computer…but I’m no morse code expert…

Had QRM from SSB and another CW signal nearby by managed to filter most of it out.

Regards

Ian Sinclair VK1DI

Update 2

I'm taking it off air while.

1 comment:

Alan Yates said...

Excellent Peter! Glad to hear you got it going OK. Drop me an email when its online next and I'll have a listen out for it, should be very loud here.

BTW, if the keyer circuit is the cause of the key clicks, the design I used in my QRSS beacon is better than the 80 metre one. Just play with the 100 nF cap to get the time constant you want:

http://www.vk2zay.net/article_attachment.php/831

Chirp might be more stubborn of a problem. I was fortunate that the colourburst xtals I use are very "stiff" and are quite hard to chirp even when the oscillator is very tightly coupled to. I have plenty if you'd like to try one of mine.