#1 General discussion » microaprs settings for agwpe? » 2015-06-11 23:08:55

Replies: 1

could anyone please provide me with info on how to use the micromodem with aprs firmware on agwpe? Thankd in advance.

#2 Hardware » New PCB Layout available? » 2015-06-04 14:54:15

Replies: 0

I was looking through the github repo and found the schematic for the new (integrated 328p) device, but no board layout. Is the board layout available? I would like to slightly modify the current board layout/schematic to include an op amp for filtering and amplification, however I don't want to reinvent the wheel, being that you already have a working layout. Thanks in advance, and I look forward to your reply. smile


#3 Re: Software & Programming » Humble Request » 2015-05-29 02:10:36

Actually, nevermind. I don't know why I didn't just use atmel studio first. smile Anyway, I finally got it built. Now, hopefully I'll be able to decode OTA packets. smile

#4 Software & Programming » Humble Request » 2015-05-29 01:44:51

Replies: 4

Hello everyone,
I have been trying to compile the microaprs firmware myself (using the non default options), but no matter what I do I can't get it to build. If anyone has a working build setup, and has a spare minute, would they mind compiling microaprs for me using 3.3v ref, open squelch = true, and using the serial option (not kiss)? I hate to be a pain, but I'm trying to build it on a windows machine, and do not currently have access to a linux box. sad Thanks in advance.


#5 Re: Hardware » OK for 1uF cap to be polarized? » 2015-05-29 01:33:58

aggh....i give up. i managed to build the kiss version, 3.3v, open squelch....but no matter what i do/try, the serial version will not compile.

#6 Re: Hardware » OK for 1uF cap to be polarized? » 2015-05-28 22:58:46

Actually, build instructions for linux would work too. I still have my desktop dual booting. Sorry for the beginner request. I've only ever used the arduino software. sad

#7 Re: Hardware » OK for 1uF cap to be polarized? » 2015-05-28 22:48:49

So, after some more testing, I have an update. smile First off, I discovered that I by adding a 1k resistor between d3 and the mosfet, and also increasing the distance between the antenna and micromodem, I was able to completely eliminate the reset issue. Secondly, I was able to successfully decode ~100% of the packets on the tnc test cd. Unfortunately, I have not been able to decode any on air yet. I believe that the issue is that none of the packets i receive provide full quieting on the radio. I have tried adjusting the volume, but I live in a rural area with relatively little aprs traffic. Sometime I have to wait for a full hour before hearing another. I plan on buying another radio (probably baofeng, which i already own one of) and building another micromodem.
So far, I am really enjoying this little gem. smile I am going to borrow my fathers o-scope this weekend so I can take a look at both the input and output.

Also, this may be a simple question, but are there instructions somewhere on how to compile this on windows? I do not currently have access to a linux machine. Thanks in advance!

#8 Re: Hardware » OK for 1uF cap to be polarized? » 2015-05-26 22:44:05

OK, so I've built the device. I am running into a couple issues though. The first is when I tell the micromodem to send any data, the arduino resets. I first thought that maybe putting a 22uF cap across 5v would help, but no dice. Could this have something to do with the mosfet that I'm using? I didn't have a 2n7000, so I had to use a IFRZ44 (big to-220 power mosfet). I have triple checked the circuit (built on breadboard so far), and everything checks out.
My second issue/question is this: I am in an area with very little aprs traffic (i do hear some every day though, just very intermittently), so while setting everything up to 'just run' for a day to hopefully hear something, I realized that I wasn't sure if I should be running open-squelch? I am using the kiss firmware with a copy of ui-view32.
Any input is very much appreciated. Thanks in advance. smile


#9 Re: Hardware » OK for 1uF cap to be polarized? » 2015-05-26 17:15:57

Thanks for your quick reply. After some more searching through my parts, I did find a big old 1uF metal film cap. I'm going to give that a try. Also, I figured that I may be able to get away with a .1uF cap in place, since the value isn't extremely critical, right? Anyway, thanks again. I will let everyone know once I have the circuit built and have started testing.

#10 Re: Hardware » OK for 1uF cap to be polarized? » 2015-05-26 02:30:31

I also managed to find an electrolytic cap. Maybe this would work better, still polarized though.

#11 Hardware » OK for 1uF cap to be polarized? » 2015-05-26 01:03:40

Replies: 11

I want to build one of these, however the only 1uF cap that I can find in my junk drawer is a tantalum polarized cap. Can I use this as a substitute, and if so, which way should I install it. Thanks in advance, and sorry if this is a stupid question. smile


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