Super low power ham radio - QRPpp QRSS / FSKCW

[Jeremy Z]

I've started messing with super low power weak signal modes. Last night I got QRSS VD setup and working with my Softrock Ensemble RXTX software defined transceiver. I was able to copy WA5DJJ who was transmitting using FSKCW (frequency shift keying morse code(continuous wave)). Doing a call sign look up I found a page on his website about doing some ultra low power tests between Las Cruces, New Mexico and Pensacola, Florida (1161.5mi). They were able to get the transmit power down to 8.51uW (that's 8.51 microwatts or 0.00000851 watts), which comes out to about 136,488,367 miles per watt! Of course the Voyager spacecraft at 11.2 billion miles and 23W transmit power @8GHz does about 486,956,521 miles/watt and that's at 160bits/sec which is much much faster than the FSKCW (side note, it takes 16h and 40min for it's signals to reach the earth!). There are a bunch of other super weak and super slow weak signal modes out there, some of which are very clever/interesting.

Side note, I ran across the QRSS type stuff while playing with dopplergrams based on a very interesting article in a 1998 RadCom called Using Doppler DSP to Study HF Propagation by Peter Martinez, G3PLX. If you're interested in the article I can email it to you or you can join the dopplergram yahoo group. This concludes my radio ramblings for now.

-Jeremy

[kc koellein]

All I can do to that is crack a big GRIN...!

Geek up!

That's some awesome rambling... thanks for sharing, man!

kc
KF5QVL

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[kc koellein]

Got my license.
Built an antenna.
Listen to chatter, nightly.

Now I'm back to my welding cart and my Gingery Foundry while enjoying tasty beer...!
Should be picking up a 3/8 or half-inch plate steel permanent proper table top TOMORROW.
Also some additional metal for the last of the workstation features I have envisioned. (Various hangers for cables, a swing-arm-mounted light, some tool drawers, magnetic holders, etc) Most are completed.
I'll also grab stock for the door at the space, if no one has done that yet. Regardless, I'll use it, so I'll pick some up!
I also order my foundry refractory cement TOMORROW, finish the welding on the body and pack in the cement next weekend. I've seen recommendations to let it cure up to a MONTH, so, while that's happening, I'll build some cope(s) and drag(s) and a waste oil burner to augment the charcoal fuel.
When that is done: turtle tank... FINALLY!
When THAT is done I'll be casting parts for the first time, trying to build that Gingery lathe...!
About the same time should be my Heavy-Metal Hackers series of classes at 10-bit.
And I have picked out a location in my yard for my Blacksmithy paddock. My resolution was to have a forge and anvil built and swinging a hammer by New Year's...
This brings me to the end of the year...!

So... why spill all this here/now?

Main reason - I intend to attend school, keep fishing once a week, and attend 10-bit and xccsa meet ups throughout, and we need to resume our ham meetings. Saturday was working for me. So would Sunday. Actually, Sunday would probably be better. But... we need to get the 10-bit ham club going if for no other reason from my perspective but to keep me getting a weekly dose of ham...! Hopefully, Mike and I can be Generals by the end of the year...?

Experts before 2014...?

I think I want to find a 4x4 spot at the space to stage my 6m CW transmitter build... and I'll work on that during our ham club meets... along with the other laid back ham-sploration chats we're sure to do during such a time period.

Sound good hams...?

kc
KF5QVL

On Jul 26, 2012 9:57 AM, "10BitWorks on behalf of zunkworks" <sa-hack...@googlegroups.com> wrote:

[mike perez]

sounds good!

--
-m.a. perez
KF5QVO

[Jeremy Z]

I Just ordered an OpenBeacon kit for 30m for $40. It'll probably be here in a week or two. Per the wiki: OpenBeacon is an open source crystal-controlled QRPp beacon transmitter which can output a variety of slow-speed modes, including QRSS, DFCW, and Sequential Multi-tone Hellschreiber at ~300mW.

What plans are you using for the 6m transmitter?

-Jeremy

[kc koellein]

Page:

http://www.hamradiodatacenter.com/ham-radio-stuff.html

 

Specific schematic:
http://www.qsl.net/yo5ofh/projects/6m_cw_tx.gif

 

I correct myself... apparently it IS a tranceiver... cool...

 

You know... I just settled on it... decided with all the BAZILLION choices, I was gonna spin the bottle and pick one and just jump in. This is the first simple one that appeared to show all the parts I'd need to source. So, I printed it out and I've been carrying it around in my pocket ever since!

 

kc

KF5QVL

[Jeremy Z]

Cool. Looks like it's actually it's just a transmitter but the link that points to the schematic says transceiver.

I have a few suggestions regarding what to build. If you're going to build a CW transmitter/transceiver/receiver I'd recommend doing one for 80m or 40m for a few reasons. First, if you're doing CW, you might as well use the limited HF transmit privileges you have on HF (3.525MHz-3.6MHz and 7.025MHz-7.125MHz) with the technician class license. Second the propagation on those bands is generally much more predictable, consistent and far reaching for QRP stuff also there are more operators on those bands than 6m. In other words you can generally turn on the radio and work someone (assuming you do it at the right time of day and the band is somewhat open). There are also a ton more kits and detailed plans out there for QRP transceivers/transmitters/receivers on the 40m and 80m bands, which means more documentation and better support should you have trouble. And lastly working with higher frequencies is generally more difficult as lead lengths and component spacing/orientation and other things start to affect the operation of the circuit much more than at low frequencies. In a practical sense this means when you're building something at higher freqs that tuning will be more finicky and you have to be extra careful about what you're doing otherwise you'll spend a bunch of time debugging and rebuilding things. And one other thing in favor of kits, and I suppose this applies to most all kits, is that you'll get a known good or known fixable board and don't have to spend a ton of time scrounging for oddball parts (some RF parts can be difficult to find). There are even a number of kits that you build Manhattan or dead bug style (aka ugly construction) both of which are very good for RF prototyping as they minimize stray inductance and capacitance. But anyway I'm drifting off frequency(topic) now, just though I'd throw in my 2 cents. Regardless of what you choose to build I'm definitely willing help you out!

-Jeremy

[kc.ko...@gmail.com]

I = schooled.

Sent via BlackBerry by AT&T

---

From: 10BitWorks on behalf of zunkworks <sa-hack...@googlegroups.com>

Sender: 10BitWorks on behalf of zunkworks <sa-hack...@googlegroups.com>

Date: Thu, 26 Jul 2012 19:52:25 -0500

To: 10BitWorks on behalf of kc koellein<sa-hack...@googlegroups.com>

Subject: Re: [10BitWorks] Super low power ham radio - QRPpp QRSS / FSKCW