If you go back through lots of amateur radio designs, you’ll find many, many circuits that use the nearly uniquitous 365pf air spaced variale capacitors that were nearly ubiquitous up until about 25 years ago. In the last couple of decades however, they have become like Avatar’s unobtanium, seemingly impossible (or at least expensive) to [...]
Archive for tag: qrp
Anyone who is subscribed to the QRP-L has likely been subjected to a long string of complaints against WSPR in the past week or so. This began with a generic complaint against a “consistent carrier” on 7.040. This rapidly decayed into a long series of rants against WSPR. Since I’m rather more fond of WSPR [...]
Paul, M1CNK, has a very nice webpage that details his QRSS beacon, constructed as several different kits assembled as modules. Very cool. qrssbeacon (wiltonpaul).
While scanning QRP-L today, I found an interesting link to a project which gave some details about a little WWV receiver that can serve as a frequency standard. I haven’t had the time to work out how it all works, but it looks reasonably straightforward: Here’s the original schematic from Chuck Adams, K7QO: Nick, WA5BDU [...]
Alan, VA3STL posted a nice list of captures of his QRP beacon on his blog, including a link to a spot of him that he got from my grabber. I didn’t notice it then, but now that I’m back on 30m, I’m seeing it nicely at the moment:
On Saturday, I sent a check off to Tony Parks, KB9YUG on Saturday along with my order for two Softrock Lite II receiver kits: one for 40m, and the other for 30m. I hope eventually to liberate my FT-817 from its current beacon duties on my grabber site and replace it with this simple little [...]
Okay, after having read WB8ICN’s postings on QRPedia, I decided to try to measure the impedence of both of my meters. I dug a 1.5M ohm resistor out of the pile, and hooked some jumper leads to it. I then did the following: Measure the resistance of the resistor, using the DVM as an ohm [...]
Well, I’ve been mucking around with my RF probe circuitry a bit tonight, and encountered something pretty strange. I have two digital multimeters lying around, and my newly rebuilt RF probe/dummy load that I described earlier. I hook one multimeter to it, and I get a reading of 14 volts. I get my other cheapie [...]
More digging around for information about the RF probe, I found this link to the NJQRP’s presentation at Atlanticon 2000. It’s a cute little QRPP rig built Manhattan style, and includes a discussions of the RF probe setup to measure it’s output. Neat. Atlanticon Kit – It’s a Snap!.
My dummy load experiment still has a few unanswered questions, but I found that the ARRL Handbook has had a circuit which is basically what I built, minus the one series resistor. It looks like this: Okay, they use a germanium diode with considerably lower voltage drop, and include a 4.7M ohm resistor in series [...]
Okay, this is pretty basic stuff really, but it’s part of my trip toward additional homebrewing, and it might be of some vague interest, so here we go. If anyone spots anything horribly wrong here, please feel free to help me learn by leaving me a comment here. Before Thanksgiving, I was having quite a [...]
W8LIW’s grabber on 30m is currently showing my “MV” beacon transmissions as well as the DFCW of VE1VDM (I presume) and the flying W of W1BW, as well as the faint sawtooth of WB3ANQ. I can’t spot myself on W1BW’s grabber at the moment: my ability to get into Concord, MA seems limited over the [...]
Okay, I hadn’t been doing any WSPR beacon operations since before Thanksgiving (which was also before my new callsign) and I was kind of bored today, so I dug out my power supply, tuner and interface and set my computer beaconing again on 30m. It’s a combination beacon: using WSPR above 10.140100, and a visual [...]
Well, this morning I decided I wanted to get the K1EL keyer that I put together mounted in a proper aluminum case. The sad thing was, I didn’t really pay enough attention to internal clearances, with the net result that I did a pretty crappy job. I’ll probably try again sometime soon, but in the [...]