Her BOM calls out an air variable cap from MFJ and a T94-2 ‘roid, so I suspect that her tuner could handle a bit more than QRP power. In typical ham fashion, it appears that she was too eager to get it on the air to worry about little things like putting it in an enclosure. FB with that Diana, I think most of us can relate.
It sounds like she had great success using this setup with her FT-817 for some SSB QRP fun:
Setting up my antenna for 20m the first time took about half an hour, and I was able to get very close to 1:1 SWR using the 9:1 input with a vertical wire supported by a tree. Over the next hour or so, operating from a park bench in Brooklyn, using 5 watts on sideband, I made contact with stations in the US, Europe, South America, the Caribbean, and Hawaii. The furthest station was about 5000 miles away, which means I was getting 1000 miles per watt out of this setup. I’m sure it was a big contest station and not another QRP operator sitting on a park bench with a wire antenna, but it was still fun.
I’ll take this opportunity to shamelessly promote my own EFHW tuner, which I’ve managed to get back up on my new website. Don’t forget to compare to AA5TB’s design, which features probably the best page on this subject matter which I’ve seen.
When I was going through some files on my USB thumbdrive, I found a panorama of Hoover Dam that I made from some photos that I took on our honeymoon last August. There are some small blemishes in the rendering (some of the power lines have discontinuities and what not), but overall the results still came out pretty good. What’s really neat is that you can see the Mike O’Callaghan – Pat Tillman Memorial Bridge under construction down the river from the spillways. At this point, the arch was just being completed. Today (March 2010), it appears that the deck is almost in place.
As I mentioned in a previous post a few days ago, I found a nice 2 watt mono audio amplifier board that’s a perfect addition to give speaker capability to a receiver with headphone output. I purchased four of these bad boys since they were so inexpensive (and I was paying for shipping from Hong Kong, so might as well order in bulk). I figured a good test would be to build up a bench amplifier so I could have the convenience of listening to any of my homebrewed phones-only receivers/transceivers (most of them) on speaker.
To the right, you can see the pleasing results of this little project. I had a nice Ten-Tec TPC-17 that turned out to be a perfect enclosure. The 1/8″ input connector is on the left, a power LED in the middle, and a mute switch on the right (the amplifier board has an active low mute line which works extremely well). I created a speaker grille drill template in Inkscape for the 3″ speaker bolted to the top lid of the enclosure (if there’s any demand for this file, I can post it here). The actual 1″ x 1″ audio amp board is on the left and a small 7805 voltage regulator board on the right.
AF Amp on the Bench
Here’s the enclosure all buttoned up for use. You can see that the speaker grille is a bit ugly, but it works well enough. There is no power switch, since the quiescent current is so low that there’s no problem in leaving it powered up. Tonight I hooked it up to my VRX-1 (with a rock on 7030) and listened to the wide-open band with the DX contest in full swing. The audio quality was quite nice; better than I remember it when testing it out in the open on the workbench. I’m guessing this is because the speaker was properly mounted instead of having the magnet rattling against the bench. Even though it’s a simple project, it’s a great addition to the shack that makes me wonder why I didn’t do this earlier. Yeah, I could have purchased a set of amplified PC speakers, but that just didn’t seem appropriate. Besides, the amp in the Ten-Tec enclosure looks spiffy next to all of the other similar looking equipment in my shack.
Update
I got a bit bored tonight, so I took a video to demonstrate the amplifier working with the VRX-1. Yes, I know there’s nothing to really look at, but the audio is a bit interesting.
I’ve noted with quite a bit of interest the recent surge of comments on QRP-L favoring a QRP exodus up from 7030/7040 kHz to [part of] the old Novice watering hole of 7100 to 7125 kHz. The esteemed Arnie Coro, CO2KK seems to have ignited the fire with this post to the reflector:
Dear amigos :
The 40 meters band changed last year … when the worldwide assignment for ITU Regions I, II and III was finally made totally compatible for the first 200 kiloHertz. According to what we have learned here, this was a difficult to work out agreement, but at the end
thanks to the presence of radio amateurs sitting as members of many of
the nation’s delegations attending the ITU WARC… it became a reality…
So, now we have the 7100 to 7200 segment for radio amateurs exclusive use. My understanding is that the US FCC decided to expand the 40 meter phone band down to 7125 kiloHertz…
That leaves the segment from 7100 to 7125 kiloHertz quite useable for CW…
My suggestion is to start using 7105 or 7110 kiloHertz as the QRP
meeting frequency, replacing 7030 and 7040 kiloHertz that are under so much QRM, especially from digital modes. I agree that many stations have already equipment with crystals for either 7030 or
7040 kHz… but for those of us with VFO capability, enjoying the much
more clear channels between 7105 and 7110 kHz opens up the possibility of many more QRM free QSO’s…
My observations carried on during the past several days confirm that
that segment of 40 meters right next to 7100 is clear much of the time !
Let’s give it a try !!!
73 and DX
Arnie Coro
CO2KK
The positive response to Arnie’s call to action was immensely gratifying to me. In addition to all of the reflector replies, there have also been some ham bloggers taking upthe topic. I’ve long been a fan of this little slice of bandwidth, but at times it has been hard to scare up contacts there. In the last couple of years, SKCC has probably been making the most extensive use of the sub-band, which has increased the traffic there a fair amount and has brought more attention to the frequencies as a place to have a nice, relaxed CW QSO.
Not to long ago, I dreamed about ways to help increase the use of these frequencies, and even started chatting with a few other hams about ways to spark some interest. However, like a whole lot of my ideas, they never get off the launchpad since I just don’t have the time to invest in all of them. After having a few unpleasant encounters with RTTY contesters running me off 40 meter frequencies last weekend, I’m even more determined to help promote 7100-7125 as a QRP (and general CW) safe spot.
I’ve become inspired enough that I’ve decided to take a new design for a minimalistic superhet rig that I’m working on and adapt it to operate on these frequencies. If there’s any interest in it, I might even take a crack at offering it as a kit for purchase. Long live 40 meter QRP!
This weekend, I’ve been participating in the SKCC Weekend Sprint when I get the opportunity in between other obligations. At about 0900 local, I heard F6HKA on 20 meters coming in pretty well with a very fluttery signal. As you can see on the azimuth map for my QTH, the path to France goes right over Greenland, so it’s not a huge stretch to assume that the unique signal quality is due to auroral effects from the increasingly active Sun.
After about an hour of trying, I finally managed to snag a QSO with Bert using 5 watts! A great day for QRP!
Take a listen to this QSO which was recorded a bit before I made my contact with F6HKA. You can definitely hear the watery, fluttery sound of his signal.
Lately, I’ve found that eBay has been one of the best ways to beef up my junk box with inexpensive electronics components (eBay Stores are my preference, the auctions often aren’t that great). I purchased a nice SMD resistor/cap assortment from a company called Sure Electronics and found that they have some other goodies that might be of interest to the homebrewer. One of those is a tiny little (about 1″ x 1″) 2 watt mono audio amplifier based on the EUA2005 IC. The spec sheet states that the IC output power is 1.5 watts, so the manufacturer might be fibbing a bit on their specs. Regardless, it’s enough power to drive a 3″ speaker to a decent volume for shack listening. The IC has a maximum VCC of 6 V, so I had to create voltage regulator to step my 12 V bench supply down to 5 V using a 7805. The audio quality is definitely what I would call “communications” grade, but the price is great: $2.22 for a 2-pack. One word of warning: your order is shipped from Hong Kong, so expect about 2-3 weeks for your order to arrive.
For those working on W8DIZ’s frequency counter project in QQ, they also have a Atmel STK500 in-circuit programmer clone for a very inexpensive price. I haven’t had a chance to try mine out yet, but if it works as advertised it’s well worth the price (I have no reason to believe that it won’t work, but if doesn’t, I will update this post).
The usual disclaimer applies: I’m not associated with the company in any way, just a satisfied customer.
I’m very pleased to report the first (to my knowledge) completed Willamette transceiver which was born in Europe. Vincenzo, IZ5GVP sent along to me a couple of photos of his very nicely constructed Willamette. He reports that it works well and that he’s considering modifying it to operate on the 30 meter band. Three cheers for Vincenzo!
I finally got fed up with my lousy custom coded main website (at www.nt7s.com), so I’ve decided to rip it down and install a CMS. Don’t be surprised to see some strange things going on there over the next days/weeks. I’m going to get all of the important content back up there. It may take me longer to get the visual design of the site in line with what I want.
I got a bit of cash for my birthday last month and it was burning a hole in my pocket for a few weeks. I decided I needed a good set of CW paddles for my station, since the only keying devices that I have (that work) are all straight keys. It was a bit of a toss-up to decide what brand of key to get until I saw the Begali name mentioned; then I remembered lots of hams saying good stuff about their keys. There was enough goodwill on the Internet that I figured I would take the plunge and give the base model Simplex (with a palladium finish) a try. It took about 3 weeks for the paddles to get here, but it was well worth it. Here’s a little visual tour of my Begali unboxing experience.
Yes, I know, an “unboxing” blog post makes me an even greater geek. I’m at peace with that. Anyway, on with the show…
Let’s open the box…
Now to open it up
Some extras included
Christmas wishes
Two different sets of aluminum finger pieces sent along, although I only ordered one. A nice extra!
First peek at the key
The key together with the dust cover
Here it is unwrapped and with the stock finger pieces installed
Now to add the nice blue aluminum finger pieces…
I’m blinded! The palladium finish with gold accents is incredible.
A macro shot of the engraved logo
Finally, here’s the key with my cable installed, sitting next to the AA0ZZ EZKeyer
I hope you got a little vicarious enjoyment out of that! I haven’t made a QSO with it yet, but just from using it on the keyer with sidetone, I can tell that it has an incredible feel. This one will be a keeper for the rest of my ham radio days.
Thanks to some prompting from a Willamette builder who inquired about some performance issues with his rig, I was able to identify an error in the bill of materials which causes a significant degradation in receiver sensitivity.
Fortunately the fix for this problem is very simple. Audio preamplifier collector resistor R49 was incorrectly called out as 10 k, when it should have been listed as 4.7 k. If you have a 4.7 k resistor in your junkbox, just swap it in at the R49 position. A 5.6 k resistor will also work fine here. Alternately, you could just parallel another 10 k resistor across the existing one. I will be happy to supply the correct resistor to any builders who purchased a kit from me and need one.
I’ve determined that this wasn’t a design flaw, but a transcription error. My original hand-written notes have the correct value and my prototype does work correctly (I’m sure NA5N would have caught this problem in the prototype he evaluated). Somewhere in the process of creating the schematics in my schematic capture program, I entered the wrong value. I did build a beta rig with all of the same schematics/BOM that everyone else did, but I didn’t catch the error at the time. I will update the schematics and BOM posted on my website in short order to prevent any further problems.
Please accept a most humble apology from me for not realizing this significant error for a very long time. I do believe that you’ll be pleased with the difference in sensitivity once you install the correct resistor. The receiver should sound like you would expect a proper direct conversion receiver to sound. After the modification, you should be able to run the AF gain at ~75% or less during most operating conditions.
I’d like to thank W0EP, N1RX, WB8ICN, and WB9VTB for their assistance in resolving this matter!
You've arrived at the blog of Jason Milldrum, NT7S. It's mostly related to amateur radio (especially homebrewing and QRP) but occasionally other topics will pop up when they strike me as amusing. The QTH is Beaverton, Oregon. I'm married to a wonderful woman who tolerates my "mad scientist" ham shack. Dad to a spoiled rotten Yellow Lab by the name of Baxter.
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