The LD-1D prototype is assembled, and I’m evaluating it. I did get “interrupted”, sort of, by a motorcycle oil change that should have taken about 30 minutes turning into 4 hours. More about that at the end of the post.

It’s a good thing I did order a prototype run of 4 PCBs. I immediately discovered a phasing error in the doubly-balanced QSD, which was easily fixed with red wire so testing can proceed, but I won’t be selling any of the prototypes. The error resulted in enhancement of even multiples of the LO, and rejection of odd multiples. That’s the exact opposite of what I intended, and it didn’t take long to find the error. After correcting it, I found that spurious responses in the AM band and below (and probably everywhere else) are greatly reduced. The AM-band response to the second harmonic of the LO seems to have been eliminated completely, which is better than I had hoped. However, sensitivity is not quite up to that of the LD-1C. I have an idea about that, and expect to correct it easily.

I will also double-check all the filter element values, and see whether the extension to 54 MHz really works.

Stay tuned, the LD-1D will be available soon.

73 de NI9N

At the top of my to-do list today is assembling one of the prototype LD-1D boards. I hope it doesn’t need any revisions, but prototype boards almost always need one or two minor changes. If this one doesn’t, the only difference in the production board will be slots for the power connector pins. Advanced Circuits routes those when I order production boards, but their prototype pricing only permits drilling, not routing slots. On the prototype boards, I hand-route those three slots with a Dremel tool.

If I don’t get interrupted (always a possibility) I’ll have test results tomorrow. The first tests will be qualitative, not quantitative. Probably. I won’t take long to find out if the doubly-balanced QSD works as I expect, and that’s the biggest improvement.

Testing it on six meters will mean some changes to the firmware and the PC software, so that could take just a little longer. The changes aren’t complex, but they will probably require some debugging.

Assembly will take just a bit longer, because there are more parts. Each of the LD-1C’s eight bandpass filters comprised 3 inductors and 3 capacitors, the LD-1D’s filters have 5 of each. There are also two additional opamps, which are required for the doubly-balanced QSD. Then I have to assemble an IF cable, which wasn’t necessary before. I normally assemble radios in batches of 5, and it takes about 40 minutes per board to populate an LD-1C with surface-mount parts. It probably takes another 40 minutes per board to reflow the solder, and then complete the assembly by populating it with through-hole parts. When I start building the LD-1D in batches, the 40 minute surface-mount portion will probably increase to about 45. I’m guessing another 5 minutes per IF cable.

As soon as I know how it works, I’ll post the news.

73 de NI9N

I’ve never announced a new product before it was available. I’ve never reduced the price on an existing product that was about to be replaced, until I announced the replacement. Until now, that is.

The price of the LD-1C is reduced to $219.95 for closeout, effective immediately. I’ll shortly be sending refunds of $64.05 to customers to whom I’ve shipped LD-1C’s recently, and to those with outstanding orders. I think this is the fair way to do it, so no one is surprised when a new and better product suddenly becomes available.

The reason for the closeout is that I expect to have the new LD-1D available within the next couple of weeks. I should receive four prototype boards within the next couple of days, so I’ll know if it works as expected. If it does, I’ll have three of them ready to ship by a week from today, and production quantities a week or two later.

The LD-1D will feature several improvements, and a change to the rear panel connectors:

1. The QSD will be doubly-balanced instead of singly-balanced. That means spurious responses resulting from even multiples of the LO frequency will be nearly eliminated. Those spurs have been particularly troublesome in the lower portion of the AM broadcast band and below. For example, in my area there is a very strong signal from the local station WLYV at 1450 kHz. Whenever I try to listen to Detroit station WJR at 760, with the LO at approximately 730 kHz, it is nearly covered up by WLYV’s signal mixing with the second harmonic of the LO at 1460 (approximately). The resulting spurs appear at 720 and 740 kHz, with sidebands covering up WJR. The new QSD topology will nearly eliminate that response, because a balanced QSD responds only to odd multiples of the LO: The desired response centered at 730, 3^rd harmonic at 2190, etc. Of course, nothing is ideal, so the even-harmonic response won’t be entirely eliminated. I expect them to be greatly reduced. As for the third-harmonic response, the new preselector filters should keep it from being a problem.
2. New, tenth-order preselector filters, replacing the old sixth order filters. Two benefits here – First, to make sure the third-harmonic response of the new QSD is attenuated sufficiently that it isn’t a problem. For the second benefit, see Item 6.
3. Provision for use with a separate transceiver or transmitter. The LD-1B, LD-1B2 and LD-1C all have a TR relay, for use with an internal transmitter module. I know that a lot of hams like to use a separate transmitter or transceiver (and the transmitter module isn’t available right now) so why not make it so an external TR switch isn’t required? I’ve added a second SMA connector for an external transmitter, switched by the internal relay. It’s controlled by software, or via the accessory connector.
4. Expanded frequency coverage, 100 kHz – 54 MHz. This is possible partly because of the new tenth order filters along with the doubly-balanced QSD can each be somewhat wider. There are still 8 filters, each covering a range of about 2.25:1 from 92 kHz to 55 MHz. Above some yet-to-be-determined frequency between 20 and 30 MHz, the QSD will use third-harmonic mixing. I’ve done some experiments with this, so I’m pretty sure it will work and will be sure after testing the prototype. Using the third harmonic of the LO results in a slight, predictable reduction in overall gain, but the two preamplifiers should overcome it.
5. The change to the rear panel connectors isn’t an improvement. Adding the second SMA connector for an external transmitter didn’t leave room for the LD-1C’s three 3.5 mm stereo jacks (RX IF to soundcard, TX IF from soundcard, and Accessory) so I’ve had to combine them into a single Mini-DIN connector. The radio will come standard with a cable that has a Mini-DIN plug on one end and a 3.5 mm stereo plug on the other, for RX IF to soundcard. You will be have the option to substitute a cable with a Mini-DIN on one end and two or three 3.5 mm plugs on the other, depending on your needs, at a slightly higher price.

At this point I expect the price of the LD-1D to be $299.95, but that’s subject to change. The increase in price compared to the LD-1C is due additional parts in the filters and QSD, plus the inclusion of a cable. The price of some parts has gone up over the last couple of years, but others have dropped, so if not for an increase in complexity I’d just leave the price as is.

The changes to the rear panel will, of course, mean a different rear panel. I haven’t ordered those yet, and I expect it to take about six weeks to get them. As a result, I’ll ship the first units with hand machined (made by me) rear panels. I did that for a while with the LD-1A and LD-1B, before I started having the enclosure manufacturer make them for me. I hated making them, and usually wasn’t quite satisfied with them. As a result, I’ll be sending replacement rear panels to anyone who isn’t satisfied with the handmade one, at no charge. I’ll send them as soon as I get them.

Of course, all of this assumes that the prototype works as I expect. If it does, I’ll be offering three of the four at a slightly lower price as soon as they’re assembled. That should be within a week.

If you order an LD-1C, you’ll be getting a good receiver at a great price and PROMPT shipping. If you wait for an LD-1D, you’ll be getting an improved receiver at a good price, also with prompt shipping.

Well, I’m way behind shipping radios, but I’ve begun catching up. To bring you all up-to-date (some of this I’ve written about in the past) I spent just about all of October and November on a consulting assignment in Warsaw, Indiana, about an hour from my house. That made for very long days, with little energy for Lazy Dog when I got home, so I started procrastinating. That got out of hand, and before long it got overwhelming. To make things worse, I now realize the same thing has happened to a lesser degree every fall for at least the last several years. I’ve concluded that I probably have some degree of Seasonal Affective Disorder. About a month ago, it was as if the “winter of my discontent” (sorry, I can’t resist quoting Shakespeare) came to an abrupt end, and my energy abruptly returned. I don’t remember the exact date, but it really was like a switch going on. Now that I’ve realized what the likely problem is, I think I know how to avoid it next fall.

To make things worse, my 23-year-old son was killed in a car accident in January. That was a very hard blow. Lucas had just had dinner with Anne and me the evening before, which was a blessing. We got to say goodbye to him, although we didn’t know it at the time. Less than 24 hours later we were planning his funeral. No one who’s lost a child would be surprised that I was pretty much useless for a few weeks after that, but I’m past that part of the grieving process. I miss Lucas terribly, and I will miss him for the rest of my life, but I don’t believe death is the end. When he was little, I used to carry him on my shoulders. Now I carry him in my heart, and I’ll carry him there until I see him again one day. I was able to function again around the time Spring hit me, which was probably late February.

So why am I still behind? About the time spring hit, I suddenly got very busy with consulting work. When it rains, it pours, and one client in particular had a very urgent need. I need and (mostly) enjoy the consulting work, but I really love developing, building and selling amateur radio products, and I’m committed to Lazy Dog.

Anyway, I’ve just shipped 5 radios, I have 10 more ready to go and parts for at least 11 more. I also have antennas I’ll be shipping over the next few days. The antennas the antennas are mostly ready to go, but need wire measured and cut. I’m confirming the status of each order before shipment to make sure I’m not shipping anything that Paypal has issued a refund for, so it may take a few days to work through the backlog. In some cases I’m phoning customers to make sure they still want their order. Lazy Dog is still in business, and will continue to develop new products. I may get a little behind at times, but I’m determined not to let things go this way ever again.

Anne and I have talked about going to Dayton this year, having missed last year. I hope we will, but we may be just too busy. I really need her to come along, but she’d have to trade weekends with someone at her job. Also, we’re building a house on 10 acres outside Fort Wayne, and she’s doing all the finish work, which may not be done by the weekend of Dayton. Plus, our daughter, her husband, and our grandchildren will be moving to Fort Wayne from Indianapolis around that time.

One of my new product ideas is a TDOA direction finder using one of TI’s little $9.99 MSP-430 Launchpad demo boards. My product would be an add-on board (TI calls such boards “booster packs”) that would plug into the Launchpad for antenna switching and signal conditioning.

I’m in the process of designing a PCB as a test vehicle for several things that I may incorporate in future products. So far it includes a switching power supply using a boost converter to step 10-16 Volts DC up to 25 Volts, as stepper motor driver “booster pack”, and I’m working on a buck converter to step 10-16 Volts down to 5. I’ve never tried designing a switching power supply before, so it’s time I tried it. I’m hoping to use the boost converter in the next version of the transmitter module, for higher output as well as less from the finals. I have several ideas for stepper motors, including a better controller for my MFJ loop antenna and maybe a tracking mount for satellite antennas.

73 de NI9N

I owme my customers, especially those who have pending orders that should have been filled, an apology. Read the rest of this entry »

The new transmitter prototypes came on Friday, and the solder stencil should be arriving within a day or two. If all goes well, I’ll have four transmitters done & ready to go by the end of the week. There’s another factor, though.

Right after Labor Day, I was presented with an opportunity I couldn’t pass up: A consulting job doing C++ IT programming about an hour away from Fort wayne. With the hour commute and lunch, I’m away from Lazy Dog Engineering 10 – 12 hours a day, Monday through Friday. When I get home, it’s often difficult to go back to work (here, at Lazy Dog) after dinner. Don’t worry, I’m making the adjustment and Lazy Dog WILL continue to operated no matter what. Deliveries may be a little slower than they generally have been, and I might not get all the new transmitters assembled until next weekend.

73 de NI9N

We sold the last of the current batch of LD-1TX transmitter modules yesterday, and need to reorder the PCBs. Of course, this means the LD-1TR is also temporarily out of stock. I’m sorry if that inconveniences anyone, and will have TXs and TRs back in stock ASAP. In the meantime, we still have plenty of LD-1C receivers which are user-upgradeable to transceivers; an LD-1C with an LD-1TX installed is IDENTICAL to an LD-1TR.

We’re making a few revisions to the PCB layout to improve cooling and correct a one or two minor issues, so we will initially order four prototypes PCBs. Assuming the revisions don’t break anything, after assembling and (successfully) testing one board we will assemble the remaining three, and order a production batch of 50. If all goes well, that means four transmitter modules will be available within 3 weeks, and many more will be available within 4-5 weeks.

The main point of the revision is to reduce quiescent current to the relays (which will reduce heat) and to improve heat transfer between the PA and the aluminum enclosure. The enclosure acts as a heat sink, and does get warm when transmitting. Improving heat transfer will help to keep the PA devices cooler, and prevent automatic shutdown.

73 de NI9N

The current line of PPA (Perfect Portable Antenna) end-fed Zepp antennas from Lazy Dog Engineering is limited to a maximum output power of 5 Watts, due to the voltage rating on the capacitor in the impedance matching network. I’ve received numerous inquiries about a 100 Watt version, and I’ve been looking for a low-cost way to do that. I think I’ve found it. There are some details to work out, but I expect the matching network to be just a little larger than the low-power PPA. The 20, 15 and 10 meter versions will probably be packaged in a very short length of PVC pipe, probably less than 6 inches in length. The terminal for the `1/2-wave radiating element will be on one end cap, the coax and counterpoise will come out of the other end cap. I expect the price for the 20, 17, 15, 12 and 10 meter versions to be less than $35.

If it works out well, it will probably be available in about 3 weeks.

73 de NI9N

Here’s a video that shows how to do what I described in my last post:  Set up an LD-1TR for PSK-31 operation using HRD and DM-780, as well as VSPE and VAC.  Enjoy!

Updated:  Better Video Resolution

The following is a draft of my instructions for setting up an LD-1TR with HDSDR, Ham Radio Deluxe, Digital Master 780, Virtual Audio Cable, and Virtual Serial Port Emulator for PSK-31 operation, or operation with other digital modes supported by DM-780. Although it is written primarily for LD-1TR owners, it may be helpful to owners of other SDRs which are compatible with HDSDR. Also, I used HRD and DM-780, which are no longer freeware. I will investigate no-cost alternatives, and add instructions for using them, if possible, in the near future. Read the rest of this entry »