[soft_radio] Re: Comparing SDR performance to FT-817
Hi, Martin! By interesting do you mean fun? A former supervisor of mine once ordered me not to use the word fun at the corporate office in Indianapolis, because upper management would take it the wrong way. I agree with you on all points. I haven't measured the noise floor of either receiver, but on 20 meters it doesn't really matter. Maybe it does on 10. A good soundcard makes a big difference. What we call an SDR is really just a front end, the receiver is comprised of the front-end, soundcard, and DSP software. The FT-817 probably is a bit cleaner overall, but it isn't nearly as versatile. The SDR is more fun. Oops, I mean interesting. 73, Pete, NI9N
[soft_radio] Comparing SDR performance to FT-817
Hi, all. Ever since I built my first Softrock clone (Version 5, but my own PCB design) I've felt that it performed every bit as well as my FT-817. Of course, using an SDR is entirely different (superior, in my opinion) to using a conventional receiver, as long as it hears well. My comparison was subjective, but I think most of you would probably agree. I've finally made an objective comparison, and I was right. For equal inputs, the output SNR for my current SDR, an LD-1A, is practically identical to the output SNR for my FT-817. Unless I've overlooked something, that means the MDS should be the same for the two receivers. Of course, an SDR is more fun. You can see the details at http://garage-shoppe.com/wordpress/?p=622#more-622 73, Pete Goodmann, P.E., M.S.E.E., NI9N www.garage-shoppe.com www.lazydogengineering.com Inconveniently located 110 km. from Radioville, Indiana
[soft_radio] E-Mu 0202
Hi, everyone. I bought a new E-Mu 0202 one week ago. I'm a little disappointed so far. I've written up my experience with it to date on my blog, garage-shoppe.com, but it boils down to image rejection (that is, phase and amplitude matching between the I and Q channels) which is inferior to my results with an SB-1090. I may be doing something wrong, and I'm not quite ready to give up on it. If you've used an E-Mu 0202, please read my blog post and tell me if I should be doing something differently. Thanks. 73, Pete, NI9N www.lazydogengineering.com www.garage-shoppe.com Inconveniently located 110 km. from Radioville, Indiana
[soft_radio] New series explaining SDRs for beginners on garage-shoppe.com
I've just started a new series of posts on my blog, www.garage-shoppe.com, for those new to SDR's. In Part I, I begin to explain how the QSD (or Tayloe detector) works by showing that a simple sample-and-hold circuit acts as a mixer. Part II will show how two or four sample and holds can be combined to form a QSD. 73, Pete, NI9N www.lazydogengineering.com www.garage-shoppe.com Inconveniently located 110 km. from Radioville, Indiana
[soft_radio] Re: LD-1A updates: a testimonial, transmitter module, and more
Hi, Dave. I think you might be comparing apples to oranges. Maybe I'm wrong, but I think the price of the Elektor SDR is about $140, 64% the price of an LD-1A, for a fully-populated and tested board. As far as I can tell, the Elektor does not come with an enclosure, while the LD-1A comes fully assembled in a very nice extruded aluminum enclosure. The Elektor appears to have no RF connector and no power connector. There's nothing wrong with that, but it does account for some of the price difference. I don't mean to denigrate someone else's product, but I think you would find that the LD-1A's preselector filters are a bit more robust than the Elektor's. The LD-1A has five electronically switched filters, one lowpass and four bandpass, all third-order. Also, the LD-1A is designed to have a transmitter module added to it. --- In soft_radio@yahoogroups.com, Dave Wade g4...@... wrote: First, I would hope that at around twice the price, the LD-1a would out-perform the Elektor SDR. However given so much of the performance depends on the PC and sound card, there is a finite limit on the performance you can achieve...
[soft_radio] Re: LD-1A updates: a testimonial, transmitter module, and more
Dave, I just looked up Elektor's add-on preselector. I have not compared that circuit to mine, but I see that it costs $75 for a kit (not assembled). If you add the costs of the Elektor SDR, preselector, and a comparable enclosure, that would make the Elektor cost at least $235, giving a slight cost advantage to the LD-1A 73, Pete, NI9N --- In soft_radio@yahoogroups.com, Dave Wade g4...@... wrote: First, I would hope that at around twice the price, the LD-1a would out-perform the Elektor SDR. However given so much of the performance depends on the PC and sound card, there is a finite limit on the performance you can achieve...
[soft_radio] Re: LD-1A updates: a testimonial, transmitter module, and more
Jose, I agree with most of your statements. By mismatch, I meant either phase or amplitude mismatch, because either witll cause imperfect cancellation. It would be nice if soundcards had perfect matching between channels, but soundcards are sold to listen to music. To a music listener, small mismatches are completely irrelevant - the ear doesn't know they're there. Matching the channels would add to the cost of the soundcard, with no value to 99.9% of buyers. SDR software packages like Winrad or Rocky include adjustments to correct for phase or amplitude mismatches, and it makes a lot more sense to do that in the software than in the hardware. At least, that's how I see it. 73, Pete, NI9N www.lazydogengineering.com www.garage-shoppe.com Inconveniently located 110 km. from Radioville, Indiana --- In soft_radio@yahoogroups.com, Jose A. Amador ama...@... wrote: El 14/03/2010 7:04, Peter escribió: Any phase error or mismatch between the two channels will cause a vestige of the image to appear. The degree to which this image is attenuated relative to the signal response is image rejection in my personal lexicon. To me, unwanted responses which result from harmonics of the LO are spurs. If my usage of these terms is wrong, please correct me. Mismatch needs a surname. That is amplitude mismatch. Analyzing it as vector addition, vectors need to be of identical amplitude and collinear to add up one sideband and entirely cancel, infinite rejection on the other. Falling short of that condition does not matter much on the adding vectors, but is very important in the cancelling ones, and minute imperfections, mismatches between channels are usually the cause that makes not possible to maintain the adjustment condition all over the rig bandwidth at infinite opposite sideband rejection. Perhaps taking some extra effort in matching amplitude and phase on the SDR front ends might make it at least slightly better. Feeding the same tones to both amplifiers, making a frequency sweep and checking the result with a two channel scope in differential mode might help to know which wrinkles to iron out. Soundcards should have matched channels as well, and that is what makes it more difficult with the cheaper ones. 73, Jose, CO2JA
[soft_radio] LD-1A updates: a testimonial, transmitter module, and more
Pierre, F8GY bought one of the first LD-1's, then bought one of the first LD-1A's. Recently, he wrote: Thursday afternoon I brought the LD1 to a friend house to make a comparison with the elektor RDS . It was a triumph for the LD1 ! It was connected to a delta 44 slound card and it was an outstanding job , better than the elektor ! I gave to the present Hams your site adress . As soon the tx add-on is ready tell me . When I told them that you were preparing a tx to go with they were very interested . I have assembled the transmitter module prototype, and will be testing it this afternoon. You can see a photo at www.garage-shoppe.com. If all goes well, the first production units will be ready very soon. Lastly, I am again offering an LD-1A on Ebay. This time I've made the starting bid $120, but there is a reserve price. The item number is 170458255741. 73, Pete, NI9N www.lazydognengineering.com www.garage-shoppe.com Incoveniently located 110 km. from Radioville, Indiana
[soft_radio] LD-1A Ebay Auction Results
My auction of one LD-1A on Ebay ended a few minutes ago, and the results are doubly gratifying. First, I beleive the auction confirmed that I have selected an appropriate price point of $218. Second, and even better, the buyer turned out to be a REPEAT BUYER! He's had his first one for a couple of weeks now, so he's had a chance to evaluate it and must really like it. He is the third person to buy two units. Woohoo! I love it The LD-1/1A is now mentioned on winrad.org By the way, I'll have a post later today on garage-shoppe.com showing how to turn a $10 aquarium pump and a few other odds and ends (that's odd bits for my friends in the UK) into an inexpensive vacuum pick for handling surface-mount parts. 73, Pete, NI9N www.lazydogengineering.com www.garage-shoppe.com
[soft_radio] Availability of original LD-1 (Plastic Enclosure)
It's come to my attention that there may be a little confusion about availability of the original LD-1, with the plastic enclosure. It is no longer available, and I have removed it from the website. The LD-1 was initially offered at a reduced initial price of $150, and was to have gone to $200 in early February. However, I received negative comments regarding the plastic enclosure, and decided to a much nicer one made of extruded aluminum. I made the switch at the time the introductory price was to have expired, but continued to offer the remaining LD-1's (original, plastic enclosure) at $150 until all were sold. All of them are sold now, and I have no plans to offer that model in the future. At that same time, I began offering the LD-1A for $218, $18 more than the original LD-1 would have cost after the introductory price expired. The aluminum enclosure costs me more, and requires more of my time to customize, that is the reason for the higher price. I do currently have one LD-1A listed on Ebay, at a current bid of $150. The auction ends in about 41 hours, so somebody might just pick up a bargain. The item number is 170449003769. 73, Pete, NI9N www.lazydogengineering.com www.garage-shoppe.com
[soft_radio] Re: New post at garage-shoppe.com
Hi, Hank! The transmitter will almost certainly be a fully assembled module, not a kit, and will be designed to fit in the LD-1's enclosure above the LD-1. No additional holes will be needed. I was thinking ahead to this when I designed the LD-1. As for the range, as you know that depends on many factors: The mode, the antenna, frequency, propagation conditions, etc. All I can tell you is that with my MFJ loop antenna I have worked Europe, Africa, South America, even New Zealand on 5 Watts or less. I'm hoping to get 3 watts out of the new transmitter, but we'll see. By the way, the LD-1 is now mentioned on the winrad.org website! 73, Pete, NI9N www.lazydogengineering.com www.garage-shoppe.com --- In soft_radio@yahoogroups.com, hank smith hanksmi...@... wrote: are these kits or actual moduals? also what is the range of the transmitter? - Original Message - From: Peter p...@... To: soft_radio@yahoogroups.com Sent: Monday, February 22, 2010 11:23 AM Subject: [soft_radio] New post at garage-shoppe.com Just published a new post: LD-1 Transmitter, More on Radioville, and More at garage-shoppe.com. Enjoy! 73, Pete, NI9N www.garage-shoppe.com www.lazydogengineering.com Yahoo! Groups Links
[soft_radio] New post at garage-shoppe.com
Just published a new post: LD-1 Transmitter, More on Radioville, and More at garage-shoppe.com. Enjoy! 73, Pete, NI9N www.garage-shoppe.com www.lazydogengineering.com
[soft_radio] New Yahoo! Group: lazydogsdr
Hi, All! I've just created a new Yahoo! group for those who have a Lazy Dog SDR, or are interested in getting one. The group name is lazydogsdr, and I hope to see you there! 73, Pete, NI9N www.lazydogengineering.com www.garage-shoppe.com
[soft_radio] LD-1 Issues and a few questions
Two or three LD-1 issues have come up over the past several days. I've solved one of them, and should have the others solved within a day or two. Details on my blog (www.garage-shoppe.com). In a seperate post on garage-shoppe.com, I ask several questions and would appreciate any information anyone can offer. I don't want to place long posts here that pertain specifically to the LD-1. I do have one more general question, though. One person has installed the LD-1 software and copied ExtIO_LD1.dll into the Winrad folder, but the LD-1 does not appear as one of their Input Options. Only one person has experienced this problem, and I don't think it could possibly be an LD-1 problem. I suspect that he may have inadvertently installed Winrad in two different folders, and the shortcut he's using to launch Winrad is actually a shortcut to the wrong one. Does anyone know of anything else that could cause this problem? 73, Pete
[soft_radio] Re: LD-1 Issues and a few questions
Thanks, Alberto.
[soft_radio] Re: LD-1 Discussion on Garage-shoppe.com Blog
I definitely agree with Larry about the SMT soldering techniques. SMT assembly is not bad IF you use the right tools and techniques. I will be posting some more info on that on my blog, probably tomorrow, but one of the things you should NEVER do (in my opinion, that is) is use wire solder and a soldering iron. More on that later. Since there has been a lot of unencouraging discussion about Hank's problems with a particular SDR in a Thread entitled LD-1 Discussion ..., I'd like to point out that the SDR Hank is struggling with is NOT, repeat, NOT an LD-1. 73, Pete, NI9N
[soft_radio] Re: LD-1 Discussion on Garage-shoppe.com Blog
I use a Weller butane soldering iron with a hot-air blower tip. It works very well, and I think I paid $65 for it, with a set of interchangeable tips - blowtorch (don't use that one for soldering), hot air, fine and not-so-fine soldering tips, and a hot knife. For prototypes, before I invest in a solder stencil, I use a veterinary syringe from a local farm supply store (Tractor Supply, there might be one near you if you're in the USA) with a #22 needle for fine-pitch pads. I use a dremel tool with a cutoff wheel to cut the needle off square for safety, and I cut it pretty short to make it easier to force the solder paste out. It still takes practice to avoid getting too much paste on the pads, but it can be done. One trick I really like is to use an electric skillet or griddle as a hot plate. Put the PCB (or PCB's if you are working on more than one) on the griddle, and use an infrared thermomter (can be found for less than $20 at Harbor Freight Tools, and probably other places as well) to monitor the temperature. When it gets close to the melting point, use the hot-air blower to take it the rest of the way. Works great, and the use of a hot-plate facilitates unsoldering. The wick technique scares me because of the risk of lifting a pad and ruining the PCB. I've done that a few times. Also, if you use a no-clean solder paste, it doesn't leave baked-on flux. I use Amtech LF-4300, which is also water-soluble. --- In soft_radio@yahoogroups.com, ward ya...@... wrote: I use one of these dam hot air guns. Absolutely worth the price. I don't use it for fine pitch ICs, I use the slobber-n-wick approach because I find applying very small amounts of solder paste nearly impossible. I have seen small solder balls between the pins. I simply slobber on more solder and wick it back off. The vast majority of the time it works fine. If it doesn't it is because the solder balls are imbedded in baked flux. I use alcohol and a stiff tooth brush to clean them out. Done. For everything else I use a diluted form of solder paste... apply the paste place the parts bake the assembly at 80c for 20 minutes (drive off the volatiles of the solder paste) 'reflow' using the hot air gun. Works beautifully and is significantly faster than through hole. Took me several projects to adapt to surface mount. I threw all my through hole parts away so I wouldn't be tempted to design with them again. Seriously. Use surface mount a few times and you'll love it. Make the investment in a hot air gun of some sort, you'll have more success earlier and make the transition less painful. ward ae6ty On Jan 28, 2010, at 3:28 PM, Dave Wade wrote: I have built both an Elector SDR and a USA QRP Club DDS board, both of which have surface mount components on. I have also repaired some circuits with surface mount components. I have a hot air gun like this:- http://www.pcb-soldering.co.uk/index.php?target=productsproduct_id=37 And while its only really essential for removing SMD ICs, at which its very good, I personally think it makes a much better job of Rs and Cs that an Iron and Solder. So if you are going to do any volume of SMD work I would highly recommend one, but its not essential and don't be put of if you don't have one... Dave G4UGM -Original Message- From: soft_radio@yahoogroups.com [mailto:soft_ra...@yahoogroups.com] On Behalf Of Dave - WB6DHW Sent: 28 January 2010 22:19 To: soft_radio@yahoogroups.com Subject: Re: [soft_radio] Re: LD-1 Discussion on Garage-shoppe.com Blog Peter: The procedure is to solder the ssop pins and not worry about shorts. Then use solder wick to remove the shorts. Easier than it sounds. Many have done this with IC's with .020 pitch. Dave - WB6DHW http://wb6dhw.com
RE: [soft_radio] Digest Number 781
Hi Walter This was using the built-in SoundMax soundchips of my Dell. You are quite correct about it being for one frequency, ie 5000MHz which is 12KHz IF 73s Peter -Original Message- From: soft_radio@yahoogroups.com [mailto:[EMAIL PROTECTED] Sent: 10 November 2007 11:16 To: soft_radio@yahoogroups.com Subject: [soft_radio] Digest Number 781 There is 1 message in this issue. Topics in this digest: 1.1. Re: elektor sdr mirror frequency rejection From: Walter Message 1.1. Re: elektor sdr mirror frequency rejection Posted by: Walter [EMAIL PROTECTED] karula4711 Date: Fri Nov 9, 2007 6:58 am ((PST)) Hallo Peter, with which soundcard did You get the result of nearly 60 dB? Let me guess. That was an example using exactly one frequency. You can tweak phase an amplitude for -60 dB as demonstrated. But for real life we need hi supression for a span of frequencies. ?? Walter Messages in this topic (27) Yahoo! Groups Links No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.15.27/1121 - Release Date: 09/11/2007 19:29 No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.15.27/1121 - Release Date: 09/11/2007 19:29
[soft_radio] Re: elektor sdr mirror frequency rejection
Hi Walter I just posted a screenshot of an Elektor SDR with nearly 60dB image rejection 73s Peter http://g8jcf.dyndns.org --- In soft_radio@yahoogroups.com, Walter [EMAIL PROTECTED] wrote: Ugly, but it worked. Immediate checking: everything ok. Now what? Somebody here who has a working Elektor board with proper mirror rejection? MAy we see a screenshot? If so we could conclude that not ALL boards are defunct. Best regards, Walter
