| Page 1 of 2 | 1 | 2 |
|
|
sig gen plans
Does anyone have a set of plans for a modulated RF generator suitable
for testing receivers in the HF/VHF bands? TIA |
Matt, for many of us building a piece of test equipment that we can
inexpensively buy used on eBay is much like wanting to build a pair of pliers or a screwdriver from scratch. It's simply not worth the time and expense. I use a simple Heatkit r.f. signal generator that I purchased on eBay, and paid something like $12 for it less shipping. It performs every function I need. If I could even find the need components to build it today, they alone would cost me far more than $20. Take this for whatever it's worth. Harry C. |
Hi Guys,
If you are not in continental US or one of it's regions, you will pay MUCH more than $20 for shipping alone! Build, therfore, becomes an option. My 2c. -- Pete . . ZS5ACT http://www.electronic-ideas.com/zs5act/ BTW I HATE bottom posters with passion! ------ Reply Separator ------ wrote in message ups.com... Matt, for many of us building a piece of test equipment that we can inexpensively buy used on eBay is much like wanting to build a pair of pliers or a screwdriver from scratch. It's simply not worth the time and expense. I use a simple Heatkit r.f. signal generator that I purchased on eBay, and paid something like $12 for it less shipping. It performs every function I need. If I could even find the need components to build it today, they alone would cost me far more than $20. Take this for whatever it's worth. Harry C. |
....the group IS called "rec.radio.amateur.homebrew"..isn't it?. Why would
someone be advised to buy when he asks for advice in a group dedicated to building??? Joe "PeteDBNZA" wrote in message ... Hi Guys, If you are not in continental US or one of it's regions, you will pay MUCH more than $20 for shipping alone! Build, therfore, becomes an option. My 2c. -- Pete . . ZS5ACT http://www.electronic-ideas.com/zs5act/ BTW I HATE bottom posters with passion! ------ Reply Separator ------ wrote in message ups.com... Matt, for many of us building a piece of test equipment that we can inexpensively buy used on eBay is much like wanting to build a pair of pliers or a screwdriver from scratch. It's simply not worth the time and expense. I use a simple Heatkit r.f. signal generator that I purchased on eBay, and paid something like $12 for it less shipping. It performs every function I need. If I could even find the need components to build it today, they alone would cost me far more than $20. Take this for whatever it's worth. Harry C. |
"W3JDR" writes:
...the group IS called "rec.radio.amateur.homebrew"..isn't it?. Why would someone be advised to buy when he asks for advice in a group dedicated to building??? Joe And it is fund to build stuff. The old sig gens were pretty simple, with most of the hard work on the dial. The Eico 320 was pretty popular and you can use the manual to build one of your own: http://www.nostalgiaair.org/Referenc.../EIC/EIC_8.zip But you can replace the triodes with fets, lower the voltage to 12 volts and get the same results. Steve. -- Steven D. Swift, , http://www.novatech-instr.com NOVATECH INSTRUMENTS, INC. P.O. Box 55997 206.301.8986, fax 206.363.4367 Seattle, Washington 98155 USA |
A lot of the modern signal generator projects are based on the Analog
Devices AD9850. Analog Devices actually encourages hams to use their sample service, so the part itself is no problem. It is relatively simple to program, so you may choose the microcontroller of your choice, although most of the projects out there seem to lean toward the PIC. The challenge could well be the circuit board. The 9850 is only available in TSSOP so you need a good quality circuit board to attach it to. If your PCB skills are good this won't be a problem. But if not, you might need to hunat around for a protoboard or something of that ilk that you can get in your location. Unfortunately, these tend to be kind of pricey. ... "Steven Swift" wrote in message ... "W3JDR" writes: ...the group IS called "rec.radio.amateur.homebrew"..isn't it?. Why would someone be advised to buy when he asks for advice in a group dedicated to building??? Joe And it is fund to build stuff. The old sig gens were pretty simple, with most of the hard work on the dial. The Eico 320 was pretty popular and you can use the manual to build one of your own: http://www.nostalgiaair.org/Referenc.../EIC/EIC_8.zip But you can replace the triodes with fets, lower the voltage to 12 volts and get the same results. Steve. -- Steven D. Swift, , http://www.novatech-instr.com NOVATECH INSTRUMENTS, INC. P.O. Box 55997 206.301.8986, fax 206.363.4367 Seattle, Washington 98155 USA |
"John Miles" wrote in message
... Which is something I can't begin to understand. With the AVRs, you get a faster chip with an industrial-strength C/C++ compiler that also happens to be free (as in beer). Well, there are a couple of things here. First of all, Microchip was early to the game. As a result, there is a lot of tutorial information out there. Admittedly, a lot of it is really bad, but it's existence helps people get over the hump. And lets face it, deploying a microcontroller really isn't very hard, but getting over the initial fear is. The huge number of PIC projects out there helps people feel like maybe it isn't so hard. A second part is the really wonderful simulation capabilities of MPLAB. It makes it pretty darned easy to see what is going on, and when people are starting out, that is a pretty big deal. If you look at the hobbyist project code out there, it looks like 90% or more of them are written by people "just starting out". Thirdly is the availability of cheap programmers. Yes, I know the AVR is even simpler to program than the PIC, but it hasn't drawn literally hundreds of programmer designs, almost all of which can be built cheaply. This is another consequence of Microchip being early to the game. And actually, I think an advantage the PIC has is that, at least for the 16F PICs, all the C compilers are truly horrid. When you are going to deploy a microcontroller, any microcontroller, you really need to understand what is happening at a pretty basic level. Once you have a lot of expertise in a particular part, then a compiler can be a big productivity boost. But until you have a lot of expertise, the compiler can really get in the way. Fortunately for the PIC community, most of the compilers are bad enough that you're not real tempted to use them. Actually the AD9850 comes in a SOIC package with 20 pins/inch, or half the spacing of a normal DIP IC, rather than a TSSOP (0.5 mm lead pitch, or about 50 pins/inch). I've never seen a 9850 in an SOIC. That certainly would be easier to use. Where did you find such a thing? When I check AD's web site, all I see is a choice whether I want my SSOP's on a reel or not. ... |
In article ,
says... And actually, I think an advantage the PIC has is that, at least for the 16F PICs, all the C compilers are truly horrid. When you are going to deploy a microcontroller, any microcontroller, you really need to understand what is happening at a pretty basic level. Once you have a lot of expertise in a particular part, then a compiler can be a big productivity boost. But until you have a lot of expertise, the compiler can really get in the way. Fortunately for the PIC community, most of the compilers are bad enough that you're not real tempted to use them. That's the cool thing about AVR-GCC, though... you really *don't* need to understand what is happening at a fundamental level. It just plain works. I've used AVR-GCC chips in a half-dozen projects, some of them *very* non-trivial, but I wouldn't know a line of AVR assembly if it bit me. It certainly doesn't hurt to master your platform's assembly language, especially if you need every bit of performance the chip can deliver. But as long as we're talking about hobby applications, I think most of us can agree that life at the bench is too short to spend it learning various proprietary assembly languages for no good reason. Actually the AD9850 comes in a SOIC package with 20 pins/inch, or half the spacing of a normal DIP IC, rather than a TSSOP (0.5 mm lead pitch, or about 50 pins/inch). I've never seen a 9850 in an SOIC. That certainly would be easier to use. Where did you find such a thing? When I check AD's web site, all I see is a choice whether I want my SSOP's on a reel or not. Sorry; you're totally right -- it's not a SOIC, but an SSOP with 0.65 mm pitch (39 pins/inch). I've only used the AD9850 in one project, and I've never actually ordered one -- I lifted mine off an old PC-VFO ISA card from 1998 or so. Seemed to remember it being a SOIC, but the photos at archive.org show that it definitely was not. There are other SOICs on the PC-VFO board, and they have a coarser lead pitch than the DDS chip. The AD9852/4 chips have the same 0.65 mm pin spacing for the record, but a heck of a lot more pins. :) -- jm ------------------------------------------------------ http://www.qsl.net/ke5fx Note: My E-mail address has been altered to avoid spam ------------------------------------------------------ |
matt vk3zmw wrote: Does anyone have a set of plans for a modulated RF generator suitable for testing receivers in the HF/VHF bands? TIA Drew Diamond, VK3XU, has published a few things in this line - in his books "Radio Projects for Amateurs" now up to Vol 3. Available from TTS Systems (one that I know of..) - excellent books, can recommend them to anyone interested in home brewing. If you want something with calibrated output, there has NEVER been a better time to get a good used one - so much high quality test gear is being sold off, as most telcos etc no longer maintain expensive gear and trained staff to run it - cheaper to replace the equipment with a new one. 73 de VK3BFA Andrew. |
| All times are GMT +1. The time now is 11:18 AM. |
|
Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
RadioBanter.com