Re: [Drakelist] RF Signal Generator
On Tue, 2010-02-09 at 12:55 -0500, James Bridgers wrote: I would like to have a rf signal generator for my use. Any suggestions as what to look for? Thanks in advance for your help Since James has not identified what his use is, the wide ranging responses to his question generated answers to the more general question of: What RF signal generators are available? And at what cost?. The very wide range of generator costs identified by other posters to this thread offer few if any inexpensive solutions. Inexpensive probably means build it from scratch or find a kit. As others have mentioned, aside from generating the signal, knowing what frequency it is on and being able to adjust the power level are probably the minimal characteristics of a useful generator. A transistorized wide frequency VFO with band-switchable coils/caps is easily made. This coupled with a frequency counter and a step attenuator makes a useful generation system. A DDS-30, DDS-60 or equivalent is better that a VFO-type oscillator for some applications, but will depend on your needs. Google for Frequency counter kit and step attenuator kit. Scan the unmentionable auction site to see what's available. Having separate pieces of gear is a plus because each may be used in more than a single way. Gear such as a crystal oscillators, RF detectors, RF mixers and the like can be easily added to the mix to give you more testing/experimenting capabilities. Also consider that simple, usable electronic equipment based on the PC sound card are easily fabricated. Do some research, decide build or buy, go for it! Joe, K9HDE ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] RF Signal Generator
I can second the HP 606 suggestion. That has been my primary generator for over 20 years. I will only add reliable, clean output and zero leakage to Garey's comments. If you can handle the bulk, it's a great value. Dennis AE6C On Tue, Feb 9, 2010 at 11:55 AM, Garey Barrell k4...@mindspring.com wrote: James - Depending upon what you intend to do with it, the price can vary from next to nothing, to infinity. That said, if you are interested in using on Drake gear, the most useful generator (aside from the Calibrator built into most receivers) is one of the XG generators from Elecraft. The XG-2 is a 'tri-band (80 / 40 / 20) calibrated source with 1 uV and 50 uV outputs. These are the two most-needed levels, 1 uV for Noise Figure or MDS testing, and 50 uV for calibrating S-Meters to S-9. This is the generator that I use most often, if for no other reason than it is about the size of two thumb drives and runs off a coin cell. For general coverage, a Heathkit IG-42 or similar will give you a decent 50 kHz to 30 MHz generator. An external attenuator, commercial or homebrew can convert it to a calibrated source. About $40 My favorite is an HP 606A/B which covers 50 kHz to 65 MHz, is stable, has a beautiful attenuator and is well calibrated. It's BIG, 10 high, 19 wide rack panel with cabinet to match. Typically sells for $100 and up. The HP 8640B is a good generator, goes to 512 MHz I think, 1024 with an optional doubler. It's only 5.5 rack panel, but weighs about as much as the 606! It does have a weak point in the internal gearing, (plastic,) that is happening often now. So watch EBay type sales. There have been talks about making a replacement gear, but Beyond this you are getting into newer stuff, from the cheap stuff from China that's not as good as the Heathkit, up to the megabuck units current with HP. There are a couple of HP units that sell in the $200-300 range that are smaller and lighter and show up on EBay, etc. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com James Bridgers wrote: I would like to have a rf signal generator for my use. Any suggestions as what to look for? Thanks in advance for your help ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] RF Signal Generator
I would like to have a rf signal generator for my use. Any suggestions as what to look for? Thanks in advance for your help ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] RF Signal Generator
James - great question! Think first you need to determine exactly what you'll use it for so you can set some parameters for what the generator will do and maybe more importantly how much it will cost. If you're simply looking for something to troubleshoot your Drake gear with you can probably get by pretty cheapif you're looking for that and other applications the following may be a start as you think about what to get. So you may want to ask yourself some of the following: How high does the generator have to go in frequency? (usually a good idea to at least double your first answer for the future!) How small/large does that signal have to be? How accurate does the output level need to be? Do I need small incremental changes (tenths of a .dB) or is the 10/20 dB switch sufficient? Do you need different modes of operation, i.e. AM, FM, I/Q, etc. In general there are probably five what I see to be different levels of generator available, with cost marking the major breakpoints. (1) For the lack of a better term, the ...couple hundred bucks range. At the low end you'll find the typical Heathkit, Eico, BK, Tenma models that generate almost up to 100 MHz and have sufficient harmonic output to work up into the 440 band (maybe). Great for general troubleshooting where accuracy and stability are not the driving factors. Probably have the ability to modulate the signal ala AM. (2) The more than a couple of hundred bucks range - now you're getting into either used HP generators, abundant over on ePay where it may be a real crapshoot but there are some gems to be had. If your bench is big enough the HP 8640B series is a good choice but they are VERY long in the toothhaving said that they're probably a mainstay of many ham workbenches. All depends on your comfort buying used test gear (and potentially your ability to troubleshoot and repair it). AM/FM modulation abounds. (3) The small kilobuck range - again mostly used equipment, higher frequency ranges up above 1 GHz and higher; more accuracy on output levels. Output attenuators tend to get fried and are then hard to repair/replace. Now you're starting into the boxes that you can tie to a cesium, rubidium, GPS standard (10 MHz for the most part) that will really ensure the output accuracy of your test signal. (4) The major kilobuck range - new instruments by Hameg and others. Ramsey used to have a nice model that would go almost up to 1296 MHz and was a good performer but now discontinuedused units may be around somewhere. (5) The maxi kilobuck range - new instruments by Rohde Shwarz, Agilent, Textronix and used units. I've had good luck here by going direct to the manufacturer's sales department to see if they had any demo units availablethey can be had if you luck into one for significant discounts. Ok, enough ramblingam sure we'll get plenty of other advice here shortly. Hope this was more helpful than a hindrance to your effort! 'Course I may be all wet herewhat do you other guys think? 73 -- Dino KL0S On 9Feb2010, at 12:55 PM, James Bridgers wrote: I would like to have a rf signal generator for my use. Any suggestions as what to look for? Thanks in advance for your help ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] RF Signal Generator
I would add to Dino's suggestions the URM-25/26 series of military generators. Plan to spend at least $100 for one, because your going to want to get one that is known to be working and fairly well calibrated (you can pick these up at flea markets and the dwindling surplus outlets for well under $100, but you don't want to have to repair or calibrate one of these). 73 Lee WB6SSW ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] RF Signal Generator
I went through that a few years back. I'd recommend something with a digital frequency readout, a meter for reading the signal output level, and a calibrated attenuator on the output so you can accurately adjust the output level. When I was looking, that narrowed the field down to a Boonton or HP. I was lucky in finding a Boonton 103F that had just been calibrated and worked perfectly. A few years later, someone gave me a working HP-8640B and I sold the Boonton. Now I wish I had the Boonton back. Note that these are both rather old technology, but the Boontons seem to hold up a bit better than the HPs. The HPs have nylon gears that often fail and are very difficult to find replacements for. The only problem I ever had with the Boonton was a failed power supply filter cap. Both of those generators have an upper frequency limit that's adequate for working on any Drake gear you're likely to have. 73, Floyd - K8AC - Original Message - From: James Bridgers n4...@coastalnet.com To: Drakelist@zerobeat.net Sent: Tuesday, February 09, 2010 12:55 PM Subject: [Drakelist] RF Signal Generator I would like to have a rf signal generator for my use. Any suggestions as what to look for? Thanks in advance for your help ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] RF Signal Generator
A URM25/26B were great signal generators but actually with all the digital requirements of Public Safety Radio now days, you can pick up a really nice service monitor that can accurately generate signals from DC up to a GHz that measure RF output of the generator, display generated modulation levels, read frequency, some have spectrum monitoring for around $500.00 dollars. In fact recently I saw a guy selling Agelent monitors that have tracking generators for $600.00 dollars on Craigslist, there a little larger than IFR's or Motorola but do a wonderful job accurately for not a lot of money. 73's, John, WA6HYQ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] RF Signal Generator
James, I also suggest the URM-25 series of signal generators. They are plentyfull and can be purchased for around $200. They are not all the same and were made by different manufactures I am told so do your homework. I have owned a URM-25F ( 10kHz to 50 mHz ) for several years and the only real drawback is they do drift and can be very difficult to tune especially at low frequencies. You will want to use a frequency counter if you plan to use one for servicing your Drake receivers and need 50 khz for instance to be accurate. I retired mine and now use a Singer CSM-1 that is rock solid. www.kiss-electronics.com/ 73, Gary W8PU http://home.roadrunner.com/~w8pu ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] RF Signal Generator
James - Depending upon what you intend to do with it, the price can vary from next to nothing, to infinity. That said, if you are interested in using on Drake gear, the most useful generator (aside from the Calibrator built into most receivers) is one of the XG generators from Elecraft. The XG-2 is a 'tri-band (80 / 40 / 20) calibrated source with 1 uV and 50 uV outputs. These are the two most-needed levels, 1 uV for Noise Figure or MDS testing, and 50 uV for calibrating S-Meters to S-9. This is the generator that I use most often, if for no other reason than it is about the size of two thumb drives and runs off a coin cell. For general coverage, a Heathkit IG-42 or similar will give you a decent 50 kHz to 30 MHz generator. An external attenuator, commercial or homebrew can convert it to a calibrated source. About $40 My favorite is an HP 606A/B which covers 50 kHz to 65 MHz, is stable, has a beautiful attenuator and is well calibrated. It's BIG, 10 high, 19 wide rack panel with cabinet to match. Typically sells for $100 and up. The HP 8640B is a good generator, goes to 512 MHz I think, 1024 with an optional doubler. It's only 5.5 rack panel, but weighs about as much as the 606! It does have a weak point in the internal gearing, (plastic,) that is happening often now. So watch EBay type sales. There have been talks about making a replacement gear, but Beyond this you are getting into newer stuff, from the cheap stuff from China that's not as good as the Heathkit, up to the megabuck units current with HP. There are a couple of HP units that sell in the $200-300 range that are smaller and lighter and show up on EBay, etc. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com James Bridgers wrote: I would like to have a rf signal generator for my use. Any suggestions as what to look for? Thanks in advance for your help ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
