"EP Swynar" <[EMAIL PROTECTED]> made an utterance to the drakelist gang ---------------------------------------------------------------------- Hi Jim,
Many thanks for sharing all your thoughts & personal experiences with me like that... Well, I've gotta tell you, the price of bells & whistles-laden peripherals like that is most discouraging to me, personally, considering what the rigs are going to cost me, & all. But you've given me reaffirmation of the notion of employing a signal generator as a crystal replacement, and I believe that's exactly what I'll do here... Initially, I'll rig up an ancient RF generator that I have here --- with a separate frequency counter --- just to see what might happen. If it works reasonably well, I found a piece by Doug DeMaw in an 80's issue of QST that describes the construction of a simple 3-transistor RF generator, employing cheap, easy-to-find (as in Radio Shack) MPF-102 & 2N2222 transistors. I could easily cobble-up a dedicated generator for this purpose using that design... JAN Crystals was nice enough to write back to me the other day, & quoted a price of $20.00 for an HC-6/U crystal...they have a minimum order of $25.00, though, and a shipping/handling charge of $6.00, so the grand total for just one crystal would be $31.00... I know I have 90% of the parts here already to make the DeMaw circuit --- for free! Thanks again for taking the time to write, Jim --- and I WILL look up those references you sent me, too, I promise...! ~73!~ Eddy VE3CUI - VE3XZ *************************************** ----- Original Message ----- From: "Jim Pruitt" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, December 20, 2007 12:08 AM Subject: Re: [drakelist] R-4 Series Crystal Alternatives > > "Jim Pruitt" <[EMAIL PROTECTED]> made an utterance to the drakelist gang > ---------------------------------------------------------------------- > Hello Eddy. > > I have built 2 of the Steve Hageman "Give that Drake Receiver a New Lease on > Life" ( http://www.arrl.org/qst/2004/06/hageman.pdf ) projects from the > June 2004 issue of QST and troubleshooting info at > http://www.geocities.com/hagtronics/r4.html and more troubleshooting info at > N0SS site at http://www.n0ss.net/drake_het_osc_xtal_elim_notes.pdf off of > his page at http://www.n0ss.net/index_general.html . Tom has an Excel > spreadsheet bill of materials at > http://www.n0ss.net/drake_xtal_elim_proj_parts_list.xls but it has not been > updated since 2005. The Hageman FS4 clone works well and looks good. The > cost is a bit high (but what DIY projects are not more expensive than > commercial products these days( (I think mine cost in the neighborhood of > $150 with all new parts and a pc board from Fred at FAR Circuits) and I was > not that impressed with some of the methods used in the design but it is > still a good item and does the job very well. The part that I did not like > was that the segments were 500khz segments (starting at 12.6mhz for 160 > meters). Why does that matter since most band segments tuned are 500khz, > you ask. I am in MARS and some of the frequencies fall close to the IF area > where Drake recommends using crystals that start in the middle of the band > segment (when using the T4X series and transceiving). This is mostly a non > issue now, since MARS outlawed older amateur gear on their frequencies. > Other than that the Hageman FS4 clone is ok. It does look nice in the MS4 > enclosure with the vinyl overlays that Tom Hammond, N0SS had made that > resemble the face of the FS4. Tom also had ovelays made for a Hammond > enclosure for those that did not want to put it in a MS4. > > I also looked very hard at the project at > http://www.jimcom.net/elehobby/r4cdds/index.html which uses an Analog > Devices AD9850 DDS chip. The web page is in Japanese (I do not read or > speak Japanese) but the schematic is viewable and the code for the Pic 16F84 > is there. > > There are other Analog Devices chips that would probably work better like > the DDS_Controllers group project that uses a AD9912 (I think) DDS chip. > > You can also cheat and use a signal generator to replace the FS4 (expensive > waste of test gear) or use a vfo if you have one that covers those ranges > that you need. > > The DDS signal generators that use the AD9850 series are probably the > easiest and cheapest to come by as there were many scattered across the web. > > I personally do not like having to buy a bunch of crystals since > International Crystal is harder to deal with these days and Jan Crystals web > page is hard to use. I guess Bomar is still in business (correct me if I am > wrong). It is getting harder to buy crystals from crystal manufacturers (at > least at a reasonable price) because the mass production market has moved to > cpu clock crystals. > > The Italian outfit that is making a DDS synthesizer for the Drake twins > makes a good product from what I have gathered on this list but that price > is way out of my budget. > > If you are inclined to make one of the DDS sythesizers you might look at the > NJQRP DDS daughtercard at http://www.amqrp.org/kits/dds60/ . It uses a > AD9851 which is not included with the kit but may still be available > directly from Analog Devices as a free sample (they are really good about > samples of current production chips but samples are not available for chips > that are at the end of their production life). > > Trev (now K6ESE) had a DDS pc board available on the QRP-L group for a while > that used an Atmel AT89S8252 cpu. That project is written up at > http://www.k6ese.com/DDS_Project.htm but is no longer available but the > schematic as well as the source code are available on his site. > > There are many many other web sites that have a AD9850-51-54 series DDS > synthesizer project outlined as well as some newer ones like the > DDS_Controller Yahoo group. > > Craig Johnson, AA0ZZ, and the group hanging out at the DDS-VFO Yahoo group > and are a great bunch of guys. Craig made the IQ-Pro DDS project for NJQRP > or AMQrp group and now are working on a better version. Craig's homepage is > at http://home.comcast.net/~aa0zz/aa0zz-main.html so you might look at that. > > I do not know if the above helps or just muddies the waters but I hope that > it shows you that there are other alternatives to the FS4. > > Good luck. > > Jim Pruitt > > ----- Original Message ----- > From: EP Swynar > To: [EMAIL PROTECTED] > Sent: Wednesday, December 19, 2007 9:33 AM > Subject: [drakelist] R-4 Series Crystal Alternatives > > > Good Afternoon All, > > I'm curious about the experience of others in the matter of utilizing > possible "...substitutes" for the frequency band oscillator crystals --- be > they synthesizers, self-excited "analog" oscillators, whatever --- in the > R-4 series of receivers, to expand the frequency coverage of same... > > To date, my research has come up with three different articles on the > subject, i.e.: > > --- August 1972 HAM RADIO magazine ("Frequency Synthesizer for the Drake > R-4"; > > --- May 1981 QST magazine ("General-Coverage Reception with the Drake R-4C", > and, > > --- June 2004 April QST magazine ("Give that Drake Receiver a New Lease on > Life"). > > Of all these, the May '81 QST appears to be about the simplest to construct, > even though it uses a pair of the now relatively expensive ECG222 (come > NTE-222) dual-gate Mosfet transistors...but how in the world does one attain > (and maintain) solid, stable, & steady crystal-like oscillation in a > relatively simple Colpitts circuit, as high as 40.8-MHz...?! > > I'm putting out feelers at this time, because in three short days from now, > I shall be the proud owner of a pair of Drake Twins here...a Christmas > present that I am presenting to myself, just a few days ahead of THE BIG > DAY, Hi Hi. > > Thanks in advance, & my vy > > ~73~ Eddy VE3CUI - VE3XZ > > > ---------------------------------------------------------------------- > Submissions: [EMAIL PROTECTED] > Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body > Hopelessly Lost: [EMAIL PROTECTED] - help in body of message > Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net > ---------------------------------------------------------------------- ---------------------------------------------------------------------- Submissions: [EMAIL PROTECTED] Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost: [EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net ----------------------------------------------------------------------
