F3WT <[EMAIL PROTECTED]> made an utterence to the drakelist gang ---------------------------------------------------------------------- Hi Peter,
Conny's design, which I have in my TR7, is quite a fine feedback-loop circuit which provides very high stabilty to an already very stable VFO . The dubed DAFC or Digital Automatic Frequency Control circuit uses the RIT input/signal to tune the VFO. Not touching to the VFO itself during installation! It takes the 500kHz signal generated by the PBT/Ref board out of its 40Mhz Xtal oscillator as a reference and, after divisions, "compares" it to a signal derived from the VFO frequency. After an integration time the error signal drives the RIT signal by addition. The systems is homing the VFO of the TR7 to the nearest reference fence- frequency of either 32, 16, 8,4, or 2 Hz apart ( programmable) within its 5 to 5.5 mHz range . Although you may run for instance PSK31 without DAFC, you are supposed to get an even more stable output , but I haven't actually measured the stability so far, nor did I install it as Conny did it during a repair. However the instructions and photos I got suggest it is not complicated to do. The only thing might be the setling or capture time due to the integration time. The finer the granularity, the longer the setling time and the more likely the hopping also!.. One would have to ask Conny for the function between both. he says 16 Hz is a good compromise. As said, it doesn' t make a bad VFO good, but what it does is turning a very good VFO into an excellent one! I work CW only and never experienced any drift sofar during a QSO. My quantization/granularity is set to 16 Hz. Hope it helps a bit . 73. Pierre. F3WT le 2/07/04 16:12, doc � [EMAIL PROTECTED] a �crit�: > > doc <[EMAIL PROTECTED]> made an utterence to the drakelist gang > ---------------------------------------------------------------------- > If the $20. TCXO I mentioned would work, and I correctly understand > $C 150 to be close to $150. in USD what is the advantage of the > more costly alternative, please? > > I was unable to figure out the German site as easily as you! ;-) > > 73, doc kd4e > > VE3AX wrote: >> "VE3AX" <[EMAIL PROTECTED]> made an utterence to the drakelist gang >> ---------------------------------------------------------------------- >> Hi all: >> >> While we're on the subject of TR7 VFO drift, has anyone tried out Conny, >> DL1SDQ,s, PLL board for the TR7? He put one on the Bay a while back but >> sells directly as well. I exchanged e-mails with him and have checked out >> his web site, but before shelling out $C 150 for each board (incl. shipping) >> , I'd love to talk to someone who has installed one first. It appears to >> tune in (at installation) selectable 2, 4 or 8 hz steps, and is tuned by the >> existing PTO (???). Takes 5 wires to install and mounts underneath the >> motherboard. >> >> I don't find the drift objectionable after the radio has been on for a while >> and I have left the PTO dial lights in place. They just look too good with >> the new blue filters! I have found that by using the external RV-7 as the >> main tuning control, drift is significantly less a problem. Or you can use >> the RV-75 if you are lucky enough to have one. Incidentally, Conny tells me >> that you can also install one of his boards in the RV-7. >> >> Conny's web site is at http://www.conny-dl1sdq.de/1312.html >> >> It is in German but you can figure out just about everything you need to >> know without knowing the language. The pictures tell a lot. He has some >> other neat ideas for the TR7 as well. I particularly like the 10 turn pots >> for replacing the frequency control/voltage control pots on the power supply >> board. Far less likely to get "bumped" and easier to put right on >> frequency/voltage. >> >> 73 >> >> Peter >> VE3AX > > ---------------------------------------------------------------------- > On Behalf of doc <[EMAIL PROTECTED]> > Submissions: [EMAIL PROTECTED] > Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body > Hopelessly Lost: [EMAIL PROTECTED] - help in body of message > Zerobeat Web Page: http://www.zerobeat.net > Brought to you courtesy of TLCHost.net http://www.tlchost.net/ > ---------------------------------------------------------------------- ---------------------------------------------------------------------- On Behalf of F3WT <[EMAIL PROTECTED]> Submissions: [EMAIL PROTECTED] Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost: [EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ ----------------------------------------------------------------------
