Jeff and Brian, To run without the preheater/thermistor you can just disconnect it on the terminal strip behind the front plate. On my newly bought second SDR1000 the thermistor is connected to the leftmost post of the black terminal strip.Unsoldering the read connecting wire from the thermistor may make Flex-Radio´s guarantee null and void.
vy 73 es gl de SM6OMH Willi ----- Original Message ----- From: "Jeff Anderson" <[EMAIL PROTECTED]> To: "Brian Kassel" <[EMAIL PROTECTED]>; "Jim Lux" <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]>; <flexradio@flex-radio.biz> Sent: Sunday, January 07, 2007 5:15 PM Subject: Re: [Flexradio] Has Anyone Else Senn the Strange FrequencyDriftProblem? > Brian, > > This modification is fairly recent, so it may be that there aren't many > units out there which incorporate it, and of those units, perhaps few of > their users, if any, are using digital modes AND monitoring this > reflector. > > Regarding troubleshooting...if you suspect the heater/thermistor might be > causing the problem, then you could try disconnecting it (for example, > unsolder the wire to the 13.5 volts - refer to Willi's email). If the > drift > remains, then you know that the thermistor isn't the problem. > > Good luck on your hunt! > > - Jeff, K6JCA > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Brian Kassel > Sent: Sunday, January 07, 2007 7:20 AM > To: Jim Lux > Cc: [EMAIL PROTECTED]; flexradio@flex-radio.biz > Subject: [Flexradio] Has Anyone Else Senn the Strange Frequency > DriftProblem? > > > Hi Jim: > > As always, thanks very much for taking the time to reply and your > help in getting this problem fixed. Yes, feeding the PTC directly off > of the main power supply must lead to some heat variance due to the > inevitable voltage sag caused when going from TX to RX. However, I just > have to ask a question here. How come no one else is seeing this 22 > Hz., 10 second drift when switching from TX back to RX? It is very > apparent on the waterfall in the digital modes, and anyone running any > digital mode would immediately see this frequency change. I amusing a > typical power supply, and see this change, let's remember, even at the > 5W TX level. > > I have not received any message from anyone on this reflector that > they have seen this phenomena at all. Let me ask again, has ANYONE at > all seen anything like this at all? Seems to me that such a design > flaw would manifest itself quite often in general usage. Unless I can > correct this problem, the radio is quite useless to me in the digital > modes, my main operating activity. With this drifting problem, I have > not been able to use my radio since I received it, several weeks ago now, > > I hate to send the radio back for repair, as the fix has to be > something quite straightforward I would think. > > Brian K7RE > > Jim Lux wrote: > >> At 02:48 AM 1/7/2007, Willi Reppel wrote: >> >>> Peter, >>> >>> You wrote: >>> >>> >I am not sure where the power for the heater on the 200MHz >>> oscillator come >>> >from >>> > >>> >>> I bought a new 1 W SDR1000 last month before the announcement about >>> the 100 >>> W-only version came. >>> I disassembled the unit to have a look at the termistor. It is a >>> small disk >>> of approx 8 mm diameter and 2 mm thickness which is soldered or glued >>> with a >>> conductive compound on to the case of oscillator QG1. A wire is >>> soldered to >>> the top of the disk which is connected directly to the terminal strip >>> and + >>> 13.8 V dc. The grounded case of the crystal oscillator serves as return >>> pass and minus. It seems to be a combined heater / termistor with >>> approx 50 >>> ohm att room temp. and 150 ohm at operation temp. >>> Hope this sheds some light upon how the preheater / termistor is fed. >> >> >> >> >> Hmm, running the thermal control heater off an unregulated bus seems >> like a dicey design. Better have a real stiff power supply and very >> short leads or good sense lines going back to the PS regulator. >> Certainly not going to be good for running off a battery. >> >> K7RE, you're running off a regulated power supply as I recall, but how >> long and resistive are the wires from supply to radio? Can you measure >> the voltage, at the thermistor, as you switch between Tx and Rx. Even >> running at lower RF power, there may be enough of a shift in voltage >> to account for your problem. >> >> Maybe Flex might want to figure out an ECO that runs the thermistor >> off a regulated supply (5V has a fair amount of current because it has >> to run the DDS which is right next to the oscillator, but I don't know >> how close to the max current the 5V reg is running at). >> >> >>> groeten van >>> >>> SM6OMH Willi >>> >>> ----- Original Message ----- >>> From: <[EMAIL PROTECTED]> >>> To: "Brian Kassel" <[EMAIL PROTECTED]>; <flexradio@flex-radio.biz> >>> Sent: Saturday, January 06, 2007 11:09 PM >>> Subject: Re: [Flexradio] More Strange Frequency Drift Problem >>> >>> >>> >I am not sure where the power for the heater on the 200MHz oscilator >>> come >>> >from >>> > >>> > power to the 200MHz oscilator: >>> > PIOboard [AVDD] IC9(TPS76833) pin5+6 to interconnect pin 10 >>> > TRXboard power to 200MHz oscilator pin14 [AVDD] J7pin10 >>> (interconnect) >>> > interconnect J7 is a 12 pin connector >>> > >>> > I hope it helps you >>> > 73 peter pa0pvn >>> > >>> > groeten Peter >>> > petervn(a)hetnet.nl <mailto:[EMAIL PROTECTED]> ; pa0pvn(a)hetnet.nl >>> > <mailto:[EMAIL PROTECTED]> ; >>> > pa0pvn(a)gmail.com ; pa0pvn(a)amsat.org . >>> > >>> > >>> > ________________________________ >>> > >>> > Van: [EMAIL PROTECTED] namens Brian Kassel >>> > Verzonden: za 6-1-2007 22:16 >>> > Aan: flexradio@flex-radio.biz >>> > Onderwerp: Re: [Flexradio] More Strange Frequency Drift Problem >>> > >>> > >>> > >>> > Folks: >>> > >>> > Can someone tell me where the regulated voltage for the 200 MHz. >>> > oscillator comes from? It isn't clear to me in the schematic. I am >>> > investigating a 22 HZ oscillator frequency change from TX to RX that >>> > occurs in the first 10 seconds, then stabilizes to less than 1 Hz >>> > change. . Temperature doesn't seem to be the culprit, and as far as I >>> > can see, there is no switching or changing of loading on the >>> > oscillator between TX and RX. >>> > Still fighting the uphill battle to determine my frequency shift >>> problem. >>> > >>> > Brian K7RE >>> > >>> > >>> > >>> > _______________________________________________ >>> > FlexRadio mailing list >>> > FlexRadio@flex-radio.biz >>> > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz >>> > Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ >>> > FlexRadio Homepage: http://www.flex-radio.com/ >>> > >>> > FlexRadio Knowledge Base: http://kb.flex-radio.com/ >>> > >>> > >>> > -------------- next part -------------- >>> > An HTML attachment was scrubbed... >>> > URL: >>> > >>> > http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/attachments/20 > 070106/87177bc4/attachment.html >>> >>> > _______________________________________________ >>> > FlexRadio mailing list >>> > FlexRadio@flex-radio.biz >>> > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz >>> > Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ >>> > FlexRadio Homepage: http://www.flex-radio.com/ >>> > >>> > FlexRadio Knowledge Base: http://kb.flex-radio.com/ >>> > >>> >>> >>> >>> _______________________________________________ >>> FlexRadio mailing list >>> FlexRadio@flex-radio.biz >>> http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz >>> Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ >>> FlexRadio Homepage: http://www.flex-radio.com/ >>> >>> FlexRadio Knowledge Base: http://kb.flex-radio.com/ >> >> >> James Lux, P.E. >> Spacecraft Radio Frequency Subsystems Group >> Flight Communications Systems Section >> Jet Propulsion Laboratory, Mail Stop 161-213 >> 4800 Oak Grove Drive >> Pasadena CA 91109 >> tel: (818)354-2075 >> fax: (818)393-6875 >> >> >> > > > > _______________________________________________ > FlexRadio mailing list > FlexRadio@flex-radio.biz > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz > Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ > FlexRadio Homepage: http://www.flex-radio.com/ > > FlexRadio Knowledge Base: http://kb.flex-radio.com/ > > > _______________________________________________ > FlexRadio mailing list > FlexRadio@flex-radio.biz > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz > Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ > FlexRadio Homepage: http://www.flex-radio.com/ > > FlexRadio Knowledge Base: http://kb.flex-radio.com/ > _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
