1703	2008-06-13 16:33:49	bkopski	A COMPONENT OF INTEREST
Message	Date	From	Subject
The 365 pF air variable is a classic component and is still available from a few suppliers. One of these is the Crystal Set Society and the site www.midnightscience.com is worth a visit. These folks are VERY nice to do business with friendly and speedy service is what I've found every time. More recently this supplier has listed a 365 pF air variable with built in 8:1 coaxial reduction drive. I got one to play with and decided to fit it with both "large" and "small" knobs "two speed" drive so to speak. But this was a challenge because the coaxial shaft arrangement has rather short shaft sections to work with. The "inner" or direct drive shaft is less than 0.2" long while the "outer" or slow speed drive is about 0.4" more. It's easy to install a knob on the latter (reduced speed) shaft but quite another thing to utilize the former. I feel both shaft sections need to be about ½" longer than they are to allow full utility with panel mounting ease and more practical knob options. That notwithstanding, I set about to make a "two knob" tuning arrangement. Some associated photos show the details. Basically, I cut a 2 ¼" disk of double sided pc board to serve as direct drive "inner" or large knob, or as a dial plate alternative. I used a ¼" X 20 brass nut to mate the disk to the short part of the shaft. The nut is drilled thru with a ¼" bit, and then the nut is cross drilled and tapped with a 4-40 thread to accept a set screw. The nut is then spot soldered to the pc board disc. When this combination is installed on the "inner" or direct drive portion of the coaxial shaft, a conventional knob can be attached to the "slow" speed shaft portion. The result is a dual speed (two knob) tuning option. While this HB approach is workable, I feel it is unfortunate that this 365 pF classic with its too-short shaft arrangement makes things so difficult. With the shaft section lengths as described, there is not much room left to accommodate panel thickness, and the 1/16" thick pc board "knob" is not pleasant to the touch. Nevertheless, this appears to be a workable "workaround" and this capacitor is destined for rapid deployment in a new HB project! Cordially, Bob K3NHI
1704	2008-06-14 07:45:51	Doug Edwards	Re: A COMPONENT OF INTEREST
Hi Bob and group ! Thanks for the info on the good ole variable. Would it be hard to take a picture of how you attatched the two knob system? I would like to see how you worked out this problem and see if I can figuere out another way. This would be a great part for the folks needing a tuning cap with two rates of tuning. I am always interested in how others work out problems both electrically and mechanically. Thanks again, 73's, 72's, Doug, KM6OR.. On 6/13/08, bkopski <kopskirl@cavtel.net> wrote: > > The 365 pF air variable is a classic component and is still available > from a few suppliers. One of these is the Crystal Set Society and > the site www.midnightscience.com is worth a visit. These folks are > VERY nice to do business with � friendly and speedy service is what > I've found every time. > > More recently this supplier has listed a 365 pF air variable with > built in 8:1 coaxial reduction drive. I got one to play with and > decided to fit it with both "large" and "small" knobs � "two speed" > drive so to speak. But this was a challenge because the coaxial > shaft arrangement has rather short shaft sections to work with. > > The "inner" or direct drive shaft is less than 0.2" long while > the "outer" or slow speed drive is about 0.4" more. It's easy to > install a knob on the latter (reduced speed) shaft but quite another > thing to utilize the former. I feel both shaft sections need to be > about �" longer than they are to allow full utility with panel > mounting ease and more practical knob options. > > That notwithstanding, I set about to make a "two knob" tuning > arrangement. Some associated photos show the details. Basically, I > cut a 2 �" disk of double sided pc board to serve as direct > drive "inner" or large knob, or as a dial plate alternative. I used > a �" X 20 brass nut to mate the disk to the short part of the shaft. > The nut is drilled thru with a �" bit, and then the nut is cross > drilled and tapped with a 4-40 thread to accept a set screw. The nut > is then spot soldered to the pc board disc. When this combination is > installed on the "inner" or direct drive portion of the coaxial > shaft, a conventional knob can be attached to the "slow" speed shaft > portion. The result is a dual speed (two knob) tuning option. > > While this HB approach is workable, I feel it is unfortunate that > this 365 pF classic with its too-short shaft arrangement makes things > so difficult. With the shaft section lengths as described, there is > not much room left to accommodate panel thickness, and the 1/16" > thick pc board "knob" is not pleasant to the touch. Nevertheless, > this appears to be a workable "workaround" and this capacitor is > destined for rapid deployment in a new HB project! > > Cordially, > Bob K3NHI > > > [Non-text portions of this message have been removed]
1705	2008-06-14 09:36:58	bkopski	Re: A COMPONENT OF INTEREST
Hi Doug, I'm a bit confused - is it that you cannot view (open) the 4 related photos already posted, or are you seeking additional details / photo views? I'd be happy to supply additional photos if you can describe more specifically what you'd like to see - just comment here or PM me and I'll do my best! Cordially, Bob K3NHI
1706	2008-06-14 11:13:21	cwfingertalker	Re: A COMPONENT OF INTEREST
Bob, Enjoyed the website concerning crystal radio sets. Brings back a lot of memories. This makes me think maybe we should review where we all buy our parts. Maybe share some ideas and experiences on part suppliers. I have a few that I use. Mouser, Ocean State Electronics, Kanga for kits and Dan's Small Parts for surplus parts and kits. Bill N7EU Sam's Valley Oregon.
1708	2008-06-14 19:02:41	Doug Edwards	Re: A COMPONENT OF INTEREST
Hi Bob. Thanks for the reply. No, I didnt see the pic's at first, not near the bottom of the screen as I usually see. After I looked (this time) to the right edge of thepage where the messege was writtem I saw the 4 new pictures added to the group photos section and low and behold, there they are ! Please excuse my dumb witted computer skills. THe perspecive of the cap / dial is clear as a bell now in my mind and I see the problem. It looks like a nice handy cap though. Thanks for calling attention to them. I will keep brain cell engaged on the problem. 73's, TKS AGN, Doug, KM6OR..
1762	2008-07-01 17:45:44	Greg Back	Re: A COMPONENT OF INTEREST
Bob, I'm a little late seeing this, but a suggesti
1767	2008-07-02 05:57:35	bkopski	Re: A COMPONENT OF INTEREST
Hi Greg, et al TNX for the input. I've used such a lid before, but there are issues in this case. Because the capacitor shaft(s) are so short, the lid would have to be "inverted" (cup side out) with the inner (slow speed) knob residing inside the outward-turned jar lid - sort of a "knob-in-a-knob"(!). Otherwise, the capacitor body would somehow have to be actually inside the large knob - not a mechanical nicety. Also, my initial reaction to epoxying a brass nut to this plastic is that of raised eyebrows - I've not had good luck with that sort of thing previously - not sure what the story is here - may need another look. Meanwhile, I'm trying to interest the supplier in providing longer shafts. Thanks again, Bob K3NHI
1770	2008-07-02 08:37:18	tg6124	vectron TCXO use
This group seems to have a wide range of knowlegable people so I figured I'd ask here first. I picked up a 5Mhz Vectron TXCO unit off ebay recently. I know the power and ground pins and it works fine. It's about 1hz off frequency according to WWV. The adjustment screw on the unit doesn't seem to vary the oscillator frequency at all. Is this usual? There are two frequency adjust pins on the unit. I've hooked a potentiometer between the pins and when I hook it up the oscillator frequency jumps up about 2hz but changing the resistance doesn't change anything. Do I need to hook a derived voltage across these pins instead of just a resistor? The unit is supposed to be a 12v unit but works just fine off 13.5v. Can I just connect 13.5 volts to the top of the pot to do a fine adjust on the oscillator frequency? tim ab0wr
1771	2008-07-02 08:41:49	Niels A. Moseley	Re: vectron TCXO use
tg6124 wrote: > This group seems to have a wide range of knowlegable people so I figured I'd > ask here first. > > I picked up a 5Mhz Vectron TXCO unit off ebay recently. > > I know the power and ground pins and it works fine. It's about 1hz off > frequency according to WWV. > > The adjustment screw on the unit doesn't seem to vary the oscillator frequency > at all. Is this usual? > > There are two frequency adjust pins on the unit. I've hooked a potentiometer > between the pins and when I hook it up the oscillator frequency jumps up > about 2hz but changing the resistance doesn't change anything. > > Do I need to hook a derived voltage across these pins instead of just a > resistor? The unit is supposed to be a 12v unit but works just fine off > 13.5v. > > Can I just connect 13.5 volts to the top of the pot to do a fine adjust on the > oscillator frequency? > > tim ab0wr What is the full model number of the TCXO? There might be a datasheet available. 73, Niels PE1OIT
1772	2008-07-02 10:42:15	tg6124	Re: vectron TCXO use
It's a Vectron 216-9135-1 Crystal Oscillator I couldn't find a datasheet for it using Google. But I searched using the whole model number. Maybe I should just use the first four digits? tim ab0wr On Wednesday 02 July 2008 10:39:49 am Niels A. Moseley wrote: > tg6124 wrote: > > This group seems to have a wide range of knowlegable people so I figured > > I'd ask here first. > > > > I picked up a 5Mhz Vectron TXCO unit off ebay recently. > > > > I know the power and ground pins and it works fine. It's about 1hz off > > frequency according to WWV. > > > > The adjustment screw on the unit doesn't seem to vary the oscillator > > frequency at all. Is this usual? > > > > There are two frequency adjust pins on the unit. I've hooked a > > potentiometer between the pins and when I hook it up the oscillator > > frequency jumps up about 2hz but changing the resistance doesn't change > > anything. > > > > Do I need to hook a derived voltage across these pins instead of just a > > resistor? The unit is supposed to be a 12v unit but works just fine off > > 13.5v. > > > > Can I just connect 13.5 volts to the top of the pot to do a fine adjust > > on the oscillator frequency? > > > > tim ab0wr > > What is the full model number of the TCXO? There might be a datasheet > available. > > 73, > Niels PE1OIT
1773	2008-07-02 12:09:15	Niels A. Moseley	Re: vectron TCXO use
> On Wednesday 02 July 2008 10:39:49 am Niels A. Moseley wrote: >> tg6124 wrote: >>> This group seems to have a wide range of knowlegable people so I figured >>> I'd ask here first. >>> >>> I picked up a 5Mhz Vectron TXCO unit off ebay recently. >>> >>> I know the power and ground pins and it works fine. It's about 1hz off >>> frequency according to WWV. >>> >>> The adjustment screw on the unit doesn't seem to vary the oscillator >>> frequency at all. Is this usual? >>> >>> There are two frequency adjust pins on the unit. I've hooked a >>> potentiometer between the pins and when I hook it up the oscillator >>> frequency jumps up about 2hz but changing the resistance doesn't change >>> anything. >>> >>> Do I need to hook a derived voltage across these pins instead of just a >>> resistor? The unit is supposed to be a 12v unit but works just fine off >>> 13.5v. >>> >>> Can I just connect 13.5 volts to the top of the pot to do a fine adjust >>> on the oscillator frequency? >>> >>> tim ab0wr >> What is the full model number of the TCXO? There might be a datasheet >> available. >> >> 73, >> Niels PE1OIT > It's a Vectron 216-9135-1 Crystal Oscillator > > I couldn't find a datasheet for it using Google. But I searched using the > whole model number. Maybe I should just use the first four digits? > > tim ab0wr > From this site (and babelfish) http://mpl.jp/ocxo/ocxo.html, I was able to find out that the correct operation of the voltage control is to put a 10K potmeter from pin 5 to GND (pins 2,3,7) and connect the wiper to pin 6. The voltage on pin 5, which is generated by the module, should be 6.3V during normal operation. Thus, the control voltage for frequency is pin 6, which must (apparently) be between 6.3 and 0 volts. Hope this helps, 73, Niels PE1OIT.
1774	2008-07-02 13:12:48	Art	Re: vectron TCXO use
I have located specs and hookup information. That is a nice find, especially if the price is low! Will send file via direct email. Regards, Art At 03:07 PM 7/2/2008, you wrote: > > On Wednesday 02 July 2008 10:39:49 am Niels A. Moseley wrote: > >> tg6124 wrote: > >>> This group seems to have a wide range of knowlegable people so I figured > >>> I'd ask here first. > >>> > >>> I picked up a 5Mhz Vectron TXCO unit off ebay recently. > >>> > >>> I know the power and ground pins and it works fine. It's about 1hz off > >>> frequency according to WWV. > >>> > >>> The adjustment screw on the unit doesn't seem to vary the oscillator > >>> frequency at all. Is this usual? > >>> > >>> There are two frequency adjust pins on the unit. I've hooked a > >>> potentiometer between the pins and when I hook it up the oscillator > >>> frequency jumps up about 2hz but changing the resistance doesn't change > >>> anything. > >>> > >>> Do I need to hook a derived voltage across these pins instead of just a > >>> resistor? The unit is supposed to be a 12v unit but works just fine off > >>> 13.5v. > >>> > >>> Can I just connect 13.5 volts to the top of the pot to do a fine adjust > >>> on the oscillator frequency? > >>> > >>> tim ab0wr > >> What is the full model number of the TCXO? There might be a datasheet > >> available. > >> > >> 73, > >> Niels PE1OIT > > > It's a Vectron 216-9135-1 Crystal Oscillator > > > > I couldn't find a datasheet for it using Google. But I searched using >the > > whole model number. Maybe I should just use the first four digits? > > > > tim ab0wr > > > > From this site (and babelfish) ><http://mpl.jp/ocxo/ocxo.html,>http://mpl.jp/ocxo/ocxo.html, I was >able to find out that the correct >operation of the voltage control is to put a 10K potmeter from pin 5 to >GND (pins 2,3,7) and connect the wiper to pin 6. > >The voltage on pin 5, which is generated by the module, should be 6.3V >during normal operation. Thus, the control voltage for frequency is pin >6, which must (apparently) be between 6.3 and 0 volts. > >Hope this helps, >73, >Niels PE1OIT. > >No virus found in this incoming message. >Checked by AVG. >Version: 8.0.100 / Virus Database: 270.4.3/1529 - Release Date: >7/1/2008 7:23 PM [Non-text portions of this message have been removed]
1775	2008-07-02 14:01:51	tg6124	Re: vectron TCXO use
Thanks for the info. I truly appreciate it. I did measure Pin 5 and it has 6.3 volts standing on it. I tied this to the top of a 10k pot, tied the bottom of the pot to ground, and took the slider of the pot to Pin 6. It works perfectly! I can tune the frequency so I have fewer than three beats per 60seconds so that is actually more accuracy than I should ever need. I appreciate everyone's help. 73, tim ab0wr On Wednesday 02 July 2008 02:07:15 pm Niels A. Moseley wrote: > From this site (and babelfish) > http://mpl.jp/ocxo/ocxo.html, I was able to find out that the correct > operation of the voltage control is to put a 10K potmeter from pin 5 to > GND (pins 2,3,7) and connect the wiper to pin 6. > > The voltage on pin 5, which is generated by the module, should be 6.3V > during normal operation. Thus, the control voltage for frequency is pin > 6, which must (apparently) be between 6.3 and 0 volts. > > Hope this helps, > 73, > Niels PE1OIT.