On 5/6/19 12:31 PM, Phil Hobbs wrote:> Measurements 59 Megacycle MeterThey should have called it the Magnificent Measurements 59 Megacycle Measuring Meter
Tuned Circuit Selectivity
Started by ●May 5, 2019
Reply by ●May 6, 20192019-05-06
Reply by ●May 6, 20192019-05-06
On 5/6/19 3:37 PM, bitrex wrote:> On 5/6/19 12:31 PM, Phil Hobbs wrote: >> Measurements 59 Megacycle Meter > > They should have called it the Magnificent Measurements 59 Megacycle > Measuring MeterYou might suggest that to their marketing department. ;) It would be less hyperbolic than some names I've seen. They later changed their name from Measurements Corp. to Boonton Radio Corp. and then got bought by HP. They made a lot of good stuff--Q meters, dip meters, true-RMS AC voltmeters, and so on. I especially like their three-terminal capacitance meters, the Boonton 72 series. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●May 6, 20192019-05-06
On Mon, 06 May 2019 12:31:55 -0400, Phil Hobbs wrote:> There are good ones and bad ones. The Heathkits are junk. The > Measurements 59 Megacycle Meter is a thing of great beauty--I have three > of them (two HF/VHF and one UHF). They give a good-sized dip with very > weak coupling, so that the measurements are pretty accurate.I think I still have an old Heathkit frequency meter somewhere. IIRC it looked rather well-made. Performance wise I've no idea; it may have sucked donkey arse for all I know.> I measured the dial calibration accuracy of one of them, and it's still > within 2% througout all ranges.I have got so many old wavemeters still lying around collecting dust. I really must do something with them at some stage. Maybe there's some old- timer on the other side of the planet who is constantly scanning Ebay looking for one and I might be able to help him out. :-/ -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition.
Reply by ●May 7, 20192019-05-07
On 5/6/19 5:52 PM, Phil Hobbs wrote:> On 5/6/19 3:37 PM, bitrex wrote: >> On 5/6/19 12:31 PM, Phil Hobbs wrote: >>> Measurements 59 Megacycle Meter >> >> They should have called it the Magnificent Measurements 59 Megacycle >> Measuring Meter > > You might suggest that to their marketing department. ;) It would be > less hyperbolic than some names I've seen. > > They later changed their name from Measurements Corp. to Boonton Radio > Corp. and then got bought by HP. They made a lot of good stuff--Q > meters, dip meters, true-RMS AC voltmeters, and so on. I especially > like their three-terminal capacitance meters, the Boonton 72 series. > > Cheers > > Phil Hobbs >I got my eye on a HP 4192A impedance analyzer as my next major lab purchase, they seem to go for between 1k-2.5k now depending on condition and calibration situation. I need some boat anchor in my life
Reply by ●May 7, 20192019-05-07
On Monday, May 6, 2019 at 6:18:16 AM UTC-7, Cursitor Doom wrote:> On Mon, 06 May 2019 07:28:29 +0000, Jan Panteltje wrote: > > > A grid dip meter was a useful instrument long ago: > > https://en.wikipedia.org/wiki/Grid_dip_oscillator > > Build one once. > > I still have a selection of them and I built one once. NEVER had any luck > with *any* of the damn things for some reason! I suspect they're only > useful if you are testing really physically large combinations of C and L.They're great for LW and medium-wave stuff if you have a hand truck to cart them around. For microwave work, well, don't. IME the problems most people have with them is down to poor construction practice, specifically not paying attention to HF wiring discipline. Too many pF to the wrong thing and whoosh, your readings are all over the place. Try taking readings holding one in different places. Seriously- if it couples to your hand differently one way it will show up instantly. Unshielded cases often look just like shielded ones... I built one decades ago (with replaceable coils, ooh) from ARRL plans which assumed you knew about good wiring practices. I didn't, and eventually tore it apart and rebuilt it with every new lesson I learned. Wish I still had it. Mark L. Fergerson
Reply by ●May 7, 20192019-05-07
On Mon, 6 May 2019 17:52:11 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:>On 5/6/19 3:37 PM, bitrex wrote: >> On 5/6/19 12:31 PM, Phil Hobbs wrote: >>> Measurements 59 Megacycle Meter >> >> They should have called it the Magnificent Measurements 59 Megacycle >> Measuring Meter > >You might suggest that to their marketing department. ;) It would be >less hyperbolic than some names I've seen. > >They later changed their name from Measurements Corp. to Boonton Radio >Corp. and then got bought by HP. They made a lot of good stuff--Q >meters, dip meters, true-RMS AC voltmeters, and so on. I especially >like their three-terminal capacitance meters, the Boonton 72 series. > >Cheers > >Phil HobbsI have several 72's and I love them. They are ancient and none has ever broken. https://www.dropbox.com/s/7k57wicymctj3s0/boonton-72.jpg?dl=0 1 pF full scale! With a bias input for making C-V curves. Well, one did fail when an intern connected a couple KV to the bias terminals. Ex-intern. -- John Larkin Highland Technology, Inc lunatic fringe electronics
Reply by ●May 7, 20192019-05-07
On Sun, 5 May 2019 22:13:25 -0000 (UTC), Cursitor Doom <curd@notformail.com> wrote:>Gentlemen, > > >I'm just trying a number of combinations of L and C to find the right >values for resonance at around 1.35Mhz. The problem I'm having is that >the resonance point is far from clear. It's as if the Q of the components >is very low (even though they actually aren't). I'm trying to think of a >way to make it more 'peaky' on the oscilloscope display to take the guess >work out of finding that sweet spot. >ATM the two components are in parallel, but I'm thinking maybe I'd have >more luck if I wired them in series and increased the Zo of the signal >generator by placing a highish value resistor into the genny's central >output pin and feeding the tank via that. >Would that work or has anyne got any better ideas? > >CDHere's my Q meter. The voltmeter is a 0.2 pF SD14 sampling probe. It uses series voltage boosting, from a very low impedance source. Q calculated from -3 dB frequencies. https://www.dropbox.com/s/ycd8ya9kwit8o0y/Q-meter.jpg?dl=0 https://www.dropbox.com/s/b4xwf1g2ldk0bfl/Q.JPG?dl=0 -- John Larkin Highland Technology, Inc lunatic fringe electronics
Reply by ●May 7, 20192019-05-07
On Tue, 07 May 2019 07:05:38 -0700, John Larkin wrote:> > 1 pF full scale! With a bias input for making C-V curves.That *is* impressive. I've got one of these instead: https://tinyurl.com/y68p9g3e It's very precise, but the lowest C FSD range is 100pF. I *was* perfectly happy with it - until you posted yours. :(> Well, one did fail when an intern connected a couple KV to the bias > terminals. Ex-intern.Like I've said before, you're far too charitable iro the people you hire. -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition.
Reply by ●May 7, 20192019-05-07
On 5/7/19 10:05 AM, John Larkin wrote:> On Mon, 6 May 2019 17:52:11 -0400, Phil Hobbs > <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> On 5/6/19 3:37 PM, bitrex wrote: >>> On 5/6/19 12:31 PM, Phil Hobbs wrote: >>>> Measurements 59 Megacycle Meter >>> >>> They should have called it the Magnificent Measurements 59 Megacycle >>> Measuring Meter >> >> You might suggest that to their marketing department. ;) It would be >> less hyperbolic than some names I've seen. >> >> They later changed their name from Measurements Corp. to Boonton Radio >> Corp. and then got bought by HP. They made a lot of good stuff--Q >> meters, dip meters, true-RMS AC voltmeters, and so on. I especially >> like their three-terminal capacitance meters, the Boonton 72 series. >> >> Cheers >> >> Phil Hobbs > > I have several 72's and I love them. They are ancient and none has > ever broken. > > https://www.dropbox.com/s/7k57wicymctj3s0/boonton-72.jpg?dl=0 > > 1 pF full scale! With a bias input for making C-V curves. > > Well, one did fail when an intern connected a couple KV to the bias > terminals. Ex-intern. > >I have a rebuilt Heathkit IT-11, the magic eye doesn't give particularly accurate results but it's for testing/re-forming high voltage caps that a DMM won't test properly. <http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_IT-NE/IT-11/IT-11.pdf>
Reply by ●May 7, 20192019-05-07
On Mon, 06 May 2019 23:41:42 -0700, nuny@bid.nes wrote:> I built one decades ago (with replaceable coils, ooh) from ARRL plans > which assumed you knew about good wiring practices. I didn't, and > eventually tore it apart and rebuilt it with every new lesson I > learned. Wish I still had it.Been there, done that! I've just had a rummage through my many rooms of old test gear and discovered I have a Boonton GDM I'd forgotten all about! This is actually a valve one, by the look of it, with about a dozen plug-in coils. THIS is one I've never tried. Maybe it could rescue my perception of GDMs! (if it doesn't, it and all the others will be heading for the reclycling facility.) -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition.
