Looking for recommendations for a Grid Dip Meter built or a kit.

--- news://freenews.netfront.net/ - complaints: ---

On Sun, 29 Nov 2015 15:35:20 -0800, OldGuy
wrote:

Looking for recommendations for a Grid Dip Meter built or a kit.

It's now called a GDO (grid dip oscillator). Here's a page of various
manufacturers and models:
http://www.n4xy.com/gdos.html

I have three Heathkit HD-1250 GDO's. Not the best. You can get what
might be a clone of a Heathkit HD-1250 from MFJ:
http://www.mfjenterprises.com/Product.php?productid=MFJ-201
Also, check out the sold listings on eBay for approximate pricing:
http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=grid%20dip%20meter& LH_Complete=1&LH_Sold=1&rt=nc&_trksid=p2045573.m16 84

Sorry, no recommendations as all my stuff is ancient.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sun, 29 Nov 2015 16:16:27 -0800, Jeff Liebermann wrote:

Sorry, no recommendations as all my stuff is ancient.

So's a lot of my stuff. But there's nothing wrong with old gear IMO it's
the quality of it and whether it's in calibration that counts. The only
issues with GDOs IME are that they're not too bad for the lower frequency
RF stuff, but hopeless for anything higher.

On 30.11.15 0:35, OldGuy wrote:
Looking for recommendations for a Grid Dip Meter built or a kit.

--- news://freenews.netfront.net/ - complaints: ---

In google (images) about 10 solutions.

On Sun, 29 Nov 2015 16:16:27 -0800, Jeff Liebermann
wrote:

This looks very interesting:
http://www.qrpproject.de/UK/dipit.htm
No clue how to purchase one and it's only 1 to 42 MHz.

May 2003 QST article on building a "modern" GDO:
http://www.qsl.net/k8mcr/downloads/Modern_GDO.pdf

Feb 2013 Circuit Cellar article on building a GDO:
http://circuitcellar.com/wp-content/uploads/2013/01/CC25_ProjCard_Pres_Ball-CC271.pdf

Goes to 1GHz by changing both the oscillator and the coil with
frequency range. See "Plug in Oscillators" section:
http://elm-chan.org/works/ddm/report_e.html

July 2014 QST. Using an MFJ-259/269 as a GDO:
http://www.ka6wke.net/finished-projects/grid-dip-meter-coils
MFJ sells these as MFJ-66C:
http://www.mfjenterprises.com/Product.php?productid=MFJ-66C

Mo
http://w5dor.com/W5DOR-GridDip.html

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Mon, 30 Nov 2015, Cursitor Doom wrote:

On Sun, 29 Nov 2015 16:16:27 -0800, Jeff Liebermann wrote:

Sorry, no recommendations as all my stuff is ancient.

So's a lot of my stuff. But there's nothing wrong with old gear IMO it's
the quality of it and whether it's in calibration that counts. The only
issues with GDOs IME are that they're not too bad for the lower frequency
RF stuff, but hopeless for anything higher.


Huh? VHF and UHF is where they really worked well, because at lower
frequencies, a lot of the coils were shielded. There were GDOs that
worked well at VHF and UHF.

Michael

On Sun, 29 Nov 2015, OldGuy wrote:

Looking for recommendations for a Grid Dip Meter built or a kit.

You can build simple or you can build complicated. With semiconductors,
the cost of extra transistors and the space they take up doesn't amount to
much, but you can end up with a better device, and one that can be used
for more things.

The biggest problem seems to be false dips, coming from an rf choke
feeding the oscillator that resonates in the wrong place, or just the
layout of the circuit. I suppose it's made worse if the oscillator
doesn't oscillate very well as you move up in frequency.

Calibration was always kind of vague, but nowadays with so many having
frequency counters, one can build something that has a buffer to feed a
frequency counter, so you can either have vague calibration on the dial,
or none at all.

It's probably also worth adding a buffer and output jack so you can use it
as a rudimentary signal generator.

SOme circuits are better than others. Something that uses a two terminal
coil is simpler (Heathkit used phono plugs in at least one of their GDOs)
but I suppose you get more control with more contacts. If nothing else,
you can pre-adjust the level of the oscillator from band to band. Of
course a circuit that uses only two terminals can then be useful in other
ways, put a crystal where the coil goes and you can test that crystal,
connect a shielded coil where the coil goes and with the variable
capacitor at minimum, you get the general frequency of that shielded coil
if you listen for it in a receiver, or have the frequency counter hooked
up. Since coupling to shielded coils can be a problem, this works out
well.

Like regen receivers, for a long time a GDO was a minimal circuit, yet
nowadays you can complicate it. Why not have a nice 3terminal voltage
regulator? Why not use an exotic oscillator circuit that uses more than
one transistor?

For a long time, most GDOs were about the same, the difference being that
anytime someone wrote about their GDO, they'd built it just like someone
else's, except changed the coils a bit or used a tube socket instead of a
phono jack for the coils, or vice versa. Even the Measurements
Corporation or the Millen GDO were fairly simple circuits, though I gather
Millen put a lot of effort into a nice flat output. It was the move to
solid state that shook things up, technically those were no longer GDOs
but everyone knew what was meant. So Heathkit used a tunnel diode in an
early sixties one, not sure if it gave any advantage. In some circuits
there wasn't anything that really dipped, so they'd measure the signal
strenght of the oscillator and see where it dipped. Bipolar transistors
often didn't work so well, at least not if someone was basically
transcribing a tube GDO to a bipolar oscillator. Later FETs and mosfets
came along, more like tube GDOs. IN the seventies, Heathkit and some
others used mosfets, and more peripheral devices, still fairly simple.
The December 1971 issue of QST (I'm pretty sure it was that issue) had an
article by someone from Millen talking about their effort to come out with
a solid state GDO. I think they set out to use the same variable
capacitor and coil set used by their tube one, but I remember one thing
was they had to use ferrite beads and RF chokes in series to get rid of
false dips.

GDOs can still be found at hamfests on the used market. I think someone
is still making new ones, but I'm not sure who. There was period when
people were taking tube GDOs and solid stating them, the magazines had
articles about that.

Michael

On 11/29/2015 6:03 PM, Michael Black wrote:
On Mon, 30 Nov 2015, Cursitor Doom wrote:

On Sun, 29 Nov 2015 16:16:27 -0800, Jeff Liebermann wrote:

Sorry, no recommendations as all my stuff is ancient.

So's a lot of my stuff. But there's nothing wrong with old gear IMO it's
the quality of it and whether it's in calibration that counts. The only
issues with GDOs IME are that they're not too bad for the lower frequency
RF stuff, but hopeless for anything higher.


Huh? VHF and UHF is where they really worked well, because at lower
frequencies, a lot of the coils were shielded. There were GDOs that
worked well at VHF and UHF.

Michael

Best one I ever used was the tube version of the Millen.
I switched to the solid state version and regretted it.
Much less sensitive and more fiddly than the tube version.
Tunnel dipper was the worst for sensitivity.

If ham swapmeets are any indicator, most GDO's
available second hand
are missing some or all of the coils.

On 11/29/2015 06:35 PM, OldGuy wrote:
Looking for recommendations for a Grid Dip Meter built or a kit.

--- news://freenews.netfront.net/ - complaints: ---

Find an old Measurements (Boonton) 59 'Megacycle Meter' on eBay. I used
to have a Heath 12something that I used for years. On Joerg's
recommendation, I got a Measurements 59, and soon afterwards the Heath
went in the trash.

The 59 has accurate frequency calibration. Mine is still within 2% over
the full range, by actual measurement, and it hasn't been trimmed in a
loooong time. It also gives a nice deep dip even with quite weak
coupling--much weaker than the Heath, especially on low-Q resonances.
I've used it to measure the coupling coefficient of toroidal
transformers, for instance. (An ISDN unit had a CC of 0.99986.)

Besides, it has such a nice retro look and feel.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

"OldGuy" wrote in message
...
Looking for recommendations for a Grid Dip Meter built or a kit.

--- news://freenews.netfront.net/ - complaints: ---

Just downloaded an archive of Radio Constructor from
Americanradiohistory.com - in the course of browsing through them, I found a
valve design that uses untapped coils.

It would probably adapt well to a JFET.

Can't remember which issue, but it was before mid 50s.

"mike" wrote in message
...
On 11/29/2015 6:03 PM, Michael Black wrote:
On Mon, 30 Nov 2015, Cursitor Doom wrote:

On Sun, 29 Nov 2015 16:16:27 -0800, Jeff Liebermann wrote:

Sorry, no recommendations as all my stuff is ancient.

So's a lot of my stuff. But there's nothing wrong with old gear IMO it's
the quality of it and whether it's in calibration that counts. The only
issues with GDOs IME are that they're not too bad for the lower
frequency
RF stuff, but hopeless for anything higher.


Huh? VHF and UHF is where they really worked well, because at lower
frequencies, a lot of the coils were shielded. There were GDOs that
worked well at VHF and UHF.

Michael

Best one I ever used was the tube version of the Millen.
I switched to the solid state version and regretted it.
Much less sensitive and more fiddly than the tube version.
Tunnel dipper was the worst for sensitivity.

A while back I acquired a small Tektronix component envelope containing very
tiny "top hat" style diodes that there's a faint possibility they could be
TDs.

Copying the Heathkit TD dipper had crossed my mind - now I probably won't.

On Mon, 30 Nov 2015, Ian Field wrote:



"mike" wrote in message
...
On 11/29/2015 6:03 PM, Michael Black wrote:
On Mon, 30 Nov 2015, Cursitor Doom wrote:

On Sun, 29 Nov 2015 16:16:27 -0800, Jeff Liebermann wrote:

Sorry, no recommendations as all my stuff is ancient.

So's a lot of my stuff. But there's nothing wrong with old gear IMO it's
the quality of it and whether it's in calibration that counts. The only
issues with GDOs IME are that they're not too bad for the lower frequency
RF stuff, but hopeless for anything higher.


Huh? VHF and UHF is where they really worked well, because at lower
frequencies, a lot of the coils were shielded. There were GDOs that
worked well at VHF and UHF.

Michael

Best one I ever used was the tube version of the Millen.
I switched to the solid state version and regretted it.
Much less sensitive and more fiddly than the tube version.
Tunnel dipper was the worst for sensitivity.

A while back I acquired a small Tektronix component envelope containing very
tiny "top hat" style diodes that there's a faint possibility they could be
TDs.

Copying the Heathkit TD dipper had crossed my mind - now I probably won't.

It seemed like the Tunnel Diode got a lot of press in the sixties in the
hobby magazines, but much of it wsa novelty. I can't remember anything
where some other device couldn't be used. I suppose when the Heathkit GDO
came out, the Tunnel Diode might have had better bandwidth, though I don't
remember that GDO has having great VHF and UHF coverage. But while neat
things were shown, that tunnel diode FM broadcast receiver was more unique
becuase of the low IF and pulse counting detector than that it used a
tunnel diode as a mixer/oscillator down to that low IF.

There were uses for tunnel diodes that hobbyists generally didn't see, and
those at least took advantage of the device at the time, but the time
passed pretty fast before other things didn't do most of what a tunnel
diode could do.

So I think the Heathkit tunnel diode dipper was mostly for novelty sake.

Michael

On Mon, 30 Nov 2015 19:05:02 -0500, Michael Black
wrote:

It seemed like the Tunnel Diode got a lot of press in the sixties in the
hobby magazines, but much of it wsa novelty.

For good reason. Tunnel diodes flew in most of the early satellites
up to about 1990 because it was the only reliable microwave device
available at the time.

I can't remember anything
where some other device couldn't be used. I suppose when the Heathkit GDO
came out, the Tunnel Diode might have had better bandwidth, though I don't
remember that GDO has having great VHF and UHF coverage. But while neat
things were shown, that tunnel diode FM broadcast receiver was more unique
becuase of the low IF and pulse counting detector than that it used a
tunnel diode as a mixer/oscillator down to that low IF.

I believe you're referring to the HW-10 GDO:
http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_H-HM/HM-10a/
http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_H-HM/HM-10a/HM-10A.gif
No pulse counting detector but rather a simple half wave RF rectifier
followed by 3 stages of DC amplification. As I vaguely recall, I had
difficulties getting a clean dip because the tunnel diode was probably
oscillating on multiple frequencies at the same time.

I may have an HW-10 GDO somewhere in my junk pile. I dropped it from
about 60ft up during an antenna raising party. It landed in some
bushes and did not appear to be damaged, but failed to function
afterwards. I also have a few new TEK tunnel diodes.

There were uses for tunnel diodes that hobbyists generally didn't see, and
those at least took advantage of the device at the time, but the time
passed pretty fast before other things didn't do most of what a tunnel
diode could do.

Tektronix also used tunnel diodes in their oscilloscope trigger
circuitry:
http://w140.com/tekwiki/wiki/Tunnel_diodes
I use one testing scope rise time:
https://richardsears.wordpress.com/2013/04/27/tunnel-diode-pulser/
GE Tunnel Diode Manual (1961):
http://w140.com/Ge1961TunnelDiodeManual.pdf
Today, Aeroflex/Cobham/Metelics currently sell tunnel diode detectors
and use them in their instruments:
http://ams.aeroflex.com/metelics/micro-metelics-prods-TD-MTD.cfm
http://ams.aeroflex.com/metelics/micro-metelics-prods-TD-MBD.cfm
Sorry, but tunnel diodes are not quite dead and obsolete.

So I think the Heathkit tunnel diode dipper was mostly for novelty sake.

Nope. During the 1960's, the big draw for Heathkit was that kits were
much cheaper than labor intensive assembled products. Heathkit had to
do something to keep the price down on their products. Cheap was the
order of the day and tunnel diodes were CHEEEEEEP.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 11/30/2015 08:05 PM, Jeff Liebermann wrote:
On Mon, 30 Nov 2015 19:05:02 -0500, Michael Black
wrote:

It seemed like the Tunnel Diode got a lot of press in the sixties
in the hobby magazines, but much of it wsa novelty.

For good reason. Tunnel diodes flew in most of the early satellites
up to about 1990 because it was the only reliable microwave device
available at the time.

I can't remember anything where some other device couldn't be
used. I suppose when the Heathkit GDO came out, the Tunnel Diode
might have had better bandwidth, though I don't remember that GDO
has having great VHF and UHF coverage. But while neat things were
shown, that tunnel diode FM broadcast receiver was more unique
becuase of the low IF and pulse counting detector than that it
used a tunnel diode as a mixer/oscillator down to that low IF.

I believe you're referring to the HW-10 GDO:
http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_H-HM/HM-10a/



http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_H-HM/HM-10a/HM-10A.gif
No pulse counting detector but rather a simple half wave RF rectifier
followed by 3 stages of DC amplification. As I vaguely recall, I had
difficulties getting a clean dip because the tunnel diode was
probably oscillating on multiple frequencies at the same time.

I may have an HW-10 GDO somewhere in my junk pile. I dropped it from
about 60ft up during an antenna raising party. It landed in some
bushes and did not appear to be damaged, but failed to function
afterwards. I also have a few new TEK tunnel diodes.

There were uses for tunnel diodes that hobbyists generally didn't
see, and those at least took advantage of the device at the time,
but the time passed pretty fast before other things didn't do most
of what a tunnel diode could do.

Tektronix also used tunnel diodes in their oscilloscope trigger
circuitry: http://w140.com/tekwiki/wiki/Tunnel_diodes I use one
testing scope rise time:
https://richardsears.wordpress.com/2013/04/27/tunnel-diode-pulser/
GE Tunnel Diode Manual (1961):
http://w140.com/Ge1961TunnelDiodeManual.pdf Today,
Aeroflex/Cobham/Metelics currently sell tunnel diode detectors and
use them in their instruments:
http://ams.aeroflex.com/metelics/micro-metelics-prods-TD-MTD.cfm
http://ams.aeroflex.com/metelics/micro-metelics-prods-TD-MBD.cfm
Sorry, but tunnel diodes are not quite dead and obsolete.

So I think the Heathkit tunnel diode dipper was mostly for novelty
sake.

Nope. During the 1960's, the big draw for Heathkit was that kits
were much cheaper than labor intensive assembled products. Heathkit
had to do something to keep the price down on their products. Cheap
was the order of the day and tunnel diodes were CHEEEEEEP.




I've never used one, but I suspect that part of the reason that tunnel
diode dippers are inferior is that you can't run a high-Z tank without
tapping the TD way way down, so that you need an impractically large
split variable capacitor.

Nuvistors are really good for that, over a pretty wide frequency range.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

"Michael Black" wrote in message
xample.org...
On Mon, 30 Nov 2015, Ian Field wrote:



"mike" wrote in message
...
On 11/29/2015 6:03 PM, Michael Black wrote:
On Mon, 30 Nov 2015, Cursitor Doom wrote:

On Sun, 29 Nov 2015 16:16:27 -0800, Jeff Liebermann wrote:

Sorry, no recommendations as all my stuff is ancient.

So's a lot of my stuff. But there's nothing wrong with old gear IMO
it's
the quality of it and whether it's in calibration that counts. The
only
issues with GDOs IME are that they're not too bad for the lower
frequency
RF stuff, but hopeless for anything higher.


Huh? VHF and UHF is where they really worked well, because at lower
frequencies, a lot of the coils were shielded. There were GDOs that
worked well at VHF and UHF.

Michael

Best one I ever used was the tube version of the Millen.
I switched to the solid state version and regretted it.
Much less sensitive and more fiddly than the tube version.
Tunnel dipper was the worst for sensitivity.

A while back I acquired a small Tektronix component envelope containing
very tiny "top hat" style diodes that there's a faint possibility they
could be TDs.

Copying the Heathkit TD dipper had crossed my mind - now I probably
won't.
It seemed like the Tunnel Diode got a lot of press in the sixties in the
hobby magazines, but much of it wsa novelty. I can't remember anything
where some other device couldn't be used.

Back then there was a fanatical craze for FM bug transmitters - with a
tunnel diode, the circuitry was always smaller than the battery.

"Phil Hobbs" wrote in message
...
On 11/30/2015 08:05 PM, Jeff Liebermann wrote:
On Mon, 30 Nov 2015 19:05:02 -0500, Michael Black
wrote:

It seemed like the Tunnel Diode got a lot of press in the sixties
in the hobby magazines, but much of it wsa novelty.

For good reason. Tunnel diodes flew in most of the early satellites
up to about 1990 because it was the only reliable microwave device
available at the time.

I can't remember anything where some other device couldn't be
used. I suppose when the Heathkit GDO came out, the Tunnel Diode
might have had better bandwidth, though I don't remember that GDO
has having great VHF and UHF coverage. But while neat things were
shown, that tunnel diode FM broadcast receiver was more unique
becuase of the low IF and pulse counting detector than that it
used a tunnel diode as a mixer/oscillator down to that low IF.

I believe you're referring to the HW-10 GDO:
http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_H-HM/HM-10a/



http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_H-HM/HM-10a/HM-10A.gif
No pulse counting detector but rather a simple half wave RF rectifier
followed by 3 stages of DC amplification. As I vaguely recall, I had
difficulties getting a clean dip because the tunnel diode was
probably oscillating on multiple frequencies at the same time.

I may have an HW-10 GDO somewhere in my junk pile. I dropped it from
about 60ft up during an antenna raising party. It landed in some
bushes and did not appear to be damaged, but failed to function
afterwards. I also have a few new TEK tunnel diodes.

There were uses for tunnel diodes that hobbyists generally didn't
see, and those at least took advantage of the device at the time,
but the time passed pretty fast before other things didn't do most
of what a tunnel diode could do.

Tektronix also used tunnel diodes in their oscilloscope trigger
circuitry: http://w140.com/tekwiki/wiki/Tunnel_diodes I use one
testing scope rise time:
https://richardsears.wordpress.com/2013/04/27/tunnel-diode-pulser/
GE Tunnel Diode Manual (1961):
http://w140.com/Ge1961TunnelDiodeManual.pdf Today,
Aeroflex/Cobham/Metelics currently sell tunnel diode detectors and
use them in their instruments:
http://ams.aeroflex.com/metelics/micro-metelics-prods-TD-MTD.cfm
http://ams.aeroflex.com/metelics/micro-metelics-prods-TD-MBD.cfm
Sorry, but tunnel diodes are not quite dead and obsolete.

So I think the Heathkit tunnel diode dipper was mostly for novelty
sake.

Nope. During the 1960's, the big draw for Heathkit was that kits
were much cheaper than labor intensive assembled products. Heathkit
had to do something to keep the price down on their products. Cheap
was the order of the day and tunnel diodes were CHEEEEEEP.




I've never used one, but I suspect that part of the reason that tunnel
diode dippers are inferior is that you can't run a high-Z tank without
tapping the TD way way down, so that you need an impractically large split
variable capacitor.

Nuvistors are really good for that, over a pretty wide frequency range.

There's a low voltage 8056 Nuvistor in my bits box waiting for a *VERY*
elusive round-tuit.

On Tue, 1 Dec 2015, Ian Field wrote:



"Phil Hobbs" wrote in message
...
On 11/30/2015 08:05 PM, Jeff Liebermann wrote:
On Mon, 30 Nov 2015 19:05:02 -0500, Michael Black
wrote:

It seemed like the Tunnel Diode got a lot of press in the sixties
in the hobby magazines, but much of it wsa novelty.

For good reason. Tunnel diodes flew in most of the early satellites
up to about 1990 because it was the only reliable microwave device
available at the time.

I can't remember anything where some other device couldn't be
used. I suppose when the Heathkit GDO came out, the Tunnel Diode
might have had better bandwidth, though I don't remember that GDO
has having great VHF and UHF coverage. But while neat things were
shown, that tunnel diode FM broadcast receiver was more unique
becuase of the low IF and pulse counting detector than that it
used a tunnel diode as a mixer/oscillator down to that low IF.

I believe you're referring to the HW-10 GDO:
http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_H-HM/HM-10a/



http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_H-HM/HM-10a/HM-10A.gif
No pulse counting detector but rather a simple half wave RF rectifier
followed by 3 stages of DC amplification. As I vaguely recall, I had
difficulties getting a clean dip because the tunnel diode was
probably oscillating on multiple frequencies at the same time.

I may have an HW-10 GDO somewhere in my junk pile. I dropped it from
about 60ft up during an antenna raising party. It landed in some
bushes and did not appear to be damaged, but failed to function
afterwards. I also have a few new TEK tunnel diodes.

There were uses for tunnel diodes that hobbyists generally didn't
see, and those at least took advantage of the device at the time,
but the time passed pretty fast before other things didn't do most
of what a tunnel diode could do.

Tektronix also used tunnel diodes in their oscilloscope trigger
circuitry: http://w140.com/tekwiki/wiki/Tunnel_diodes I use one
testing scope rise time:
https://richardsears.wordpress.com/2013/04/27/tunnel-diode-pulser/
GE Tunnel Diode Manual (1961):
http://w140.com/Ge1961TunnelDiodeManual.pdf Today,
Aeroflex/Cobham/Metelics currently sell tunnel diode detectors and
use them in their instruments:
http://ams.aeroflex.com/metelics/micro-metelics-prods-TD-MTD.cfm
http://ams.aeroflex.com/metelics/micro-metelics-prods-TD-MBD.cfm
Sorry, but tunnel diodes are not quite dead and obsolete.

So I think the Heathkit tunnel diode dipper was mostly for novelty
sake.

Nope. During the 1960's, the big draw for Heathkit was that kits
were much cheaper than labor intensive assembled products. Heathkit
had to do something to keep the price down on their products. Cheap
was the order of the day and tunnel diodes were CHEEEEEEP.




I've never used one, but I suspect that part of the reason that tunnel
diode dippers are inferior is that you can't run a high-Z tank without
tapping the TD way way down, so that you need an impractically large split
variable capacitor.

Nuvistors are really good for that, over a pretty wide frequency range.

There's a low voltage 8056 Nuvistor in my bits box waiting for a *VERY*
elusive round-tuit.

I'd forgotten about those. The only time I remember seeing them mentioned
(and this was after the fact) was one or two converters that used them, no
need to have a high voltage power supply.

Nuvistors came in just on the cusp of transistors taking off. So other
than tv set front ends, they didn't see a lot of use, people going after
transistors instead.

I remember one review for a nuvistor converter (I think it was for
144MHz), where someone compared it to their existing converter and said
"the noise figure is better, which probably means my old converter needs
returning). The Nuvistor did give good noise figure without the fussing
needed with previous devices. Or the cost, the previous converter in the
article was either a 416 or 417.

Michael

In article ,
Ian Field wrote:

Best one I ever used was the tube version of the Millen.
I switched to the solid state version and regretted it.
Much less sensitive and more fiddly than the tube version.
Tunnel dipper was the worst for sensitivity.

A while back I acquired a small Tektronix component envelope containing very
tiny "top hat" style diodes that there's a faint possibility they could be
TDs.

Copying the Heathkit TD dipper had crossed my mind - now I probably
won't.

By all accounts I've ever read, the Heathkit TD dipper isn't a good
performer. I've played around with one briefly and it had a very
difficult time sensing a resonance even with a large high-Q air-core
inductor and an air-variable cap.

It was actually worse than the "grid dip meter" accessory for an
MFJ-259/269 antenna analyzer, and that's saying something... something
profoundly bad :-(

I compared the MFJ to a more recent Heathkit solid-state dipper (an
HD-1250 if I recall correctly), to a B&W, and to a Measurements 59.
Sensitivity was in that order... the Heathkit was better than the MFJ,
the B&W next, and the Measurement 59 was the stand-out winner. I've
never had a chance to test a Millen; from what I've heard they'd
probably come in between the B&W and the 59.

There are a couple of projects out on the net which show how to make a
GD meter using a (composite) lambda diode. These are
negative-resistance devices which behave a bit like a tunnel
diode. These can be made from two JFETs (one N-channel, one P-channel)
or an N-JFET and a bipolar transistor.

http://users.tpg.com.au/ldbutler/NegResDipMeter.htm

Lambda diodes typically require more voltage and use more power than a
tunnel diode - the negative-resistance part of their curve covers
several volts. Strong oscillators... the dip-meter design requires a
band-specific resistor to tame the strength of the oscillator so that
the dip can be seen.

"Michael Black" wrote in message
xample.org...
On Tue, 1 Dec 2015, Ian Field wrote:



"Phil Hobbs" wrote in message
...
On 11/30/2015 08:05 PM, Jeff Liebermann wrote:
On Mon, 30 Nov 2015 19:05:02 -0500, Michael Black
wrote:

It seemed like the Tunnel Diode got a lot of press in the sixties
in the hobby magazines, but much of it wsa novelty.

For good reason. Tunnel diodes flew in most of the early satellites
up to about 1990 because it was the only reliable microwave device
available at the time.

I can't remember anything where some other device couldn't be
used. I suppose when the Heathkit GDO came out, the Tunnel Diode
might have had better bandwidth, though I don't remember that GDO
has having great VHF and UHF coverage. But while neat things were
shown, that tunnel diode FM broadcast receiver was more unique
becuase of the low IF and pulse counting detector than that it
used a tunnel diode as a mixer/oscillator down to that low IF.

I believe you're referring to the HW-10 GDO:
http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_H-HM/HM-10a/



http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_H-HM/HM-10a/HM-10A.gif
No pulse counting detector but rather a simple half wave RF rectifier
followed by 3 stages of DC amplification. As I vaguely recall, I had
difficulties getting a clean dip because the tunnel diode was
probably oscillating on multiple frequencies at the same time.

I may have an HW-10 GDO somewhere in my junk pile. I dropped it from
about 60ft up during an antenna raising party. It landed in some
bushes and did not appear to be damaged, but failed to function
afterwards. I also have a few new TEK tunnel diodes.

There were uses for tunnel diodes that hobbyists generally didn't
see, and those at least took advantage of the device at the time,
but the time passed pretty fast before other things didn't do most
of what a tunnel diode could do.

Tektronix also used tunnel diodes in their oscilloscope trigger
circuitry: http://w140.com/tekwiki/wiki/Tunnel_diodes I use one
testing scope rise time:
https://richardsears.wordpress.com/2013/04/27/tunnel-diode-pulser/
GE Tunnel Diode Manual (1961):
http://w140.com/Ge1961TunnelDiodeManual.pdf Today,
Aeroflex/Cobham/Metelics currently sell tunnel diode detectors and
use them in their instruments:
http://ams.aeroflex.com/metelics/micro-metelics-prods-TD-MTD.cfm
http://ams.aeroflex.com/metelics/micro-metelics-prods-TD-MBD.cfm
Sorry, but tunnel diodes are not quite dead and obsolete.

So I think the Heathkit tunnel diode dipper was mostly for novelty
sake.

Nope. During the 1960's, the big draw for Heathkit was that kits
were much cheaper than labor intensive assembled products. Heathkit
had to do something to keep the price down on their products. Cheap
was the order of the day and tunnel diodes were CHEEEEEEP.




I've never used one, but I suspect that part of the reason that tunnel
diode dippers are inferior is that you can't run a high-Z tank without
tapping the TD way way down, so that you need an impractically large
split variable capacitor.

Nuvistors are really good for that, over a pretty wide frequency range.

There's a low voltage 8056 Nuvistor in my bits box waiting for a *VERY*
elusive round-tuit.
I'd forgotten about those. The only time I remember seeing them mentioned
(and this was after the fact) was one or two converters that used them, no
need to have a high voltage power supply.

Nuvistors came in just on the cusp of transistors taking off. So other
than tv set front ends, they didn't see a lot of use, people going after
transistors instead.

Mine came from an old Sealy TV that someone left in the bin room at the
flats.

It didn't suit the UK standard so I just pulled the back off to look for
interesting bits.

Apparently there was a time that most remote garage door openers had a
Nuvistor of some description.

On 12/01/2015 01:41 PM, Ian Field wrote:


"Michael Black" wrote in message
xample.org...
On Mon, 30 Nov 2015, Ian Field wrote:



"mike" wrote in message
...
On 11/29/2015 6:03 PM, Michael Black wrote:
On Mon, 30 Nov 2015, Cursitor Doom wrote:

On Sun, 29 Nov 2015 16:16:27 -0800, Jeff Liebermann wrote:

Sorry, no recommendations as all my stuff is ancient.

So's a lot of my stuff. But there's nothing wrong with old gear
IMO it's
the quality of it and whether it's in calibration that counts. The
only
issues with GDOs IME are that they're not too bad for the lower
frequency
RF stuff, but hopeless for anything higher.


Huh? VHF and UHF is where they really worked well, because at lower
frequencies, a lot of the coils were shielded. There were GDOs that
worked well at VHF and UHF.

Michael

Best one I ever used was the tube version of the Millen.
I switched to the solid state version and regretted it.
Much less sensitive and more fiddly than the tube version.
Tunnel dipper was the worst for sensitivity.

A while back I acquired a small Tektronix component envelope
containing very tiny "top hat" style diodes that there's a faint
possibility they could be TDs.

Copying the Heathkit TD dipper had crossed my mind - now I probably
won't.
It seemed like the Tunnel Diode got a lot of press in the sixties in
the hobby magazines, but much of it wsa novelty. I can't remember
anything where some other device couldn't be used.

Back then there was a fanatical craze for FM bug transmitters - with a
tunnel diode, the circuitry was always smaller than the battery.

The problem was that TDs had such a lot of capacitance that it was only
the ones with the huge peak currents (200 mA!) that were really fast.
I have a bunch of 2 mA TDs with 200 pF of capacitance. Fast? Not so much.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

On Tue, 1 Dec 2015, Ian Field wrote:



"Michael Black" wrote in message
xample.org...
On Tue, 1 Dec 2015, Ian Field wrote:



"Phil Hobbs" wrote in message
...
On 11/30/2015 08:05 PM, Jeff Liebermann wrote:
On Mon, 30 Nov 2015 19:05:02 -0500, Michael Black
wrote:

It seemed like the Tunnel Diode got a lot of press in the sixties
in the hobby magazines, but much of it wsa novelty.

For good reason. Tunnel diodes flew in most of the early satellites
up to about 1990 because it was the only reliable microwave device
available at the time.

I can't remember anything where some other device couldn't be
used. I suppose when the Heathkit GDO came out, the Tunnel Diode
might have had better bandwidth, though I don't remember that GDO
has having great VHF and UHF coverage. But while neat things were
shown, that tunnel diode FM broadcast receiver was more unique
becuase of the low IF and pulse counting detector than that it
used a tunnel diode as a mixer/oscillator down to that low IF.

I believe you're referring to the HW-10 GDO:
http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_H-HM/HM-10a/



http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_H-HM/HM-10a/HM-10A.gif
No pulse counting detector but rather a simple half wave RF rectifier
followed by 3 stages of DC amplification. As I vaguely recall, I had
difficulties getting a clean dip because the tunnel diode was
probably oscillating on multiple frequencies at the same time.

I may have an HW-10 GDO somewhere in my junk pile. I dropped it from
about 60ft up during an antenna raising party. It landed in some
bushes and did not appear to be damaged, but failed to function
afterwards. I also have a few new TEK tunnel diodes.

There were uses for tunnel diodes that hobbyists generally didn't
see, and those at least took advantage of the device at the time,
but the time passed pretty fast before other things didn't do most
of what a tunnel diode could do.

Tektronix also used tunnel diodes in their oscilloscope trigger
circuitry: http://w140.com/tekwiki/wiki/Tunnel_diodes I use one
testing scope rise time:
https://richardsears.wordpress.com/2013/04/27/tunnel-diode-pulser/
GE Tunnel Diode Manual (1961):
http://w140.com/Ge1961TunnelDiodeManual.pdf Today,
Aeroflex/Cobham/Metelics currently sell tunnel diode detectors and
use them in their instruments:
http://ams.aeroflex.com/metelics/micro-metelics-prods-TD-MTD.cfm
http://ams.aeroflex.com/metelics/micro-metelics-prods-TD-MBD.cfm
Sorry, but tunnel diodes are not quite dead and obsolete.

So I think the Heathkit tunnel diode dipper was mostly for novelty
sake.

Nope. During the 1960's, the big draw for Heathkit was that kits
were much cheaper than labor intensive assembled products. Heathkit
had to do something to keep the price down on their products. Cheap
was the order of the day and tunnel diodes were CHEEEEEEP.




I've never used one, but I suspect that part of the reason that tunnel
diode dippers are inferior is that you can't run a high-Z tank without
tapping the TD way way down, so that you need an impractically large
split variable capacitor.

Nuvistors are really good for that, over a pretty wide frequency range.

There's a low voltage 8056 Nuvistor in my bits box waiting for a *VERY*
elusive round-tuit.
I'd forgotten about those. The only time I remember seeing them mentioned
(and this was after the fact) was one or two converters that used them, no
need to have a high voltage power supply.

Nuvistors came in just on the cusp of transistors taking off. So other
than tv set front ends, they didn't see a lot of use, people going after
transistors instead.

Mine came from an old Sealy TV that someone left in the bin room at the
flats.

It didn't suit the UK standard so I just pulled the back off to look for
interesting bits.

Apparently there was a time that most remote garage door openers had a
Nuvistor of some description.

I've never heard of that, but it's possible. There were those subminiature
tubes (the leads were generally laid out in parallel with each other, and
the leads were relatively low gauge wire) seen in hearing aids and some
portable radios. I think those came early enough that they had a longer
span, but they too were whiped out by transistors.

Michael

On Tuesday, December 1, 2015 at 5:23:03 PM UTC-8, Michael Black wrote:
On Tue, 1 Dec 2015, Ian Field wrote:


Apparently there was a time that most remote garage door openers had a
Nuvistor of some description.

I've never heard of that, but it's possible. There were those subminiature
tubes (the leads were generally laid out in parallel with each other, and
the leads were relatively low gauge wire) seen in hearing aids and some
portable radios.

I've heard those called 'pencil tubes'; the ones in hybrid walkie-talkies
(for the transmitter) didn't get replaced with semiconductors until mid-to-late
seventies.
Nuvistors were ceramic-metal base, metal envelope tubes, very rugged,
and much less microphonic than other vacuum tubes. There was a long
period when they were the best fast-slewing amplifiers around, and for
HV handling (like electrostatic deflection in CRTs) very hard to replace
with silicon.

On Wed, 2 Dec 2015, whit3rd wrote:

On Tuesday, December 1, 2015 at 5:23:03 PM UTC-8, Michael Black wrote:
On Tue, 1 Dec 2015, Ian Field wrote:


Apparently there was a time that most remote garage door openers had a
Nuvistor of some description.

I've never heard of that, but it's possible. There were those subminiature
tubes (the leads were generally laid out in parallel with each other, and
the leads were relatively low gauge wire) seen in hearing aids and some
portable radios.

I've heard those called 'pencil tubes'; the ones in hybrid walkie-talkies
(for the transmitter) didn't get replaced with semiconductors until mid-to-late
seventies.
I dont' think anything much new got released after a certain point. But
those tubes did offer the chance to make equipment smaller, and certainly
in the early days of transistors, the tubes had better high frequency
response. I had one of those hybrid lunch box walkie talkies, never used
it, and if I recall properly the transmitter was all tube, the receiver
had a diode mixer (no rf stage ahead of it) and a tube oscillator and
multiplier chain, with the transistors in the IF strip and audio.

But by the end of the sixties, you could get Motorola handie talkies like
the HT-200, which were all solid state. Hearing aids must have made the
transition to transistors by then, and you could get portable radios that
used transistors.


Nuvistors were ceramic-metal base, metal envelope tubes, very rugged,
and much less microphonic than other vacuum tubes. There was a long
period when they were the best fast-slewing amplifiers around, and for
HV handling (like electrostatic deflection in CRTs) very hard to replace
with silicon.

But at the time, top end test equipment wasn't as well known to the
hobbyist. It was only later that I learned the Tek 454? (the mostly solid
state one, not the one from 1959 with the plugins) used nuvistors.

Michael

"Michael Black" wrote in message
news:alpine.LNX.2.02.1512021325170.11559@darkstar. example.org...
On Wed, 2 Dec 2015, whit3rd wrote:

On Tuesday, December 1, 2015 at 5:23:03 PM UTC-8, Michael Black wrote:
On Tue, 1 Dec 2015, Ian Field wrote:


Apparently there was a time that most remote garage door openers had a
Nuvistor of some description.

I've never heard of that, but it's possible. There were those
subminiature
tubes (the leads were generally laid out in parallel with each other,
and
the leads were relatively low gauge wire) seen in hearing aids and some
portable radios.

I've heard those called 'pencil tubes'; the ones in hybrid walkie-talkies
(for the transmitter) didn't get replaced with semiconductors until
mid-to-late
seventies.
I dont' think anything much new got released after a certain point. But
those tubes did offer the chance to make equipment smaller, and certainly
in the early days of transistors, the tubes had better high frequency
response.

They didn't have any transistors in WW2 - but they needed a crude doppler
radar for proximity shells that could be fired out of an anti-aircraft gun.

AFAIK: they used what were basically ruggedised hearing aid valves potted in
wax to stop them bouncing about.

In article ple.org,
says...
Nuvistors came in just on the cusp of transistors taking off. So other
than tv set front ends, they didn't see a lot of use, people going after
transistors instead.

Mine came from an old Sealy TV that someone left in the bin room at the
flats.

It didn't suit the UK standard so I just pulled the back off to look for
interesting bits.

Apparently there was a time that most remote garage door openers had a
Nuvistor of some description.

I've never heard of that, but it's possible. There were those subminiature
tubes (the leads were generally laid out in parallel with each other, and
the leads were relatively low gauge wire) seen in hearing aids and some
portable radios. I think those came early enough that they had a longer
span, but they too were whiped out by transistors.

Michael




Yup, I have a drawer full of unused/new

Jamie