|
Radial Query
Fred, In addition to using gloves, you should buy the stuff without barbs. ;-) Last year I hand pulled 12.5 gauge barbed wire off of 1/4 mile 85 pound spools to replace some 100 year old barbed wire f
Fred, In addition to using gloves, you should buy the stuff without barbs. ;-) Last year I hand pulled 12.5 gauge barbed wire off of 1/4 mile 85 pound spools to replace some 100 year old barbed wire f
|
By
Jerry Gaffke
· #63608
·
|
|
Sideband cancellation -- unwanted sideband not 180 degrees
Ryan, Here's a another cheap capacitance meter design, to be added to Arv's list. Especially cheap if you happen to have a $2 Arduino Nano collecting dust. You can display the result on your host comp
Ryan, Here's a another cheap capacitance meter design, to be added to Arv's list. Especially cheap if you happen to have a $2 Arduino Nano collecting dust. You can display the result on your host comp
|
By
Jerry Gaffke
· #59738
·
|
|
#gps
#gps
Shane Justice wrote: "there was a period of time where cell boosters were marketed as boosting cell phone performance in rural areas. I've never known anyone to try them." A quick look on the web tell
Shane Justice wrote: "there was a period of time where cell boosters were marketed as boosting cell phone performance in rural areas. I've never known anyone to try them." A quick look on the web tell
|
By
Jerry Gaffke
· #53915
·
|
|
40 meter QCX+ and fifteen feet of wire
Shane, So which dit are we speaking of? Originally WN7WDK around 1972, became WA7WDK when I passed General and Advanced in one go a year or so later. Never really liked that call, too many W's, and th
Shane, So which dit are we speaking of? Originally WN7WDK around 1972, became WA7WDK when I passed General and Advanced in one go a year or so later. Never really liked that call, too many W's, and th
|
By
Jerry Gaffke
· #53805
·
|
|
QCX-mini update: solving the microphonics problem
Those photos of polite white gloved Japanese pushers make good click bait. I click them. Such pushers apparently exist in a number of countries. Japan gets the most press, with Shinjuku Eki front and
Those photos of polite white gloved Japanese pushers make good click bait. I click them. Such pushers apparently exist in a number of countries. Japan gets the most press, with Shinjuku Eki front and
|
By
Jerry Gaffke
· #53582
·
|
|
QCX-mini update: solving the microphonics problem
Hans, Your Japanese co-workers were probably just trying to avoid that weird gaijin. They know all about tightly packed methods of transport. For those that don't, do a google image search for "Tokyo
Hans, Your Japanese co-workers were probably just trying to avoid that weird gaijin. They know all about tightly packed methods of transport. For those that don't, do a google image search for "Tokyo
|
By
Jerry Gaffke
· #53553
·
|
|
QCX wspr mode question.
#40m
George, That first resistor in the pi network directly across the transmitter output is dissipating most of the power, a little bit more than 3 Watts in this case.. Given the long transmission times o
George, That first resistor in the pi network directly across the transmitter output is dissipating most of the power, a little bit more than 3 Watts in this case.. Given the long transmission times o
|
By
Jerry Gaffke
· #42953
·
|
|
QCX wspr mode question.
#40m
George, You are probably best off getting those 3W resistors and building an attenuator. That way there are no mods to the rig, and it is pretty much guaranteed to work. But, if somebody wants to try
George, You are probably best off getting those 3W resistors and building an attenuator. That way there are no mods to the rig, and it is pretty much guaranteed to work. But, if somebody wants to try
|
By
Jerry Gaffke
· #42947
·
|
|
QCX wspr mode question.
#40m
Three resistors set up as an attenuator between the QCX and the antenna would work. A 10dB attenuator would bring your 5W down to 0.5W. Another 3dB of attenuation would cut that in half to 0.25W. So y
Three resistors set up as an attenuator between the QCX and the antenna would work. A 10dB attenuator would bring your 5W down to 0.5W. Another 3dB of attenuation would cut that in half to 0.25W. So y
|
By
Jerry Gaffke
· #42939
·
|
|
QCX-SSB Help what do I do now?
#qcx
That firmware was a demo of a difficult to implement method of transmitting SSB in a very power efficient way. Impossible to implement well on a small 8 bit processor such as used on the QCX. Absolute
That firmware was a demo of a difficult to implement method of transmitting SSB in a very power efficient way. Impossible to implement well on a small 8 bit processor such as used on the QCX. Absolute
|
By
Jerry Gaffke
· #42881
·
|
|
Experiences with 50 watt Amp
To be clear, the IRF510 intrinsic diodes plus fuse only protect the IRF510's from a reversed supply. There may be several volts across those intrinsic diodes and traces and inductors before the fuse b
To be clear, the IRF510 intrinsic diodes plus fuse only protect the IRF510's from a reversed supply. There may be several volts across those intrinsic diodes and traces and inductors before the fuse b
|
By
Jerry Gaffke
· #42745
·
|
|
Experiences with 50 watt Amp
For most applications, a series schottky diode of sufficient current rating and sufficient reverse voltage rating is likely best. The only penalty is a forward voltage drop of a few tenths of a volt.
For most applications, a series schottky diode of sufficient current rating and sufficient reverse voltage rating is likely best. The only penalty is a forward voltage drop of a few tenths of a volt.
|
By
Jerry Gaffke
· #42626
·
|
|
Dupont Leads get loose
That Lithium Ion board is "5S", so assumes 5 cells in series, about 21v when fully charged. Also, it does not have cell balancing, just protection from over-under cell voltage, over current. For stuff
That Lithium Ion board is "5S", so assumes 5 cells in series, about 21v when fully charged. Also, it does not have cell balancing, just protection from over-under cell voltage, over current. For stuff
|
By
Jerry Gaffke
· #42350
·
|
|
Alternative method of deriving a 1pps for keeping time / calibration ?
I started out in this discussion recommending a $2 TCXO that doesn't jump around. Beyond that I hope nobody is taking me just too seriously. A rubidium standard would be fun to play with, but not wort
I started out in this discussion recommending a $2 TCXO that doesn't jump around. Beyond that I hope nobody is taking me just too seriously. A rubidium standard would be fun to play with, but not wort
|
By
Jerry Gaffke
· #42334
·
|
|
Alternative method of deriving a 1pps for keeping time / calibration ?
That's a lousy way to check the accuracy of a rubidium standard. They probably track due to experiencing the same number of neutrino hits or something. You need one of these: https://www.ebay.com/c/14
That's a lousy way to check the accuracy of a rubidium standard. They probably track due to experiencing the same number of neutrino hits or something. You need one of these: https://www.ebay.com/c/14
|
By
Jerry Gaffke
· #42320
·
|
|
Alternative method of deriving a 1pps for keeping time / calibration ?
If you figure OCXO's aren't good enough and don't want to depend on GPS, a rubidium standard can be had for $250 on ebay. Accurate to around 0.1 ppb, so at 10 GHz it might be off by 1 Hz I'm sure the
If you figure OCXO's aren't good enough and don't want to depend on GPS, a rubidium standard can be had for $250 on ebay. Accurate to around 0.1 ppb, so at 10 GHz it might be off by 1 Hz I'm sure the
|
By
Jerry Gaffke
· #42311
·
|
|
Close up
I looked hard at building Don's binocular microscope. That probably would have been the best option. But not having much time, I instead opted for the AmScope SE400-Z And since Bezos is already plenty
I looked hard at building Don's binocular microscope. That probably would have been the best option. But not having much time, I instead opted for the AmScope SE400-Z And since Bezos is already plenty
|
By
Jerry Gaffke
· #42286
·
|
|
Alternative method of deriving a 1pps for keeping time / calibration ?
Power grid frequency can slow a bit when they get hit with a big load. But they do try to keep the total cycle count per day a constant so clocks stay on time. The 1% error at 50.5Hz means if you are
Power grid frequency can slow a bit when they get hit with a big load. But they do try to keep the total cycle count per day a constant so clocks stay on time. The 1% error at 50.5Hz means if you are
|
By
Jerry Gaffke
· #42260
·
|
|
Old hands, tiny screws, and a lack of patience
Flux is used to remove oxides and such, exposing the surface of the bare metal to be soldered. Which means flux can be corrosive, even rosin fluxes can have acids added. All different kinds of fluxes
Flux is used to remove oxides and such, exposing the surface of the bare metal to be soldered. Which means flux can be corrosive, even rosin fluxes can have acids added. All different kinds of fluxes
|
By
Jerry Gaffke
· #42242
·
|
|
LC-100 L and C meter
The old "qrp-tech" yahoo forum has been archived on groups.io, That group is locked down and inactive, just an archive. Everybody has moved over to "QRP Tech", with a new moderator. Here's a search fo
The old "qrp-tech" yahoo forum has been archived on groups.io, That group is locked down and inactive, just an archive. Everybody has moved over to "QRP Tech", with a new moderator. Here's a search fo
|
By
Jerry Gaffke
· #41628
·
|