I have posted some pictures of the hi pot test setup of my new Eimac YC-179 vacuum tube (MRI pull). This is for a future legal limit (LA amateur regulations) amplifier for digimode and contest CCS amateur radio use. It is better to run a tube cool than to stress a smaller tube for high dutycycle modes. Let’s hope the tube behaves OK. It measured less than 15uA at 16KV DC from A to G so I might have a good pull. (The reason for measuring at such a high voltage is to ensure that the swing that the PI circuit contributes when driven by the tube can be tolerated w/o breakdown).
HV setup to test to 16 KV (below)
Tube in the test rig (below)
Click on the pictures to see the gallery (below)
The HV meter to the left is on the hot side of the rectifier / smoothing cap and has a multiplier shunt that gives 200 x. That means that 80 on the meter on the left indicates 16KV (DC) output. The uA meter on the right is in line and measures leakage current. (uA) The o/p is current limited on this output. The meter panels are insulated with plexiglass and air gaps to prevent arc overs to the operator. Not that this would help since the HV leads are exposed. However in a future version… (below)
The newest version of PileUP! magazine from Contest Club Finland has been uploaded to http://www.helsinki.fi/~korpela/PU/PU3_2011.pdf
Take a look. Very good contesting and technical info as well as very good jokes.
We have 4 badgers in our garden that digs up our lawn. I needed a way to scare the badgers off without needing to use more drastic methods.
I have modified a passive infrared detector that I purchased at Clas Ohlson for another project several years ago. The modification makes the detector more sensitive. I take out the signals from before the logic that does an AND between sensor 1 and sensor 2. The signals are scaled down to 3,3V and are sent to two inputs of an Arduino mini PRO.
The modded PIR sensor with the uC and the radiolink mounted inside the existing chassis. (Note: the antenna is 1/4 wavelength, not 1/2 wavelength as is written in Norwegian on the picture)
The Arduino uC runs a C program that detects infrared thermal events. In case a valid detection is sensed, packets are generated and sent to a nRF2401 13 cm radiolink from Sparkfun. The radiolink sends the data to the base station in my house signalling that a badger is detected. I can then verify the operation of the sensor. Later the plan is to generate some noise to scare off the badger.
The sensor in its test configuration for detecting badgers. The sensor is mounted close to the ground to have their path in the sensors FOV.
Testing radiolink code with logic analyzer
Three wire signalling and nRF2401 chip control signals are analyzed.
Link check terminal. Good to check proper positioning of the RX antenna.
The conditions lately have been very good on 20, 17, 15 and 12 meters. I have worked a lot of new stations on the HF bands above 40 lately. Finally the nice sound of a wide open high band that I remember from last time the SSN stayed above 100 is here again.
The SSN peaked above 100 between 12. and 13. April. The SFI also peaked around 14.-16. April. The K-index also stayed low and the auroral activity has been modest. Perfect settings for working DX!
Antenna: broadband vertical with computer controlled tuner. Large groundplane.
Rig: Yaesu FT-1000MP MKV
I have been working on a new HI-POT tester ( high voltage tester) for checking breakdown voltage of vacuum tubes, RF vacuum capacitors, HV cables, RF relays etc.
You can check out the comprehensive photo gallery:here
I have now published the PPT from the OH8X ARRL CW operation. I held this presentation at the NRRL annual meeting at Letohallen in 2010. Note: some of the text is in norwegian but the presentation is mostly images.
Download the PPT as a PDF file
I have posted the PileUp! magazine article that covers the OH8X (Radio Arcala) ARRL DX CW 2010 operation. The article also covers the antenna switching, the OH8X shack, the rotor systems and the full size 160m / 80m yagis. I have also covered contest experience itself and the contest results that ended in a new Finnish record. (Go to page 38 in the PDF for the article)
Download the PileUp! Magazine article as a PDF file
Goto page 38 for the arcticle
I have posted some images from the OH8X ARRL CW contest operation in 2010. More images will be posted later