The latest additions to this
site:The latest additions to this
site:- OH2AUE Web Portal statistics, status (06.12.2018)
- some demonstration and presentation material on 160m NVIS propagation and x-mode absorption using active quadrature magnetic loops (Spring 2020)
- signal strength of OH2QM on two linear polarizations and with x-mode vs. o-mode circular (elliptical) polarizations (31.05.2019)
- strong High Latitude Sporadic E during this experiment getting much stronger a bit later, masking out (NVIS) F1o and F1x completely (plots from SGO)
- here is a typical example of 160m NVIS propagation with different polarizations using the above setup (more on my YouTube channel) (06.06.2020)
- a new subpage on my HF Polarimeter and S band Frequency Extender (03.03.2019)
- experimental Paracitically Excited Trifilar Backfire Helix for reception L Band frequency 1067 MHz of the Coherent Trible Band Beacon (CERTO) on board the Cassiope spacecraft (08.01.2019)
- matching of the tuned RHCP Trifilar Backfire Helix, with the the Even and Odd mode resonances of the fed filaments visible either side of the center frequency (paracitical filament) (08.01.2019)
- preparation of filaments for the Cassiope L Band Trifilar Helix (08.01.2019)
- the Es'hail-2/QO-100 satellite X band KiwiSDR receiver hardware ready for intergration into 19" 2RU rack mechanics (29.12.2018)
- radio silenced 5.0V and 5.1V switch mode regulators for the X band KiwiSDR and Leo Bodnar GPSDO (01.11.2019)
- appearance of another HF antenna circular polarization control box - this one with hemisphere switch, in case someday I "go south" :-) (27.09.2017)
- verified a second hand, battered, but cheap Microlab CA-84N Quadrature Hybrid for input port and sigma port matching, splitting amplitude balance and quadrature imbalance (23.12.2018)
- a photo of one of my calorimetric studies, here a high power X band waveguide experiment built around a discarded Argon noise tube source (23.12.2018)
- overhauled my Inoue Communications IC-490E, phase 1, phase 2, phase 3 (12.12.2018)
- modified my trusty old Inoue Communications IC-R7000 memory backup battery to accept more field replaceable types (12.12.2018)
- here is a photo of my IC-R7000 AGC ON/OFF switch modification for e.g. Noise Figure measurement or Radio Astronomy and +12Vdc output modification for feeding converters etc. (12.12.2018)
- into my fifth trisade mission year of replacing turnstiles and the like with tripoles (01.12.2018)
- put together a page on my Es'hailsat Es'hail-2/Phase 4A satellite KiwiSDR web receiver and related experiments (15.08.2018)
- calculation of WR-62 waveguide impedance for TE10 propagation mode (15.08.2018)
- calculation of freespace wavelength (15.08.2018)
- calculation of wavelength in WR-62 waveguide for TE10 propagation mode(15.08.2018)
- calculation of wavelength in WR-90 waveguide for TE10 propagation mode(15.08.2018)
- summa summarum: WR-62 is totally useable for 10 - 10.5 GHz IF you take into account propagation velocity, i.e. guide wavelength and the slight increase in loss (and impedance if you are fussy)
- modified three Octagon Oslo PLL LNB's for external 27 MHz referencing over the IF cable, no external changes needed, the plastic shrouding remains intact (27.07.2018)
- successfully tested my idea for downconverting the geostationary Es'hailsat-2 satellite AMSAT X band downlink segments to HF for feeding an IP-based KiwiSDR receiver (27.07:2018)
- repaired an HP715A Klystron Laboratory Power Supply to it's original specification - a real treasure to me as a thorough microwave enthusiast (video: testing a 12 GHz Reflex Klystron) (27.05.2018)
- embarked on a mission to repair and restore a VE301Wn found at a local recycling center (17.05.2018)
- experimenting with the OH3BHX Web Radio Control system, based on the Raspberry (photo: Raspberry, LTE modem, IC-7200 radio over USB) (28.04.2018)
- removed pins and rubber from some old military standard connectors to use as antisquirrel and antiwoodpecker hardening devices for some backyard birdhouses (28.04.2018)
- repaired an dual channel, 40 MHz, delay HC5604 oscilloscope with readout and CH1 ouput, excellent value for money (10.04.2018)
- some 60m band experimenting with crossed magnetic loops for NVIS circular polarisation using an automatically switching broadband quadrature hybrid (30.03.2018)
- again, not for the faint-hearted, tuning for perfect quadrature can be challenging due to the very high Q antennas (30.03.2018)
- my 728 kbit/s, PAL B/G 5.85 MHz subcarrier NICAM test setup: modulator, demodulator, IQ/constellation/Eye-Height analyzer, and spectrum (17.01.2018)
- added photos of experimental automatically polarization switching antenna hybrid NVIS system for operating x or o mode with LHCP/RHCP (28.09.2017)
- the second generation NVIS controller also supports hemisphere selection (28.09.2017)
- RF shielding and environmental protection is important for field testing the chiral antenna NVIS hybrid system (28.09.2017)
- crossed T2FD antenna ports, test interface and diagnostic BIT indicators are easily accessible, but protected in the NVIS Chiral Antenna Hybrid (28.09.2017)
- my faithful Kenwood TS-430S providing RHCP/LHCP operation for optimal o and x mode propagation (28.09.2017)
- the hybrid is also perfect for feeding a wideband log-periodic NVIS antenna, for providing full polarisation control when using legacy radios (20.12.2018)
- experimenting with dielectric antennas on 10 GHz using PTFE and Trolitul (Rexolite) - thoroughly enjoyable to work on the lathe every now and then (01.05.2017)
- finally a single phase fed 1/120/240 degree RHCP Paracitical Tripole experiment giving promising test results, but more work needed (01.05.2017)
- the Paracitical Tripole polarisation rotation could be electronically flipped simply with two PIN diodes biased via the RF coax - next implementation: NVIS HF :-)
- dismantled a very unbalanced cheap NiMH battery to understand why (01.05.2017)
- some info on the H. Vesala CT1610 Cable Location Equipment (01.05.2017)
- testing my low pressure RF excited sodium lamp yielding almost monocromatic light for excitation and other experiments (01.02.2017)
- spectrum from 300 to 1000 nm, linear vertical scale (01.02.2017)
- zoomed spectrum from 570 to 600 nm (01.02.2017)
- made some more measurements on the 2400 MHz Tripole: phasing network, Trigature Hybrid input and Tripole Element matching (added 21.11.2015)
- photo of the experimental 2400 MHz Tripole with Trigature Hybrid, Directional Couplers and Matching Network (added 21.11.2015)
- ellipticity less than 1 dB, cross polarisation more than 15 dB, matching 20 dB radiation pattern optimized for hemispherical coverage
- photo of an experimental Two Phase Fed Parasitic Tripole with Quadrature Hybrid + 30 degree Delay Feed Network (RHCP, ellipticity less than 1 dB) (added 21.11.2015)
- polarisation (chirality) switching of both Tripoles is accomplished with a Transfer Relay
- the preliminary test antennas were an RHCP and LHCP short helix and Linearly Polarised simple horn (added 21.11.2015)
- my brother found some photos of Triac assembly taken by our Mom at the Denford Brighouse Huddersfield factory back in June 1986 (added 02.11.2015):
- just for fun, here is the X band noise impulse screenshot triggered by popping off a 1970'ies style Camera Flash Bulb (28.10.2015)
- the PC sound card scope was set to trigger on the rising edge of detected X band thermal emission from the fired camera magnesium based flash bulb
- some common path Intermodulation laboratory experiments with different multiple 2 Mbit/s QPSK/PSK carrier (1/2 and 3/4 FEC) scenarios (21.09.2015)
- some test data on my narrowband 3699 kHz tripole receive antenna 3-phase combiner for RHCP/LHCP NVIS to be used on the OH web stream feed (22.08.2015):
- a photo of my Inverted Y Tripole Controller inerfaced with a Yaesu FT-897D (21.08.2015)
- the controller acts as a polarization control interface between the radio and the experimental Trigature Hybrid
- the Trigature Hybrid feeds the HF Tripole with 3-phase RF over about 20 meters of TriLead
- Monopole, Dipole, Tripole, Goubau, Twinlead, TriLead ;-)
- ideally the TriLead feedline is a twisted balanced affair that STRUCTURALLY looks like this (absolutely dangerous, illegal and FORBIDDEN due to the IEC 60446 Green/Yellow Sleeving !!!)
- a reminder: there are several HF Circular Polarization videos on my 'oh2aue' YouTube video channel !
- an experimental Scott-T type three phase HF broadband power splitter (28.7.2015)
- block diagram of a highly experimental 6 - 9 MHz Trigature Hybrid fed Inverted Y NVIS Tripole (27.07.2015)
- a screenshot taken during modelling and simulation of a narrowband Inverted Y NVIS Tripole
- a photo of an inverted S band tripole experment (12.07.2015)
- put together a physical layer test inferface for radio testing, dissipation 150 W RMS (DC-30 MHz), attenuation -80 dB +-0.5 dB, return loss >20dB, Test Port coupling -60 dB +-0.5 dB (14,05.2015)
- this is a first prototype, but it is possible to extend the frequency range to at least 1 GHz with careful design
- after a few years of reverse engineering, contemplating and procrustination, I finally got round to testing a GPS downconverter for my ED167MP GPS locked secondary reference (03.05.2015)
- one of my first attempts at a wideband HF NVIS quadrature hybrid yields pretty good channel amplitude balance at +-0.5 dB from 800 kHz to 12 MHz (02.05.2015)
- got the loss down to less than 1 dB (over the 3 dB splitting loss) with excellent common port matching in excess of 20 dB. Next task: flatten phase response.
- also the differential phase is fairly OK with quadrature tracking within 10 degrees from 800 kHz to 12 MHz, but can be readily improved to +-1 degree (02.05.2015)
- this is what the thing looks like before gluing down, with eleven toroids and sixteen capacitors (03.05.2015)
- so now you know why I quickly bolted cover down ;-) (03.05.2015)
- some circuits for generating spot frequency circular polarisation on HF (30.04.2015)
- layout of crossed dipoles for HF circular polarisation (in Finnish) (30.04.2015)
- schematic of crossed HF dipole RHCP/LHCP polarisation switch (in Finnish) (30.04.2015)
- put together this test box primarily for elliptical polarisation experiments (ionospheric o, x and z modes - it is just useable down to 1750 kHz) on HF (15.03.2015)
- switching arrangement of the versatile Elliptical HF Antenna Test Box giving access to all signals for SDR
- the second generation quadrature hybrid switch box (1800 - 7800 kHz) in a VW T4 mobile setup along with my versatile FT-897D (01.04.2015)
- my portable magnetic field active antenna setup for elliptical polarisation experimenting (01.04.2015)
- my mobile magnetic field antenna setup for elliptical polarisation experimenting on the move (01.04.2015)
- wanted some original lookalike frequency table printouts for my trusty Barlow Wadley XCR-30, so generated this spreadsheet tool (16.01.2015)
- some experimenting going on with circular polarisation for NVIS, here is a receiver setup for 1843 kHz LHCP reception (13.01.2015)
- a photo of an experimental APRS setup (13.01.2015)
- I have quite a few different scale models that I use for e.g. radiation pattern verification etc., here is a photo of an NVIS-antenna model vehicle scale 1:18 (added 13.01.2015)
- a couple of temporary attempts to improve mobile data throughput, one with a horn antenna and the other with an indoors short yagi
- made some temperature coeffcient (23k) verification measurements on a slightly mismatched SAW filter at -20°C, +15°C and +45°C (13.01.2015)
- initiated a page devoted to interference, especially to HF communications, domestic COTS appliances (23.12.2014)
- some of the devices I have plugged into my LISN have been so scary I decided to design an effective limiter for DC - 30 MHz and beyond to protect my instruments from excessive RF (26.12.2014)
- a shot of a 16 channel coherent ionospheric scatter receiver system with Pikku-Malla in the background (08.06.2014)
- and a photo of an incoherent monitoring station for the same with Salla in the background (09.06.2014)
- generated a plot for estimating ice thickness growth (in Finnish) under ideal conditions (14.01.2014)
- added a couple of spectrum plots of LRO in the locked state and going from unlocked to uplink locked coherent ranging state (23.12.2014)
- added a graph of ice thickness growth rate under ideal conditions (23.12.2014)
- put together crystal controlled crystal controlled VHF source for phasing measurements (29.12.2013)
- some stuff on the AN/PSM-40 a.k.a. the Systron Donner 5220 Transline Analyzer (28.12.2013):
- checking out potential local 900 MHz UMTS service providers
- test antennas were flat within +- 1dB over the operator bandwidths (22.12.2013)
- rigged a 12 V DC supply for my SPA and drove 450 km around the municipality testing UMTS900 coverage - I was not particularly impressed :-( (23.12.2013)
- highly inhabited areas sometimes had pretty impressive service however (22.12.2013)
- fighting some serious local 144.800 MHz APRS overload using a very sharp notch filter, AO-73 satellite beacon finally undisturbed at the marker (12.12.2013)
- OH9VHF was back in the lab in April 2013 with no output power, this time the culprit was burned backplane connector
- notes on the connector repair (Finnish, 549 kb, 03.07.2013)
- OH9VHF and OH9SHF got their periodical overhaul (VHF power, SHF power, SHF power verification) (added 18.08.2012)
- addes some experimental Meteor Scatter results from the 2012 Perseids (data from 11-12.08.2012, uploaded 18.08.2012):
- added a drawing of some ideas for optical experiments with the receiver mounted on our ATV repeater remotely controlled camera (04.01.2012)
- finally added some stuff on my Minimalistic Rain Scatter experiments (03.01.2012)
- put together some notes and photographs of the only two R&S HFH Field Strength Receivers in Finland that I am aware of (02.01.2012)
- wanted to tune up up several 22/23 GHz BPF's up to 24048 MHz, so put together an ad hoc test system, starting off with RL tuning and ending up with bandpass optimisation
- the forward coupler is for frequency measurement, the source is a modified Gunn oscillator equipped with LPF and isolator and level is optimized with a variable depth vane attenuator
- the Gunn is AM modulated 100 % at 1 kHz or 10 kHz and it's varactor is swept with a Function Generator ramp signal via HB linearizer, giving a 500 MHz wide sweep
- detection is either linear or 10 dB/div via an HP3581C Selective Voltmeter using a narrow detection BPF. I usually use 1, 10 or even 50 kHz PRF for higher update rate
- here is a block diagram of the 24 GHz Swept Test System made with second hand, junked lab gear and equipment (20.01.2012)
- note the WG attenuators after the Gunn, before the DUT and after the DUT to force tuning to matched loads, IL loss is measured against a digitally calibrated motorized vane attenuator
- a photo of my Mobira DT50 APRS terminal with DK50 printer, closeup of the DT50 terminal and closeup of the DK50 thermal paper printer (08.05.2011)
- since picking up signals from the JAXA Kaguya-Selene Lunar Orbiter, I have been enjoying the NASA LRO signals too, though not with a paper clip any more ;-)
- added some photos of my old (08.01.1990) homebrew spectrum analyser display: analogue display, digital display and a commercial digital analyser for comparison
- settings for the screenshots: 1 MHz/div, 10 dB/div, 20 ms/div, RBW 200 kHz, input level -12 dBm, triggering on video blanking pulse, digital: 600 points/div (!), sample rate 500 kHz
- added some info on my old 3.4 GHz beacon experiment:
- added the block dagram of my 1987 era 10 GHz CW beacon and a photo of the intermediate spectrum at 10 MHz/div, 10 dB/div with 50 mW output (08.05.2011)
- drilled some accurate holes for an RF relay with a simple G-code routine for my Denford Triac CNC Mill: "wood" prototype, "engineering" model and "flight" model
- finally got my 8 m telescopic Geroh 8SPM spindle mast erected, overall photo of mast extended to full hight, view of base plate installation, photo of top section 130 mm interface
- this special mast sports integral run tracks that practically eliminate rotary slack - this solid mast is just perfect for my higher frequency microwave experiments ;-) (26.04.2011)
- here is a web page dedicated to our (the Padasjoki Scientific Research Society) OH3RUD APRS repeater and OH3RUD 70 cm R-NET voice repeater - in Finnish (01.01.2011)
- the very latest additions to my web pages may be found under the link W band (25.03.2011)
- some data on the Hertsien Herruus 2008 frequency measurement competition (20.08.2014)
- recently found this intriguing article on my Grandad's patent, the Fletcher Two-Stroke
