Q band experimenting with Ilkka Kojola, OH1KHH, ex-OH4KHH (Silent Key 16.07.2004):


Plot of 144 MHz two tone IF test signal driving prototype 47 GHz harmonic mixer, IMD <-20 dBc


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- kickoff meeting on May 15th; Ilkka and myself, photo (84 k) by Jukka Klemola, OH6LI

- Ilkka built a Test Mixer (65k) we designed for measuring purposes (machining by Pekka Kakko - tnx !)

- A closer view of the input LO Doubler (60k) using the MGF1302-15 GaAs-FET

- A closer view of the actual harmonic diode (HSCH-5312) mixer (50k) device glued with silver epoxy

- Overall view of the harmonic mixer (56k) matching circuitry

- The used test configuration (32k) using a DB6NT LO module for 11736 MHz

- Spectrum analyser ( Anritsu MS2668C) plot of the LO signal (10k) at 46.944 GHz, under no IF drive conditions

- Spectrum analyser plot of the LO signal (3k) under full IF drive conditions (+7 dBm)

- Spectrum analyser plot of an unmodulated CW carrier (3k) at 47.088 GHz (100 kHz/div dispersion)

- Spectrum analyser plot of an CW carrier (3k) at 47.088 GHz (20 kHz/div dispersion)

- Spectrum of 1 kHz FM modulated carrier (3k), 3.5 kHz deviation (dispersion 10 kHz/div), IF 144.2 MHz @ + 7 dBm

- Spectrum of a 47088 MHz two tone carrier(3k) with IF carriers at 144.200 and 144.250 MHz, +1 dBm each

- Spectrum of a "real" two tone test (3k) of 700 Hz and 2100 Hz carriers at the microphone input of an IC202S IF driver

- This is what our 47 GHz SSB sounds like (224 k) against the spectrum analyser LO with a Drake R7A at the IF ;-)

- And here is a sound file (356 k) of 47 GHz CW downconverted with the spectrum analyser a copied on the R7A

- Conceptual idea (13k) for generating 15 mW of SSB/CW compatible partially envelope restored PLL-SSB power on 47 GHz (Could be a DSP solution !!!)

- Considering an SSB tripler (31k) to 76.032 GHz using a DSP based constant amplitude SSB generator and envelope restorer - need DSP guru to join the team ;-)

- same block diagram, but for the 75.976 GHz (31k) band used in the UK

Finlands very first two way 47 GHz ham band QSO held on 22.06.2000 between OH1KHH and OH2AUE/p at 0701 UTC; QRB 8 metres, raports 59/59 on SSB. The experiment took place in WGS84 referenced Maidenhead square KP10NJ. The longest distance covered during these experiments was just over 100 metres with 59/59 raports on SSB at 0808 UTC using 28 cm dishes at both ends and with plenty of link budget margin. Also FM and CW were tested with excellent results. These QSO's were made with the test mixers described above, i.e. these were not designed for this QSO, rather they are designed for testing and aligning our actual rigs that are still under way !. The signal stability was fairly good considering the conditions. The 12 GHz local oscillators were held in styrox boxes to protect them from excessive thermal drift due to wind etc. The frequency was verified by using a waveguide high pass filter and by checking the output spectrum with a 40 GHz spectrum analyser with a home-brew harmonic mixer. Using different IF's of 144 and 432 MHz also helps to ensure verification of operation on correct frequency. Also reflection experiments were made with good copy on CW. FM was perfect with line of sight contact of course. Signals tended to drift a bit, but not bad considering the multiplication factor !. The photos below were mostly taken by Jukka Klemola, OH6LI and myself, OH2AUE:

- First OH 47 GHz ham band QSO held on 22.06.00, QRB 8 metres, 59/59 on SSB !!! (quarter wave GP (57k) as antenna)

- closer view of 47 GHz quarter wave (61k) radiator used for frequency alignment to start with

- here is an overall view (77k) of the OH1KHH station

- and a closer view of Ilkka's 47 GHz subharmonic mixer (68k) module

- another view of Ilkka's 47 GHz subharmonic mixer (57k) module

- Ilkka, OH1KHH, and the setup (69k) as used for this historical QSO on June 22. 2000

- here is an overall view (53k) of the OH2AUE/p station using a 144 MHz IC202S at the IF

- and a closer view of my 47 GHz subharmonic mixer (69k) module

- myself, OH2AUE, and the setup (57K as used for this historical QSO on June 22. 2000

- closeup view of the OH2AUE 47 GHz subharmonic mixer (53k); note copper foil waveguide and waveguide high pass filter

- a portrait (65k) of Ilkka and myself beside the OH1KHH "fixed" 47 GHz station

- one of the two 28 cm prime focus dishes (47k) used in the experimental contact

- a photo showing our current line of site (54k) record distance of over 100 metres

- the old russian CW key and the 432 MHz IC402S (66k) IF rig used at one end of the contacts

- a sound recording of Ilkka transmitting (117k) on 47088.100 MHz SSB during our experiments

(All alignment and tuning has been accomplished with own ham shack equipment. Spectrum analyser plots made with external homebrew mixer. The measurements on this page were made afterwards with a loaned analyser as my shack does not have a decent 50 GHz analyser - yet! The next problem will be viewing 76 GHz, but this may turn out to be quite simple...)

Here is some more info on the final transverter ready for testing:

- photo of the final real transverter (40k) with RF VOX switching etc.

- overall view (47k) of the transverter with 12 GHz DB6NT local oscillator and waveguide attenuator

- spectrum analyser plot of LO leakage (3k) taken with with an MS2668C and external mixer (calibration with power meter)

- here is a plot of the transverter (3k) output with full IF drive at 144.2 MHz

- overall view (45k) of the transverter, IC202S IF radio, MG3681A signal generator and harmonic source

- this is what the signal stability sounds like (116k) after 30 minutes warmup time

- and THIS (234k) is what Doppler sounds like at 47 GHz !!! (hand moving in front of waveguide opening)

- plot of the drift (110k) over a period of a couple of minutes or so taken with R.S.Horne's software

- for initial testing the transverter is packaged in a styrox box (68k) behind a surplus ~40 dBi lens horn antenna

Since then the Finnish record has been extended a couple of times on the 18th of February, 2001. The shorter QSO was to align the rifle telescope on my equipment to ease pointing. The longer path of 9.07 km was between KP10NL and KP10OJ. Raports were a solid 54/59 (with an attenuator problem at the other end) are we estimate that 50 km + QSO's should be possible, at least on CW. Here is some more info on this Sunday afternoons activity:

- a raport in Finnish can be found here

- here is an overall view (96k) of the rig at OH2AUE/p in KP10NL

- and here is a view from the other side (80k) of the rig

- a view of the setup from the rear (56k) pointing towards OH1KHH/p in KP10OJ

- and here is a closeup view (57k) of the OH2AUE/p station

- this is a photo of Ilkka's, OH1KHH, 47 GHz equipment (67k) during balcony tests earlier that day

- during the record breaking experiments there was a slight wind that waved around the canopy in front of Ilkka's antenna

- this caused a lot of varying flutter and Doppler shift over the 9 km path as can be heard in this recording (647k)

- and also in this sample recording (525k) of the 9 km + QSO too

- this is current circuitry (22k) around my own transverter, Ilkka's is basically very similar

- here is a photo (68k) of Ilkka's doubler and SHM

- claiming a new Finnish record on 47 GHz at ~28 km 56/56 on SSB with OH2AXH/p on July 4th, 2001 !

- first we calibrated our frequencies over a short 4 km path (38k) - only about 12 kHz off ;-)

- OM Pertti was in KP20LE and I was in KP20FD, both stations battery operated portable

- this is a photo of my rig (48k) in KP20FD copying excellent sigs from OH2AXH/p

- another view from the operators position (40k) towards OH2AXH/p

- unfortunately my Mini-Disk sound recording was spoilt by the strong wind :-(

- running some more tests attempting a 52 km path. Foiled by bad weather & pointing problems (18.07.2001):

- photo of the transverter setup from the left (73k)

- photo of the transverter setup from the rear (57k)

- photo of the transverter setup from the right(75k)

- current mixer setup yields about 0.03 dB cold sky/ground noise

- here is some info on the Millimeter Wave equipment of Masatake Hemmi, JA1ATI

- also made QSO's with OH1JJC (212k) during on of our microwave contests

- and this is an inside photo (89k) of OH1JJC's DB6NT type 47 GHz transverter

- just for fun: I also put together an ad hoc 3.4 GHz (197k) mixer diode transverter for OH1JJC/P

- photo of transverter (60k) version 2 mechanics (under repair, blown 23 GHz stage), photo OH1JJC

- photo of OH1JJC's 47 GHz (133k) station during an early August 2003 test session (Left to right: OH2JMS, OH2LKV)

- this photo, taken by OH1JJC, was from the other end of our 200 m test QSO in Katajanokka

- photo of OH1JJC/p (86k) 47 GHz with OH2JMS during a 5 km test QSO between Kaivopuisto and Santahamina

- and a third photo by OH1JJC of his portable 47 GHz setup (162k) with OH2JMS aligning

- photo taken during the 5 km test at the Kaivopuisto end (I was on the Santahamina bridge)


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Updated 15.08.2004