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The OK2KKW's hardware on July 2011 144 MHz
Our first 2m PA was built by Lada, OK1DIX together with Vlada, OK1VPZ (in OK1KRA during 80's we used PA with 2xGI7b) in middle 90's with Czech tube RE041XL and it still deliver to 75 Ohm load about one horse power PEP. As a driver we made in year 2000 solid state driver with LDMOS MRF 141 which gives max. 120 W. As a transceiver we used TXR 210 "Snezka" which has even for today needs still satisfactory RF performance. However we were looking for some better CW filters, so during M.M.C 2001 we used for the first time our new home made 21/144 MHz transvertor called "Sitno" (btw. with very similar performance as TR144H+40 from DB6NT) together with FT1000MP transceiver. As a antenna we used over 20 years old 16el F9FT and KLM17LBX (10,5m long). During VHF contest 2003 we used for the first time new 16el OK1RI yagi from ZACH company and new 30m high Hungarian telescopic military mast. Since May contest 2005, after change of Czech license rules, which allow us to use in contests even higher power, than 750W, we have started to use as well as more PAs - the first with GU78b tube by OK1BAF and the next one with 2xGI14b - all of them were connected into separate antenna system. As a 75ohms coax we used pretty thick one from aluminum used previously for a cable TV. In 2005 we added to new PA's also new antennas, first 4x 5el DK7ZB system and later also the second 4x 5el group made by OK2BJL/OL6R and our first 20m high RDM-6 telescopic mast. During years 2005 - 2006 we were able to put up 5 antenna systems, but due to lack of "arms" we've never used more then 4 systems. So first was KLM17LBX, second 10el OK1RI, third 16el F9FT a two times 4x 5el DK7ZB. These 2 short groups we used to fixed directions to the South East and North West. During last contest with this "old iron" (which was May contest 2006) we used for the first time our new MF preselector quartz filter. And then came the "black Thursday" just before the July Field Day contest 2006. Only few days before contest some robbers stole all of our 2m equipment which we had been getting during last 20 years: all antennas except 16el OK1RI, both of telescopic masts, rotators, coaxial cables, anchors, pins for fixing, 400m long power wires, HV supply for PA, dishes for 23 and 3cm, aluminum ladder, 22el K1FO for 70cm, etc... Since then we have been focused on UHF & SHF frequencies and 2m band we join just during single band contests like M.M.C or IARU Region 1. VHF Contest. Current configuration is based on: 2x20m high masts RDM-6 with 10el DK7ZB + 16el OK1RI, 2x 25m long Andrew 1/2" coax cables and two power amplifiers, first from year 2006 is 950W PA I0JXX with transistors SD2942 (normally used by OK1TEH for EME) and second the old OK1DIX's PA with GU34b tube (replacement of RE041XL), FT1000MP with 21/144 MHz Sitno transvertor and MF preselector quartz filters, followed with 120W LDMOS driver with MRF 141. As a rotators we use home made type rebuilt from "Sever" 25 years old type (check out 432 MHz section below) with home made LED controllers, as the RX switch we use this one. 2m LNA we don't use because of 3km far neighbors OL7C/OK1KVK with QRO.
432 MHz On 432 MHz we use FT 847 (with Collins CW filter and ALC modification) which is driving with aprox. 8W new 120W SSPA (made in 2009) and this PA is driving with about 50W older PA with Russian GS31b tube (first contest with this PA was in October 1990). This PA gives output max. 1 horse power PEP (of course if tube is new ;) Antenna from the year 1988 is based on K1FO 33el. Yagi design (ca 8 m long), but adjusted to 75 Ohms impedance. Our signal is usually well receivable almost in all western Europe - for an example here you can listen to our 70cm signals recorded by G4LIP/G8P (QRB 806km) during May Contest 2000. 70cm LNA is made in 1990 by OK1VPZ with MGF-1502 DJ9BV's design with measured 0,45 dB Noise Figure and gain of 15dB (smaller because of contest usage). This LNA is situated in our ham shack (our hill used to be very sexy for lightening ;-). The 25m long coax with 75 Ohms impedance is pretty thick one and mast is (again) RDM-6 20m high telescopic "Magirus" (both 20m masts as well as all of our equipment we have to transport for each contest by car). In 2008 we bought new 4x 38el M2 yagies and Jirka, OK1RW (ex OK1ZAD) made a new transistor PA with maximal output power of about 300W so since May 2008 we are able to run a contest into 2 directions. Since that time we don't run 70cm contest from caravan but from our house with both 20m high masts. To 2nd antenna 1x 38el M2 we use 25m long Andrew 1/2" coax. Since May contest 2009 we have new GI7b PA by OK1VPZ with about 300W out (1750V on anode) for 3rd direction and 3rd antenna is 1x 38el M2 in 8m AGL. Finally in July Field day contest 2009 we finally replaced that single 38el M2 to the 3x 38el M2 system in 20m AGL. In July 2010 we add new 800W solid state PA made by OK1VPZ, TR432H transverter from DB6NT, IC7700 (tnx OK1BAF) and better home made 0,4dB NF 15dB Au LNA with ATF54143. The 800W PA is used for 3rd direction and 300W PA from Jirka OK1RW we use now as an backup. The total power after count up is no more then some 1800W (all electricity at our hill is fed only by 1 phase power line few km long - we use one 16A cirtcuit breaker ;). In future we plan to improve our RX path with LNA box.
Since July contest 2010 we use new 800W solid state PA made by OK1VPZ, TR432H transverter from DB6NT and IC7600 or IC7700 (tnx OK1BAF)
The configuration of OK2KKW's contest equipment for 432 MHz - 2009
1296 MHz
On 23cm we are active since July field day Contest 1996. Long time we had been using FT290R and later TXR 210 transceiver called "Snezka" with home made transvertor based on DB6NT's design with output power of about 14W. Our first antenna was 12el collinear type from OK1ANQ with gain of 14dBd on the same mast as 70cm antenna (btw. in UHF Contest 1997 we made on this antenna our ODX F6CRP in IN96 1132km). Since July Field day contest 2001 until fatal July contest 2006 we had been using 160cm solid dish. In UHF Contest 2001 we used for the first time new PA with GI7b made by OK1VMS and OK1VPZ. This PA was able to deliver about 150W in peek but real (stable) power out during contest was about 80W. As a rotator we used our modified "Sever" (with LED controller) situated on the ground fixed by caravan left wheel. Since year 2004 we have been using our second FT-847 (both of them have CW and SSB filters with ALC modification). After stolen 160cm dish just before Field day Contest 2006 our whole 23cm equipment was fully modified during Winter 2006 and the first contest with new equipment was May contest 2007. As a new antenna we used 2 times elliptic dishes from WiFi (120x170cm) with gain of 21dBd, which are mounted during a contest on their backs. As a feed we used DL4MEA's Ring feed modified by OM6AA. Since 2007 we used LNA from OK1CA with MGF-1302 with measured Noise Figure of 0,8dB. The cable from PA's to antennas are 2 times Andrew 1/2" about 5m long. The old unstable PA with GI7b was changed by 2x modern PA's based on hybrids RA18H1213G. One of them deliver 120W PEP (to 50 Ohms load and) and second aprox. 300W (btw. for the temperature check we use also front panel thermometer). Our total power after count up in contest is about 400W Both amplifiers are home made work by Vlada, OK1VPZ. For the future we plan to use new 28/1296MHz transverter with IC7600, new HEMT LNA and maybe small PA for 3rd direction with our old 12el collinear antenna.
The configuration of OK2KKW's contest equipment for 1296 MHz - 2011
2320 MHz
And finally our HW collection consist of some FM transceivers for packet radio, rotators, wattmeters and many of other things. And some-how as well as OK0EP beacon. But it is already quite different story. |
OK1DIX on 2m operation stand
with FT 1000 MP + transverter 
2x 4x5el DK7ZB 
144 MHz antennas during
September VHF Contest 2005
Rebuilt rotator "Sever"
A view from opposite side
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