Update: 17.05.2014. Hits:  since 20050614.


Amateur Radio


IY assembling a 2 W AF PA kit in
          1976OH5IY's first ham radio station 4 years after first ham
          licence, Yunost TV, 120 W GS9b 144 MHz PA, IC-211E, TS-120V,
          432 Tripler/conv., DC PSU, FC, DC PSU, Stolle rotator
Early days...10 W on HF, 120W on 144, 1 W (TX varactor& RX converter) on 432 MHz

While studying to become an electronics technician, I received my first ham radio license in 1978 and after working quickly those 500 CW QSOs on HF and passed general-class exam, I soon specialized on VHF/UHF weak signal modes (MS, EME, Aurora, Es, Tropo....) and have now worked 526 squares on 144 MHz since 1979 and on 50 MHz 81 DXCC countries and 348 Maidenhead squares.

A few words in Finnish:
Tämäkin (ns. tähtitietellisten/geofysiikkaan liittyvien lisäksi) on yksi minun harrastuksistani, jonka eri nurkkia kolutessani olen joutunut katselemaan ja opettelemaan yhtä sun toista ilmiöistä, niiden syistä, laitteista, ohjelmista, joilla voi tehdä jotakin hyödyllistä - en näe mielekkäksi tehdä kapistuksia, tai ohjelmia, joille ei ole mitään "tilausta". Työelemän kiireiden lisääntyessä ja iän karttuessa on turha luulla, että joka ikinen vuosi pystyy luomaan/tekemään jotain uutta ja ainutlaatusta. Siihen ei yksinkertaisesti riitä resursseja, olkoon ne mitä hyvänsä. Nykyisten systeemien (havainto-ohjelmien) operointi jo yksistään vie aikaa - sekin on osa harrastetta, vaikkei siinä ole mitään "uutta" - pitää olla pitkäjänteisyyttä, eikä pinnallisesti vaan sählätä pari kuukautta sitä ja seuraavat toista. Omien ja yhteisten asemien ylläpito vie aikaa ja rahaakin (onneksi on takooapuakin saatu), vaikkei sitä kukaan mistään oikeastaa edes huomaa - kiitoksilla kissa elää, kyllä motivaaatiot tekemisen täytyy löytyä itseltään. Harrasteesta ei varmastikaan ole tarkoitus aiheutua stressiä, se ei saa olla pakkopullaa - tehdään ja harrastetaan sen verran, kun tuntuu mukavalta - ja annetaan toistenkin harrastaa - on kyse sitteen laadusta, tai määrästä. Harrastamista voi yhtä hyvin olla radioputkilaitteiden kanssa puuhastelu, tai antenneiden rakentelu, aina ei tarvitse olla tekemässä sitä, mitä ns. nörtit pitävät päivän sanana.... joo, digitaalitekniikallahan voi tehdä kaikenlaista - joka on ensi viikolla täysin vanhentunutta ja sen päälle syljetään - muistamme hyvin miten 25 v. sitten latailtiin TELMACiin konekielellä ohjelmanpätkiä. Voipi olla, että monikaan ei niitä konekieliohjelmia ole jatkossa joutunut laatimaan, enempi on ollut kai hyötyä siitä, että osaa ylipäätään käyttää tietokonetta. Kotiohjelmointi muuttui harvojen huviksi 1990-luvun puolivälin jälkeen ja uusien ohjelmointikielten opiskelu vaatii jonkilaista motivaatiota, varsinkin kun vähän kaikkeen on saatavilla tietoverkoista valmista softaa. Radioamatöörejä on kyllä yhä olemassa ja ripiiterilläkin silloin tällöin puheliikennettä ja HF:llä sähkötellään, jos joltain on tuntuma näihin asiohin päässyt hypetysten lumossa katoamaan. Tavataan bandeilla ja harrastetaan!
 
 

My longest QSOs on VHF & UHF:

Propagation mode / Band
50 MHz
144 MHz
432 MHz
1296 MHz
2320
MHz
10 368 MHz
Tropo
520 km (SM)
1491 km (ER)
1346 km (DK)
1346 km (DK)
490 km
(SM3)
349 km
(OH2)
Aurora
1643 km (GM)
1947 km (G )
1005 km (OZ)
-
-
-
MS
1147 km (OZ)
2146 km (TA)
-
-
-
-
Es
7454 km (JH)
2557 km (SV)
-
-
-
-
F2
13452 km (VK)
-
-
-
-
-
Equipment @ KP30HV
4-el. 50 W
4*15-el. 800 W
8*21-el. 700 W
23-el. 15 W
/p 55 cm dish
/p 55 cm dish
Equipment @ KP31JK
5-el. 110 W
4*14-el. 250 W
-
-
-
-
SRAL (OH-) Worked squares Honor Roll, status: Jan. 2011
#11
#5
#8
#10
#3
#8

You might also be interested to see the Finnish (OH-) V/U/SHF locator square statistics of other stations, but SRAL does not seem to maintain that page any longer.

Anything unmarked: I am interested!

Is your call sign on this list?
European squares worked on 144 MHz by OH5IY, August 2010. (Display from MS-Soft 5.1)

Meteor Scatter contacts led to a long term commitment of writing and updating Meteor Scatter software for Ham Radio service. During the 1980-1995 period MS evolved technically (i.e. increase of CW speed), but there also was room for improvements on predicting meteoric propagation conditions. This paved the way for diverting my efforts towards Meteor Astronomy after mid 1990's, another hobby that does not seem to be cheap or easy, if one wishes to make some results. On workdays I move around the upper part of this image's area.
 
 


 

As you see the Aurora first gives plenty of new squares, but the limit comes after just a few years of activity. On Es and tropo the good years have lasted up to about 10 years, with some lucky strikes even later. MS has been the most sustainable mode with 15 years of nearly constant number of squares worked each year. EME would also perhaps give the same results, but it would need a lot more sleepless nights. There have been variations in my activity for personal reasons and this can be seen as well. It is not caused by poor conditions. The station has technically evolved from 1978 to 1993. After 1994 there has not been any meaningful upgrades and it also shows. The curve follows a negative polynomial distribution.
 
 

OH5IY'a  rigs & projects timeline (H.B. = home made):

  1977 Josty-kit VHF (100-200 MHz) to FM-band RX converter and 7-el Yagi for 145 MHz

  1978 144 MHz FM only (Pye Bantam HP1FM), H.B. 10W PA (w. BLY88), H.B. 2*7-el, no pre amp.

  1978 HF Heathkit SW-717 receiver & 2-tube 3.5&7 MHz 10 W TX with PL501 tube

  1979 144 MHz IC-211E 10 W Multimode, H.B. 2*11-el, H.B. 40673 FET pre amp (indoor)

  1979 TS-120V HF rig, 3.5 MHZ dipole, 21 MHz GP, later 3-el Yagi for 28 MHz.

  1980 144 MHz H.B. 45W PA (w. BLY90), H.B. 4*11-el (per RSGB) odd stacked, H.B. BF900 pre amp (indoor)

  1981 144 MHz H.B. 120W (GS9b tube) PA, 18 m tower and H-frame & elev, 1/2" air-spaced feedline, 4*11-el, H.B. BF981 pre amp at tower with RK-500 relay, 432 MHz IC-402  and 10W PA with CTC12/20 and 8*15-el. NBS Yagis . 19-el H.B. C-C Boomer at KP31JK QTH

  1982 144 MHz H.B. 250W (2*GS9b tubes) PA, 4*15-el H.B. CUEDEEs (1'st of CAD designed), BF981 and H.B. S3000 pre amps at mid tower

  1983 144 MHz H.B. 400W (8874 tube) PA, 1296 MHz F9FT 23-el. Yagi on roof mast

  1984 144 MHz H.B. 1000W (2*8874 tubes) PA, new OH6RM- built telescopic tilt-over aluminum tower, larger H-frame, H.B. MGF1200 pre amp at mid tower height, RK-500 relays, 432 MHz 8*21-el. F9FT's, MGF1xxx preamp, RX downfeeds AJS75-5

  1985 144 MHz H.B. 4*14el at /4 QTH with H.B. S3030 pre amp at the "new" (ex. KP30 top section) tower with H frame & elev. at KP31JK

  1986 TET-tribander for HF

  1987 28 / 144 MHz H.B. transverter built for IC-720A as spare 2 m radio for KP31 QTH. Sold with IC-720A in July 2007.

  1988 144 MHz Yagis extended to 4*18-el, H.B. MGF1202 pre amp, HF-1000 relays (144 and 432), H.B. MGF1200 pre amp at KP31JK QTH

  1989 144&432 MHz feedlines now 7/8" Heliax foam,  H.B. 290 W (4CX250R tube)  PA for KP31JK

  1990 144 MHz Yagis cut to 4*17-el, semi air-spaced phasing lines (Flexwell 103-type)

  1991 new 4*15-el K1FO-design Yagis (commercial), phasing cables 1/2" Cellflex foam, H.B. MGF1302 pre amp.

  1992 built 144/50 MHz H.B. transverter (taken to /4 QTH in y. 2000).

  1993 H.B. MGF4316C HEMT 144 and 432 MHz pre amps, w. HF-1000 relays moved to a new tower-top box, RX downfeeds AJS75-5

  1994 DTR for MS CW reception

  1997 FT-736R Multimode (50 MHz added in y. 2000)

  1998 1296 MHz F9FT 23-el. Yagi moved to tower top with MGF-1402 + MMIC pre amp and Mitsubishi 10 W hybrid Pa.

  1998 432 MHz antennas changed to 2-by, 4-stack configuration with added vertical pipes on the H-frame and 1-to-4, 1-to-2 power dividers, 1296 MHz 10 W Mitsubishi hybrid PA and  MGF-1402 pre-amp. installed at tower-top

  2002 extensive tower-to-house cable re-routing via underground SS-pipe and a grounded Entrance Panel with surge arrestors, etc.

and moving up in bands:

  2006 new (dual band) transverter built for 23 cm also with 13 cm from DB6NT's MKU 13G2 and MKU 23G2 kit modules

  2007 10 GHz OH5TEN beacon built from ex-SHF converter LO multipler chain and DB6NT's 10 GHz LO PCB + FLX102MH 0.9 W PA and installed on 1.8 m dish

  2007 transverter built for 3 cm from DB6NT's MKU 10G2 kit module + H.B. FMM1011 FET PA with about 1.2 W output to 52 cm dish feed of a portable setup with FT-790R2 and a FT-290R driving the 13 cm transverter with H.B. 4 W FET PA

  2008 /4 QTH's IC-211E replaced with IC-703 and the H.B. 144/50 transverter modified to 50/144MHz with IC-703, also built a 100 W HF-broadband transitor linear amplifier for the system

  2008 built 28.8 MHz OH5TEN G3RUH-10 MHz-GPSDO locked frequency standard beacon built, 2 W to a canted dipole@ 9 m AGL

  2009 summer/fall: time consuming field-strength surveys with portable SPA of all local radio beacons up to 2,3 GHz to verify radiation patterns at distances from 10 m to 40 km LOS paths

  2009 70 MHz  beacon built with USB synthesizer and 5 W FET PA, 5 W

  2009 10 GHz OH5TEN beacon  QRT, beacon taken down and modified to use 108 MHz drive from new USB-synt. source ovenized for stability and uC Morse ID keyer

  2010 10 GHz beacon installed to a new site as OH5SHF and in operation since April with 8 W ERP H-pol. omni

  2010 70 MHz OH5RBG beacon installed and in operation since late May with 5 W RF output and AV 1462-70 (5dBd) antenna towards SW

  2010 New high gain sector antenna built and installed on OH5SHF 2.3 GHz beacon resulting more F/S data field work to verify result and gather 10 GHz beacon F/S data

  2010 Home station on-roof antennas taken down and reconditioned, modified/downsized and installed back on roof on 3 new Aluminum masts of which one bent under snow load and was replaced with a steel mast

  2010 OH5SHF 1296 MHz driver rebuilt with MMICs and a 1W Mitsubishi hybrid driver added, slot antenna retuned and fitted with better radome resulting in-band resonace, low SWR and some 8 dB more ERP to horizon partly by full 10 W output instead of 4...6 W as before

  2010 2.3 &10 GHz portable rig's transceivers replaced with a FT-817ND w. home made paddle and the 1296 MHz transverter separated to home stn use with FT-290R

  IC-211E rebuilt as 1296 MHz home station with PA0KLT synthesized VFO and built-in MKU13 G2 transverter

2011 a 2 week overhaul of mast and antennas, water in one 432 MHz RG-8 balun (replaced), 1296 MHz 1/2" Heliax TX coax found to be lossy and wet: replaced with Ecoflex 15 and RG-8 (now w. rotator bypass loop), 1296 MHz BFQ68 driver re-located to tower top box, 1296 Yagi moved up 35 cm, CCTV camera plastic window replaced, camera tested: OK, 144 and 432 MHz HF-400 coax relays serviced. Rusted bolts and clamps replaced, corrosion prevention, lubrication, new tower top bearing's water shield cone, new upper mast section release-by-wire safety lock, new pulley for tilt-over winch cable, new stainless shackle pin on upper mast  hoist cable pulley. Some 70 h of work.

2017 one+ day overhaul, 144 MHz and 432 MHz RX preamps' downfeeds from tower top box replaced with Tasker RG59 Flex coaxes (total length 30 m both) to house outer wall entry box;  The Swedish made unsoldered Cu braid 432 MHz AJS75-5 coax's inner core had slid down  (hanging loose 10 m from H-frame) by 2.3 mm and BNC center pin failed to make contact at tower top box since Sept. 2016 after 23 years. This cable cover had minor chaffings -> slight braid oxidation, tower base BCN joint to RG59 found full of water, but no oxidation. Emotator rotating mast tube clamps were very loose!!! (wind?), tightened and top bearing greased with PTFE vaseline spray. The 432 MHz preamp input selector coax relay failed to make contact to back-up preamp, not fixed - should be replaced with better relay. 10 h of work.

 

HF rigs: H.B. 2-valve 3.5 MHz transmitter and Heathkit SW-717 receiver + a dipole (Nov. 1978 -Mar. 1979), Kenwood TS-120V + a 21 MHz GP (March 1979-1986?), Icom IC-720A (sold to OH6NNZ July 2007) + TET HB-33M tribander 1986-2010...and then as tri-band dipole, 2-el. 14 MHz wire beam 1987-, 21 MHz GP 1979-1980, 21 MHz HB9CV 1980-1982, 28 MHz 3-el 1982-1986, 14 MHz GP 1981-1986, 3.5 MHz dipole1978-2000), Yaesu FT-757GX (since May 2005). KP31JK: IC-703 and 100 W transistor PA and TET 3-el. tri-bander since 1988).

50 MHz rigs: H.B. xverter (pre 2000, after:) FT-736R, Tokyo HyPower HL55V (55W). After 03-2002 120W TE 0510G PA. Ant: 7-el (pre. 1994), 4-el (after 1994). KP31JK: H.B. xverter  + (pre. 2001) BLY88 10W PA, (after 2001:) Tokyo HyPower HL55V (55W), after 2008 IC-703, 5-el Yagi since 1988.

VHF-LOW & FM band antennas: currently LPDA 60-110 MHz, two 3-el. Yagis for MS reception.

144 MHz Aurora receivers: Nokia SV-1300 (1995-2000), Salora SRP-22 (2000-2005), Yaesu FR-101 (2005-)

432 MHz rigs have been: a varactor tripler+H.B. converter (few months), IC402 (1981-1989?), SSB-Electronics xverter TV144/432, (1987-1997) FT736R (1997-). Antennas: 17 element, 2*15 el NBS, 8*15-el NBS, 8*21-el F9FT. Preamps: BFR90 or BFT66, 3SK97, MGF1402, MGF4316C. PAs: (20W) CTC 12/20, (50W) MRF-648, (800W) 2*8874. KP31JK: 15-el 1986-1988

1296 MHz rigs: 1982: H.B. 144/1296 MHz xverter and 1 W PA, 1985: FT-290R driving xverter with SSB-Electronic USM-, UEM-series modules and Mitsubishi 15W hybrid PA, since 1998 also on tower top. From Nov. 2006: FT-290R driving DB6NT MKU23 G2 kit transverter for 23 cm. From Dec. 2010: re-built IC-211E for 23 cm with DB6NT MKU23 G2 transverter inside. Antennas: horn, 23-el F9FT, modified 21 el F9FT. Preamps: BFR-90, MGF-1402.

2320 MHz rigs: FT-817ND (Sept. 2010-) driving DB6NT MKU23 G2 kit transverter with 24 Vdc 4 W PTF10041 FET PA (May 2007-). Antenna: 4-loop panel (2006-2010 April). For portable operation a 0.64 m (0.54 m 2007-2013 TD54) aluminum offset dish on a tripod with the rigs. Only /P operations in summer.

10368 MHz rigs: FT-817ND driving DB6NT MKU10 G2 kit transverter with 1 W FLM1011 PA (May 2007-). Antenna: 0.54 m aluminum offset dish on tripod. Only /P operations in summer.
 
 

Ham Radio Stations

Due to my professional and personal interest in electronics (RF) projects, I have spent a lot of my free time in designing, modeling, constructing and testing antennas, pre-amps, RF power amplifiers, transverters, two Meteosat SDUS receiving systems, etc. I live alone in my own house which has plenty of garden for the antennas here in KP30HV, the KP31JK QTH is nowadays my brother's property and I have spent little time there since. Besides the home station, I have built, installed and maintain two 10 m, 6 m, 4 m, 70 cm, 23 cm, 13 cm and 3 cm beacons: OH5RBG on 70.033 MHz in KP30HW, OH5SHF on 28.2285 MHz, 50.033 MHz, 432.435 MHz, 1296.935 MHz, 2320.935 MHz and 10368.935 MHz in KP30HV, the GPSDO frequency standard radio beacon OH5TEN on 28.8000 MHz and the local 2 m FM repeater OH5RAC on 145.700/145.100 MHz, all licenced under the local radio club OH5AG. All these, except 28.8000 MHz OH5TEN are in Kuusankoski at high location 145 m above sea level. The 28.2285 MHz beacon has been reported heard in USA, the 50 MHz and 70 MHz beacons all over Europe via sporadic E. The 23 cm beacon has been heard in Czech Republic during tropo, 13 cm beacon in Poland and the 70 cm beacon in Germany and 3 cm beacon in Sweden. The repeater provides mobile coverage for the upper part of the river Kymi (Kymijoki) valley area.


Spectator comments: "Se on tutka!".
"...se puhuu ympäri Eurooppaa, mutten tiedä millä kielellä...".
"Kato!" - "Mitä?" - "No tota tuolla ylhäällä - se on iso!"

At my home location I have antennas for 7 ham bands and many non-ham bands. HF-tribander (cut to a trap dipole in 2010) with add-on 50 MHz elements, an array of 4 Yagis for 144 MHz (<68 kW ERP with 800 W RF) and an array of 8 Yagis for 432 MHz (<95 kW ERP with 700 W RF), which enables contacts on all available VHF propagation modes. The second 144 MHz 4-Yagi array is in KP31JK with a 4CX250R PA.

I had special perimit to run 1 kW on 2 m and 70 cm on 400 kHz wide segments from 1982 to 2003, but in 2003 these segments were sliced due to Ficora's policy change, to include just random EME & MS frequencies and called for extensive studies verifying certain field-strength values would not be exceeded at any nearby receiver or antenna. In 2005 the paper included just 2 m EME & MS random segments and nothing on 70 cm, so the revised permit was made worthless to me and it was not renewed - the present general class licence allows 600 W CW output on 2 m and 70 cm, I lost just about nothing and EME is still quite possible. Other QSOs I  run barefoot with minimal power. Noise level in KP30HV (360&deg; picture!) on 144 MHz is high from some directions, not what it was in 1980.

On mobile I use a 50 W 2 m Icom FM transceiver.

Portable V/UHF contesting

 VHF-UHF-SHF contesting is best done from locations where antenna can be located high above the surrounding terrain and tree tops. The higher the frequency, the more it helps to go portable. I have taken part on the NACC contest from numerous sites on 50, 144, 432 and 1296 MHz over the past two decades and more recently, on 2320 and 10368 MHz. The 1296 MHz results have been better than what I can do from home, but even 50 MHz contesting has been successful and  fun to run outdoors in the summer. Mosquitoes and rain have sometimes given some troubles and in August and September full darkness, when hauling the equipment back to the car at midnight - the job often assisted by local hams who have joined these 4 h long expeditions - thanks!

The best site used to be in the (northern Kymi-river valley) area inside KP31-grid has been the Mustalampi in the Repovesi sanctuary view tower located now in the roads-closed area. Other sites inaccessible with car, have been an unfinished slalom hill-top near Siikava, Jaala (treetops to SW) and Hiidenvuori on the other side of Pyhäjärvi-lake (1 km walk up). Sites accessible which car, are the broadcast microwave link tower's hill in Jaala, Vuohivuori in Voikkaa (unfortunately not in KP31-grid), and top of a high ridge, top of a mountain and a private commercial lookout tower near Jaala and occationally an open field with a very low hill near the KP31JK QTH. At home 2,3 and 10 GHz QSOs work out fine from middle of nearby large field with 1 km take-off of slightly setting slope.

Of the truly hilltop sites, the most beautiful sunsets are seen from Mustalampi and Hiidenvuori with wide open views for tens of km, but you need to walk all the way up and Mustalamminvuori being part of sactuary, is of course closed for car traffic - can be accessed better with a boat nowadays. The portable activity was revived in 2007 July by the radio club OH5AG leasing the late evening hours at historical Elving watch tower (KP31JD) and activating probably for the first time ever 2.3 GHz  and 10 GHz bands from KP31-square.

The equipment has consisted of sealed 12 V lead-acid battery (15 to 40 Ah) or power tool battery pack, a lightweight 4 m Alu-tube as mast, feeder cable, antenna, transceiver + PA, memory keyer, mic., logs, fastening accessories and some food - sometimes including a portable grill for BBQ, if there has been more than 3 fellows sharing the loads.

We operated in drizzle, in sunshine, fighting mosquitos, sometimes in freezing cold under starry skies in late April's dark nights. Some of the most memorable incidences include getting lost after walking 100 m in midnight's darkness in September after signing off - only the tower's silhouette against the sky guided us back to take the right heading. The other occasion was during a 1296 MHz NACC, along the CW contest exchange OH2TI relayed me an unexpected, but interesting 2 m meteor scatter sked with a rare and distant Danish MS expedition in Turkey, scheduled to be 4 hours later from my home station. On one occation we enjoyed a visit by a sergeant with AK-47 - the tower was planned to be used for distance evaluation practice spot for some military training, but fortunately they re-scheduled for us.

For 10 GHz (or those bands) portable work the Finnish lake area is terrible. It is hard to find (new) sites for portable microwaving, most of the promising hilltops with high ASL typically have narrow sectors clear of trees opening to directions with nobody to work with. This was again noted also at Tahkovuori area during the 2011 expedition to KP43, KP33 squares (and KP42 on way back), though with help of rain scatter, aroplane reflection and hard trying, most of the QSOs attempts were succesfull. Lake shorelines are either unaccessible by car or are full of summerhouses or just thick tall bushes.  As the lakes here were formed by ice age, all run SE-NW, so the free path over a lake towards SW is fairly short anyway. Open fields in the lake areas are found in the flat areas between the hills, with low elevation with always a hill full of forest behind it. Local area's three bird-watch towers have all nearby blocking tree tops or some nearby hill blocking the take-off to OH2. Microwave contest have been most successful from lookout towers since there are absolutely no nearby trees in the horizon. Some dump site hills also have few trees, but getting on top may mean carrying the equipment up.
 

Small HF tribander & 6m on same boom


A tribander is basically a long-spaced 28 MHz Yagi. To make a 28 MHz Yagi resonate also on 21 and 14 MHz, the elements are electrically lengthened with coils, which have two parallel resonant circuits in series; the inner trap cuts 28 MHz because this coil's inductance + trap's inner tubing vs. outer tubing capacitance resonate on 28 MHz. The coil closer to boom serves also as loading coil for trap's outer tubing to make the element resonate on 21 MHz. The element tip-side coil resonates on 21 MHz with the trap tubing capacitance and blocks 21 MHz current from entering the element tip, while both coils in series pass 14 MHz and act as series loading coils and makes use of the full tip-to-tip length of the element which resonates on 14 MHz. However, such electrically shortened element  is not merely a good thing - the more coil(s), the shorter the element mechanically, the narrower the bandwidth of good SWR (on 14 MHz).

3-element HF tribander's trap's resonant frequencies are usually around 27.6 & 20.9 MHz for Reflector, 28.3 & 21.2 MHz for Radiator and 29.6 & 21.4 MHz for Director element. The mini beam design below is little different since it does not have a passive Yagi-type of reflector and I only have measured the inductances of those traps (with MFJ-259B). In case you are interested why Yagi's directors are (successively) resonant at higher frequencies, it's because Yagi basically is a dielectric-type of antenna that uses directors to slow-down and gradually bend the approaching EM-wavefronts from around the antenna (to increase it's effective surface collecting area, in 3-D) to focus them on the Driver-element(s), from which the RF power is drained from with the feed arrangement. This applies to receiving, same works the other way around when transmitting. The passive reflector-element is just a back-stopper that reflects the energy uncaptured (or re-radiated?) by the driver, back to the driver - otherwise it would leak out and escape from the back of the Yagi (giving a bad F/B-ratio and a little lower gain).

Below is a diagram of a HF tribander antenna - detailed enough to build one, if one wishes, though it takes some time, material and tools, but it is entirely possible. Perhaps the most trickiest part are the traps - the basic 28 MHz 3-el. Yagi, which the antenna without the traps actually is, works for sure (as it is - on 32 MHz). The construction is a dual-feed type, where so-called "reflector" and radiator are both fed with a balanced line at 180 degrees out of phase, while the third is a parasitic element, a director, is as in any Yagi. The tribander's feed point is balanced, so a 1/1 ferrite balun for HF is used to feed it with a 50 ohm coaxial. Maybe this can be left off, if you don't have it and be replaced with roll of coaxial acting as a choke, or ferrite sleeve balun, but they do not provide DC-short to remove static buildup. It would be useful to connect the feeder's braid to the boom (but not from the feed point side of the choke) of the antenna, which is grounded via the mast clamp. The original commercial balun was a stub made with 2 parallel coaxial of about 1.2 m long, the otther coax (just braid used) connecting the feeder's center conductor from feedpoint to braid of the coax 1.2 m away (wrapped in a roll). After 30 years the sealant material gave away and the DC short began to fluctuate and so did signal, down to about -7 dB on 28 MHz, just 1 dB when heated with 100 W RF, but that did not last longer the some minutes and the signal faded again. It was also prone to mechanical shocks, ie. turning the antenna. That balun  got replaced with ferrite sleeve balun. The feeder runs via grounded transient protection box, which provides the DC short.

The TE-33M antenna in a new design form is manufactured and available from Australia at TET-Emtron.

This antenna takes little space, is relatively light and we have added 50 MHz Yagi elements (4-element) on the same boom (with a separate feed line). The tribander's performance on 14 MHz of course is not very impressive and the SWR bandwidth does not cover the full 350 kHz band there, but if you rotate it, you get some F/B ratio and side minimas which you can't get from GP or a dipole.

The 50 MHz elements (Alu. OD 15 mm, isolated from boom&clamps with pieces of PVC tubes):
 


which, when built inside the HF antenna, MMANA antenna modeling software gives a bit less gain: 4.2 dBd vs. 6.6 dBd and lower F/B ratio: 7...10 dB vs. 17 dB on 50.1 MHz compared to similar 50 MHz Yagi on it's own in free space. The troublemaker seems to be the tribander's Director-element, which also sinks the 6 m feedpoint impedance very low and makes optimization attempts waste of time - the gain can be raised some, but at the cost of very high losses in the 50 MHz low-impedance driver-element.

Note: if the 50 MHz elements are added, you need to add a 30 MHz LPF on you HF radio to filter out from HF radio's receiver the 50 MHz power coupled to the HF antenna while you are working on 6 m. The 50 MHz mutual coupling is in the order of 13 dB, which means your HF radio will get 4 W of 50 MHz RF, if you run 100 W on 6 m band. 4 W of RF can burn attenuator or switching diodes depending up on how you HF radio's front-end is built.

I spent some time trying to model this antenna with MMANA and got these realistic-looking specifications for the HF tribander:

Gain (free space, 14 / 21 / 28 MHz bands):
2.2...4.1 dBd / 3...4.6 dBd / 4...6 dBd

F/B ratios:
5...7 dB / 6...10 dB / 7...16 dB.

With real-ground modeling you get 8....11 dB of gain for low-angle ionospheric propagation depending on antenna's height and ground quality. The radiation patterns are clear and dull, much like figure 8, so  no need to show them here. 14 MHz band modeling of the tribander with MMANA software proved quite difficult, as the nominal set of elements and loads tended to resonate on 13 MHz.

14 - 21 - 28 - 50 MHz Yagi antenna

As a conclusion, I would say nothing beats a monobander with un-shortened elements - I have had them on 20, 15, 10 and 6 m, but if you are not a competitive contest freak, DXer with 300 countries worked, you don't need high gain, don't want to darken the skies with monobanders and upset neighbours, or have little space to set up rotatable beam antennas for HF high-bands and 6 m, an antenna like this may be the solution. I have made contacts around the world with it on all 4 bands.
 

Downsizing the tri-bander

 After roof renovation in 2010 there was eventually not enough space to rotate the TET HB-33M beam and the windload for the new mast was just too much to raise it at any resonable height over the roof.

I removed the reflector and director elements and phasing line -  making it a 3-band HF-dipole built on a boom that had 4- element Yagi for 50 MHz too. Naturally the loss of directivity resulted on HF and also antenna gain went down on 28.2 MHz by -3.2 dB and 28.8 MHz by -3.9 dB with SWR hovering around 1:1.7 (best on 30 MHz) (mounted low over metal roof). So did the 3-element antenna ever have more than 3 to 4 dBd gain on my roof (even on 28 MHz)?  I have no data for 21 or 14 MHz but I assume the gain loss was alike or worse and now the HF antenna that worked like a trap dipole, is a trap dipole.  I noted the 28 MHz band does have -0.2 dB F/B ratio (caused by the 50 MHz elements).

The 50 MHz Yagi's reflector was pulled back by 15 cm and last director forward by 20 cm and all elements were cut in lenght by 40 mm to make SWR better on 50.1 MHz. The result of these changes (biggest of which was removing the HF beam's director) resulted in increase of gain by 2.4 dB (now perhaps 7 dBd) and better SWR on 50 MHz band. Since I work mostly on 50 MHz and above,  I gained more than I lost, but I can still listen and also transmit if necessary, on 14-21-28 MHz bands with a rotating resonance antenna.

Antenna gain bandwidth by using static noise as source.
 
 

Home Computers

OH5IY's Computer timeline:   1981 Commodore VIC-20 +  16 kB RAM  + H.B.-converted C-cass. tape rec + Teletype prn + 14" ASA 7000B TV (VIC-20+C-cass tape stored)
  1984 Commodore C-64 w. SX-64 kernal + C-1541 floppy drive + MPS-802 matrix printer (sold in 1991)
  1991 IBM clone PC XT 8086 9 MHz + 640 MB RAM + 20 MB HD + 360 kB FD + Hercules green monitor + CGA output to TV (trashed)
  1991 PC AT clone 286+287 16 MHz + 2 MB RAM + 20 MB HD + 1.44 FD + 14" VGA (trashed)
  1993 two Toshiba T-1000 SE  B/W XT 8086 Laptops + 2 MB RAM cards (MSDATA) (floppies gone bad)
  1994 PC Intel 486 DX 33 MHz, 4 MB RAM, 120 MB HD, 1.44 FD (trashed)
  1996 PC Intel 486/120DX4 120 MHz, Opti Green + 16 MB RAM, 1.2 GB HD, 4xCD-R,Canon BJ-10e printer (trashed)
  1997 Dual 286 B/W laptop (RF noise generator, trashed!)
  1998 PC Intel Pentium II 233 MHz, Intel AL440LX + 64 MB  (given away... KP31)
  1999 Compaq Contura 400  386 25 MHz B/W laptop (trashed)
  1999 Compaq LTE-5200 Pentium 120 MHz laptop, no CD drive (trashed!)
  2000 PC AMD K7/1200 KT7A 384MB, 6.4GB....(runs MetRec)
  2002 Dell Latitude Cp Pentium II 233 MHz (runs MS-data collection under DOS)
  2003 IBM 486DX 120 MHz laptop (trashed)
  2003 PC AMD 2.3+, A7V8X-X ...(in use)
  2004 Compaq Armada M300 (uploads MSDATA and grabs webcam images)
  2009 Used IBM laptop (misc. use, several)
Copyright 1997... 2017  Ilkka Yrjölä.