Hits:  since 20050614

OH5TEN & OH5RBG HF, VHF and SHF Beacons

Tout door[C] / f[kHz] 10 m BCN
4 m BCN 6 cm BCN 3 cm BCN GPSDO locked <2*10-10
+20 C

<1 min from start-up: GPS lock
+15 C
70 032.823 5760 935.260
(Ta +23.8C)
@ 5 min: +-10 Hz
@ 15 min: +-3 Hz
+10 C

+5 C 28 227.982 70 032.784 5760 934.800
(Ta +23.8C)
10 368 935.040
0 C

-5 C 28 228.007
5760 935.030
(Ta +22.9C)

-10 C

-15 C

Most recent measured  "mark" QRGs underlined:

Equipment used: MT8802A locked to GPSDO reference.

Try your DSP FFT display on these at great ranges!

OH5TEN&RBG Beacons' ODXes

OH5TEN 10 m bcn:  EA5OM 2965 km (40 spots/a)
OH5TEN 6 cm bcn:  OH2AXH 92 km

OH5TEN 3 cm bcn:  OH2AXH 92 km
OH5RBG 4 m bcn:   CT1HZE  3606 km (50 spots/a)

Ham , BC & air frequencies in KP30: Link to: Six and Ten Reporting Club
114.599 MHz 200  W ERP UTTI VOR, AM CW ID: "UTT"+FM voice WX
105.700 MHz  30 kW ERP Radio Nova RDS: 6209 __NOVA__
102.700 MHz  30 kW ERP The Voice RDS: 62AB _VOICE__
 99.500 MHz  30 kW ERP FSR Mix RDS: YLE_X3M_ YLE_VEGA
 96.900 MHz  30 kW ERP YLE Radio Suomi 6203 YLESUOMI
 92.800 MHz  30 kW ERP YLE X RDS: 6202 __YLEX__
 88.500 MHz  30 kW ERP YLE Radio 1 RDS: 6201 YLE_YKSI
 70.033 MHz  15 W  ERP
 28.228 MHz   4 W  ERP

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            We also QSL (OH5TEN OH5RBG    via OH5IY )

"Corrected" Tropospheric Path Loss = TX ERP [in dBm] + RX Ant. Gain [dB]  -  RX feed line loss [in dB, often negligible] - antenna height loss  [in dB, see graph below] -  -145 dBm [CW RX sensitivity level] - band noise above 290 K [in dB, from upper graph per  your location's man-made noise level]

It is expected your RX system Noise Figure is substantially below 3 dB! (RX k curve)

Using the calculated Corrected Tropospheric Path Loss value, you are able to determine the approximate maximum range (CW mode) from upper graph (signal received 50% of time).

Note: the "Corrected" Path loss here is used include effects that reduce RX S/N ratio specially on 50 and 28 MHz due to higher noise levels on those bands to get the true range and not just pure path loss. If you need only the path loss for shorter range to estimate signal level when S/N is not an issue, do not correct for band noise!

Note: Range can be reduced by lower TX and/or RX antenna's height,  terrain and other obstructions and by factors such as poor RX system Noise Figure, higher local noise level which to some degree, can be corrected using the graphs.

OH5RBG 70.033 MHz 5 W beacon

OH5RBG's 70 MHz  beacon's ground wave coverage. Computed signal strengths (S-units) with 8.5 dBd RX antenna at 25 m above average ground level with unobstructed take-off, S 1 = 0.2 uV (-121 dBm) @ RX input.

The 70 MHz beacon was built during fall of 2009 with latest technology: USB-controlled synthesizer, PIC-based PC-configurable keyer and MMIC driving the FET PA. The basic scheme works for all bands from 28 to 70 MHz with just modifications to driver LPF and PA stage coils and capacitors - the single-ended FET PA is narrow-band type. Using the 175 MHz application sheet for RD06HVF1 FET, the beacon can be built for 144 MHz operation also. 432 MHz model would need different version for the synthesizer chip - the faster LVDS reaching up to 910 MHz.

The first built beacon module was for 40 MHz, but uncertain and troublesome licencing caused a rebuild to 70 MHz (took some 2 h) which has been a ham band in Finland since 4th Nov. 2009. The enclosure holds the 70 MHz beacon TX module with G4JNT keyer and a 4.5 A SMPSU. FET PA feeds some 5 W to a horizontally polarized low-gain (7 dBi) antenna (Aerial AV1462-70) beaming Az. 232 (SW for sporadic-E propagation) mounted on a cellular tower on a hilltop 131 m + 8 m ASL and delivering 15 W of ERP.


In detail, the synthesizer, which is configurable for any QRG from 3.5 to 260 MHz in 1 Hz steps (and for exact FSK shift) via the USB connection, delivers a 0 dBm (square wave) fed via 2- section LPF to ERA-5SM MMIC amplifier. G4JNT RS-232-configurable PIC-keyer keys the SDR-Kits USB-synthesizer. The +16 dBm drive feeds a low-cost SWR tolerant Mitsubishi PA FET delivering 5 W RF-output. The output is filtered with several LPF stages, one for UHF for added attenuation on cellular frequencies (harmonics are attenuated by 119 dBc on 900 MHz UMTS band). Total currrent is monitored with a 2 A analog panel meter. The antenna output circuit has a 230 V gas-disharge tube, 2 kV series capacitor and antenna connector & case bonded to site ground bar.

28.228 MHz 50 MHz 70 MHz 432 MHz 1296 MHz 2320 MHz 5760 MHz 10368 MHz
TX Pout
+37 dBm,
5 W
+49 dBm,
75 W
+37 dBm,
5 W
+40 dBm,
10 W
+40 dBm,
10 W
+29.3 dBm,
0.83 W
+32.2 dBm
1.66 W
+28 dBm,
1 W
Refl. coeff, VSWR
pi (LC)-match -26.5 dB,
-14.6 dB,
-18.4 dB,
-15.6 dB,
<-16 dB,
1/1.37 or better
<-8 dB,
1/2.3 or better
Pant, ERP
4 W,
46 W,
4 W,
8.4 W, 
26.5 WERP
8.3 W,
0.68 W, 
30.4 WERP
1.66 W,
0.6 W,


OH5TEN 28.228 MHz 11 W beacon


 This TX uses QRP2000 Si570 synthetizer followed by MMIC amplifier stage driving RD16HHF1 10 W FET power amplifier. The MMIC is CW keyed with a G4JNT keyer.  With 1.4 dB cable lossses and mid-line power splitter LC-match, some 4+4 W of RF is fed to crossed dipoles for circular polarisation at 8 m AGL. The ID "OH5TEN KP30HV" is send  every 50 seconds and in between 30 seconds of carrier.  Expected frequency stability is +-50 Hz annually. Si570 chip is thermally stabilized with QH40A heater. Ambient temperature varies from +10 C to +25 C (winter/summer).

Hor. pol. Vert. pol.

OH5TEN's 28.228 MHz  beacon's ground wave coverage. Computed signal strengths (S-units) as received with a 6 dBd antenna at 25 m AGL.

OH5TEN 5760.935  and 10 368.935  MHz beacons

5.7 GHz: Si570 local oscillator (120 MHz) with QH40A heater, indoors, at room temperature. The Si570 synthetizer drives ODU via LPF, an ERA5SM MMIC stage followed by BPF and is +Vcc CW keyed from G4JNT keyer.
14 V DC from 4 A SMPSU is fed to ODU via Lo coaxial cable with bias-Ts, ODU drawing about 1 A current. The mutiplier is a DB6NT kit (5.7 GHz modified link TX kit). 5.7 GHz PA is a commercial Walkera PA5801.

10 GHz: GPSDO (108 MHz) indoors at room temperature, drives via LPF and 6 dB pad a +Vcc CW keyed (G4JNT keyer) ERA5SM MMIC stage followed by BPF. The 14 V DC power from shared SMPSU is fed to ODU via Lo coaxial cable with bias-Ts,
 ODU is drawing about 1 A current. Multiplier is a DB6NT kit (10 GHz BCN TX unit). 10 GHz 1 W GaAs-FET PA is from Dirk Fisher Elektronik. Exact frequency of this beacon is  10 368 935 040 Hz.

ODU is build inside an ex. Allgon 900 MHz base station panel, enclosing two 1 m long home-made waveguide slot antennas, one each for both bands, made from std aluminium profiles, slots milled with Dremel-type hand tools and
 delivering horizontal polarisation, very flat beams, 13 dBd (5.7 GHz) and 16 dBd  (10 GHz) of gain illuminating 100 wide sectors centered at WSW with 5 of up-tilt to climb over an adjacent hill and treetops there.
 Because of the tilt, these beacons work better on rainscatter propagation, than on tropo. Except for the opening towards WSW, there is substantial treecover, but also some narrow gaps to S and SSW.
The 10 GHz coverage map is modified to account for the trees blocking the takeoff.

Radioclub of Kouvola (Kouvolan Radiokerho ry.), OH5AG is the license holder of  OH5TEN and OH5RBG.

Non-ionospheric path F-S measurement data of OH5SHF,  OH5TEN and OH5RBG beacons, Aug. 2015....:

OH5IY measured Prx (@input) Ga , line loss hant

28.228 MHz @ QRB 10 m, TET dipole +8.8 dBm (HF ant. 70, VHF array: 130) 2-2017
+0 dBd, 1.0 dB 9 m
28.228 MHz @ QRB 2.1 km 260.43 deg, dipole
-54.5 dBm H, -52.5 dBm V
0 dB, 0.5 dB
6 m
70 MHz , LPDA -55.6 dBm 07-2016
+2.5 dBd, 2.5 dB 10 m

5.76 GHz, 13 dBi horn -43 dBm at 335 m  az 226 (TX high tilt 5) 07-2016 / -44 dBm 05-2017 11 dBd, 0.5 dB 2 m


10 GHz, TV SAT LNB +3.2 dBm at 335 m  az 226 (TX low tilt 0.5 - just for the test) +49 dBd (horn+LNB), -1 dB 2 m
10 GHz, TV SAT LNB -17 dBm at 335 m  az 226 (TX med. tilt 3.5 - first weeks) +49 dBd (horn+LNB), -1 dB 2 m
10 GHz, TV SAT LNB -25.7 dBm at 335 m  az 226 (TX high tilt 5 in use) 07-2016
+49 dBd (horn+LNB), -1 dB 2 m




OH5ADB received in KP30HV on 144.455 827 MHz with 19.7 dBd antenna and 1.4 dB feed losses at -117 dBm.

Copyright 2004...2017  OH5IY, the beacon keeper