Amateur radio station since 1993
RA3WDK `s Homepage
LOW BAND DXing
Direct link : How make 4-directional Flag and Preamp (old vers.)
New design injector (new version with buttons and USB control)
Schematic new injector -Beta version
Season 2020 starts soon !
Winter Season 2019
News for me on Top for last time
CE8EIO, PJ0DX, FG/F6HMQ, V84SAA, A5A, V31MA, V31VP, V31YN, TO3Z, RI1ANL, AH7C, HK3W , ZL3RJ, VP2MKG, ET3AA, 9LY1JM, 5X3C, 3B8XF
Beverage on the ground... or on the snow with preamp (2N3866)
About 100 m RG-58 to 230 degrees azimut (for SA ?) L=l* velocity factor (0.66)
2018 year ~ New GP antenna for 160/80/40/30m
Signal of ET3AA on 160m has been received and make QSO 19 Jan 2019
2018 year ......Modification of the preamplifier and new experiments....................................................................................
Signal of H7/RM0F on 160m has been received and make QSO 28 Nov 2018
Signal of TJ2TT in Pile-Up on 160m has been received by Quad Direction Flag (+attenuator of TS570)
2017 year ...... I improved my RX system for winter (2017-2018) season, made Quad Direction Flag with new preamplifier
Why Flag ? Why not K9AY ? K9AY or Flag ?
The K9AY antenna doesn't work without ground. It loses the f/b directivity. It needs good ground. Pennant and Flag antennas are ground free antennas. Not problem with good ground ! The Flag and Pennant are much less dependent on the surrounding ground.
The Flag Antenna is in the family of terminated loops that can yield a cardioid (heart-shaped, single-direction null) pick-up pattern. You can direct null of pattern to local source of noise. Switch ortogonal Flags or reversing direction can be rotate the antenna pattern.
The July 2000 issue of QST magazine published an article by Earl W. Cunningham, K6SE, entitled "Flags, Pennants, and Other Ground-Independent Low Band Receiving Antennas". The work presented in the article includes research by several other hams including Jose, EA3VY. The class of antennas discussed comprises single-turn loops terminated on the side opposite the feedpoint. The termination effects a null off the end where the terminator is located, thereby producing a cardioid (heart-shaped) directional pick-up pattern. The antenna is broadband rather than resonant. The pattern produced holds up well over a wide frequency range.
DL2KQ Igor suggested using a reversible flag and gave the idea to use the AD8129 in a preamplifier for a terminated loop (FLAG). Be sure to detuning transmitting antenna - you can switch antennas tuner to other band, better 30 m or 40 m.
1. Kunningham E. W., K6SE. Flags, Pennants and Other Ground-Independent Low-Band Receiving Antennas. QST, July 2000, p. 3437.
2. Breed G. The K9AY Terminated Loop A Compact, Directional Receiving Antenna. QST, Sept. 1997, p. 4346.
New version Preamplifier with optional filter for 160m band
Circuit with optoconverter for making PTT voltage
Second circuit with two power supply (one power supply only for PTT)
Schematic of connect board for flag
New version PCB (corrected place for transistor)
Signal of 9Y4/UA4CC on 160m has been received by Quad Direction Flag (attenuator of TS570+DSP NR2)
Signal of TN5R on 160m has been received by Quad Direction Flag
Signal of 3C1L on 160m has been received by Quad Direction Flag (attenuator of TS830)
Signal of E31A on 160m has been received by Quad Direction Flag (attenuator of TS570)
2016 year ...... I improved my RX system for winter (2016-2017) season 160/80 m and use for TX inv L with 10m long spiral vertical part and 26 m long horisontal line. I use pre-amplifier for Bi-Directional Flag 4,5x3,5 m with AD8129 and control switch "Front to Back" only by single RF coaxial cable.
My Bi-Directional Flag (H x V 4,5x3,5m)
Signal 9M2TO 160m has been received by Bi-Directional Flag
2014 ......After many years of QRV on VHF and UHF I come back to HF ......
I changed QTH some time ago, but got also high level of noise from neighbourhood. I did not find source of noise - may be modern Led Light, may be remoute control for water tower - I did know. But as result I have noise S9+20 db on 3,5 MHz and S9 on 7 MHz from my GP antenna. Using Magnetic Loop is forced state for this time.
160m QSLs has arrived