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LOW BAND DXing ....... direct link : How make 4-directional Flag and Preamp










New GP antenna for 160/80/40/30m

PreAmpAD8129 PreAmpAD8129

GP160/80/40/30 GP160/80/40/30 GP160/80/40/30 GP160/80/40/30

2018 year ......Modification of the preamplifier and new experiments....................................................................................


Signal of ZF9CW ARRL 160m contest

Signal of K1LZ ARRL 160m contest


PJ4/K4BAI 160m Pile-Up 20 Nov 2018

8P9AE CQ on 160m 12 Nov 2018

9X0T Pile UP on 160m

Signal of 9X0T on 160m

Signal of 3B7A on 160m

Signal of 3C0W


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. 34—37.

2. Breed G. The K9AY Terminated Loop — A Compact, Directional Receiving Antenna. QST, Sept. 1997, p. 43—46.


You can download all info about this project as one file





Block Diagram


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 Injector inside



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)








PCB Preamp




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