Active antenna for  10Khz - 30Mhz frequencies

"Radio Corner"  di R.Chirio

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[Italian version]

August 2013-March 2015

Active antenna, small,  suitable for receiving signals in the HF Band, navtex and meteofax aboard boats and also for lower frequencies up to 10 kHz VLF.
Excellent reception for AM, and Amateur bands SSB and CW. Suitable for all type of receivers for HF band ( ALINCO, ICOM, YAESU, KENWOOD YUPITERU, Tecsun etc..)
The type of operation is that capacitive antenna, electrostatic. The two Armors are represented, the first from the receiving plate positioned on the base provided, while the second refers to the plate earthing. The reception sensitivity is given by the distance between the active and the earth plate. Moving away from the ground improves the input signal as well as the bandwidth down. Accommodation in 3-4 metres from the ground give already receive significant results.
The MiniWhip is available on simple PCB circuit, compact design for use on the scanner and the base unit to be mounted outside on PVC pole with a separate cable.
Can be change, modify and customizations to meet the needs of enthusiasts receiving radio signals.



Full SMD + PCB + 9V socket and BNC-F



Wiring diagram basic amplifier circuit/impedance of adapter (version 2013)



-SMD Strip mounted on the antenna plate, complete with BNC connector (female) and 9V battery socket.

-Total size 40 x 110 mm, 40 x 70 mm surface sensitive 


 Technical characteristics


-With 9V battery the absorption is approximately 4mA. With 12V about 6mA.
-Bandwidth from 10 kHz to 30 MHz (-30dB), a-80dB is still receives up to 150 MHz
-Output Impedance of 200 ohms is suitable for all receiver inputs.
-All MiniWhip can be powered at 12V voltage is accepted from 3 to 15V, lowering the voltage up to 3V reduces the gain and reduce strong signals.


Signal present on the Chirio Mini Whip, you see all frequencies from 0 to 20 MHz. The signal is stronger and leaving many broadcasters do not listen with a conventional wired antenna. Very present all signals up to a few tens of Khz. The antenna was mounted outside the House on a PVC pole from 3 Mt.

mini_whip_008.jpg (55807 byte)



Tube 20 mm version for PVC pole 32 mm suitable for external installation.




January 2014

-In this latest version, the circuit amplifier and receiver plate, are protected inside the pipe from 20 mm. The whole pipe is completely closed and sealed with resin to withstand inclement weather.
-Should be placed at least 2-4 meters high, 32 mm PVC pipe for electrical use. Possibly use nylon cables 3 for fixing upwind.
-The group is fully sealed, vent moisture takes place down through the cable passage.
-With the XP II the descent signal occurs with RG58/U cable and separate power supply with multiple shielded, this solution that reach up to 30 meters of cable down.
-Always presents a great sensitivity on all frequencies from 30 Mhz 0.10-improved low-range of the LW and MW.
-Are easily listenable average and strong signals up to 150 MHz.
-Is recommended with 12V battery, typically with a 12V 7Ah it has over 1 month of battery life. Or via the multi-connector cable you can bring home, always use only 9-12V battery.
-Very discouraged with the MiniWhip network power supply, linear or switching type, introduces too many ailments upon receipt.



- This is the performance of the external antenna, a 12V battery-powered, the spectrum represents all frequencies from 10 kHz to 20 MHz, each horizontal Division represents 2 MHz, while the vertical divisions represent the intensity of signals, we note a marked improvement over the entire range received also the improvement is more pronounced for frequencies below the 20 Mhz.

- The reception was done at hour 22:00 and you can see clearly all the ranges below 20 MHz shortwave SW and their intensity.

- From 100 kHz to 2 Mhz MW and LW received with an excellent signal.

- From 2 to 5 MHz tropical bands-Most other peaks represent the bands of 49 metres, 41 metres long, 31 metres, 25 meters 22 meters 19, m. The last two smaller peaks represent the bands of 16 and 15 yards.

- Not represented by the spectre can still hear well the bands of 21Mhz, 25 Mhz, 27 Mhz CB band and 28 Mhz amateur radio. (All bands more suitable to be heard during the day)





Mini WHIP-XP-II VLF antenna for listening to frequencies below 10 MHz
30 mm tube for version PVC pole 32 mm suitable for external installation.


September 2014

- This is the new version of MiniWhip. The XP II VLF designed to improve reception of VLF, capacitive surface increased over the MiniWhip base.

- PVC tubular Container always but from 30 mm of diameter, length 250 mm

- The DC12V is brought to the antenna through the shielded cables separate from signal, the length can reach even 50 metres without creating problems.

- Output signal on RG58/U cable and BNC connector.

- Internal low pass Filter with-15dB to 50 MHz.

- Ideal Antenna for receiving the frequencies below 100 kHz

- Download Software for VLF reception




- An example of what you can receive under the 25 kHz using the PC's sound card input:    

          VLF mini whip.jpg (1046846 byte)


   Friday, February 13, 2015 rendezvous with the GRIMETON RADIO/SAQ 17.2 Khz


SAQ starting.jpg (1005092 byte)


- Signal received from 14.44.44 using the Spectravue\r program (UTC) 3.28


SAQ sv+v94.jpg (771920 byte)


- Received signal even with SAQ VLF receiver 0.94 Panoramic


SAQ cw decoded.jpg (322797 byte)


-Translation of CW code received





 MINI-WHIP-SR  (Black cap)

BNC connector SMD version for Communications Receiver ICOM IC-R20 



Chirio Mini Whip 2014 scanner version

March 2015


-This new version is designed to apply the Mini Whip directly to the BNC connector of the ICOM IC-R20, okay anyway with all scanners and receivers for HF-band type ICOM, ALINCO, YAESU, KENWOOD YUPITERU, etc..

-The circuit is modified to reduce noise and was reduced to half-body antenna.

-The sturdy brass tube and good quality BNC connector to handle safely the scanner, holding the battery.

-For low signals bring the GAIN of the ICOM IC-R20 until MAX.

-Very good Listening on all HF. Particularly for Longwave and Mediumwave even during daylight hours.

-Enable the receiving party is protected against electrostatic discharge as it was placed inside the insulated pipe, as is already the case for the Mini Whip XP for the base unit.

– with this version, it is not necessary to connect the metal part of the BNC with a ground cable. It is sufficient to hold the scanner to get good receptions.

- 9V Battery, power consumption nom 4.0 mA max 5mA

- Length 160 mm, diameter 16 mm weight 40 g



  See the characteristics of Communications Receiver ICOM IC-R20:






Segnali ricevuti con MiniWhip XP II:


- Segnale a 7.1555 Mhz 40 metri ricevuto il 18/03/2015  17:22  ( Video MP4 14MB )


   Russian RSDN-20 Navigation System “Alpha”


-  Segnale -55 dBm  a 11.905 khz ricevuto il 29/03/2015  15:17  ( Video MP4 11MB )

-  Segnale -54 dBm a 12.649 khz ricevuto il 29/03/2015  15:22  ( Video MP4 8MB )

-  Segnale -58 dBm a 14.881 khz ricevuto il 29/03/2015  15:37  ( Video MP4 8MB )




-  Segnale -68 dBm a 60.000 khz  from UK ricevuto il 29/03/2015  15:47  ( Video MP4 8MB )

-  Segnale -52 dBm a 77.500 khz  from Germany ricevuto il 29/03/2015  15:50  ( Video MP4 9MB )




 Test on Communications Receiver ICOM IC-R20


Ascolta la ricezione in banda 40 metri LSB a 7.075 Mhz, vari OM si parlano tra loro da diverse località del Nord Italia.

-Audio files (Wav) recorded directly with ICOM IC-R20 at the October 19, 2013 15:10.
Excellent reception in the 40 metre Band 7,075 Mhz from various locations in Northern Italy, Chirio Mini Whip antenna 20 mm, 12V power supply.


 Video: test with ICOM IC-R5 

 VIDEO AVI  Prova di ascolto con ICOM IC-R5 con antenna Chirio Mini Whip 9V battery

( Video Avi 40MB )





 How to give new life to leave radio in the drawer ...

-Many economic radio despite having short-wave bands don't have the external antenna input, but only the stylus can be extended.

-Using the Chirio Mini Whip positioned on the roof down with RG-58 cable, the cable is connected to a crocodile and connects to the stilo antenna, the screen must be connected to an aluminum or copper plate in the size 20 x 30, which will be the basis for the radio.
If you can connect the radio to the negative plate with a condenser from 0,1uF, though in practice I have seen that is more than enough the ground plane.


mini_whip_018.jpg (52618 byte)

Sony ICF SW40


-The signal sometimes is quite strong that tends to saturate the input, using the DX/Local switch you can return to normal values, excellent listening to 7, CW 020Mhz, fine tuning in steps of 1 kHz helps achieve good stations.
-Having regard to the possibility of receiving the 7 and 14 MHz bands feels the lack of conversion SSB.
-Commercial stations are received well on all bands, unfortunately the Mediumwave have ferrite antenna inside and cannot benefit from the good external signal.

mini_whip_017.jpg (57699 byte)

Sony ICF 4900

-Also here the strongest stations tend to saturate the input, using the DX/Local switch it improves reception.
-Excellent radio 80 years with manual tuning, good reception on all SW bands, bad for Mediumwave antenna not connected.

mini_whip_019.jpg (49733 byte)

Silver Crest SWE100 B1

-This small radio 9.9 euro cost sold in supermarkets LIDL astonishes for the excellent sound quality, and the SW bands 6 allow a good reception of short-wave stations. Good for MW connected to the antenna.
-Unfortunately the tune is just fine, it allows a precise centring of the issuer's ....



 Tips and tricks  for mounting antenna:


-Place the antenna on top, minimum 4 meters away from power lines or cables, for descent okay RG58/U cable, for lengths of 15-30metri. Even with 75 ohm TV cables or shielded cables for audio you will get good results.

-More you climb, the more the antenna gets signal gain. Usually a height of 10-12 meters gives an increase of + 10dB compared to 2 meters.

-There are no major differences in using a pole in iron or plastic, as the coaxial cable down from the same characteristics of a metal pole and ... important that small diameter with both cables upwind of nylon.

-Important to have a good ground connection, ideal dedicated just to this antenna and not in the common point with the home. A pole of 1 meter long iron planted in moist soil is fine, the connection to the antenna should be as short as possible, avoiding loops and long cable rides.

-Improved Land should be created with 4 steel/copper poles planted in moist ground where down the rainwater ducts or garden tap. Join the 4 poles with 16 mm copper cable and lead with a single cable to a common terminal box, connect all grounded metal roof structures, including copper gutters and iron poles.

-Avoid as much as possible sources of disturbance in the vicinity of the antenna, as neon lamps/LEDs, WiFi antennas, electric cables.


Ottima installazione di MiniWhip fatta da un radioamatore

-The drawing shows how to better external position the Mini Whip XP II with double descent cables.
-PVC pole must be located away from obstacles such as walls, fences and tall trees.
-Use cables type Nylon fishing wire or braid.
-To run the cables on the ground to avoid RF inputs
-By connecting to Earth the power shielded cable, typically reduces noise.
-Do not burn the input FET, all MiniWhip are required to at least 10 metres from a transmitting antenna.


About shortwave a tuned antenna and definitely has a more centered and clean, but would you put the cost and size ... and ...

We are talking about a duck antenna that my son uses with the scanner to listen to foreign stations .... It lets you listen to during the day, a 50-100 issuers to full scale between 100kz and 30 MHz while in the evening/night more than 500 broadcasters from around the world ... you!
The only foresight is out of the House and get away from any type of structure and electric cables, even the trees with leaves absorb signal, there is a spot open and on top ... and the cell phone is off!

This antenna MiniWhip allows fans to receive weak signals without mount roof truss, or rather make a hike in the mountains and listen to radio amateurs and issuers maybe from New Zealand .... the whole valuing a shortwave radio remained in the drawer that received very little with its creation.....

Chinese stations are increasing the power of issuing about shortwave to bring news throughout the world to their countrymen, a good compact antenna completes the opera ...


Prime prove con antenna Chirio Mini Whip



 Listening tips: stations, timetables, frequencies and seasons

- Radioascolto, BCL, SWL e tutto quanto attorno

- Associazione Italiana Radioascolto

- International Shortwave Broadcast Bands



- Manuali e schemi per radioamatori, CB e BCL




© Roberto Chirio: all rights reserved.