<< DIY blanc PCB set for
Pa0nhc improved version of pa0rdt "Miniwhip" active wideband receiving antenna.
NOW FIRST press F5 to update this page to its newest version !
Update : 20201223 / 20240203 (Layout and BF998). 20240215 (ant properties).
 First see my Youtube presentation of The Miniwhip.

(C) The use, copy and modification of all info on  this site is permitted, but only for non-commercial purposes, and
 thereby explicitly stating my radio amateur call sign "PA0NHC" as the original writer / designer / photographer / publisher.

REM : To prevent un-authorized commercial copies, NO component details are given in the schematic diagrams below.
The parts list will coincide with the white PCB topsilk imprints at the PCBs, and part placement drawings.
Installing all parts should be easy for experienced builders.
 Construction details, test data and de-noising instructions are given in the downloadable texts.

Properties
v.20180628
(Full detailed schema 20240215)		 Component list 
for ordering at Conrad.nl
(ver 20240123) 		Assemblage
v.20200213		 Installation
v20181217		 Available blanc 2-PCBset
for DIY

 

 
 My version Miniwhip :
Is an excellent DX antenna for vertically polarized wide band reception of
VLF,LW,MW,SW,FM broadcast, airplane band and 2m amateur band.

However : The vertical polarized Miniwhip ia NOT an NVIS antenna !
Reception of signals between 1.8 MHz and 7 MHz from distances between 20km and 400km wil be very weak.

Measured properties :

Bandwidth : 5kHz to 148MHz +0/-3dB.
Sensitivity (< 30MHz) : 
- Using the internal antenna surface only : abt. -17dB.
- With added external 1,5m x 1cm antenna rod : abt. -12dB.
Input RF impedance abt. 7 Mohm // 6pF.
Input DC resistance 22 Mohm.
Includes over-voltage protection.
Output impedance : 50 Ohms asymmetrical.
Unique pa0nhc antenna input circuit for highest IMD-free output, widest bandwidth,
and a wideband output circuit including an effective common mode choke.

Measured frequency characteristics (L1 on the antenna PCB is short circuited).


50kHz - 30 MHz.
The -2 dB dip at 15 MHz is a weak choke resonance in the splitter.
Orange = nanoVNA Ch0 reflection damping
(70cm coax, 50 Ohm // 3p5 coupling).


50 kHz to 200 MHz, -3 dB @ 147 MHz.

IMPORTANT :
Every active receiving antnna needs careful de-noising measures.
E-field antennas (like all Miniwhips) also must be connected to a dedicated NOISEFREE ground.

 

  
UPDATES 20200828.
Antenna unit.
 Common mode choke L5 :
a. For best results ONLY use #31 ferrite (high loss Ui=1500).
202008 : FairRite item 2631801202.
If unavailable :
Better (longer) replacements : 2631101902 or 26311020202

Wind the coax until  the core hole is fully  filled.  
Every turn must lay beside the former as shown below.
Do NOT cross another turn.
Coax CMC made from 29mm #31 ferrite core
(Fairrite  2631801202)
with the maximal number of 13 turns
thin 50 Ohms coax (RG316 or RG174 ).
 Splitter unit.Two versions of BF998
 b. Insert an extra choke between the PWR+ connection on the PCB, and the power+ connection on the PWR-bus.

c. Do NOT connect the PWR-minus point at the PCB.
The PCB mass planes must electrically only be connected to the INSIDE of the splitter box through the 3mm screws.

d. The BNC-recepticles MUST be in perfect electrical contact with the OUTside of the  METAL splitter housing.
e. Use CMC's on all cables (see de-noising)

f. GROUND the antenna PCB, nothing else..


20240203 : Extra info about the used BF998 dualgate MOSfet :

 Two versions of BF998 exsist : version B (fig.1)  and version R 9fig2).
The PCB is designed for BF998B. 
But a BF998R can be used by soldering it with the top in contact with the PCB (topside down).