The famous Miniwhip (by pa0nhc vastly improved version). 
Active E-field wideband DX receiving antenna. 
See my Youtube video presentation  English 18 min.

Two PCB set will be supplied WITHOUT any component. (see PCB service).

==>> All components have to be purchased and placed by yourself.

Updated 20240303.

Can twin-line CMCs be inserted into coax feed lines ?
 pa0nhc V20220524-5  PDF.

Smoorspoelen (CMCs) en transformatoren
voor ontvang antenne circuits.
pa0nhc 20210121 

Mantelstroom smoorspoelen (CMCs).

Beknopte theorie over CMCs.
Elke HF amateur zou dit moeten weten.
Snap het, maak het. 
Nieuw :
De invloed van tempatuur variaties op mantelstroom smoorspoelen.  

Mijn information source : 
http://k9yc.com/RFI-Ham.pdf 
Common mode chokes (CMCs).
A theory subset.
Some secrets of Common Mode Chokes revealed.
Every HAM should know this.
Understand them, make them.
New :
The influence of temperature changes in Common Mode Chokes. pa0nhc 20211003

Silences webSDR sound while you are transmitting.
No software, only simple hardware.
No latency.

Update : 20210505
Project : Shortwave RF power amplifier "QRPblog A600 PCB v 2.1". 
400W low IMD SSB with 1W drive. (see also Hermes Lite2).
After important modifications : now reliable.

20210414 : The new peak metering PCB is available.

Loop impedance converter+amplifier.                 Signal / DC combiner                  Coax cable loop Balanced screened input. Balanced COAX output. Loop                                                                           Loop To splitter Shielded antenna unit. Balanced COAX input. Unbalanced coax output.         From antenna          To receiver  12-14Vdc from PS      Shielded DC/RF splitter unit. Shielded loop Connected by 20m 2.5mm PTFE coax with every 3m a #31 CMC. The coax thus acts as a screened  balanced line !

PCBs are available

Page update 20211009.
Small, active, wideband active receiving loop antenna 15 kHz - 30 MHz.
200 kHz - 30 MHz +/- 3 dB, good reception and superb noise immunity down to VLF.
Special :
The antenna unit is not grounded => easy installation and best noise immunity.
Superb common mode immunity guaranties magnetic-field-only / ANTENNA ONLY receiving and best noise immunity.
Also : Far weaker thunder storm lightning noises.
Very low system noise floor, equivalent to S1, or -120dBm.@ 20 MHz (IARU 6dB/Spoint).
This sturdy amplifier withstands :
- Lightning strike at 100m distance (proven).
- More than 1 kW radiated power at 10m distance.

This spectrum is recorded in my very noisy location, and demonstrates the impressive common mode suppression !


Measuring conditions :
SDRconsole software, recorded at my locally very noisy 80m band (S9+10dB noise).
Given facts : 
1. A 1/2 wave 50 Ohms dipole has, in an RF field of 0.02 V/m, 0 dBm output.
2. This loop system has, in an RF field of 0.02V/m, -30dBm output.
3. =>> No signals with power off means : no common mode noises <==
By in SDRconsole adding +30dB "software gain", the S-meter indication is automatically calibrated for -73 dBm (S9) for this loop system. 

The signal strength difference between power on and off is 50 dB to 70 dB over the full system bandwidth of 15 kHz - 30MHz.
The common mode suppression of this antenna system is that good, that one can only judge it, while observing very strong signals >-40dBm.

De overeenkomsten en verschillen tussen een
Miniwhip E-veld antenne en de
pa0nhc RXloop H-veld antenne.
 pa0nhc  20200708.

The similitudes and differences between a 
Miniwhip E-field antenna and my
pa0nhc RX loop H-field antenna.
20200811.

Outdoor, all whether, high efficiency, balanced 3-band transmit/receive (magnetic) loop antenna.
  ©opyright.
Unique, wide band, pa0nhc © transformer matching.

Good performing loop. Cheap and simple construction.
Remote tuning and band switching mechanism.
Optimal cost / performance ratio.
No TVI nor BCI.
NO antenna matcher needed. Once tuned : perfect VSWR.
Small size : Only 2.5m x 2.5m square.
3-band operation. : 40m,60m,80m
Optimal performance on 7.1  MHz.
Still good performance on 3.65 MHz.
Maximal allowable power on 80m : 400 Wssb
with a 2x 600pF 3kV split stator tuning capacitor :
Higher power levels need a higher voltage tuning capacitor
and a transformer made with two stacked ring cores.

Press F5 to get the updated page version.
Updated text and pictures : 20221204
Capacitor setup with NanoVNA / Partslist.

Developed by pa0nhc. ©opyright

Tune able, very selective, narrow band
Active MAGNETIC (NVIS) receiving antenna.

PCB set is available

- The directive pattern is like a full size dipole @ 1/4 lambda height.
- If installed rotate able : 
Weakens horizontally and vertically polarized low incidence interference.
- From 1.8MHz to 7.2 MHz good (high angle) NVIS antenna .
- Very small size, smaller and more signal than a small loop antenna.
- Using standard available components.
- Internal noise free filtered power supply.
- Adaptable to frequency bands between VLF and 21 MHz.    
- Adjustable tuning-"span". (Prototype 3.65 MHz +-150 kHz).

- Very good sensitivity and selectivity due to
     Hi-Q ferrite antenna followed by a Hi-Z FET buffer.

- Acts like a very good pre-selector.
- Tuning by back-to-back varicaps and special pa0nhc electronics,
   resulting in very good strong signal handling.

© pa0nhc development :
One thin coax line transports all signals :
1. The DC power towards the antenna unit,
2. The DC tuning voltage towards the antenna unit,
3. The received RF signal back towards the tuner unit.

Radically new designed :
Top quality 80m ARDF direction finding receiver © .
See also the 2m version.
PCB is available.

Single super,10.7MHz IF.
Build-in high-Q BALANCED ferrite antenna.
BALANCED Jfet buffer stage.
BALANCED IC mixer.

Very sensitive.
Gain adjustment range >= 90 dB.
Very positive sense action.
Pwr : 16-26 mA @ 9V-6V.
Cheap light weight ABS housing.
Small and light (305 g).
Commonly available modern components.
Only 4 SMD components.
Ready wound Neosid, or self wound coils.

Last update : 20180130

All info in easy printable PDF files.

Two versions with different sense antenna's.

  The left hand version above uses a 17cm rubber whip as sense antenna.
The right hand version uses a piece of ALU pipe on top as sense antenna. 

Lineaire voedingen ontstoren.

De-noising a linear power supplies.
20191224

Radio stoor bronnen vinden met de EMVspion..

Rugged 2 Watts CW / AM transmitter for "80m radiofox hunt"
and 3.579545 MHz ARDF ©.

2W CW into 50 Ohms load.
and AM when externally modulated.
Withstands very high SWR.
Fixed accurate carrier frequency without any adjustments.

Unconditionaly stable and sturdy.

Special designed single sided PCB for good performance and good efficiency.
Resulting in a well filtered signal, no parasitics,
 
Quick setup in the field without further adjustments, 
when using a 50 Ohms antenna  2013

80m milliwatt beeper (Sputnik) ©.

          PCB

Single frequency, simple, stable, clean signal.
CW keyed.
Well filtered, 50 Ohms.  No adjustments.
201305

Magnetic RF Field Sniffer.
pa0nhc 20190228 / EN : 20190726

Calibrate your S-meter ! 20180713.
ON9BOG / PA0NHC 
Accurate calibration-free 50 Ohms 0dBm generator (3.579,545 MHz).
7 PCB set including neat lacquered housing.

Simple manual "magloop" tuner ©.
20181213

Drives a 12Vdc tuning motor. 
Bi-directional, two speed.

Build-in clean power supply.
(New simplified schematic).

Article is under reconstruction.

Automatic "magloop" tuner.
3 PCB set.
Drives a 12Vdc tuning capacitor motor.
Pure analog (NO software).
Build-in clean power supply.

Tunes for zero phase difference between the RF current and the RF voltage in the transmission line.

Set of professional PCBs is available.

Low power 4mW RF rms meter © .
Internal 50 Ohms load.
Accurate, calibration-free.
PCB

Measuring ranges :
32kHz up to 2.5GHz.
FSD = -14 and +6 dBm.
Indication range : -55 dBm to +6 dBm (3nW - 4mW)

(Battery) powered 4 - 5V, 3 - 8mA.
Cheap small standard ABS housing 9 x 9 x 6 cm³.
Available :
- Small double sided professional PCB in SHF design.
- dBm scale / switch scale drawings
- Full detailed info for building as easy printable PDF files 
pa0nhc  20171218

The grounding and de-noising of my antenna system.
20160526
De aarding en ontstoring van mijn antenne installatie.

De-noising a commonly used scoot mobile charger.

Ontstoren van een algemeen gebruikte scootmobiel lader.

Ferriet transformator experimenten.

Ferrite transformer experiments.

NanoVNA modification.
pa0nhc 20100114