f 4X4XM, Doron Tal - Personal Bio


home 4X4XMQRZ, Doron


Thank you for visiting this website.   I hope you enjoy reading it and benefit from the resources given.

Topics: * Preface * Current Rig * Ham Activities * 1965 QSL * Vintage Rig * Education * Professions * Interests * Websites * Networks

Being a radio amateur involves creating connections and friendships with individuals you may never meet otherwise. This hobby inspired me to learn about technology and social issues through study and experience. Following retirement, I try to give back to the hobby by reviewing amateur radio practical and theoretical material on radio propagation topics to understand the impact of solar activity on HF propagation.

Name: Doron.   QTH: Karmiel, Israel.

↑ My current rig (2020-24) is fairly basic. Everything is SDR and QRP in tiny. (See Vintage Rig)

  1. Malachite DSP v3 Receiver
    50KHz-2GHz DSP; 3.5" touch screen
  2. Belka 0.1-31 MHz pocket SDR
    developed by Alexander Buevsky, EU1ME
  4. Tecsun PL-330 digital RX / Scanner
    LW, MW, SW(SSB), FM
conected to K-180WLA

Magnetic Loop Antenna 70cm diameter
Battery Powered 20 dB amplifier
Frequency range 0.1-180 MHz

Meanwhile, I am a casual FT8 reporter, playing with a QRP uSDX Transceiver
on 160, 80, 60, 40, 30, 20, 17, 15, 12 and 10 m.

I plan to erect efficient transmission antennas above my home
that meet the restrictions imposed by my community.

As a child, I was fascinated by the "radio miracle," as seen in the video below.
The above video tells anecdotes about radio amateurs wishing to save lives or assist society.
Most of these hams used junk as equipment. QSL cards proudly cover the wall of their stations.
My curiosity grew after watching the movie "If All the Guys in the World"; French: "Si tous les gars du monde"
A French fishing boat crew in the North Sea eats contaminated food, making them unable to continue their duties.
The story focuses on the attempts of a global group of amateur radio operators to deliver an antidote.

A few years later I got the desired operating license, Novice in 1964 and General in 1965.

4X4XM enjoying a field day in 1967
Rig: Drake R-4A HF RX attached to SCR522 VHF TRX
4X4XM in a field day 1967

In 1992, I took a break due to my family's needs, and returned to ham radio in June 2020, after a 28-year absence.

In light of the current 25th solar cycle, I've been thinking how the Sun affects HF radio propagation, focusing on forecasting skywave propagation.

Space technology advancements, SDR (Software Designed Radio), and the internet have all greatly aided my understanding of HF propagation.

As planned, I'm gathering data on HF Propagation Forecasting, conducting research, and evaluating the findings. See the table of contents.

Due to the current security situation in Israel (since October 7, 2023), I am no longer available for a scheduled QSO.

↑      My First Homemade QSL 1965
The first homemade QSL of 4X4XM in 1965 front

My birth surname was Tirkel rather Türkel. I changed it to Tal in 1969.

back side of the QSL card

The first homemade QSL of 4X4XM in 1965 back

↑   QTH History:
1957-1975  KM72LT - Haifa Israel
1972           JO21RK - Eindhoven, Holland   (PA9UV)
1975-1984  KM72MU - Kiryat Yam, Israel
1984-1990  KM72PW - Karmiel, Israel
1990-1992  FN20QH - Plainsboro, NJ, USA   (4X4XM/W2) see the rig
 after 1992  KM72PW - Karmiel, Israel

A view of Karmiel, Israel
from East to West (2008)
from West to East (2009)

↑      Amateur Radio Activity:

↑   Vintage Rig:

Until 1964 (age 17), my entire rig was homebrew. Then I began modifying vintage and surplus equipment.
See the list below for the gear I've preferred over other gadgets I've collected and used over the years.

Hallicrafters SX-110
In 1964, I bought a second-hand commercial receiver, a Hallicrafters SX-110. It was a single conversion (I.F. 455 kHz) general coverage receiver in four bands ranging from 535 to 34000 kHz. I have added a Product Detector (ECH81) and replaced the Noise Limiter with a Noise Blanker US 3,195,052 patent. A year later, I added an external Xtal-controlled front-end that converted the higher HF and VHF bands, down to 3.5, 7, or 10.7 MHz with 50Hz stability and image rejection greater than 75 dB. It was considered a remarkable achievement at the time.

In 1966 the late Erik Friedman MD, 4X4WF (SP5WF), lent me Bandmaster Delux TBS-50D Transmitter (Harvey Radio Laboratories, Brookline, Southbridge, MA, USA) covering 80m through 2m.

I have added a homebrew VFO.

Using this transmitter I made thousands of CW and AM QSOs.

In the same year (1966) I fixed a 19 years old broken Hallicrafter S-37, 130-210 MHz Single Conversion VHF receiver (I.F. 18 MHz) found in a junkyard. This was a true gem that enabled me to search for spurious signals, listen to (audio of) TV channels (from Israel, Cyprus, Lebanon, Jordan, and Egypt), 2m ham radio, civil and military aircrafts, ships, and police. I have operated this amazing receiver from 1966 to 1970.
S-37 VHF Receiver

At the same time I refurbished and modified a ground based SCR-522 WWII transceiver, originally covering 100-156 Mhz in 4 preselected channels.
Related versions: UK Airbourne Transceiver; USS Pampanito. General Instructions: 1944 handbook
SCR-522 WWII transceiver
Assembly in Rack
The BC625A transmitter and BC624A receiver were both Xtal controlled.

The VHF front-end receiver was fed into any HF receiver that operated on 10.7 MHz.
This configuration allowed easy tuning, clear and stable reception of CW and SSB modes on the 2 meter band.

The following picture shows such operation during a field day in 1967.
Field Day 1967 rig
The I.F. output of the VHF front-end (BC624A) was fed into the HF receiver (Drake R-4A).

A 16dBi pseudo-horn antenna enabled S9+ AM QSOs on the 2 m band between
Haifa, Israel, and Larnaca, Cyprus, spanning 270 kilometers across the Mediterranean Sea.
This antenna was constructed from an aluminum expanded mesh in the shape of two isoscale triangles, attached to a rectangular wood pyramid.
The pyrmid's base and the triangles' sides measure 2450 mm. The mesh triangles were aligned at a 60-degree angle.

The next decade

In 1975 I bought a second-hand Yaesu FT200. It was an SSB/CW transceiver that covered the pre-WARC amateur bands from 80m to 10m and provided up to 180 watts PEP. Modification were added to improve operations. Various wire antennas allowed flexibility in 5-band HF operation around the clock.

In 1977, I purchased ICOM IC-240, a two-meter FM transceiver, and modified it to double the number of channels by adding two diodes. It was my favorite "Taxi Radio" that I'd ever used; it was simple, cute, and durable. Antenas used: Classic GP, Ringo Ranger, and 2-el Quad at home; 5/8 mobile.

In 1982, I won a raffle for a broken Siemens E311 receiver. I restored it until it operated like new and used it as a high-quality receiver for eight years in my shack, with an accuracy of 100 Hz and stability of 20 Hz over 24 hours.

While on Sabbatical Leave (1990-1992) in Plainsboro, NJ - the late Sid Gogel, W2FUR (1919-2015) lent me a vintage rig:

This Collins 51S-1 receiver enabled me to listen to the Voice of Israel on HF every day from New Jersey, USA.

While operating this Swan-350 living in Plainsboro, New Jersey, USA, I kept contacts with Israel using camouflaged vertical antenna.
Fortunately, cycle 22 of the sunspots was at its peak at that period.


↑ Education: 1977 MSc. Physics (Molecular Physics, Physical Chem., Electro-Optics, Sys Eng.)

Specialties: Scientific R&D, Sys Eng. & Analysis, Management, Planning, Audit, Arbitration, Expert Witness

↑     Professions:

  • R&D Physics 1973-1997 (Laser Systems, Combustion, Night Vision, RDF, IDFF, Artificial Soldier)
  • System Engineering 1982-1997 (Advanced Physical Systems)
  • Project Manager 1987-1990 (Airborne Night Vision)
  • Expert Witness 1997-2014 Speed Enforcement by Lidar & RADAR (SHF)
  • Control Boards - Volunteer member of Audit Committees (NGOs) from 2006 until today

↑      Interests:

↑     Websites NOT related to Radio Amateur:

↑     Public Networks:

↑    Last but not least:

The world is changing as the radio amateur spectrum is being sold off to commercial users since few amateurs operate SHF and above.

If you have comments, questions or requests please e-mail me.

73 de Doron

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