4X4XM, Doron Tal - Personal Bio

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

Shalom!

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

Name: Doron. QTH : Karmiel, Israel .

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

Malachite DSP v3 Receiver
50KHz-2GHz DSP; 3.5" touch screen
Belka 0.1-31 MHz pocket SDR
developed by Alexander Buevsky, EU1ME
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

I plan to set up effective HF transmitting antennas
that comply with the restrictions imposed by my community.

I'm a casual FT8 reporter who also enjoys playing with a 10 band QRP uSDX transceiver.

A personal flashback to the 1960's

As a child, I was fascinated by the "radio miracle," as seen in the video below, that tells anecdotes about radio amateurs wishing to save lives or assist society. Most of them use junk as equipment. QSL cards proudly cover the wall of their station.

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.

From 1963 to 1992 I made antennas and gadgets, constructed and refurbished vintage rig, and was quite active on the ham bands from home and participated in field days.

4X4XM operating on a field day (1966)
Rig: Drake R-4A HF RX attached to SCR522 VHF TRX

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.

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.

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.

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.

For example, during a field day the I.F. output from the BC624A (2m band receiver's front-end) was fed into Drake R-4A:

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.

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 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.

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.

Personal Bio 4X4XM - Doron

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