Friday, 6 March 2020

Ham Radio-DIY VHF ANTENNA TUNER made from junk

Ham Radio-DIY VHF ANTENNA TUNER made from junk

Ham Radio-DIY VHF ANTENNA TUNER made from junk.  I had a question a few days ago from a reader about an ATU for his scanner, I like to call the device an Aerial Matching Unit. Robert said he had a Discone aerial in his loft and wondered if he could improve reception-he did tell me about his research for an AMU. He likes to listen to aircraft.

The circuit used in the video will work very well, I calculate variable capacitors to match the coil and load using the formulae for XC reactive capacitance  =1 divided by 2 Pi F C

2 Pi is 3.142 x2 = 6.284
F (Frequency) for aircraft band 124 Mhz

Your coil is calculated using 2 x pi x F x L (L is the inductance in uh microhenries) F frequency in megahertz.

Choosing a capacitor, we need 50 ohms at 124 MHZ these will be in the pf range picofarads. They may be difficult to get a hold of, but you can always used fixed values in series or parallel with a variable capacitor, it is an interesting experiment at the end of the day.

When C and L are equal we have the resonant frequency calculated from

1 divided by the square root of  L inductance multiplied by C capacitance.

This equation will give you the resonant frequency where the reactance of L and C are equal, canceling each other, we have only the resistance left of 50 ohms.

This little A.M.U. will improve your reception, but it does add loss to the signal, being a filter it will help block out band breakthrough.

You can also build a dipole CLICK HERE

Enjoy experiment and building radio and electronic projects, knowing comes from doing...73

Ham Radio-DIY VHF ANTENNA TUNER made from junk

Ham Radio-9J2LA Zambia

Ham Radio-9J2LA Zambia

9J2LA Zambia News 5 March 2020

9J2LA team arrived in Zambia. Immigration and customs went smoothly within 90 minutes. All the luggage made it with us to Lusaka.
First test antennas are already up and operation will start very soon.
See you later in the pileups

Operating freqs/modes.
1826,5 (1) —– —– 1844 / 1908(2)
3524 —– —– 3590
7024 7082 7045 7060
10124 —— 10142 10140
14024 14185 14082 14086
18074 18140 18096 18104
21024 21295 21082 21095
24894 24955 24912 24918
28024 28495 28082 28095
50104 —— —– 50313

9J2LA Chisamba, Zambia Antenna

Victoria Fall Zambia

Ham Radio-9J2LA Zambia   Victoria Falls

Ham Radio-9J2LA Zambia

Ham Radio-V55A Namibia

Ham Radio-V55A Namibia

ZR2A will be active as V55A from Namibia in ARRL DX SSB Contest, 7 - 8 March 2020.
He will operate in Single Operator All Band Category.
Recent DX Spots V55A

Some beautiful wild-life pictures from Namibia

Ham Radio-VP8PJ South Orkney Islands News 2 February 2020

VP8PJ South Orkney Islands News 2 February 2020

For Immediate Release
Press Release #11
Feb. 2,2020
South Orkneys2020 DX-pedition
We’re on autopilot, next stop Punta Arenas, Chile.

The project is on schedule
Team members will begin arriving in Punta Arenas on February 9th, Braveheart is scheduled to arrive on February 13th, we load the ship on Feb 14th and depart on Feb 15th for Signy Island. Nigel Jolly will have already arrived by air to arrange for refueling and resupplying Braveheart.

Logging – Log Search
We will use N1MM+ for logging and WSJT-X Version 2.1.2 for FT8
Assuming a stable satellite connection, QSOs will be uploaded to the log server in near real-time, you can monitor logging activity at:
We do not upload by the band, by mode or by operating position.
OQRS will be available within 10 days after we leave the island. We need time to validate the logs.
QSL Manager, Tim M0URX, will work on Busted Calls and Not in Log issues after the log is validated. Please use the form on Tim’s OQRS site, do not send e-mails.

Split Operation and Fox/Hound

The Band Plan is posted on our website (Island Operations) unless otherwise announced by the operator, all radio operations will be split.FT8 will use Fox / Hound mode on all bands except 60m, where we will use normal FT8 operation.
VP8PJ at

A reflector is available at for you to provide input to the team. The pilots will monitor the reflector and summarize pertinent information by region. There’s a one-time registration for the reflector, please review the “Sticky Notes” at the top of the message list. Please, no requests for log checks, busted calls, Not in Log, or schedules. We appreciate thoughtful and helpful information from your

Follow the Braveheart
Shortly before we leave Punta Arenas, we'll activate the Garmin inReach personal locator. You'll be able to follow our journey on the web during the estimated 6 days at sea to and from the island. You can Follow Braveheart from our website or
K6TU’s Propagation as a Service

We thank Stu K6TU for making available his K6TU Propagation as a Service tool at no cost to you. Accessed from our website (K6TU Propagation Tools), Stu's website is configured with our station and antenna specifications. The tool automates and greatly simplifies the process of building VOCAP predictions customized for your location. Knowing the details of our station configurations, location, and antenna heights, the tool will generate your customized propagation charts.

WSPR Beacon
"A QRP Labs Ultimate 3 WSPR beacon will be on board Braveheart running 30dBm on 40, 20 and 15m sequentially every 10 minutes whenever the VP8PJ/MM station is not in use."

Early donors (those that donated before we sail on February 15th) will receive their LoTW confirmation(s) while we’re on the island, usually within 24 hours of the contact(s). All other donors will receive their LoTW confirmation(s) when OQRS opens.

With the Braveheart and freight bills paid and the equipment in Chile, our last remaining major expenses reshipping the equipment back home, generator fuel, port fees, general surcharges, fuel surcharge and a few smaller but still significant expense items. It’s not unusual for unexpected fees and other charges to materialize so we remain vigilant with the budget management.

We have over 600 individual (early)donors, 73 Premier Sponsors and 55 club/foundation sponsors. Is your club or name/call sign listed on our website? All donations are appreciated and will help offset the project’s estimated cost of ~$310,000(USD).

We want to thank everyone that helped us along the way to plan this project, especially members of the 2011 VP8ORK DX-pedition, Ralph K0IR and Don N1DGwho provided invaluable assistance and information. Their guidance through the landing permit process and island logistics are greatly appreciated.

Thanks for your continued interest and support of our project.
Good luck in the pileups.
Team VP8PJ