Mount Diablo
Amateur Radio Club

The Mount Diablo Amateur Radio Club (MDARC) was founded in 1947. Today it has a membership of over 300 dedicated hams and is one of the largest amateur radio clubs in California. MDARC's purpose is to encourage innovation in amateur radio, provide public service and educational opportunities, foster goodwill within our community, and have fun in the process.               

COVID-19 Note:
Our Club is aware that vaccines are becoming available and we encourage  our members to take advantage of the opportunity to receive these. We encourage members and guests to continue following the health order requirements from the various Counties by wearing face coverings, washing our hands, and abiding by in-person restrictions based on the County tier.

Until we receive the “All Clear” from the County for meeting in person, we will continue holding meetings using Zoom which we have found to be very effective for conduction Club business and continuing camaraderie.

Take advantage of the many Nets on our W6CX repeater. 

As we all work through these times, please bookmark these websites and for more information .

Link to Contra Costa Health Services

Link to the Alameda County Public Health Department

Link to the Solano County Public Health Department

On behalf of the MDARC Board and all members, please stay safe.
MDARC President

[For previous notes, please see our Announcements page.]


MDARC provides a wide variety of programs and activities for its members. These include hosting and staffing PACIFICON (ARRL Pacific Division convention) each October, bringing in great speakers and offering ham radio classes to the public.  Our annual picnic, holiday party and radio equipment auction are all enjoyable events!

About us

is an ARRL Special 
Services Club

Help us support our Repeaters!
Join us or Donate

Donate to MDARC
You can donate to MDARC just by shopping at AmazonSmile.Com.

Click Here for details.

We also accept donations to the club via PayPal. Please click this link to make a donation.
Note: MDARC is a 501c3 organization.

Join our Club email reflector, to stay up to date on what's happening in the Club, meeting announcements, etc. See our Communicating With You page for details.

MDARC Facebook Page


in MDARC includes autopatch access to all three MDARC voice repeaters (W6CX). We also maintain an ATV repeater, and support Packet / APS EchoLink, and IRLP. The W6CX D-STAR repeater is operational and connected to our gateway on the Internet.
About us

Pacificon 2020 Logo

See our PACIFICON site for details on  the best ham radio convention in the Western United States! 

Our website has two new pages. 
A number of the frequency bands allocated to amateur radio operators by the FCC are dedicated only to us. But we must share several other bands, or segments of bands, with other services. The new page, Secondary Status of Amateur Radio Frequency Allocations, summarizes which bands and band segments are secondary, and to whom. Check it out.

Also, the FCC's regulations require that "A station within 1600 m (1 mile) of an FCC monitoring facility must protect that facility from harmful interference." But finding out just where those monitoring facilities are requires the ability to find your way around the U.S. Code of Federal Regulations. Not always an easy task. So we've done the work for you. See our FCC Monitoring Station Locations page.

A Getting-on-the-Air (GOTA) class for new Technician Class licensees will be held on Zoom tomorrow evening 03/12/2021, starting at 7:00 PM. This one will include discussions, demonstrations and Q&A on choosing and using your first radio.

A follow-up GOTA class will be held in-person this Saturday morning, 03/13/2021, where you will be able to look at and practice using various radios. The session will be at the Clayton Valley Presbyterian Church on Kirker Pass Road, just east of Clayton Road. Because this is an in-person class, it will be held in two separate sessions, with a limit of 10 attendees per session. You must schedule a time slot in one of the sessions in advance. If there's enough demand, two more sessions will be held the following Saturday, 03/20/2021.

For Zoom access information to the first class or to sign up for one of the in-person sessions, contact Larry Loomer, KI6LNB, at

A recording of Bob Heil's presentation to our Club at our Holiday Celebration is now available. See the link below his description on our Speakers page.

Bob Heil to speak at our Holiday Get-Together!
Bob Heil, K9EID is set to kick off our holiday Zoom event beginning at 16:00 local time on December 6th Note the early start, to accommodate Bob's time zone. Mark your calendar now.

The list of candidates for our upcoming election has been updated. See it below right.

At last night's meeting, the MDARC Board approved a plan to hold a holiday celebration, even though it will not be the traditional in-person Banquet. It will be on Sunday, Dec. 6, 2020. See our Holiday Banquet page for more information.

Search this website!
In case you've wondered why there is no search box on our website, it's because of restrictions Google places on it's location. But you can still search for any text string on our site. Just enter into your browser's address field or your favorite search engine the following (without the quotes):
" yourtextstring"
replacing "
yourtextstring" with the text you're searching for.
For example, if you want to find the word "license", enter:
" license"
You can search the Pacificon web site in a similar manner.


MDARC elections are coming up! See the right column of the home page for a list of candidates. If you're interested in running for the Board, or know someone who may be, contact one of the Election Committee shown.

Our General Class license upgrade course will begin Tuesday, Aug. 4. It will be completely online, via Zoom. If you're thinking of upgrading, go to our Class Details page and register right away.

There will be a Getting-on-the-Air (GOTA) class for the recent candidates of the Concord license testing sessions, and for any other hams that would like to get started in using their amateur handheld radios.

The classes will be held on the Zoom format on Friday, July 17, at 6:00 PM, and in-person, with masks and social distancing, on July 18, at 6:00 PM.

Please contact Larry Loomer, KI6LNB, at <> for further information and to reserve a spot in the classes.

The President's COVID-19 note has been updated at the top of this page.

The video recording of Friday evening’s Club meeting and presentation is now available on MDARC’s YouTube channel, at:

It’s also available on the Club’s web site Speaker’s page, under the description of the presentation.

The Field Day page has been updated with the latest information about how it will work this year. Take a look and get ready!

The abstract and biographies for our June meeting presentation are now on our Speakers page. Take a look.

Remember that this will be a Zoom videoconference meeting only, and the access information will be sent out via our forum. So if you're not a member of the forum, join now.

Our President, Larry Bradley, KK6QPE, has updated his COVID-19 note. Please see it at the top of the Home page.

Our Annual Auction is canceled, but we've not giving up! We're hosting a Virtual Get-Together on our normal meeting night; this Friday, April 17 at 7:00 on the Zoom videoconferencing system. See our Speakers page for details.


Did you know there are 13 ways the Club has for communicating with you, our members and the ham community at large? Yes, 13. See our new Communicating With You page for the list.

Our Pacificon 2020 web site is Live!
Attendee registration will open in early May; and we have much to add as we get closer to this event. So check it out now and come back for updates. See it at

Registration for our Holiday Banquet is Open!! See our Banquet page for details.

Remember, our Club meeting this month will be held this Friday night, at Pacificon in San Ramon. It will not be at our usual location in Lafayette. See our Club Meetings page for the full year's schedule. And see our Speakers page to see what the presentation is about.

Also, there will be no license testing Friday, but we will have extended testing sessions at Pacificon on Saturday and Sunday. See you there.

October 5, 2019
To accommodate a need by our long-term Banquet host, Zio Fraedo's; our Banquet date for this year has been changed from Sunday, December 8, 2019 to Saturday, December 7, 2019. See our Banquet page for details on the evening and remember to update your calendar with the new date.

July 7, 2019
Two more pages have been added to our web page. Our Club's two vehicles, a van and a trailer, now have their own pages, and the main Vehicles page has been revised. Have a look, starting at our Vehicles page.

July 5, 2019
Our web site has a new page; Latitude, Longitude, UTM. It's a summary description of two major geographic coordinate systems often useful for hams. Check it out.

June 19, 2019
Field Day is this weekend! We'll be at Heather Farm Park in Walnut Creek again this year. Come on down! See our Field Day page for details.

June 7, 2019
Our June speaker has now been announced.  Ed Muns, W0YK, will give us a good education on the new protocol, FT8. See our Speakers Page for details.

The Pacificon web site and registration is now Open! Get your registrations in and see what happening this year. More details will be added as we have them, so check back occasionally.

We now have our Speaker for the May Club meeting. Marcel Stieber, AI6MS will tell us about "ARKnet - Wireless Emergency Intranet". We'll post details on our Speakers Page shortly after the Auction, April 26.

The annual MDARC Campout has been scheduled. Capacity is limited, so sign up early. See the Campout-2019 page for details.

The Club's bylaws were amended by a vote of the membership to allow voting electronically. See the amended bylaws on the Bylaws page.

Several new pages have been added to the web site over the last several weeks., as well as updates to others. See the list of new pages on the main Club Announcements page.
Carrier Newsletter

Public Service

General Club Meeting

, May 21, 7:00PM
Walnut Creek CERT Winlink
Test System
by John Trintrud, K9ONR

See the details on our Speakers page.

About us

Our Repeater systems are among the best in Northern California!