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 Final Note:

The much-anticipated June 15th announcement is now behind us, but what does it mean for MDARC and you? I believe this quote from the Contra Costa Health Services website helps us look into the future:

“As of June 15, 2021, the state has moved Beyond the Blueprint for a Safer Economy and eliminated the color-coded tier system for counties. This means there are far fewer restrictions on business and social activity, although things still aren't exactly like they were before the pandemic. There are no longer capacity limits on businesses, although masking will still be required in many situations and settings.”

Looking at the details on the CCHS website, I notice the following:

No restrictions on capacity limitations for indoor and outdoor setting.
         Except for “mega events” of 5000 or more people.
No restrictions with regards to physical distancing.

I invite you to review the CCHS website to get more details, but it seems to me that MDARC members are free to gather in-person and be maskless if they so choose.  On this latter point, it is okay to wear a mask if you wish. 

Beyond the Blueprint | Coronavirus (

Vaccinated? I hope so, but if not, and you are not medically cautioned not to be vaccinated, then I encourage you to get it. This would benefit you, your friends and family, including your “MDARC family.”


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

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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 2021 Logo

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

We're targeting our July 16 meeting to return to live, in-person gatherings at Our Savior's Lutheran Church in Lafayette. The goal is to have a hybrid meeting; both in-person and on Zoom, So plan on joining us for an eye-ball QSO. But if you can't, Zoom will still be there.

Our Board meetings will continue to be Zoom only for at least the rest of this year.

The page describing Obtaining an FCC Registration Number (FRN) has been updated with the new requirements, which are effective May 20, 2021. 

We have a new page on the website. This one explains just what Peak Envelope Power means, in the context of the FCC's definition. Have a look.

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
Carrier Newsletter

Public Service

General Club Meeting

, July 16, 7:00PM
The miraculous nanoVNA
by Rob Rowlands, NZ6J

See the details on our Speakers page.

Club Meeting Address:
Hybrid Meeting!
Both In-Person and on Zoom

Our Savior's Lutheran Church

1035 Carol Lane

Lafayette CA

About us

Our Repeater systems are among the best in Northern California!