Friday, April 27, 2018

Net Training - Cross Band Repeaters

The following information is taken from “The ARRL Operating Manual for Radio Amateurs, 9th Edition.”
I was, recently, asked if I knew anything about CROSSBAND REPEATING.  If you have a dual band, dual-display mobile radio and a handheld radio you can set up your own repeated system.

Why do so?  There are several reasons.  My personal reason is as follows.  I have two separate radios installed in my vehicle.  One radio is a dual-band dual-display Kenwood, TM-V7 and one is a Motorola, Spectra, single band UHF radio.  My Motorola has a public address system with an external speaker, so I can hear the radio outside my vehicle.  The Kenwood does not.  There have been times when I was out of my vehicle and did not have a handheld radio with me, but I wanted to keep track of what was going on on-the-air.  I set my Kenwood as a repeater from 2 meter frequency to 70 centimeter frequency.  Any call that came in on 2 meters was repeated on the UHF and came out through the external radio speaker.  I could now hear what was happening and also hear if someone called me.

Let us say you want to operate your handheld radio, but you need the extra power of your mobile radio to hit a repeater.  For example, you’re on the lower level of a shopping mall with your handheld.  You can’t reach the local repeater from down there, but you can the repeater from your vehicle in the parking lot.  Again you repeat through your vehicle to the repeater and you have coverage from your handheld.

You may be in one of the hospitals and you have your handheld, but cannot reach the local repeater, but you can reach your vehicle in the parking lot…I think you get the idea.
Cross-band repeat operation in most mobile radios is very simple.  When the cross-band function is turned on, anything the radio hears on one band is retransmitted to the other.  When the signal stops the radio goes into receive on both bands and waits for the next signal, on either band, to repeat.  So down in the mall or down in city hall or down in the hospital, you transmit on UHF.  Your mobile hears its UHF received, and repeats you to the main repeater on VHF, flips itself around and repeats the main repeater back to you using the UHF transmitter.  Simple as this is, it can take a while to wrap your mind around the concept.

There are some problems that limit the utility of cross-band repeat.  The biggest problem is hang-time on the main repeater – the time after someone stops talking, but the repeater stays on the air, beeps, and finally drops.  On many repeaters that’s several seconds, and when two hams are in conversation, the repeater never drops until they are done.  It will automatically reset the time-out timer as each one un-keys their mike so it does not time-out.  Your cross-band repeater can’t tell the difference between a ham’s transmission through the repeater and the hang time afterwards.  It’s all just one long signal being received.  So, if you, down in city hall, are listening to two hams talk, you can’t break in until they’re done.  As long as they are talking, your mobile never stops sending the signal to you, and never listens for you. (Something else to keep in mind here is that your mobile is now transmitting a lot, and it is not designed for continuous transmission.  Keep it in low power.)

A repeater can be made “cross-band repeat friendly” by having a very short hang-time, or by specially designed CTCSS system.  If the repeater sends the tone only when a signal is on the input, and turns it off during the hang-time, your cross-band repeater can use the tone to know when to transmit and w2hen to shut off, allowing you to access the repeater between transmissions normally.  Or, if you can hear the main repeater directly on your handheld but just can’t get back to it, you do one-way cross-band repeat, from your handheld through the cross-band repeat, from your handheld through the cross-band mobile, but not back to your handheld.

A few notes of caution:  first, be careful in configuring your cross-band repeater.  Choose frequencies wisely – your coordination group may have identified band segments for cross-band repeat operation, so don’t just plunk down anywhere you want.  Do some research.  Guard the “local” side of your cross-band mobile with CTCSS or DCS.  If you don’t, and the squelch opens on your mobile, it will spew noise out to the main repeater.  Cross-band operation I particularly useful for emergency and public service event work, but a noise spewing, out of control cross-band mobile can render a vital repeater useless.

Second, maintain control.  The FCC rules require you be in control of the transmitter, but are not specific about how you do that.  If you can reach the vehicle in a few minutes from the inside of city hall, that’s probably good enough.  But don’t stop paying attention to it or leave the area.

Finally, you are required to ID both your mobile transmitter with your call sign.  How do you ID the transmitter that’s sending the main repeater signal back to you?  If you ID at the end of a transmission it goes out on the handheld and is repeated on the other frequency.  I don’t know many hams that talk for ten minutes, but you are to ID every ten minutes.

Thursday, April 26, 2018

April 21st Drill - Recap

First off, hats off to all those that participated in our April 21st drill.  You all did great!  We were able to have a check in from every school in West Valley City which totaled 32 schools.  It took us about 80 min to complete and I felt things went pretty well.  I appreciate the input I also received during the drill and will see how best I can incorporate them in the future.

We also had the opportunity to work out of the City's new communications trailer and give it a proper shake down.  When doing these type of exercises you always find little things that need to be fixed which is the purpose of doing this.  I appreciate WVCFD for their willingness to bring out the trailer and allow us to use it.

Wednesday, April 18, 2018

The Great Utah Shake Out

The Great Utah Shake Out is this Thursday, April 18th.  WVCARC will be holding a quick NET at 12:00 PM on our normal repeater which is 146.700 Mhz, negative offset, 100 Hz tone.  This is always an interesting NET as people are generally at a different location then our normal Thursday Night NET.

Mat Murdock

April 21st Drill Instructions and Resources

First off thank you for all those who have signed up to participate in the April 21st Drill.  The goal of the drill is to check in from each of the 31 elementary schools in West Valley City.  The drill starts at 10:00 AM.   Net Control will be online by that time.  We will be operating on our simplex frequency which is 147.58 Mhz.  Net Control will be operating from City Hall.  Relay stations will be setup at Fire Stations 74 and 73.  Net Control will start with a quick check in to verify which operators are participating.

Once you arrive at a location you need to follow steps below.

  1. Prepare a short message using the FEMA ICS-213 form found here: ICS-213 Form
  2. Contact Net Control and let them know of your location.  When asked relay your message
  3. Wait for Net Control to dispatch you to your next location

The current deployment roster can be found here: Deployment Roster

You will notice that an order has been set as to which school you should go to first.

Following the drill you are all invited to come to City Hall to check out the new communications trailer.

If you are unable to participate please let me know ASAP so I can make alternative arrangements.  If your name is not on the roster and you would like to participate also let me know.


Mat Murdock

Wednesday, April 11, 2018

April 14th - In Person Meet

Saturday will be our monthly in person meet.  It will be held at Fire Station 74 at 9:00 AM.  We will have a couple of things going on.

First a brief overview of the drill that will be held on April 21st.

Second, I will lead those who want to build their TNC's through the process.  Please bring a soldering iron with the finest tip you have as well as solder.  A pair of side cutters or toe nail clippers as well as something to hold the board is helpful.  We will have a few extras on hand if you don't have one.  We do have a few extra kits available if you decide to build one.  Cost is $45.

Third, those who want to have their radios programmed with the Standard Load can bring their radios and we will do our best to make that happen.  If you are a new Ham we will answer any questions that you may have and get you on the air.  If you have any questions let us know!


Sunday, April 1, 2018

Soldering Pro-Tip

I use a vise very similar to this about every time I solder something. It does a couple things for you.  It holds the item you are soldering and you don't burn your fingers.  I noticed Harbor Freight had these on sale for $14.99 at the moment and thought I would share this little pro tip with you all.  You can find them here:

Of course this isn't an endorsement of any kind, just looking to save some finger tips!


TNC-Pi 9k Kits - Last Call

This is the final call for anyone interested in purchasing one of our clubs TNC-Pi 9K Kits.  You can find out more about it here:

In short it is a 300 / 1200 / 9600 baud TNC that can run stand alone or be connected to a Raspberry Pi.  We will be building them at our April 14th in person meet.

We are selling kits for those that are interested for $45 (case additional $8).

If you are interested sign up here:

Let me know if you have any questions.


Ham Radio Manufactures Decide On Single Digital Standard!

Icom, Kenwood, and Yaesu have just announced a joint digital standard.  Currently there are three competing digital modes, namely D-Star, System Fusion, and DMR.  This division has been both challenging and confusion for new and old amateur radio operators alike. 

The new standard will be called DHR (Digital Ham Radio)  "It will combine the best parts of all the existing digital voice and data standards" according to Ray Novak, N9JA of Icom America.  One of the most exciting aspects of this announcement is that all existing digital mode handsets will be upgraded to support this new standard.  Expect firmware upgrades to be available starting today.  This is an unprecedented showing of collaboration and cooperation.  For more information regarding this announcement click here: