Category Archive: SWIARC University

Educational articles by SWIARC club members to help amateur radio operators everywhere.

Tone Out Denies No One

Tone Board Option for Old Rigs

Tone Board Option for Old Rigs

It’s called Tone Encoded Squelch. Requiring it to get in the repeater has a downside. However, did you know you could keep the input open and still have a tone on the repeater output? If you don’t care, you probably won’t even know its there.

 

An open repeater not requiring a PL Tone (correctly known as CTCSS) is accessible by ham within range, even those using an old transceiver not capable tone encoded transmit.   The same repeater may implement a PL tone on the output. But, what will happen to people using those older rigs?

 

No One Gets Left Out

 

Individuals without a tone board or PL / CTCSS capable transceiver will still be able to use the repeater. If there is no tone requirement to get into the repeater, no individual will be denied access. The presence of PL on the output (when the repeater transmits) creates the “option” for users to utilize PL as a way to squelch out interference.

 

With a tone present on the repeater output, your radio will simply receive the transmission from the repeater as usual, and you will “probably” be blissfully unaware of the presence of the PL tone. There are instances where certain radios make it possible to hear a faint tone, but that is the exception, not the rule and it certainly does not impede any communication.

*I have an old Kenwood TR-7400A without a tone board, and I don’t hear the tone when listening to repeaters using PL on the output.   However, with that being said, I admittedly have poor hearing.

 

The Kenwood TR-7400A comes without a tone board, but an optional one was available.

 

Output Tone Ousts Interference

 

If you are a station with a transceiver capable of CTCSS squelch, then you will be able to use it and isolate the repeater you want to use from other transmissions that are not using the same tone, such as distant repeaters that become audible during periods of a band opening. Your radio squelch will only open for the desired repeater having the matching PL tone.  It is also a way to prevent your transceiver squelch from opening from other sources of noise (aka QRM.).

ARGH! TONE!

ARGH! TONE!

So it is really a feature that can be used, and perhaps should be utilized on every repeater with no real downside. Yes there are people that claim they are aware of the tone in the transmission, even though it is sub-audible by definition. In that event, the complaining party need only enable tone encoded squelch and thus eliminate what the individual perceives to be a completely intolerable slight whisper of a sound (so they can find something else trivial to complain about.)

 

In conclusion, don’t confuse “tone-in” with “tone-out.” Tone-in makes the repeater “exclusive,” while tone out keeps it “all-inclusive.” Tone-out provides an optional feature that repeater users may choose to utilize, ignore, or be blissfully unaware of.

 

-W0DBW  Derek Winterstien

 


related terms:  CTCSS/DCS/5Tone/2Tone/DTMF SET CTCSS / PL Tone

KE0GKF’s Digital Hotspot

STORYPIC0B-256x128Turn your home Internet connection into a minature repeater for your DMR, D-Star and C4FM radios so you’re always within range of a repeater and able to access a wide variety of digital networks. Two such products are now available. Read the rest of this entry »

Electronic Builder’s Toolkit by Russ AD0QH

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Kit building has become very popular among local hams. Our club President, Russ, has provided us with a follow-up shopping list of supplies the kit builder will surely need as illustrated during his presentation at the January club meeting. Whether you made the meeting or not, you will undoubtedly find his Amazon shopping list useful.

 

Russ has put together a comprehensive shopping list using Amazon.com that you can view by following this link: Amazon Wish List AD0QH – Ham Radio

 

You would have seen many of these items during his January presentation. The presentation not only applies to kit building, but electronic circuit work, rework, and service. This is entirely an excellent starter kit for the electronics service enthusiast.

 

Here is a TEXT list of those items mentioned above:

*Carson LumiLoupe 10X Power Stand Magnifier With Dual Lens (LL-20)
*Chemtronics 10-25L Chem-Wik Rosin Desoldering Braid
*Excelvan M6013 Digital Auto Ranging Capacitance Meter Tester Capacitor Tester
*MagnifyLabs Headband Magnifier (Optical Visor / Binocular Magnifier) – with One Optical Glass Lens Plate (2.5x at 8″ Focal Length)
*Dual Wall Adhesive Lined Heat Shrink KIT – 85 Pieces – 3:1 Shrink Ratio – Size Range: 3/32″ to 1/2″ – Black, Clear, Red
*Hakko FX888D-23BY Digital Soldering Station FX-888D FX-888 (blue & yellow)
*PanaVise Model 201 “Junior” Miniature Vise
*Hakko CHP CSP-30-2 Wire Stripper, 20-10 Gauge Maximum Cutting Capacity
*Hakko CHP CSP-30-1 Wire Stripper, 30-20 Gauge Maximum Cutting Capacity
*Hakko CHP PN-2007 Long-Nose Pliers, Flat Nose, Flat Outside Edge, Serrated Jaws, 32mm Jaw Length, 3mm Nose Width, 3mm Thick Steel
*Hakko CHP-170 Micro Soft Wire Cutter, 1.5mm Stand-off, Flush Cut, 2.5mm Hardened Carbon Steel Construction, 21-Degree Angled Jaw, 8mm Jaw Length, 16 Gauge Maximum Cutting Capacity

Enjoy shopping!!!

 

note:  If Russ puts together some of his presentation notes with informative tips they will be added to this article as an update.  It pays to check back and keep track of whats on the SWIARC web site.

Transceiver Coaxial Cable Selector Switch

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If you are going to connect two or more transceivers to a single antenna using an antenna selector switch, be warned, you need to consider how much RF you are dumping into the unused transceiver. There are antenna selector switches that cannot be safely used as a transceiver selector switch. Never assume you can use them interchangeably.

Not all antenna selector switches are up to the task of using multiple transceivers on the switch. They are typically designed for using a single transceiver on multiple antennas.

Two factors need to be considered when selecting a coaxial switch: 1. Output Isolation 2. Grounded Unused Connector

The first factor is the Output Isolation of the signal, which is to say how much signal from your transmission is bleeding onto the unused connection. The better the isolation the less signal will be getting into the unused transceiver. This mostly has to do with the spacing of the internal wiring.

The second factor is the grounding of the unused connector. Most low-end antenna switches do not ground the unused connection. Grounding the unused connection helps to bleed off stray signal to ground rather than into the unused transceiver.

The MFJ-2702 is an inexpensive antenna selector switch that should not be used to connect two transceivers to a single antenna. Although it has suitable output isolation at 70dB or more for the HF band, it does not ground the unused output connector. The MFJ-2703 does more than simply add an additional connector. It also has additional internal parts to ground the unused connectors, which helps mitigate RF from entering into the unused transceiver.

When you are using an antenna switch box as it is intended, to select from two or more antennas for a single transceiver, then these factors are less important in that they are relative to signal loss. When you are using an antenna switch box to connect two or more transceivers to a single antenna, then you take a chance at damaging an expensive transceiver. Don’t use a cheap antenna switch box unless you are certain that it can be used in this manner either by design or by carefully considering its output isolation as well as whether or not it grounds the unused connector. Some coaxial cable switch boxes are advertised as both a transceiver and antenna selector. You should still verify that the unused connectors are grounded rather than open.

Consider the Workman model CX-3 as an example of an antenna selector switch which is barely suitable for its intended purpose. With poor RF isolation of 42dB at HF frequencies and completely lacking a center conductor ground at the unused connectors it isn’t even an ideal antenna switch. If you planned to use it to connect multiple transceivers to a single antenna you risk damaging those transceivers because power from the selected transceiver is going to bleed into the unused transceivers. This would not be a problem at QRP power levels, however, at 100 watts it would be a bad idea. Although immediate damage may not necessarily occur, over time it would inevitably lead to failure of your radios.

Finally, when you are using a coaxial cable switch to connect two or more transceivers to an antenna, be care to observe the switch position before you transmit. Human error can still result in damage to your expensive transceiver. Make sure you never transmit when the switch is not set to the transceiver you are using.

 

-w0dbw

Kit Built mini Power Supply

Variable Power Supply costs under $20 (on Amazon)

Variable Power Supply
costs under $20
(on Amazon)

Mike KC0FAN, Football At Nebraska, went to the Hearland Hams sponsored Kit Building program
in Glenwood IA recently, and has now built this cute little variable power supply. It’s only
eighteen bucks on Amazon, and comes complete with a transparent plastic case to keep your
fingers from contacting the 120VAC. He says:
.
It was a fun project to do. The board is laid out well and I do like the case so I’ll keep my
fingers out of the line voltage. If I was doing a class on kit building this project would make
a great starting point.
Toughest thing on this one was the IC base and mods to the display leads so it can be hardwired
and mounted to the board. I did use the ps last night to check the led (just for the fun of it.)
on the transistor checker.
.
The ‘transistor checker’ is Mike’s second kit project.

Car Antenna Hole Fix

Car Antenna hole fix using nylon parts

Car Antenna hole fix
using nylon parts

Sooner or later you’re going to sell your mobile and likely as not, the new owner
won’t be a Ham and won’t understand why there’s a hole in the roof. Here’s a fix.
First of all, go down to hte hardware store and buy a couple Nylon washers about
an inch diameter. Then, a small container of Nylon wall clamps or whatchacallit,
wall hole covers. Second, pull off your antenna and put down a Nylon washer over
the hole and the clamp with expanding stud (click on pic to see what I mean)
through it. The expanding stud expects a half inch of wallboard to work against
so put another couple, 3 or 4 more, Nylon washers on the inside of the hole.
Finally, tap the ‘nail’ through the stud to expand the bottom and you’re done.
.
Oh yeah, it helps if you bought a WHITE car to begin with, and no, this wasn’t
a roof mount antenna. The stick looks a lot racier on the trunk with a slight
backwards rake.
.
P. S. One more caveat: You shoulda been removing the antenna each year to
wax the paint under the mount. If not, in this case maybe twice in eight
years, you get a circle of rust around the mount.

 

-Rich WA0ZQG