I didn't quite know what I was looking at when I missed out on a deal at a HamFest on a Dentron MT-3000 Antenna tuner. On searching, everyone says it's built like a tank and I'm kicking myself in the face for missing out on that deal.

Anyhow, I just now ended up with another tuner which I can't find much info about...

It's made by Advanced Electronics Applications, Model AT-3000.

It's got a cross needle Forward/Reverse Power meter with SWR readings where the needles intersect.

Upon dismantling it, it also appears to have a crude balun inside, consisting of wiring to the antenna posts being wound through some ferrite cores.



It has two adjustable inductors, with spring loaded contacts for transmitter and antenna matching and a bread slicer style adjustable capacitor for reactance tuning...

This is the exact opposite compared to the Dentron which has two capacitors for antenna and transmitter matching and a single inductor for reactance. Plus the inductor is switched with a rotary switch rather than the spring loaded contacts.

Can anyone tell me more info about the unit I have purchased? Did I get a worthwhile unit? Will it really handle more power when I upgrade to an amp later?

I've heard inexperienced hams (me) can damage antenna tuners by misuse. What should I do to preserve the tuner?

There's always good stuff to be had, it just depends on what you're looking for and who shows up...

I don't like the non-ham related tables, but there's always a little tool that could be useful...

I just wish HamFests had some WiFi access so I could research what I'm buying. I skipped out on a deal on a Dentron MT-3000 Antenna tuner and I'm still kicking myself in the teeth about that one. I ended up getting an Advance Electronics Applications unit instead.

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The goal of lightning protection is NOT to prevent the antenna from being hit. It is to give it a low impedance path for current flow WITHOUT flowing into the house via the coax cable. This applies to currents induced into the antenna and feed line via a nearby strike to a tree or some other object.
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I think that's the single most important item that needs to be taught to green amateurs such as myself.

So as far as I'm understanding from all my reading about Motorola's R56 standard, Polyphaser and Transtector products, and other HAMs' info, let me see if I've got this all figured out.

Due to the sudden and intense nature of lightning, it shouldn't be thought of as just DC as it can induce strong currents in nearby conductors. (Basic Electronics 101: Think of a giant transformer.) This is why the doorframe at cell sites and radio stations is grounded, along with any conduit and racks for cable and equipment. Even the chassis of the radio is susceptible.

Low impedance ground is KEY, hence use the largest diameter wire affordable and use multiple ground rods in parallel. (Basic Electronics 101, Parallel impedance reduces circuit total impedance.) Impedance to ground should not be more than 25 ohms according to NEC. Less than 5 Ohms is generally unachievable. Use Epsom salt or fertilizer to improve ground soil conductivity.

Connect multiple ground rods together and bond utility power ground to them. This is the Common Point of Ground (CPG). Bond any metallic structures in the premeses (tower, guy wires, etc) to their own ground rod AND the CPG. Use a heavy copper plate in the shack to ground equipment to and bond this to the CPG. Bond all surge arrestors for utility power, telephone lines, and coax to the CPG.

This way, even if you do sustain a direct hit, everything is at the same potential, similar to how birds and linemen can climb on multiple KV high tension lines and not be harmed...

Any surge current induced in any metal object due to nearby hit, or any current taken in a direct hit will be dissipated into the ground.

This is how broadcast stations, cell sites, and public safety radios stay online even during storms.


Sound like I've got it down packed?

I'm attempting to hang a Alpha-Delta DX-CC Dipole antenna from some trees.

It's been advisable to get it at least a half wave up... At 80 meters, that's over 120 feet. Not gonna happen, as I can't get into the trees that high...

After I put it as high as I can get it, how should I install a lightning rod?

Should I just count on an even taller tree to act as a lightning rod?

Should I climb said taller tree (I am not sure how... There's no branches down low.) to put a lightning rod up there?

What is a reasonable gauge wire to use for lightning protection?

Oh I'm all too familiar with the sun causing "better" propagation on the higher bands.

I maintain KSL841 as my day job. We run VHF.

I get calls from my people complaining of hearing stations in New York, Pennsylvania, and New Jersey. I get calls from all of them claiming to hear us in Washington D.C. And everyone expects me to do something about it.

*shakes fist at the sun*

I suppose we're getting a bit off topic now though. I'm gonna go out and hang my antenna in the trees today.

I'm not really sure what bands I plan on working, as I'm still pretty new at this HF stuff.

I only know that I plan on running PSK31 because I'm terrible at CW.

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I would add, though, that "I worked Western Europe and most of the West Coast" is not a very glowing report of antenna performance from the East Coast USA ;-)

On most of the bands the DX-CC covers, I would consider it a bad day when I couldn't get further than W. EU or California. On 20m, for example, many West Coast USA and W. EU stations come in 59+20dB on my little two element beam up 30 feet. I'm not saying there's anything wrong with the antenna itself; the A-D DX-CC seem to work well for people, but I'm wondering if your neighbor's expectations were a little low or his noise was high?
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Well, we are right near Washington D.C. So the QRM might be a bit high.

I'm also not sure if he tried to work Asia or anywhere else, or if he was just citing examples, or frequent contacts...

Well, it seems good because I have a set of very tall trees that's perfect for hanging an antenna from. They're just oriented 90 deg to where he had it.

Just got my first HF rig (Kenwood TS-570) from a hamfest and my neighbor sold me his Alpha-Delta DX-CC dipole antenna. Time to set this puppy up.

So he told me that he used to work most of Western Europe and some of the west coast of the USA. However, when we took the dipole antenna down, I noticed that the wires were pointing East and West (Assuming his and everyone else's DirectTV dish was pointed south.)

This didn't quite make sense to me because I thought the dipole radiated out the broad side (Perpendicular to the wire ends) The way he had his antenna pointed, it should work Canada and South America.



Was this confusion because I'm used to thinking of the world as a flat, wide rectangle?

With this map:
http://www.qsl.net/crosscarc/GreatCircle.html

It seems to make a little more sense.

RoHS - Reduction of Hazardous Substances

Lead, Mercury, and other heavy metals, ChloroFluoroCarbons, etc.

I got there at 10 AM and found my deal at about 11:30. Some say it had been out for sometime before.

I've seen mobile ATM's either small portable units or ones built into the side of a van of some sort. They're usually used for street festivals and the like, I'm not sure how much it'd cost or if it'd be beyond the means of  Hamfest organizers.

It wasn't so bad, save for the heat and the ATM being tapped out. I had to drive down the road to the 7-11 to get money.

(Useful self control tip: Take some cash for small items. If you see an expensive rig and you want it, you have to think about it on the trip to and from the ATM.)

I got a Kenwood TS-570 and a whole mess of accessories (Kenwood Power supply, Interface cables and adapter for PSK31, headphones) for $600, good shape, manuals, box and all.

Now, I've just gotta figure out what I'm gonna do with it, seeing as how it's my first HF rig any my first one that does anything other than FM/Voice modulation.

N3KQX:

I've seen some reports that the Kenwood units support the KISS protocol, but it's just not documented officially in the manuals.
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K1CJS:

It's kinda hard to talk underwater. I suppose I could still communicate if I knew CW better.

It's more for the "oops" factor. Dropping it in a creek, getting caught in a hard rainstorm, etc.

I bought an aluminum laptop once thinking aluminum is more durable than plastic. Dropped it and realized aluminum bends. Plastic, provided it doesn't break, will return to it's original shape after impact.

After that $1800 mistake, I like to plan ahead for drops and the like.

Does the TinyTracker have the ability to send and receive data messages, weather, status reports, etc?

I thought APRS is a little more than just position tracking.

Heya. New ham here.

My first HT was (is) a Yaesu VX-7R. Why? Because I knew I was gonna get it dirty/wet/beaten up... It says Submersible right on it and Motorola bought Yaesu. We all know how sturdy Motorola gear is. (I use my work radio, a Motorola XTS-3000 as a hammer, doorstop, self defense billy club, etc.)

I'm getting involved in Skywarn and ARES and I'm setting up my 4x4 with a TM-D710a mobile unit. I'd like to get the matching HT.

I figure they've been making the thing for ten years, it's gotta be good.

The TH-D7A is advertised at having a MIL-SPEC 810 C/D/E Water resistance... What exactly does this mean? Can I use it in the rain/sleet/snow? Out four-wheeling on the trails? On a boat?

How's yours holding up?

Is a diagram available for those that want to build it or possibly scale it up to supply more current?