Galaxy DX 979 CB Radio Review.

Started by gil, May 12, 2012, 11:18:32 AM

Previous topic - Next topic

gil

I wanted a small CB radio with Single Side Band (SSB) that could be used for emergencies. The Galaxy DX 979 seemed to fit the bill. At a mere $140, there wasn't much of a risk. I knew I was getting a cheap radio and did not have high expectations, only a few requirements: Small size, SSB, and perfectly legal. That means forty channels, AM, USB, LSB modes, with 4W max on AM and 12W on SSB (PEP). Not much, but you would be surprised (I was tonight) at how far you can reach with just a few watts, as much power as a small bicycle light bulb!

Most people know the Citizen Band through movies like "Smokey and The Bandit," "Convoy" and others, mostly involving truckers. That is just one side of the coin. The other side are the operators trying to cover the greatest distance possible, and activity called "DX."

CB has a good thing going for itself right now, that is the peak of solar cycle 24. Propagation is going to be very good for probably another couple years. Radio waves in the 11m (27Mhz) band do bounce off the ionosphere when conditions are right. SSB being excellent at receiving weak signals, you have a very good chance to skip pretty far.

The Galaxy is cheaply made (compared to a Yaesu HAM radio of similar price). The buttons on the front panel are "chromed" plastic and look cheesy. The whole radio looks and feels cheap. I even had a very hard time putting in the mounting bracket screws. I had to tighten them with a pair of pliers and was lucky not to strip any thread. Looking inside the box gave me the same feeling. I like the big meter and the fact that you can dim the blue LEDs.

I connected the transceiver to my Solarcon Max2000, a 24ft. antenna mounted about 15ft off the ground, surrounded by trees, and an Astron power supply. Good thinking from Galaxy for putting the microphone plug on the front panel by the way, which I plugged in, then turned the volume knob to ON. It worked! I shouldn't be so negative, since I suspect that most CB radio manufacturers produce the same lever of "quality." I tuned to 38LSB and listened, playing with the clarifier whenever I heard someone calling DX.

[tip]The clarifier is the knob that turns the "Donald Duck" voices you hear on SSB into something you can understand.[/tip]

If you are a safe cracker by trade, you won't have any trouble with the clarifier on the 979. It takes that kind of finger dexterity to operate the darn thing. Before you have a caller "clarified," he is usually done talking.. Aggravating.. The range on the clarifier is too broad. My old President Jackson has a much better clarifier, but of course, that radio has acquired a quasi legendary status in the CB world. With a little practice, you get better at it, but geez!

Compared to HAM transceivers, CBs are noisy... I plan on replacing a few diodes with Schottky Barrier Diodes, and replace an RF amp transistor with a 2sc2999, High Gain, Low Noise model. The procedure is described here; part are on the way (about $1.60!).

I remembered that I should check the SWR before transmitting, which was a perfect opportunity to test the inboard SWR meter. I also plugged in a Workman el-cheapo meter on the antenna output. They did not agree with each other! The Galaxy SWR meter barely moved while the workman showed 1:1.8! I tuned the antenna and got down to 1.6 (probably all those trees..). Oh well. Just keep an eye on the SWR warning LED.. It works (I had a short in one plug); the SWR meter also jumped up. It might not be the most sensitive SWR meter, but it will let you know when you risk frying your final transistors.

It was getting late and the band was dying down when I heard "476" calling. He did not say where he was from, but I could hear him very well, good audio and a signal of 7. I expected him to be within fifty miles of me. I asked him about his location and he said "Jamaica!" I had a low signal but good audio (mike gain turned all the way up). Not bad for a $140 piece of gear. The antenna is everything, mind you, and the IMax2000 did it's part. The Galaxy... I hadn't wasted my money..

The Galaxy DX 979 won't win manufacturing quality contests. It does however work well. For the price, you can buy two and box one up in an ammo can for EMP protection. It is a small price for never being entirely cut off from the rest of the world.


gil

I made the modification tonight, replace Q17 with a 2sc2999, and Dl, D2, D30, D31 with 1N6263 Schottky Barrier Diodes. The radio does sound a bit quieter. For ten minutes and less than $2, I'd say it was worth it...

Gil.

Geek

Sorry to reopen an old thread.  Can you post some pictures showing your modifications?

gil

Hello Geek,

I didn't take any, and it isn't something you would see on the PCB. It's pretty easy to do mind you, just unsolder the components and replace them.. That said, the radio as sold works just fine. The mod does lower the noise floor a bit, and it helps for weak signals copy...
I like the DX 979 because it has SSB, is cheap and legal.

Gil.

Geek

You've recommended this model CB in a couple places and I am inclined toward buying one, but I would be nervous about opening up a brand new radio and starting to unsolder parts and replace them with other parts without knowing exactly what I was doing.

gil

My suggestion would be to open it up and locate the parts. If you can find them, you can change them, assuming that you are familiar with unsoldering and soldering components on circuit boards. The improvement is not substantial, just noticeable, so it isn't a mod you must necessarily do...
Attached is the PCB layout. Make sure you click on the link that describes the procedure. See my original post..

Gil.

cockpitbob

Gil, I have very little experience with AM vs SSB in CB radios.  Can you educate me a bit?
-- If you are on SSB and the other guy has using a plain AM CB, how will he receive you vs. him having an SSB CB? 
-- If the other guy is Tx-ing AM and you are receiving SSB, don't you loose half his signal?
-- How do you choose between USB and LSB if the other guy is AM.  I'm guessing it doesn't matter.

gil

Hello Bob,

AM or SSB is the same whether you are talking about Ham or CB. It's just a legal distinction. AM has a carrier and two sidebands. SSB has one of the sidebands, period. You can listen to AM while in SSB mode, if you tune off the carrier to one of the sidebands. I never tried to listen to SSB while on AM.. Bottom line is, you want to be in the same mode. You will hear the other guy if he is in the other mode, and you then just flip the switch to make it intelligible. LSB and USB are mirror images of each other...

Trying to communicate using different modes, AM and SSB is not going to work...

AM has less local range but sounds better. The problem with CB is the noise. When you listen to the CB band using a Ham radio, it sounds very quiet. Switch to the CB and you get a lot of static. Why? That's the difference between $150 and $700... When I listen to channel 38 LSB with my KX3, it seems like the radio is off, until a signal appears. Of course we're talking about a $900 radio with DSP filtering... That said, an MFJ-9410 will beat the pants off a CB and costs $300. I have nothing against CB, because you get a lot for your money though.

Maybe someone else here can tell us if you can listen to SSB while in AM mode?

Gil.

KC9TNH

This is still a nice thread. CB still has relevance. There may be people you need who are not hams & never will be, but are important overall. And the only thing they may have is the CB bolted to the mounting bracket overhead in the tractor and maybe a base in the farm house. And, frankly, in some ways, they are in better shape than many who are relying on cell towers. It might be the least common denominator but if that's where you have to go...

Tools in the box.
  8)

Geek

What types of HAM radios can I transmit and receive CB on?  From your last post, it sounds like I really don't need a separate CB radio at all.

gil

QuoteWhat types of HAM radios can I transmit and receive CB on?

You can't legally transmit, only receive. My KX3 for example can listen to CB but will not transmit. The only Ham radios that can do that are some kits or modified radios. My K2 would transmit on the CB band. It is still illegal to do so. Some export model CBs can transmit above and below the CB band, but that is illegal as well. Too bad... the CB band should be part of any Ham radio, but unfortunatelt it isn't going to happen...

Gil.

Geek

Got it.  That explains your desire to upgrade a CB instead of trying to locate a better model.  I think it is beyond me at this point, but interesting nonetheless.

cockpitbob

#12
Gil, thanks for the explanation.

I have a CB gathering dust, but I'm keeping for reasons stated above.  I think an emcomm kit should have some of everything (ham, CB, FRS/GMRS, smoke signal blanket).  The more you have covered, the more comm options you have when the SHTF.  Only about 1 person in 400 is a licensed ham in the USA.  Most people have FRS/GMRS radios and I bet a lot still have a CB in a box in the basement.

Geek

"Most" is giving too much credit to the non-HAMs.  There are some people, like me, who have some FRS/GMRS handhelds, either for emergencies or simply as toys.  Truckers have CBs and older folks who were driving in the 70s may have an old one in the garage.  However, I would expect that 95% of Americans do not have even those simple non-licensed radios around, let alone sitting in a Faraday cage.  In fact, from the dialog I have seen on other "prepper" forums, I'd say less than 50% of the folks who are into prepping have any sort of radio capable of transmitting.

White Tiger

Quote from: Geek on February 12, 2013, 03:54:17 AM
"Most" is giving too much credit to the non-HAMs.  There are some people, like me, who have some FRS/GMRS handhelds, either for emergencies or simply as toys.  Truckers have CBs and older folks who were driving in the 70s may have an old one in the garage.  However, I would expect that 95% of Americans do not have even those simple non-licensed radios around, let alone sitting in a Faraday cage.  In fact, from the dialog I have seen on other "prepper" forums, I'd say less than 50% of the folks who are into prepping have any sort of radio capable of transmitting.
I agree, and even those that have some type of radio have no concept of how to use them, have an antenna, etc.

Many who have jammed FRS/GMRS handhelds into some Bug Out Bag...or even their CB under their bed...don't realize that those systems are channelized...when the SHTF hits the fan there will be thousands of people trying to use 3, 6, 12 - or maybe even 40 channels! Can you imagine trying to call for help at the exact moment hundreds or thousands of other people will be flooding those same few channels?

That's why ham radio, with it's thousands of frequencies, and licensing requirements, offers much more/plenty of access during times of trouble.
If you're looking for me, you're probably looking in the wrong place.