Rock-Mite success!

Started by gil, September 27, 2012, 04:12:53 pm

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September 27, 2012, 04:12:53 pm Last Edit: March 26, 2013, 12:54:06 am by gil

It doesn't take much power to make contact...

Yesterday I added a few inches of wire to my PAR End-Fed antenna, which got it centered on 7040kHz. This is ideal for my Rock-Mite, which is somewhere between 7029 and 7030. So I plugged in the little guy, which incidentally is my paddle base!

I am thus never without a backup radio. I started callind CQ but the keyer was lagging and ignoring some dits and dahs. That was the Pico Keyer chip. I replaced it with the original provided by Dave Benson in the kit and all was well. A few minutes later I was in a short QSO with a station 625 miles away, with 1W of power! My signal wasn't great, but he heard me.

Operating QRP (low power) isn't some kind of black art. It is about reducing losses. Most people who run 100W are not radiating 100W, 30 or 50 maybe, or even less.
In my opinion, 5W for CW and 10W for SSB is all one needs, assuming the antenna system is well designed and losses kept to a minimum.

Why would anyone want 100W, or even 1500, for heaven's sake, I don't know...




How do you like the RockMite? I've been thinking about building one (40m 7030), and I'd love to get the opinion of someone who's been actually using one. Also, is that an American Morse Mity Box/Porta Paddle combo you've got it built in? If so, you've already built the exact rig I'm planning on. Thanks for the beta testing.  :)

If you're into QRP/CW, you should think about joining NAQCC. I know the guys who actually started the club, and it's a really great group.



September 28, 2012, 02:29:01 am #2 Last Edit: September 28, 2012, 02:47:14 am by gil
Hello Ray,

I love the Rock-Mite. It's unbelievable what such a small radio can do. It does have it's limitations mind you: No RIT or VFO (can be added). There is the button to switch sides, sort of like a channelized RIT. The bandwidth is 3kHz, so when it's busy around 7030, forget it. Though, I'm sure if you sent a legitimate SOS, you'd have the 3kHz for yourself! Mine has a 2SC799 for 1W+ output (depending on DC voltage). I will probably build another RM40 soon, maybe with some add-ons, like a RIT and built-in tuner plus SWR indicator. But I like the small size, so I might go for a box of Altoids.

That is the DCP paddle from American Morse you see on it. It is screwed to the lid of the Mity-Box.

Get one, you won't regret it! At $29, it's not much of a risk..
And if you don't like it, just send it to me then  ;)



Congratulations! Neat little gem. Ahh, the world of baby fixed-freq CW transmitters in curtain-darkened, dank apartments with wire strewn about and counterpoise to the radiator, where we find our hero somewhere near Rostock...

Can't recall exactly 'cause I don't do it but somewhere I think there's some kind of award or something when you make a contact at over 1,000 miles per watt.

All that said, I've learned to never say never. I can work QRP, 20W, 100W (and yes I do get pretty close to full participation out of my antennas). I can also work up to a KW if needed in certain base situations. Never know, the distant-end may be the one with lousy conditions.  In our neck of the woods Aurora dipping below 60?N can truly squash signals even when one doesn't detect notable noise level. As somes old-timers will say, we don't run amps for us, we run them for our friends.

From a preparation point of view, your CW stuff with 1W is a very neat thing.  The lower you go in power the more someone who doesn't like you has to ramp up their efforts to find you. (If you can stand the continuous workload, get ahold of a local RC and offer to be "the fox" sometime in a DF hunt.)

The other thing I've found by periodically going back to low-power and CW opns is that it hones my listening skills in a measurable way for other things.
I think your Rock-Mite and some wire is a success.


Thanks. It is definitely fun to use and doesn't take much space in a bug-out bag..



September 28, 2012, 11:41:17 am #5 Last Edit: September 28, 2012, 02:51:42 pm by RadioRay
The Award is the "Thousand Mile per Watt" award.  The little RockMite is a wonder.  I just got off the air with my 20 meter RockMite - half Watt rig.  A good fellow in Georgia and I talked for about a half hour in slow CW.  Now - it's a LOT easier with power, but after about 10 - 20 Watts it's  a law of diminishing returns.  You burn more power, carry more weight and add to the complexity, yet gain little more in return - if at all.  That sweet spot of a few Watts and GOOD Antenna, like the dipole or one of Gil's EndFedz and you're able to communicate. 

Down sides of the RockMite:

1. Basically a single frequency, though you can shift it a few hundred Hz for a 'side tone.

2. VERY low power, so that you must have a good antenna, or else...

3. The little receiver IS very sensitive and that's a plus, but it has no filtering, so it's wide as a barn door and so it hears ALL signals in the pass band along with the ham you're trying listening to.  BTW - this is nothing new to old time hams and with practice, your brain tunes in on ONLY the signal that you want, but that requires a little bit of practice.  The Good Thing: practice is enjoyable.

Up side -

A.  It's a complete ham radio transceiver for under $30... 

B. It runs on anything from a 9 volt battery up to a car battery -

C. It draws so little power that you could keep it running with little effort.

D. They are very small & lite. You could put a few of them into your shirt pocket.

Mine is built into a little pipe tobacco tin and still has room for plenty more 'stuff' in there...

"When we cannot do the good we would, we must be ready to do the good we can."  ~ Matthew Henry


Thanks, all above led me to the site, and a pic gallery. Nice to see the personal innovation in choices of case.
I liked the box of band-aids, as well as the simple waterproof container which they make in a boatload (no pun) of dimensions these days, like baby Pelican cases.

Very cute. Actually one of those, and using a diff op-amp to get 1.5W as I saw someone do, would make an interesting companion to the little T1 if I had a different length piece of wire up for some other reason... winter project maybe.

Thanks all.


Excellent post Ray, thanks. A mini Pelican case, that's a great idea!

The ATS-3b, 4b? is very interesting too, but hard to find...



October 10, 2012, 01:19:04 pm #8 Last Edit: October 10, 2012, 01:22:12 pm by Sunflower

Is Rock- mite the name of this product?

Can this be used as a practice  oscillator?



Yes it can! You just need to plug in a dummy load.



Great discovery tonight.. I often got AM stations coming in so loud, copying weak signals was impossible.. Until I noticed that when I used my magnetic loop antenna, there was no QRM! The loop filters out everything outside of the lower part of the 40m band!

Also, my RM it turns out transmits on either 7028.1 or 7028.8kHz. I regularly get picked up by reverse beacons about 800 to 1300 miles away. It seems like the best range is 900 miles.



My record so far is 1000 miles with an unmodified RM-20. Great Little radios.

My only criticism is that the sidetone is utter filth. Square wave, and too loud. I've made a couple of mods but it's still not acceptable.

I made two, and swapped out the PA on the RM40 to put out about a watt.


Good looking RMs.. What did you do to take the sidetone volume down?




Great looking RockMites!  I like the very clean case & etc.  That would make it quite 'trail friendly' to take on a hike/weekend.

Gil has used his to talk with me , over 800 miles away.  It was really not a problem to copy.  Frankly, if the QRP frequencyies were respected, we could have great conversations on a regular basis with very low power, but I do not see that happening any time soon. Still, it's been a fun QRPp rig for me here in the States, chatting with fellows all over and they ger a real KICK out of talking with a tiny , half Watt transceiver.

>de RadioRay
"When we cannot do the good we would, we must be ready to do the good we can."  ~ Matthew Henry