| K4SRQ |
Rating:  |
2022-04-19 | |
| 20 Meter Excellent Rig For The Price |
Time Owned: 0 to 3 months. |
This was a fun build. I modified my enclosure from a box bought surplus at the local electronics store. A knob, some 5/16" parts for the key, earphone, potentiometer, power, and a bigger hole for the SO239, I was ready to rock. Most like BNC and in the future I will use it but all I had was SO239 in the shack.
The kit is not difficult to build. The results are stunning for the price. The receiver is very quiet and the transmitter, though a little off from 14.060, is a good clean signal. The only drawback is the volume of the side tone as it is a bit loud. There are mods for this.
I am in Sarasota Florida and my first contacts were in Texas via my 4btv verticle. Then I made a resonant 20-meter dipole and was able to hit middle Pennsylvania! Not bad for 250 mw. I look forward to Field Day using this rig and a battery on the resonant dipole to see what I can muster. Well worth the price and build time. I want to pick up the amp and get a full 5 watts! The rig is now available from http://qrpme.com/
This is going to be a fun little rig. BTW, the LO on this rig will generate tone on a local receiver a few hundred hurtz away from center. This is normal behavior. Have fun! I give this rig a 5 as it is beyond expectation, and priced incredibly cheap for what it does so well. |
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| N3AFS |
Rating: |
2017-01-09 | |
| Still a Winner |
Time Owned: more than 12 months. |
I just fired-up my ten year old Rockmite 20 (14.060 MHz) on 9 January 2017 and it is still a surprising transceiver. I had two QSOs when 20 meters opened briefly this afternoon to/from the northeast USA. I had a great QSO with a ham from Quebec and another with a ham from Maine. I got 579 reports from each! While there was some strong QRM, I got through with my 500 mWatts on 8 AA batteries! This little rig is still amazing!
73, Ken - KG4LLQ |
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| F1VJT |
Rating: |
2013-04-24 | |
| Rockmite20 power mods |
Time Owned: 6 to 12 months. |
You can replace final transistor with a 2N1711, BLW16, 2N3053, 2N3553....R18 fixed to 6.8 Ohm.
The power output (with BLW16 and R18=3.3 Ohm) rise to 1.2 Watt @ 12Volt, the current rise proportionally.
To faciliy the replacement of Q6, you can mount it on a dip pins, you can repair your PA without iron soldernig!
Very great QRP transceiver, i found it more performant than a Hendricks DC-20.
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| AE5VM |
Rating: |
2012-12-24 | |
| great for Feild Kit |
Time Owned: 3 to 6 months. |
I'm working on a feild kit...Can be seen on QRZ-
AE5vm.
I've followed instructions from one of the postings on changing out the 2n2222A to a 2n3053
and resistor 10 ohm to a 6.2 ohm... to give it over a watt.
had excellent results..
I will be adding another rockmite to my feild kit soon to have two bands..
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Earlier 5-star review posted by KE5LZL on 2012-07-16
built one 2 1/2 years ago.for 40m .
planing on builind another for 20 meters |
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| KB2HSH |
Rating: |
2012-11-27 | |
| Work of Art |
Time Owned: 0 to 3 months. |
I recently purchased a RM40 so that I could get back on the air. Many in my circle of friends has known that 2012 was a tough year in telecommunications, and I was forced to sell nearly everything in the shack. (Family comes first!) So, "needing" new gear, I decided to try out the SWL Rockmite. And I am thrilled that I did. For $29, you get a radio that is an incredible performer, is durable (more on that later), and is tiny enough to build into many unique configurations.
Last week, as I was attempting to install my RM into a metal box, I forgot to disconnect the DC power leads from the power supply, and I mistakenly shorted the board to the box. This caused the circuit trace from the V+ connection to the first onboard capacitor to "explode" from the board. A little piece of wire, and a small 12 watt pencil iron, and the RM was as good as new. NO component damage. The SMD amp chip and the keyer and the 2N7000 FETs ALL survived the short.
With a little modification, the RM is capable of triple the power it came from the factory capable of. I swapped out the 2N2222A for a 2N3053 at Q6, as well as the adjacent 10-ohm capacitor for a 6.2 ohm unit...and my RM emits 1.3 watts. This is more power out than my Ramsey QRP-40...and it was 2/3 the price!!!
With a good antenna, this rig is tough to beat for a lot of reasons. Even with the lousy antenna I'm using at my "temporary QTH" (a 200' random wire, and 33' counterpoise), I have been making QSOs and having a blast. Looking forward to using it on my 4BTV at HOME.
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| K4WOW |
Rating: |
2012-07-24 | |
| Excellent! |
Time Owned: 0 to 3 months. |
| Received the Rockmite 20 about a week ago. Haven't built a kit in probably 20 years, so knew I had an adventure ahead. Everything went together perfectly. A magnifying lamp is highly recommended. I apparently lost a small cap while opening things up. A note to Dave and the same day I received an email back from him saying, "It's on the way!". What great service. I installed the Rockmite in a Mitybox last night. Fired the little guy up and started calling CQ on my 40 meter dipole with a tuner. After a few calls (showing about 300 mw out) I got a call from a station in Berkeley, CA. He couldn't copy me above the QRM, but still, he heard me from Florida! Now it's time to start experimenting with antennas, trying to get as much of that 300 mw into the aether I can. Fun stuff! Get one and start a whole new challenging adventure in QRPp! |
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| K4EQ |
Rating: |
2012-07-17 | |
| Fun Radio |
Time Owned: more than 12 months. |
| I built one for 40 meters a couple of years ago. A few weeks ago I decided to build another one for 20 meters. Both kits went together smoothly. It's always fun to build something then have it actually work when you put power to it for the first time. That was the case with both of these slick little radios. I bought the MityBox for each of them, which gives them a very professional look. The Rock-Mite is a fun radio, but you certainly need patience when working at the milliwatt level, especially with the band conditions we've been experiencing. The Rock-Mite is an affordable and quality way for someone to get their feet wet with QRP. And it's fun! |
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| PS7HD |
Rating: |
2012-01-26 | |
| EM BOA HORA |
Time Owned: 0 to 3 months. |
ACHO QUE ,COM ESSA COMPRA, ANTECIPEI EM ALGUNS ANOS A PERCEPÇÃO DE QUE TRABALHAR EM QRP NOS LEVA A BUSCA DE QUALIDADES INTERESSANTES PARA UM RADIO AMADOR, MAS, COMO DIRIA JACK, VAMOS POR PARTES.
-COMPRA TRANQUILA, CHEGOU EM 20 DIAS, BRAZIL HI, COMPLETO E BEM EMBALADO, GRANDE QUALIDADE DE PLACA E COMPONENTES.
-MONTAGEM SEM PROBLEMAS, AJUDA DO EXPERIENTE TÉCNICO E FUTURO HAM(STÉFANO), UMAS QUATRO HORAS.
-OS MANUAIS, SWL E DO NE1RD, NECESSÁRIOS.
-FUNCIONOU DE PRIMEIRA, AINDA SEM CAIXA, MAS A ESTAÇÃO 900KHz AM TOMOU CONTA, COMEÇA ENTÃO AS MODs:
# RESISTOR DE 1K NAS ILHAS LIVRES COM OPÇÃO LIGA/DESLIGA EM CHAVE NO PAINEL TRASEIRO, FUNCIONA COMO UM FILTRO PARA BCI,
# MICRO CHOQUE 3,3uH E CAP. 150pF NPO EM SÉRIE DO VIVO CONECTOR ANT. A TERRA, ADEUS RAIO NORDESTE,
# CAP. ELETROLÍTICO E CERÃMICO PARALELO NA ALIMENTAÇÃO (FILTRO),
# 2N3053 NO LUGAR DO 2N2222, R18 DESCE PARA 6R8,
# DIODO SÉRIE NO +13,3 (ANTI ESTÚPIDO) ENTRADA,
# CHAVE COM LED PARA "NO AR".
BEM, E AS QUALIDADES INTERESSANTES PRO HAM?
COMEÇA COM UM OLHAR QUESTIONADOR PARA AS ANTENAS E ..., SEGUE COM MUITA PESQUISAS E TESTES, REFINA AS HABILIDADES. A IDÉIA É ESSA O RESTO É UMA QUESTÃO DE TÉCNICA.
HE..., O FT897D DESCANSA QUANDO VOU PRA 7030 KHz, O RM ASSUME A DIPOLO DE FIO A 9m E LANÇA SEUS AFOITOS 600mW, ENTRE OS OUVINTES ALBERTO WP4L, PORTO RICO, 4369,3 Km.
É ISSO!
FORTE ABRAÇO, NATHAN - PS7HD |
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| KJ4QAN |
Rating: |
2011-07-19 | |
| It's a great little kit for a beginner. |
Time Owned: 0 to 3 months. |
This is a great little kit for the first time builder. Don't believe the postings that claim it's not. Or the guys that say they can build it in one evening. They drink too much coffee ;-> Take your time putting it together and do a good job. It's not a race. The time NOT taken putting it together carefully is always paid back twice during troubleshooting what went wrong.
It's amazing what such a simple receiver will pick up even though its stuck on one frequency. Use a dipole thrown up in a tree and feed it with a short length of coax. This neat little unit is meant for sitting outside in your easy chair or out camping. It's not really a toy, but it's not meant to be a permanent fixture of your shack either. It's made to have fun with! There are all sorts of mods on the internet so that you can spend 5 times what you originally spent. But to me that seems to defeat the purpose of this great little kit. It's meant to demonstrate how little radio you need to get on the air. If you look at it from a historical standpoint, it's far more complicated than the tube circuits I have in my 1963 edition of the ARRL Handbook. Count each transistor (6) as one triode and each op amp (3) as at least a pentode. Then you'd need a heavy multi-turn transformer to get them all warmed up...you see what I mean.
I've noticed that some people on the internet are bothered by the thump they hear at the beginning and end of T/R. That's normal for such a simple setup. It's the sound your headphones cause during the load dump (impedance change) that takes place when Q1 switches to mute the receiver or let it back in. You'll notice that you don't hear that click again during transmitting or while changing the keyer speed with S1. If it really bothers you, U1 (the audio amp) is an LM1458 which is a dual op amp. You could make a 2-pole filter without to much effort, but I doubt that it would get rid of all the thump. What do you want for 29 bucks? Live with it, get it, love it.
I got the little 'MityBox' for mine from American Morse. It's made especially for the Rockmite and it's a real beauty. I didn't use a pot to adjust volume. Seemed kind of pointless. Instead, I used a miniature toggle switch from Radio Shack to switch a 1M resistor in parallel with R5 on the AF. It gives a -3dB cut and it helps with QRN.
If there's ever an EMP from a nuke flash over the USA this might be the only radio I have left to contact the outside world! There will be plenty of batteries left to draw upon for help.
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| KE7OPK |
Rating: |
2011-04-04 | |
| HAPPY CUSTOMER |
Time Owned: 0 to 3 months. |
| Terrific seller, great communication. Order placed on a Saturday night, kit was in my mailbox by Thursday. Built the circuit board in an evening. Used one small drop of high viscosity CA glue (hobby shop item, use accelerator) to mount the SMD IC to the PC board, and soldered with a 12 watt grounded iron from Radio Shack using a fine pencil tip. This is the most sensitive operation, and is done first. Instructions are good, as are the quality of the components and PC board, and I had a 100% working kit when finished. I highly recommend buying the connector/gain knob/wire kit for the extra $15. You cannot beat his price on all those goodies. Also included in the connector kit is a diode for the power supply input, which is a mod. not shown with the basic kit. The gain control is set up so that when the pot is at max resistance (1 meg), the gain is highest. I am using the "Near End Fed Antenna for 20 Meter" project which was Featured in March 2011 QST. Checked the transmit against my Yaesu Ft-857D, and heard the frequency shift from the Rockmite, and the 5 watt signal from the Yaesu was received VERY strong. Nice introduction to modern PCB construction, considering I am used to working on old Heathkits and breadboarding tube circuits and crystal radios! Recommended to all who can be methodical and use patience. Clean your soldering iron often, and keep the tip sharp with some 120 grit sandpaper. Amazing what a little patience and extreme care to be certain all components are identified and placed correctly can produce. If I can succeed... |
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