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Storyteller
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Discussion Starter · #1 ·


Slightly larger the diminutive MTR-3B but with many features offered for a tiny penalty in weight.

Broadband RX - 5 to 16 Mhz. Covers several SW broadcast bands, in addition to full band coverage on 40M/30M/20 meters. 5 watts, CW/CWR/ (rx only in the LSB/USB mode) Despite being CW tx only, this fill many needs and provides NVIS capability on 40 M (7 Mhz)

Waiting for mine to arrive as it will replace my MFJ-9200. While it is just 3 bands, these bands are the most popular for QRP work in the field.

Input can be 8 to 15 VDc,an important distinction from the MTR-3b.

At $188 USD, much less expensive the the LNR Precision MTR-#b ($300 USD)



These are very compact radio sets.

More data and photos at the vendor website
https://www.venus-itech.com/product/sw-3b-qrp-cw-transceiver/
 

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Ok I'm stupid when it comes to Ham even though I have my Technicians ticket, What is this and how does it work. Can you talk on it or is it like Morris code?
 

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Yeah I didn't catch that, I had misspelled Morse :D:

But that still don"t answer my question :thumb:
I'm not familiar with this radio but from the description it is CW transmit only. CW=Continuous Wave=Morse Code.
Very effective for low power communications. And something I still need to learn.

Sent from my SM-G960U using Tapatalk
 

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Storyteller
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Discussion Starter · #6 ·
Ok I'm stupid when it comes to Ham even though I have my Technicians ticket, What is this and how does it work. Can you talk on it or is it like Morris code?
Not stupid...just new.

CW is Morse code only.

My bad I thought that posting both CW and. Qrp would help folks to quickly grok the operation.

Slick rig if this is something you want to do while camping...
 

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Is this a kit or pre-built?
If a kit, what is a very rough assembly time ? Rating on assembly on a 1-10 scale, easy-complicated?
What would be the basic license required to fully operate this radio?
Thanks
 

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Storyteller
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2,694 Posts
Discussion Starter · #11 ·
Is this a kit or pre-built?
If a kit, what is a very rough assembly time ? Rating on assembly on a 1-10 scale, easy-complicated?
What would be the basic license required to fully operate this radio?
Thanks
Not a kit, fully assembled

To use 20 and 30 meters, you need a General clas license (USA)
 

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Storyteller
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2,694 Posts
Discussion Starter · #16 ·
Who makes sells a compatable small key for this set?
Go over to 3rd Planet Solar, John sells some nice keys printed in the USA.

https://kc9on.com/product-category/cw-morse-code-keys/

I have a set of the paddles (thanks fto my DD) and they work very nicely, and are adjustable.

While a straight key will work, you will quickly run into a speed trap (low rate sending) that IMO, paddles might help you overcome.

Best of luck.
 

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Storyteller
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Discussion Starter · #17 ·
I plan on using a EFHW. End Fed Half Wave.

I can use a whip with a tuner.

Both are easier, IMO, to put up in the field than a dipole.
Several tuners are on the market as a kit

4 States QRP Group - has a nice tuner - http://www.4sqrp.com/4stuner.php
has a nice SWR bridge build in

QRP Guys have a couple - https://qrpguys.com/antennas and tuners - https://qrpguys.com/tuners

There are many commercial tuners, with MFJ leading the pack at low cost (your mileage may vary considerably)

or as was asked, a simple dipole with work just fine.
 

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Storyteller
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Discussion Starter · #18 ·
Overview of radio set SW-3B

The SW-3B is a lightweight, rugged, miniature, single-conversion transceiver that operates (transmits) on three Internationally allocated high frequency bands within the Amateur Radio Service in A1A (CW) only.

It may be powered with any stable DC source between 8 and 15 VDC.

Power consumption in is minimal . With the backlight on (display illuminated), the radio draws ~43 mA in recieve. With backlight off, it draws only ~37 mA (@13.8 VDC). Actual current used will vary slightly based ion input voltage. Transmit draw is on the order of 800mA.

The SW-3B also offers broadband reception from 5 to 16 MHz in the so-called shortwave bands. This broadband feature also allows reception of WWV on 5, 10 and 15 Mhz for frequency check, time and weather reports. Reception of International Shortwave Broadcasts using USB mode is possible with careful tuning. Nice for staying in touch with the rest of the world while out in the wilds away from commercial AM/FM services. (I'm talking North Slope AK here). Sadly BWBC stations are becoming a thing of the past.- except, of course, for the Chinese.

The unit is all digital. The VFO control provides for tuning in 10 Hz, 100 Hz. 1kHz, 100KHz increments. The RIT/XIT function permits receiver offset tuning in 10 Hz increments and transmitter offset tuning in 100 Hz increments.
In addition to manual tuning via the rotary encoder, eight memories per band are provided to store frequency/mode. Changing between stored Memory and the VFO is by a pushbutton. Changing between Memory locations is via the Tune (VFO) knob. A slide switch is used to change between bands.

Placement of the operator controls and connectors only on the sides of the chassis clearly puts this radio in the class generally known as Trail Friendly. With both the top and bottom of the chassis free of control ports, you may place the radio set upright, on a stand or tilt the radio set for the best viewing angle and not impact any connections. While seemingly a minor detail, this flexibility is a nice touch for operating in the field. This is no small thing.

The high-contrast digital display is large enough to easily read in bright sunlight and it has a backlight for viewing at night. The backlight may be turned off during daylight operations for a ~15+% saving in current draw on receive. The backlight may be set to on, off or AUTO. In AUTO mode, the unit will light the display for 10 seconds on any command input, such as adjusting the VFO. After 10 seconds with no operator input, the display backlight will extinguish.

The receiver is single conversion, with a crystal ladder filter to reduce noise and adjacent signal interference. The Beat Frequency Oscillator (BFO) operates at 4.914 MHz. The BFO injection signal to the second mixer signal is provided directly by the Si5351 DDS source. Very clever, decuses the parts count and ensures the signal stays in the filter passband.

The filter may be set for narrow (CW/CWR) and wide (USB/LSB). This bandwidth change is controlled by a simple pushbutton and is automatic, depending on the mode selected. Receiver performance is impressive, with Minimum Discernible Signal (MDS) levels of 0.1 to 0.2 microvolts (-127 dBm @ 50 ohms) typical.

The transmitter is a classic Master Oscillator/Power Amplifier (MOPA) type fed directly by the DDS system. The transmitted signal passes through several filters to reduce harmonic content in the output.

The transmitter final amplifier (PA), is a robust 2SC2078 PNP transistor (Q3). The PA is protected from high VSWR by a Zener diode, type 1N4756A. The antenna is attached via a BNC connector mounted on side of the unit. Both are inexpensive and available from more than one vendor.

The internal keyer supports iambic keying via a set of operator-supplied paddles. Use of a straight key is supported as well. (See operation manual for more on keys). A keyer memory allows automated calling of CQ w/Operator callsign at the push of a button.

Operating on a DC input between 8 and 15 Volts DC, the radio transmits with a nominal power of five watts output with 12.6 DCV applied. The power input is protected against reverse polarity. External power supplies should be able to provide up to 2 amperes of current with no AC ripple. A simple battery pack made up of eight "AA" (or 10 NiMH) batteries provides ample power.

Please note that the unit transmitted power output drops off with lower input (supply) voltage. Operation is possible from a common 9 VDC battery for a limited time, at reduced power (TX) levels.

All of this in a radio set slightly larger than a common Altoids tins.
 

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Storyteller
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Discussion Starter · #20 ·
What is a current reccomedation for a practice key?
Straight or paddle?

As I noted earlier 3rd Planet has a very nice selection of US made keys.

If you go for a straight key, I would recommend a so called Navy knob.
 
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