Posts Tagged ‘Transmitter’
Just Get On The Air! (A Makeshift Temporary Dipole Shortwave Antenna)
It might not take as much antenna as you may think would be necessary to make two-way contacts on shortwave radio (as an amateur radio operator putting an HF transceiver on the air). However, often, makeshift antennae are effective enough to be viable–just look at all the contacts many amateur radio operators make with their low-power (QRP) rigs (transceivers) using short, helically-wound, mobile antenna sticks. If they can work magic with such inefficient antenna setups, surely your effort at an antenna would pay off to some degree. Right?
[embedyt] https://www.youtube.com/watch?v=-k5Su–ez2Y[/embedyt]
Of course, I want to make a proper dipole out of this example antenna. But, while I wait for the rest of the parts I need to complete this antenna project (pulleys and a ladder, and maybe a potato launcher), I’ve put this makeshift antenna on the air, with it just high enough so that I can enjoy some time on the shortwave bands.
With this antenna, I’ve made successful two-way voice and Morse code contacts (QSOs) with stations in Europe and across North America. I am able to tune it on the 60-, 40-, 30-, 20-, 15-, 17-, 12-, and 10-Meter bands. Reverse beacon detection picks up my Morse-code CW signals, especially on 40 meters (the band on which it is tuned physically).
The bottom line: just get something up in the air and start communicating. Improve things over time. You’ll have much fun that way.
73 de NW7US dit dit
LHS Episode #164: Ancient Antenna Modeling
We're done with the editing of Episode #164 and here it is for your listening pleasure. In this episode, your hosts tackle topics from Bugbook computers to permanent amateur radio licenses, from Turing phones to Raspberry Pi computers and from antenna modeling software to lobster on pizza. We hope everyone will find something to enjoy. Please let us know by sending us feedback. We'd love to hear from you.
73 de The LHS Crew
I Need You in My Log! SKCC K3Y/0 Special Event (January 2016)
I need your help!
Come meet me on the shortwave (HF) ham bands for the Morse code (CW mode) special event, the Straight Key Century Club (SKCC) celebration, with special callsign, K3Y. During the shifts (time slots) listed below, I am the control operator as K3Y/0.
I need you to make a contact with me.
This special event takes place every year during January. We celebrate the legacy of Morse code, and promote Morse code and manual creation of the code by any non-electronic (digital) device and method. Which means that we love mechanical bugs, straight keys, two ends of a wire, or any other manual device, if Morse code is generated. The Straight Key Century Club is a free membership group. The link to their website is below.
I need you to make a contact with me, during my scheduled times, listed below.
NOTE: YOU DO NOT NEED TO BE A MEMBER OF THE (free) SKCC GROUP. To get into my logbook, you meet me on my frequency, and use Morse code to communicate with me. It is painless. If you must, you can use computer-generated Morse code. Or, you can tap it out on any Morse code signalling device, like a bug, a set of paddles, or a straight key; whatever you choose to make Morse code emanate from your HF transmitter.
HOWEVER: For those of you who want to get fully immersed in the spirit of this event, you are invited to use a straight key. And, as a bonus, you may and can join the SKCC group for FREE. Then, you would have your own SKCC number. That’d be cool; we SKCC members use that number in our exchange during our QSO information exchange. But, you don’t need that. Since it is free, why not?
What is needed is simply you, getting on the shortwave band, finding me, hearing me, and responding to me with Morse code. In other words, we need to have a QSO using Morse code. I am not a fast operator, so no problem if you are not very fast. I’ll meet your speed.
In any case, here are some of the times I will be on the air as K3Y/0… please dust off your straight key, bug, paddles, whatever, and make a QSO with me. Thanks!
My current schedule:
UTC Start/End (remember, these are NOT your local times, but are the UTC (GMT) times!)
(revised times, as of edit date)
00:00 - 02:59 19-Jan-16
00:00 - 02:59 20-Jan-16
00:00 - 02:59 21-Jan-16
00:00 - 02:59 22-Jan-16
00:00 - 05:59 23-Jan-16
14:00 - 18:59 23-Jan-16
20:00 - 21:59 23-Jan-16
00:00 - 02:59 24-Jan-16
14:00 - 18:59 24-Jan-16
21:00 - 21:59 24-Jan-16
00:00 - 02:59 25-Jan-16
00:00 - 02:59 26-Jan-16
00:00 - 02:59 27-Jan-16
00:00 - 02:59 28-Jan-16
00:00 - 02:59 29-Jan-16
00:00 - 05:59 30-Jan-16
13:00 - 18:59 30-Jan-16
20:00 - 21:59 30-Jan-16
00:00 - 03:59 31-Jan-16
13:00 - 23:59 31-Jan-16
Now, what frequency will I be on?
To find out what frequency I am on:
Visit http://g.nw7us.us/sched4SKCC and look on the right side for my callsign, NW7US. I usually post my frequency of operation right after my call sign.
Typically, evening operation is 30m, then 40m, and then possibly 80m.
If you are trying to alert me to your presence, you may message me on my personal Facebook profile, under my “Tomas David Hood” profile messages, but I may not see that right away.
Here is the detail covering the K3Y operation and the SKCC group: http://skccgroup.com/k3y
73 de NW7US
dit dit
This was last year:
https://www.youtube.com/watch?v=UfRvITFpTb4
..
Using the RTL-SDR as a transmitter
OK, this is very low power but it shows you what can be done. A QRPP transmitter or signal generator anywhere between 500MHz and 1.5GHz.
Please note the image below is not on my blog (it is linked as shown) and will be immediately removed if this is a problem.
http://rtlsdrblog.rtlsdrblog.netdna-cdn.com/wp-content/uploads/2015/06/transmit_hack_rtlsdr-500×375.jpg |
See http://www.rtl-sdr.com/using-the-rtl-sdr-as-a-transmitter/
Spark transmitters and modern simple rigs
In the early days of wireless, spark transmitters were all they had. Selectivity and bandwidths were not major concerns. These days it is all so different with sometimes very crowded bands and the bandwidth of both transmitter and receiver being of major importance.
See http://en.wikipedia.org/wiki/Spark-gap_transmitter for some interesting reading. I recommend you do not try a spark transmitter as you would be very unpopular because of the wide signal and interference caused. By all means read about them though.
A modern challenge is to see just how simple rigs can be made yet still function credibly on the amateur bands today. Rigs like the Pixie are fun, but such ultra-simple transceivers are let down by deaf or easily overloaded receivers. To my mind, the receivers have to be selective, sensitive, have netting, and not be easily overloaded. The challenge is to overcome these issues! Often TX power is not the deal breaker.
UPDATE 1740z: W5OLF has just shown me a photo of is tiny 1 inch ferrite rod antenna on which he has had some success with on 10m WSPR. I tried some WSPR experiments with ferrite antennas some years ago on 40m, 30m and 20m. As long as the ferrite does not saturate they do work. See www.g3xbm.co.uk .