AmateurRadio.com

My assembled 40m Pixie

The Pixie is a very simple HF transceiver. Usual power out is in the 200-1000mW region, depending on band and DC power source.  It was first developed some years ago but the basic concept is using a PA transistor as a mixer in a simple direct-conversion receiver. On TX this is used as the TX PA.

Being simple, it has a number of limitations but it certainly works. A major issue can be AM broadcast breakthrough, although my 40m version is perfectly usable. I was very impressed with my little kit that came with all parts including a silk-screened PCB, all sockets and a crystal. It needed low-Z Walkman type headphones, a morse key and battery – that was all. On 40m the sensitivity is pretty good with 0.5uV clearly audible and my RF power out is around 400mW. A lack of both RF and AF RX selectivity is also noticeable.

Kits are available from several sources at prices that are hard to beat. I recently bought a kit for $10 with free airmail from China. It is available for less than half this price I subsequently found out. Unbelievable for a fully functional HF transceiver. Of course, being so simple you may prefer just to build it dead-bug fashion. I bought a kit as I wanted to see how my building skills were.

As a mature design, it has been through several iterations, some improve the basic design, but most do so at the expense of increased complexity. You’d be hard pressed to find a circuit for a complete HF CW transceiver much simpler.

See www.gqrp.com/The_Sprat_Pixie_File.pdf .

Roger Lapthorn, G3XBM, is a regular contributor to AmateurRadio.com and writes from Cambridge, England.

at your next Club meeting?  Plan a presentation or an activity! Publicize it well and ahead of time and you're sure to draw out some people - new faces as well as old.


Thanks to Drew Moore W2OU for arranging for Mike Terruso WA4LOQ to come to our ETS of NJ meeting last Friday evening to talk about his high altitude ballooning experiments.  What started out as a science project for his son is turning into a combination of ballooning and Amateur Radio for Mike. In fact, ballooning is what got Mike in gear to earn his Amateur Radio license, as he realized it's potential to help him in his endeavors.

The technology that he uses is interesting. A combination of radios, cameras, Raspberry Pi's, GPS devices, temperature and humidity sensors - it was all fantastic to listen to. I've embedded his YouTube video which is a compilation of stills (taken at 5 second intervals) of his maiden launch last October.  The balloon was released near Lebanon, PA and landed in Boonton, NJ. It's an hour long video, but you can skip around it if you wish to see the "near space" photos which clearly show the black sky of space and the curvature of the earth's horizon. As Mr. Spock would say - "Fascinating!"


Larry Makoski, W2LJ, is a regular contributor to AmateurRadio.com and writes from New Jersey, USA. Contact him at [email protected].

SDR Sharp GUI

DXer John Bellini in Colorado, and maker of those informative Low Noise Vertical videos, has been at it again.


This time it's a good demonstration of a pair of filters that he built to mitigate the front end overload experienced on his SDR receiver.

John is one of many radio hobbyists that have been playing with the very inexpensive RTL 2832 SDR dongle receiver. Being very close to several high-powered broadcast stations has been a bit problematic for him when using the low cost SDR but his new video shows exactly what was needed at his location to solve the problem:


It looks like John is using the SDR Sharp GUI (graphical interface) to operate the dongle SDR receiver. Those wishing to learn more about this might find this 'getting started' page of interest.

Good stuff John.
Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].

One of the nice things of D-Star and DMR is the ability to talk all over the world without the need of an HF rig and a bunch of big antennas. While this largely reduces a radio to a simple Internet-driven communication tool – just like Skype or other VoIP apps – it’s definitely nice to use.

There are a few problems surrounding DMR, one of which is the lack of more than two time slots. For example, if hams are using the Dutch Hytera network and occupying talk group 204 on slot 1, World Wide (which uses the same time slot) will be unavailable. Because 204-1 is a busy place, world wide QSOs are often impossible. It’s one of the reasons I thought of dumping DMR all together — I can talk to the same Dutch guys on analog while enjoying a much better quality audio.

There are reasons to keep DMR too. DMR is maturing; there are more than enough possibilities to put less pressure on the nation-wide network by going local. Now if only hams would do that…. but most don’t. Another reason to keep DMR for now is the gateway we recently added, which connects D-Star to our DMR network.

Not available on the Motorola network, sorry — some people responsible for that network appear to be so scared of such innovations that they will ban a repeater from the network if such a gateway is detected.

Talk group ‘USA 1776’ could add to the appeal of DMR. It’s unclear on which network this talk group will reside, but my best guess is that it will be the Motorola network.  MITCON writes:

The “USA 1776″ (English preferred) Talk Group will be distributed worldwide to DMR networks upon request.  The spirit of “1776” is to continue the Amateur Radio tradition of international friendship and to push the boundaries of technology in the new frontier of digital communications.

USA 1776 is intended to be a flexible, politically neutral, unrestricted Talk Group that can be used as Push-To-Talk (PTT) or Full-Time (FT) to meet the operating requirements of a DMR Network.  DMR subscribers are welcome to use 1776 as a universal meeting place to “Rag Chew” or as a jumping off point and QSY to an alternative Talk Group if desired.  To add USA 1776 to your DMR Network please contact us to schedule a time for configuration & testing.

Hans, PD0AC, is a regular contributor to AmateurRadio.com and writes from Almere, The Netherlands. Contact him at [email protected].

One of the nice things of D-Star and DMR is the ability to talk all over the world without the need of an HF rig and a bunch of big antennas. While this largely reduces a radio to a simple Internet-driven communication tool – just like Skype or other VoIP apps – it’s definitely nice to use.

There are a few problems surrounding DMR, one of which is the lack of more than two time slots. For example, if hams are using the Dutch Hytera network and occupying talk group 204 on slot 1, World Wide (which uses the same time slot) will be unavailable. Because 204-1 is a busy place, world wide QSOs are often impossible. It’s one of the reasons I thought of dumping DMR all together — I can talk to the same Dutch guys on analog while enjoying a much better quality audio.

There are reasons to keep DMR too. DMR is maturing; there are more than enough possibilities to put less pressure on the nation-wide network by going local. Now if only hams would do that…. but most don’t. Another reason to keep DMR for now is the gateway we recently added, which connects D-Star to our DMR network.

Not available on the Motorola network, sorry — some people responsible for that network appear to be so scared of such innovations that they will ban a repeater from the network if such a gateway is detected.

Talk group ‘USA 1776′ could add to the appeal of DMR. It’s unclear on which network this talk group will reside, but my best guess is that it will be the Motorola network.  MITCON writes:

The “USA 1776″ (English preferred) Talk Group will be distributed worldwide to DMR networks upon request.  The spirit of “1776” is to continue the Amateur Radio tradition of international friendship and to push the boundaries of technology in the new frontier of digital communications.

USA 1776 is intended to be a flexible, politically neutral, unrestricted Talk Group that can be used as Push-To-Talk (PTT) or Full-Time (FT) to meet the operating requirements of a DMR Network.  DMR subscribers are welcome to use 1776 as a universal meeting place to “Rag Chew” or as a jumping off point and QSY to an alternative Talk Group if desired.  To add USA 1776 to your DMR Network please contact us to schedule a time for configuration & testing.

Hans, PD0AC, is a regular contributor to AmateurRadio.com and writes from Almere, The Netherlands. Contact him at [email protected].

My first rig the Yaesu FT-857D has proved a more than capable radio and as a shack in a box covering HF-VHF-UHF it is excellent and has allowed me to try my hand at most things since becoming licensed but I wanted a dedicated HF set up that was a bit less fiddly to use.   

So last month I succumbed to temptation and ordered a Yaesu FT-450D. While it is still an entry level rig I had heard good things about it and liked the look and feel of it. Martin Lynch & Sons had them at a low price and combined with Yaesu's 'Late Winter Warmer 2015' cash-back promotion made it an opportunity I didn't want to miss.

It arrived last week but I only got to properly have a play this weekend even then not for as long as I really would have wanted. I know people might detest HF contests but I was quite glad of the CQ WPX to try out the radio with plenty of contacts on 10/15/20 and 40m while keeping the output below 50W.

I have still to work out all the settings and the DSP functions but first impressions are of an excellent receiver with good tone and clear audio from the internal speaker. Being a very popular contest the bands were crowded at the weekend but I had no trouble picking out weaker stations even with very strong adjacent stations. Using the supplied microphone and the default processing settings I had no issue getting out either, working nearly all of the stations I called.

I have previously used a manual ATU and found the internal ATU is a nice feature when switching bands and it did a excellent job of fine tuning the M0CVO OCFD. It couldn't tune it on 40m directly as the VSWR was greater than 3:1 so had to revert back to the external ATU.

Only very minor gripe I had was the CAT connection, In my research I noted it was a standard RS232C 9-pin connector and assumed I would just plug in a standard PC serial lead, but I hadn't spotted the radio had a male connector not female!

I wanted to try out the CAT but hadn't got a gender changer or connectors in the shack to make up a lead. I did have a number of commercial RS232 extension leads moulded male connector one end, female the other, so chopped up two and spliced the appropriate halves together. It works fine with a USB-Serial adapter in Ham Radio Deluxe but refused to work with the Omnirig control used by PZTLog until I disabled the hardware handshaking. 

Still early days and I do need to read the manual but more than happy with it.
Andrew Garratt, MØNRD, is a regular contributor to AmateurRadio.com and writes from East Midlands, England. Contact him at [email protected].

Ham College episode 3 is now available for download.

Ham College, the new show for those new to the hobby and those wishing to get into Amateur Radio.

In episode 3 we talk about voltage, demonstrate using voltmeters and cover 14 more questions and answers from the Technical class question pool.

59:07

Download
YouTube

George Thomas, W5JDX, is co-host of AmateurLogic.TV, an original amateur radio video program hosted by George Thomas (W5JDX), Tommy Martin (N5ZNO), Peter Berrett (VK3PB), and Emile Diodene (KE5QKR). Contact him at [email protected].