Qrp project – filters

Figure 2: The extra harmonic filter is ready for action in this photo.

I’d used a kit for the PA output LPF in the TX box, but when I added an additional filter between the Progrock and the BS170 driver, I just put it on perf board.

I also cobbled together a little coffin for the filter.  using double sided copper clad board pieces, and a lot of solder.  Note the solder does the most good when it’s used on the inside seams, where there is copper-to-copper contact.

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Purple Power

Figure 1: The “separates” approach to QRP (click to enlarge).

On page one of this blog post, I mentioned that 10 or 20 milli-watts probably wasn’t going to cut it, at least not for regular CW (and not the weak signal stuff). So, I procured an amplifier kit from the same folks who provided the “Progrock” kit, and started to assemble it. It’s nice and compact, and (hopefully) will deliver around five watts of power to the antenna when I’m done.

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A New QRP Setup


Figure 1: My recent purchase (from QRP-Labs.com) is shown along with homebrew TTL/RS232. Click to enlarge

I was looking at the kitsandparts “one watter” transceiver, but it’s a “one bander” rig. It looks nice, but I decided that I wanted a little more flexibility in my new QRP rig. So, I went to the QRP-Labs.com site, and found a good way to get the flexibility I wanted. In figure 1 can be seen the Progrock kit. It went together in nothing flat and cost me $18 bux. I’m a happy camper with this setup …

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Looking more Deeply at the Alda 103A

Figure 1: Closer look at the Alda 103A transceiver. Click to enlarge.

The Alda 103 is a favorite of mine (it’s a tranceiver from the seventies, that covers the 80/40/20 or 80/40/15 meter bands on SSB and CW, and is entirely analog). I’ve worked up an “unofficial block diagram” for it – since its creators are, sadly, no longer here to create a colorful, official one.  Forgive the crude Gimp drawing.  I think its etch-a-sketch mode works in a pinch 🙂 .

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Remote CW with Old Analog Rig

opustrxrtplFigure 1: Rough diagram of remote (TX end) for old analog CW rig.

Posted 02/11/2017

I have a couple old analog rigs here in the shack, and I thought it’d be nice to remote them to the easy chair in the living room, or the dining room table, or the back porch deck. Just to complicate things, I decided that I couldn’t revert back to Windows to do this task, and additionally I wanted it to be at least *feasible* to use the remote radio capability from an internet connected place (like a hotel in another state).

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The Alda 103 on CW

pot-on-alda-cw-osc-level-1
Figure 1: CW oscillator level control on the Alda 103 (see text).

I had been operating the Alda 103 CW/SSB triband ham radio, a gem from the seventies, for a couple weeks on the SSB end of forty meters. I received nothing but good reports, such as “very clear and clean” – and “an easy to listen to signal” since I resolved an issue with the microphone input impedance, which on the Alda is slighty different than *any* other amateur transceiver. This was done by putting a Triad audio impedance transformer between the Alda and the Shure 414A Hi-Z microphone…

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The Alda 103A

alda103a-001Figure 1:  An almost forty year old Alda 103A amateur band transceiver. Click to enlarge.

The Alda 103 has a very interesting history. It was manufactured (IIRC) in 1977 and 1978, which means it has a nice complement of the discrete bipolar transistors that are fairly common (now, almost 40 years later) – and thus replaceable. Readers of some of my other articles may have observed that I like to have the ability to fix …

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For the curious, my Alda 103A rig is on youtube:

Youtube Alda transceiver tour

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A Cloud Warmer for Eighty Meters

cloudburneraFigure 1:  The cloud warmer for eighty meters.  Click to enlarge.

So, on eighty meters my signals were always in the dust. In the fall season, with thunderstorms hundreds of miles away, I had an S6 static noise level, with crashes above that.  It was enough to drive me back to the forty meter CW band.  The problem was twofold.  First, I had a very “loaded” 80 meter attic dipole, and secondly, it was a dipole.  Hence it was poor to begin with (being both loaded and in the attic), and a great static noise scooper (like all dipoles are).

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Shortwave Weather Faxes with the Ten Tec RX320D

rx320-and-supply-1

Figure 1: RX320D, by Ten Tec, with “homemade” serial gender changer. Click to enlarge

So, I’d been trying to obtain weather faxes, of the type transmitted by the shortwave weather transmitters run by the US Coast Guard, and do that by using the little Soft66 Lite SDR board.  I’d added a preamp to that line-up in order to improve results, yet it seemed that improvement was needed still. So …

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A Preamp for the SDR

preamp8Figure 1:  A preamp tossed together on a piece of proto-board. Click to enlarge.

The performance of the Soft66 Lite is alright for the price of a couple fast food dinners, so I’ve no complaints.  But, I thought maybe some shoes could help it get a better footing, and bring those sought-after WX faxes down to earth with more clarity.  I thought “Why not give it a shot?”

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Using a Pi SBC with Shortwave Radio

butterworthon-16dip-soc-6

Figure 1: The DIP socket in the little SDR board is populated for a BPF.

New Orleans Coast Guard weather fax operates at 4.317 MHz, so it is far outside of the default (7 MHz) filter bandwidth of the little sidecar SDR. Currently, I have no bandpass switching arrangement in the sidecar, so I have to pull and insert different 16 pin dip sockets loaded with the correct components for the BPF for the frequency I’m using.  Yes – that is a little inconvenient …

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Another Look at the Vanguard 260

vng9Figure 1: Vanguard 260 PL NOAA weather satellite receiver (click to enlarge).

This blog article revisits the Vanguard 260 PL, a weather satellite receiver from the seventies that I found (as a rare bargain) on Ebay.  It covers the 137 MHz NOAA low earth orbit (LEO) APT (image) weather satellite frequencies, when it’s fixed up with the correct crystals.  I love the simplicity of the unit, and it reportedly works well given both the time period of the technology, and the low parts count.

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SoC/SBC Boards for Ham Radio (2)

fldigi-on-pi2withcirrus44Figure 1: FLDigi is shown running on the Pi2, decoding a BPSK signal, using Cirrus audio.

The Cirrus adapter worked just fine on the Pi2, as can be seen in figure 1.0. I took the audio first from the “phones” jack of an old amateur radio receiver, and then from the sound card of a second PC running a browser webSDR page. This audio was connected via the “line-in” connector of the Cirrus adapter in the Pi2 box. In both cases the audio was very good, and was adequate to decode signals while using a only a moderate input level. The noise and spur levels were much less than on an i386 PC based machine I had used for FLDigi/ham activities in the past.

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2.4 GHz Unlicensed Band

nrf24-showing-status-byte33

Figure 1: Status and printDetail() screen of the pingpair_dyn sample app (click to enlarge).

Finally, the unlicensed band nRF24 devices are talking to each other!  It was a bit of a road trip.  One thing to note is the importance of the status byte, and the other status data.  While a hex 0x0e is normal, a hex 0x00 in the status byte, and/or lots of zeros in the printDetail() output are pretty good indicators that your SPI is not operational, and you’re not talking to the transceiver.  More on this issue follows …

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Ham Radio on a Pi2

quiskplussdrhardwareplusraspberry-1Figure 1: Quisk running on the second “homemade” tablet, which use a Pi2 SoC SBC board. (Click to enlarge).

Some of the other posts on this site refer to my “homemade” tablet, which I subsequently outfitted with components for ham radio usage.  I recently built another “homemade” tablet, this time using a Raspberry Pi2 board for the computing power.

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Note: This author is not affiliated with the Raspberry Pi/Pi2. For information about those projects visit http://www.raspberrypi.org. “Raspberry Pi is a trademark of the Raspberry Pi Foundation.  Figure 1 contains elements of a desktop system and associated programs that have been released under a free software license (Copyright: LXDE team: http://lxde.org). As a derivative work, the respective part of the screenshot in Figure 2 falls under that same license. The full text of the licences may be found at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html.  Fig1 contains another program that has been released under a free software license (Quisk). As a derivative work of that program, the respective part of the screenshot in Figure 1 falls under the same license (GNU GPL). This site/author has no affiliation with the author of the Quisk program. The code and full text license for Quisk may be found at https://pypi.python.org/pypi/quisk/.

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SoC/SBC Boards for Ham Radio

audio-gameplan4

Figure 1: Various combinations that have, thus far been considered for ham radio audio duty (see text for explanation).

For the past couple years, I have been attempting to determine what might be the best platform for ham radio and other communications related applications, with a bias projected towards looking at mobile platforms. The graphic (above) shows a few options that I have seriously considered, and a couple for which I have built prototypes to aid in the testing process. The graphic is not intended to imply any capability or lack of capability with respect to the hardware, the SoC chip based SBC boards, or the operating systems. The selection only implies what I have made as a personal preference, for reasons that (shortly) – I’ll enumerate. In other words, the Raspberry Pi may use USB Audio, but I would prefer I2S if I can make it work.  Many alternate combinations are possible, and I have refined a list of preferences for the audio configurations I’ll use.  I have more info about this subject at:

https://programmingmiscellany.wordpress.com
(The link goes to another of my blogs)

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Simple SDR + FLDigi

sdr-graphC57

Figure 1: The graphic shows the layout of SDR, as utilized by hams.  Click to enlarge.

I decided to utilize the simple SDR hardware by using Quisk as the SDR software, and FLDigi as the digital mode software. It was simply a matter of stopping the WSJTx process and starting FLDigi. The FLDigi software picked up the audio feed with no manual intervention. After launch, it presented itself in the Pulseaudio control app (pavucontrol) recording tab, as …

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A Second SDR for the Desktop

soft66-in-box1
Figure 1: I liked the “Soft66 Lite” so much I decided I needed another for the desktop, in addition to the one purchased for the homemade tablet. For the desktop unit, a separate enclosure was needed.

These tiny little things are addicting! The enclosure was outfitted with a couple switches to do bandswitch duty, since (unlike the homemade tablet) there will be no GPIO to apply for that function. A big, clunky SO-238 connector was attached to the box, to accept the PL-259 plug from the antenna coax. And of course, holes were made for the audio and power connectors.

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Using Simple SDR hardware

wsjt-scrn1 Figure 1: The combination of the “Soft66 Lite SDR hardware, the Quisk SDR software, and the WSJTx digital mode software is displayed in the graphic (the WSJTx screen shows two CW signals).

The Soft66 Lite SDR hardware worked well with the Linrad SDR software, for copying CW signals or SSB signals on a variety of ham bands. While that was fun, I decided to take it a bit further, and use the Soft66 SDR hardware, the Quisk SDR software, and the WSJTx digital mode software to copy JT-9 and JT-65 style digital communications.

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A Shortwave Receiver for the “Homemade” Tablet

soft66-build2
Figure 1: The “soft66 Lite” SDR (software defined radio) board. It’s a fun thing to build in a spare three hours, and even more fun to operate!

Recently I’d integrated a “homemade”  tablet into the station, for things like receiving weather faxes and BPSK31 transmissions.  I’d been using external receivers to do that, but mentioned that I really wanted to put a “shortwave” receiver board inside the tablet, for an all-in-one effect…

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Weather Fax via Shortwave

coastguard-boston-sept152015-1 Figure 1: Received from Boston Coast Guard Transmitter (4 kilowatts) with the fldigi ham software.

The received transmission was not very strong, so the resulting facsimile came through with some rough spots, and the bottom half is relatively poor, but it should be observed that good results are possible.

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New (For Me) Omni-A (Analog)

newomni-a-rig

I have always been a Ten Tec fan. As a kid I dreamed about the PM-1, but had to settle for home brew and (eventually) an old (even then) DX-40 transmitter / Lafayette-HA350 RX combo. When I was older, I purchased a Triton 4, and fell in love with the quietness of its noise blanker assisted audio, its filters, and its fabulous QSK. Some time ago, I decided to find another Triton (I’ve had and subsequently sold several, when I wish I’d kept them all!) The prices have crept up, as the numbers dwindle, and Ebay resellers have ascertained that hams will give blood for these units. They are made primarily of discrete transistors, with a smattering of commodity ICs, and so are relatively easy to fix in a pinch.

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Maritime Mobile and the Weather Fax

pieces-QDH-antenna
Figure 1: The pieces and parts for a QDH weather fax antenna

Posted 08/17/2015:

My eventual intent to go maritime mobile is connected with amateur radio in more ways than the obvious. Homebrew construction technique is valuable for other things, and in this case I intend to put it to use while building a satellite weather fax station (maritime mobile version).

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WB8LZR

collage4 A younger me, as part of a collage pic made a number of years ago. This is WB8LZR / CW aficionado extreme.

This WP blog is dedicated to the author’s amateur radio hobby, and related pursuits.

 

 

 

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