KIX-OnlineLinks to amateur (ham) radio goodies on the web

I attended a great fox hunting presentation at Dayton this year, hence a few posts on the topic.

I had some posts in the past about tape measure beam antennas.  Really neat antennas and they have multiple purpose use (they are GREAT for hitting distant repeaters when you orient them vertically!).  Much like the picture on the right (courtesy of Joe Moell K0OV) they are more useful for fox hunting when you add the active attenuator to your setup.  FYI, Joe is the co-author of the great book “TRANSMITTER HUNTING, Radio Direction Finding Simplified” available where most ham books are sold.  His website has more information on the book at http://www.homingin.com/THRDFSinfo.html and he contributes to CQ and CQ VHF.

So….. just what is an offset attenuator?  Joe explains it on his “Homing in” site as:

An RF attenuator is a device that goes between antenna and receiver to reduce the signal strength down to within the range that the receiver S-meter can handle. Without one, you may think you’re close to the fox when you’re still far away. You won’t be able to get close enough to a camouflaged hidden T to identify it. The amount of attenuation should be adjustable so that you can add just a little when your S-meter first pins, up to a lot as you get within a few feet. Special ARDF receivers used by champion foxhunters have electronic attenuation built in, but ordinary handi-talkies don’t. Adding it would require major micro-surgery in the HT.

His attenuator page is:

http://www.homingin.com/joek0ov/offatten.html

I recommend his site in general, many great projects:

http://www.homingin.com

On his attenuator page, he has full schematics to make an offset attenuator.

But wait…… there’s more!

Further on his page, you see one made in a sweet Pomona box.  I like this box and thought it was a bit pricey at first, until I did the math and figured out the cost/time to do it myself.  These boxes are shielded with the connector of your choosing (BNC/SMA/259, etc).

They generally cost around $25 or so and are shielded!  Great to have.  When you add the cost of connectors and such, it isn’t really so expensive after all.

I really advise using such a case or a metal case in general, makes things work out much smoother in the end.  More information on this box at: http://www.pomonaelectronics.com/index.php?i=prodsub&parent=BOX&cat=BONCONN&getDetails=

But wait….. there’s even more!

Marvin Johnston KE6HTS is now offering a “semi-kit” for this attenuator on his website.  I’ve seen this kit when I was at Dayton this year and encouraged a friend to pick it up and build.  I may end up running a buildathon here in CT on these attenuators.

The price is really not bad at $22.00.  You can purchase them built for a few dollars more.

Information on the kits and pre-built models are at:
http://www.west.net/~marvin/k0ov.htm

And yep……. there’s even more (again!).

If you would like to “roll your own” from parts you may have on your bench, but don’t want to make a circuit board, you can get one from……. you guessed it…… Far circuits.  I picked one up and am going this route myself.

There are a few boards/projects on the Far circuits website at:

http://www.farcircuits.net/

There are a ton of great resources out there on the web, these will really get you going right from the start.  Fox hunting is a really fun and useful part of our hobby and one that doesn’t cost a ton of money to get started in.  If there are no active fox hunts in your area – start ‘em!  There are plenty of options as far as transmitters and such and really doesn’t cost a club much money to get started.

Ahhhh, those lovely days in May when a QRP’er can go to Dayton a few days early and enjoy the companionship of his fellow knack sufferers.  One of the nice things about the QRP Amateur Radio Club International (QRPARCI) is their annual Dayton “Four Days in May” (FDIM).

FDIM is a great way to enjoy seminars and discussions on a whole range of topics.  There was a really good presentation by Hans Summers (G0UPL) on QRSS.  Many of you may be familiar with QRSS from podcasts such as “Soldersmoke”.  Essentially, it’s CW so slow, it’s pretty much impossible to decipher by ear, but sent at a VERY low power (if you’re using a full watt, you’re probably just plain rude!!!!

You build yourself a little low power transmitter and usually use some sort CW keyer circuit of sorts to send your call, short message or whatever.  The call is usually received by other hams and shared online.  It’s kinda neat to see your low power signal making it’s way over long distances.  It’s really a neat beacon.

Images are available on the web, but examples of reception are like below (from Hans Summers site):

Hans had a great discussion and was nice enough to produce a kit for FDIM (maybe he was earning his flight home, who knows!!!).  The kits were INSANELY popular and I think he might have just made a huge jump in the use of this unique operating mode.

Hans painstakingly took orders from hams and even programmed their Atmel chips with their calls.  What a nice guy!

He has plenty of information, schematics and such on his website.  If you’re interested, point your browser to:

http://www.hanssummers.com

Man, sometimes a topic starts going through your head, you do a little research and then start going all over the place.  This is one of them – antenna analyzers.  I’m a huge fan of them and run antenna clinics for our local club.  This tool is one quick way to get a snapshot of your antennas performance in a jiffy.

For those that have seen the MFJ analyzers, they basically consist of a low power transmitter and various circuitry to do the math and display the antenna or feedline information on an LCD screen.

Oztales strikes again with a very well done video.  The descriptions should give hams without an engineering background a very strong understanding of what is going on behind this “mystery box”.

While I’m “down under” let me show you a really neat analyzer kit that can be had for a fraction of the cost of the larger analyzers like the MFJ.  If you’re willing to burn a little solder, you can make a very sweet analyzer (I’m thinking of getting this kit as well, seems a good companion piece to my AADE LCR Meter).  As of this writing, the kit mentioned here costs $150.00 AUD for DX orders – which is a bargain!

As you can see, it has many things in common with the higher priced analyzers as far as layout and such.  Just keep in mind, from what I’ve seen in the picture and on their site, this is an HF only analyzer and does not have six meters – strictly 10 and up.

The kit is available from the South Coast Amateur Radio Club and on their website at:

http://www.scarc.org.au/kits.html

But……….

Across the pond, someone built one of these kits and you can get a really good idea of what is inside the kit.  This video is what is now making me consider purchasing this kit:

BYRONLOCAL’s Youtube channel has a few other videos that may be part of the kit (components) but I haven’t watch them yet, so check his channel if you want more information.

Oztales has scratched the surface of what you can do with an analyzer.  If you practice your google-fu, you’ll find lots of other great uses/mods for analyzers to expand their capability.

For me, digital nirvana!

This is one of those projects that come along now and then and just make my jaw drop.  I fell in love with this project in 2007 at the TAPR/ARRL Digital Communications Conference in Hartford.

Disclaimer:  I haven’t yet had the chance to build this kit.  I have been hit early on with this economy thing and haven’t been able to afford a kit.  But, I do come from Hartford, CT where we have the Mark Twain home.  Like Tom Sawyer….. I “convinced” a few friends to check it out and had a chance to play with their kits.

Just what is this thing?  It is a PSK modem.  But, it is also a bit more than that.  Unlike PC modems, this one has an LCD screen with all the input/output information right on the modem itself.  You get the kit (or buy it pre-built) and connect it to your radio and a PC keyboard.  Tune up your radio to the PSK action and go from there.  I’ve seen this set up running with the DC to daylight rigs from Yaesu and Kenwood.  I’d like to get one of these and play around with one of the PSK Warbler kits from Small Wonder Labs (http://www.smallwonderlabs.com/Warbler.htm)  QRP and this modem are a PERFECT match.

It is lightweight and runs off a couple of 9 volt batteries.  Unless you’re KE4WLE, who has a video I’ll embed below, who runs his off of solar power!  Like many homebrew projects, since you build it, you are free to find many ways to tinker around and play with the kit.

I recently received permission from George Heron, N2APB to upload a couple of videos to YouTube and link in this post.  The videos below are of the prototype version (the one I got to check out at TAPR) and the battery installation of the new kit.

NUE-PSK prototype video (the final kit looks like the image at the top of this post)

New NUE-PSK kit battery install

What’s the price of admission?  Really rather inexpensive, consdidering.  You can get a full kit for $185.00 and fully assembled modem for $250.00.  If you’re an experienced kit builder, then you have a few other options (purchasing printed circuit boards, partial kits, etc).  Cables are most radios are also available.

Below is the Solar Powered NUE-PSK station of KE4WLE.

Final thoughts:

This is one of my favorite projects available for the radio amateur.  You can purchase the kit or get all the information to roll your own on the NUE-PSK website.  Something I think is really promising.  I have been involved in the creative commons and open source community for almost 20 years now and appreciate when ALL the information is freely available.

This kit is a full functioning modem/display with no personal computer required.  Great for a home station, even more fun for those of us that play radio in the great outdoors.  I’ve gotten my hands on a few of these and it’s always great to help others build them.  I hope to get one of these myself in the future so I can take them on some of my IOTA activations.

More information and ordering options are available on the new NUE-PSK site at http://www.nue-psk.com

I didn’t actually get to use one of these meters until the 2007 Dayton QRPARCI FDIM (Four Days In May).  After trying out two units, I don’t know how I got along without ‘em.

I have more experience with the Almost All Digital Electronics LC meter.

Almost All Digital Electronics L/C Meter II, Kit - $99.95

I used this when I built the SP-1 kit and borrowed one when I made parts for my BitX-20.  It is truly an indispensable took for the bench.  Especially working on projects where you are winding a lot of toroids and making other inductors.  That feature alone made it worthwhile for me.

That’s not all, from the AADE website:

L/C Meter IIB is a hand-held, digital Inductor inductance meter, Capacitor capacitance meter
with a four digit display,

It is ideal for RF and audio work where accurate measurement of small values is needed.
maximum resolution of 1 nHy / .01 pF
maximum range of 150 mHy / 1.5 uF.

Capacitors must be non-polorized as the test signal is AC.

The unit features
AUTOMATIC RANGING and SELF-CALIBRATION.

The L/C Meter IIB is available as a kit or fully assembled from Almost All Digital Electronics from their website at http://www.aade.com .

There is also a site with plenty of information on this kit, including how to use the meter.  Ian Purdie (VK2TIP) put together a list of his experiences with the kit and it’s many functions.  http://my.integritynet.com.au/purdic/lc-meter-project.htm

There is another similar product on the market that is worth mentioning.  Also at Dayton, I was able to look at the M3 Digital LCRZ meter.

M3 LCRZ Meter, kit starts at $175.00 and goes up depending on accessories

I have not built either of these kits (I’m hoping to get one in my budget soon).  I have used both meters.  The M3 is a truly neat project.

I met the guys at M3 at the FDIM program and was floored by the quality of this meter.  Not only the meter itself, but the cables as well.  M3 also has the option to purchase 4 wire Kelvin cables (really neat).  You can also purchase SMD cables as well – another neat option.

There are a couple more accessories available for the M3 meter a varactor diode test fixture and their multi test fixture.

According to the M3 website:

The M3 Digital LCRZ meter is a multi-frequency impedance measuring instrument capable of measuring resistance, capacitance, inductance or transformer parameters from 1 milliohm to 1 Megohm impedance. The LCRZ meter is controlled by a high speed micro controller with embedded logic that operates the display, keypad, as well as setting measurement conditions and performing calculations.

Measurement Modes (automatic or manual) and display ranges:

Inductance (L) + Q (quality)
L: 0.01uH to 99.99H   Q: 0.001 to 100

Inductance (L) + AL
L: 0.01uH to 99.99H   AL: L/N2 (N set by user from 1 to 999)

Capacitance (C) + D (dissipation)
C: 0.001pF to 99999uF   D: 0.001 to 10

Resistance (R) + Q
R: 1 milliOhm to 99.9 MegOhms   Q: 0.001 to 100

Absolute Impedance (|Z|) + Theta (Phase Angle)
|Z|: 1 milliohm to 99.9 MegOhms   Theta: -180 to +180 degrees

Resistance (R) + X (reactance)
R: 1 milliOhm to 99.9 MegOhms   X: 1 milliOhm to 99.99 MegOhms

Conductance (G) + B (Susceptance)

Transformers: Turns Ratio (N)+ Phase Angle, Power transformer Primary/Secondary voltages (Vp+Vs), and Mutual Inductance (M)

Varactor Diodes (with optional test fixture)

Automatic or manual selection of Equivalent Circuit Model (Series or Parallel).
Six automatic or manually selected impedance ranges.
Binning/Sorting by value or percentage
10 User selectable test frequencies: 100Hz, 120Hz, 250Hz, 500Hz, 1KHz, 2.5KHz, 5KHz, 7.8125KHz, 12.5KHz, 15.625KHz
Drive voltage = 0.5Vrms +/- 5%.
Measurement Rate = 2 measurements per second.
Basic Accuracy = 0.2%.
Open/Short zeroing.
4-wire connection to device under test.
Power requirement: 7.5VDC to 13VDC at 200mA

Information on the M3 LCRZ meter can be found on their website at http://www.m3electronix.com .

Bottom line, which one is for you?

Depends.

If you’re new to homebrew or QRP kit building, the AADE might be the kit for you.  It’s easier to build and will indeed fulfill many of those needs.

If you are an experienced builder and have a lot of kit building experience, the M3 might be for you.  It’s definitely a kit for a more experienced builder.  I looked at the contents and think it would indeed take an experienced builder a few nights to assemble.

But, as with all kit building, the final result is indeed rewarding.  Except instead of a transmitter or receiver, with these kits, you will have a valuable tool for your bench that will get plenty of use for years to come.