EMRFD Message Archive 2808
Message Date From Subject 2808 2009-03-27 18:04:44 bignick73_2000 noob questions on building a tiny tornado First off I just got my tech ticket a week or so ago, after looking around I've decided I want to try CW via QRP rig. I found the schematics for the tiny tornado and ordered all the parts and some perf board to build 2 with 7.122 mhz crystals. I solder a lot, and can easily follow schematics but my electronics knowledge is minimal.
Once this is built how do I go about testing it to check output wattage, and frequency to make sure I'm where I want to be. Also the c14 variable capacitor, what does this control? I couldn't find a 20-90pf so I got a 12-100pf or something in that range.
Anything I should watch for while building/after it's built?
Things to watch for winding the toroid?
Also I live in an apartment, with a 2nd floor balcony, any recommendations on a stealth antenna that will work decent?
2809 2009-03-27 18:54:46 Nick Kennedy Re: noob questions on building a tiny tornado Good that you want to give CW a shot. The Pixie and derivatives are a
fun thing everyone should try, as long as you're aware it's more of a
novelty than a transceiver you'd expect lots of QSOs with. One of my
biggest thrills was my (one and only) QSO on an 80 meter Pixie I built
a long time ago.
You shouldn't have much difficulty since you can solder and the board
dictates the layout. The toroid won't be a big problem for you.
Getting full insulation removal when you strip the ends is important.
I just looked at W5USJ's page for a schematic. In the photos you can
see how Chuck distributed the windings fairly evenly on the toroid.
The variable capacitor sets the amount of offset between transmit and
receive. I you have an offset of say, 700 Hz, and you hear the other
guy with that note, you'll be on frequency. (Unless you're hearing
the wrong side of zero beat, then you'll be 1.4 kHz off, but I don't
want to complicate things that much. Best to call CQ and let the
other guy get on *your* frequency.)
Anyway, your cap will be fine. If you have a receiver or counter or
friend with a rig, you could set it. But if you don't, try half scale
or something and give it a go.
You could give it a try without measuring power, but if you want to do
it, search the web for a simple diode RF voltage detector you can use
with your DMM. Solder a couple 1/4 watt 100 ohm resistors in parallel
across the antenna terminals and check the voltage and you can
calculate the power from that.
OK, I like N5ESE's approach:
The antenna will definitely be a challenge with a flea powered rig.
Ideally, you'd want something huge to compensate for the minimalist
rig. If you don't want to have to build some kind of a matching
device right away, try an end fed quarter wave (33 feet or so?) with
one or more good counterpoise wires and or ground connections. Sounds
difficult from your location, but a dipole would be great. Next
choice would be an end fed half wave (65 feet or so) with a matcher
designed for that purpose. The antenna is twice as long, but the need
for a ground or counterpoise just about goes away.
It would be great if you could find a ham in the 0 to 100 mile
distance range to initially listen for you and try to QSO you.,
2810 2009-03-27 21:48:08 bignick73_2000 Re: noob questions on building a tiny tornado Thanks for the info. I'm using these schematics and some plain perf board since I couldn't find a printed circuit for it.
I plan to build 2 one with a 9V wall wart and another with a 9V battery (Parts were so cheap I figured why not). Can I use one to transmit and set the cap
2811 2009-03-29 00:02:18 Stan Re: noob questions on building a tiny tornado Hi Nick,
I hope you give a good try to low power. It can give a great deal of plaeasure to the hobby. It can also make one depressed. I have ran QRP and QRPp on and off now for over 50 years. I have logged 42 states on the HF bands. What is the secret?
Put up the best antenna your skills and pocket book will allow. That will reward you no matter if you run 0.1 watt or 100 or even a KW.
For best results hang where the other QRP stations operate. 7040 and 7030 and even a few at 7015 on forty meters.
Keep your QSO short. Expect a lot of 439 or 539 QSO reports. Note a S3 signal can be 100 percent copy.
The weakest in QRP is that many handcap themselves by using a poor receiver. The tiny tornado and pixie units are only slightly better than using a crystal set for receiving. However, their 300 milliwatt RF output into a good antenna will result in numerous contacts.
A Rockmite is a step up and I recommend them at a cost of $30. I also recommend stick with something simple until you know that you want to operate QRP. Then look for a K1, K2 or TenTec 516 or 817 transceiver.
If you succeed in your QRP operation it means you have become an excellent receiving operator. YOu know how to play with the RF gain control, bandwidth, noise blanker, etc on your receiver.
I have a tiny tornado that I often use for a transmitter. I like to mate it up with a old glowbug reciever such as a HRO-50 or R390A.
Dont spend a lot of time calling CQ. Spend your time calling others who have called CQ.
Learn to be surprised by your signal reports. Yes you will get 229 but you will also get 599 reports. Neither is the norm. 339 to 579 will be average.
Remember keep the transmission short or you will often be talking to yourself.
QRP frequency xtals are available for about $2.55 each and often available on ebay. 3560, 7030,7040,14060, 10106 are all good frequencies for QRP
Remember good antenna first, good receiver second, learn how to receive, then run from 50 milliwatts to 5 or 10 and you will make a lot of contacts. However, it is ok to also run higher power our hobby allows us to do so and it can be very enjoyable also.
hope to cu around 7040 some day.
73 cheers de Stan ak0b
2812 2009-03-29 09:06:07 Nick Kennedy Re: noob questions on building a tiny tornado >Well, an outboard amp on a Pixie would be kind of like putting a $100
> Could I build an amp and use a smaller antenna?
saddle on a $50 horse.
If the antenna size limitation is a major problem, you might try a
higher band -- 30M or 20M.
>Getting into PSK is a major step in complexity from simple QRP CW
> I'd also like to try PSK. Is there a repository of plans somewhere? I see
> plenty of kits, but like the idea of building it myself from scratch.
only rigs, since PSK rigs are typically SSB transceivers interfaced to
a computer. Here's one example to the contrary by the legendary
2813 2009-03-29 10:03:56 Stephen Wandling Re: noob questions on building a tiny tornado Putting an RF amp on a Pixie would change it from a transceiver to a
transmitter only. The interesting feature for the Pixie and a bunch of
similar rigs is that Q2 is not only the PA, but it is the detector on
receive. So, when you mess with the PA circuit, you have to consider
how it works as a part of the receive function.
I have been playing with these little rigs for awhile and you can
believe it when you're told that a good antenna is more important on
these minimalist rigs, both for transmit and receive. I have a 550'
horizontal delta loop and its well worth the effort it took to get it up.
I am currently planning/designing a Pixie for the MAS "Minimal Art
Session" event on May 21. You can see more about the MAS, my earlier
Pixie project and my trials and tribulations with the pesky Flea
The 80M Pixie I want will have at least 600 mW of power and maybe 1 W.
It will use a 3.58 Mhz ceramic resonator ($2 on eBay) instead of a
crystal and will tune 3500 to 3575 Khz of range. And, it will have a
sidetone generator. Currently for sidetone, I have to listen to myself
in another receiver to monitor the code I'm sending.
As an example of what you can do with low power, a couple of evenings
ago I worked a Sacramento station, K6LQ, on 40M with my re-born Flea one
transistor transceiver, running less than 1 watt, from my QTH of 150
miles north of Vancouver, BC. He gave me a 459 and solid copy. He was
booming in here. That's 830 miles, according to QRZ.
Nick Kennedy wrote:
>> Could I build an amp and use a smaller antenna?--
> Well, an outboard amp on a Pixie would be kind of like putting a $100 saddle on a $50 horse
Hunger is not caused by a scarcity of food
but a scarcity of democracy - Frances Moore Lappé
2814 2009-03-29 17:01:51 bignick73_2000 Re: noob questions on building a tiny tornado Well for an amp I was thinking of the texas/tuna topper via qrpme.com type of deal. I do plan to upgrade if I enjoy it.
I also realize an antenna tuner would probably be a good idea, since I don't have room for anything huge, I've been researching the MFJ 904/914 types, since they'll do random wire.
Thanks for the info! -Nick
2816 2009-03-29 17:49:43 Stephen Wandling Re: noob questions on building a tiny tornado Nick,
I'm not sure whose post you were responding to. If it was mine, then
you missed the critical point.
You can't just put a texas/tuna topper (or any similar amplifier)
between the tiny tornado and the antenna without removing the tiny
tornado's receive function.
If you have any questions about this, feel free to ask.
> Well for an amp I was thinking of the texas/tuna topper via qrpme.com type of deal. I do plan to upgrade if I enjoy it.--
> I also realize an antenna tuner would probably be a good idea, since I don't have room for anything huge, I've been researching the MFJ 904/914 types, since they'll do random wire.
> Thanks for the info! -Nick
> Yahoo! Groups Links
Hunger is not caused by a scarcity of food
but a scarcity of democracy - Frances Moore Lappé
2817 2009-03-29 18:07:29 Bruce K3CMZ Re: noob questions on building a tiny tornado Hi Nick
Ref your antenna plans,
do a goggle search on magnetic loop antennas
three to six feet square, made out of copper tube
this antenna is the antenna tuner
Also, search for the softrock recievers/transceivers
Lots of luck
On Mon, 30 Mar 2009 00:00:55 +0000, you wrote:
>Well for an amp I was thinking of the texas/tuna topper via qrpme.com type of deal. I do plan to upgrade if I enjoy it.
>I also realize an antenna tuner would probably be a good idea, since I don't have room for anything huge, I've been researching the MFJ 904/914 types, since they'll do random wire.
>Thanks for the info! -Nick