News & Information

Announcing the "Jersey Fireball 40" ! ... December 3, 1998

The NJ-QRP Club is pleased to announce availability of a small, cool and fun "stocking stuffer" QRPp transmitter for all to enjoy:  the Jersey Fireball 40.

One of our club elmers, Clark Fishman, WA2UNN came up with a couple of twists on the popular theme of using a TTL crystal oscillator "can" as the heart of a milliwatt-level transmitter.  The basic transmitter was previously published a number of years ago in "73 Amateur Radio Today", Radio Fun" and in our own QRP Quarterly, and he decided to brush the dust off the design and extend the functionality just a bit for the holiday season.

Clark chose an oscillator can frequency of 28.322 MHz as a starting point, added some simple circuits to divide down the fundamental frequency so as to hit 80m, 40m, 20m as well as 10m.   Being the technical purist he is (or as much as he can be in this category of projects :-), Clark also decided to put a 5-element elliptical filter on the output ... man the output looks sweet indeed! Amazing how the theory works for turning a square wave into a sine wave.

Now here's a bonus ... we've provided pads on the printed circuit board for an optional TiCK keyer chip! This is a small IC that's programmed as a fully-featured iambic keyer, including speed control and other options. All you have to do is drop this chip (from the Embedded Research guys) into the board, add a couple of components and you'll be paddling to your heart's content.

And yet another option that should thrill many of you is that we've provided circuit board pads for an optional RF power amplifier! Once you get expert at making contacts at 40 mW levels, you might want to add a few more parts from your junk box to boost the FB40's output power to almost 1 watt. The assembly guide and schematic make this a piece of cake to do.

This little transmitter was christened the "Jersey Fireball 40" ... the design puts out about 40 milliwatts, and we're providing the filter components for 40 meter operation. Jumper-selectable band operation will allow you to operate on the fundamental of 28.322 MHz, or on 14.161 MHz, or 7.080 MHz, or 3.540 MHz ... it's your choice!!  And if you want to turn your project into the Fireball 80, Fireball 20 or Fireball 10, just substitute some L's and C's from your junk box per the filter charts provided.

Okay guys, now here's the real kicker ... the NJ-QRP gang is kitting up the "Jersey Fire-ball 40" and making it available to the QRP community for only $10, postpaid anywhere.  Ten dollars!  Oscillator can, voltage regulator, divider IC, filter components, pcb with pads for a TiCK keyer and RF power amp, and a *real* nifty instruction sheet and web page construction guide.  Ten dollars!  We got a fabulous break on the parts and we're passing it along to everybody here as a holiday deal.  Did I mention that this kit is only $10? :-)

The Jersey Fireball 40 isn't going to get you any trophies in the DX contests, any pelts in the Fox hunts, or any ooh's & aah's in the "bells & whistles" category of equipment in your shack ... BUT this this little gem will go together in about 15 minutes and provide all sorts of amazing contacts for you.  See how many miles-per-watt you can get with just a 9V battery and antenna!

You can order the Jersey Fireball 40 with a $10 check or M.O. drawn on a U.S. bank, made out to "G. Heron".  Send it to: The NJ-QRP Club, 45 Fieldstone Trail, Sparta, NJ  07871.

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FB40 "Tech Manual" Review ... Doug Hendricks, KI6DS (Dec 18, 1998)

Yesterday I got to look at a preview copy of the manual for the Jersey Fireball 40 Transmitter kit that was announced last week by the NJ QRP Club. The manual is unbelievable for a $10 kit!!  8 pages!!  It is very, very well done, as good as anything that I have ever seen.

It has the following sections:

Ok, Just What is the "FB40"
A Little History
Circuit Description
Building the Kit
Set Up
Parts Inventory
PC Board Orientation
Install the Voltage Regulator
Measurement #1: Voltage Regulator
Install the Jumpers
Measurement #2: Jumper Continuity
Install the Oscillator
Install Bypass Capacitors
Install U2 & U3 "74LS74" ICs
Measurement #3: Check for U1-U3 pin shorts
Install Filter Caps C4, C5, C6
Wind the Filter Inductors
Putting the FB40 on the Air
Optional Installation of a TiCK Keyer
Optional Installation of an RF Power Amp

Tables & Figures:

Table 1: Output Filter Values
Figure 1: PC Board, Component Side
Figure 2: PC Board, Bottom Side
Figure 3: Schematic for Jersey Fireball 40
Figure 4: Component Layout for Stock 40 Meter Operation
Figure 5: Optional TiCK Keyer
Figure 6: Optional RF Power Amp

Plus there are 5 drawings of component placings, winding toroids, etc.

The circuit description section is outstanding.  There is a full explanation of what is happening and why.   Very nice job here.

The building instructions are the check off type.   There is a box to check as you install each component, and there is a full description of each component.  My only criticism here is that they did not include a pictorial drawing of each component, which would have been a nice touch for the first time builders.  But, the text description is quite adequate.

Guys, I think that this just might be the ideal first time kit.  It is cheap, (only $10 POSTPAID), all of the parts are there, it has a high quality board, the manual is very, very complete.   And when you get done, you have a useful little rig.   If you do the optional RF Power Amp mod, you will get almost a watt out.  Plenty of power to make a QRP contact!!

If you have never built anything before, order one of these and give yourself a well deserved Christmas present.   Or, if you are like me and love to build, order one of these, it is only $10.   This and the Smite kit done by the North Carolina group may be the bargains of the century in kit building.

Sorry for the length of this posting but I am quite excited by what I see the NJ Club doing.  They are promoting QRP in a huge way.  Think about what they have done in the past 3 months alone:  (1) Announced that they are sponsoring Atlanticon, complete with a major league lineup of speakers, two nights of qrp open house, and a building contest, all in March at the Timonium Hamfest.  (2) Produced the excellent slide show on QRP, that has been copied and used by many, many of us for presentations at local ham clubs.  It has been an invaluable aid.  (3) The Jersey Fireball 40 kit, for $10 which includes all board mounted parts for the stock kit, a manual (8 pages!!) and pads on the board to add a TiCK keyer and an RF Amp that will give almost 1 Watt out on the finished kit.

Guys order the Fireball, and if you live anywhere near the east coast, make plans to attend Atlanticon, the first big QRP gathering of 1999.

Here are the details to order the Jersey Fireball 40 kit:

The NJ-QRP QRP Club is selling the Basic 40m kit of parts and pc board for $10 postpaid.  Order from NJ-QRP Club, George Heron, N2APB, 45 Fieldstone Trail, Sparta, NJ 07871.

Check the NJ-QRP Club Website at for information on Atlanticon.

Check the Embedded Research Website at for information on the TiCK series of keyer chips.

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Fireball 40 News ... December 19, 1998

All "Jersey Fireball 40" QRPp Transmitter orders received prior to Monday were shipped early this week and people should be receiving them right about now.  We sure hope you enjoy building your FB40 and getting it on the air!  Please let us know how it works out for you.  

And as for the orders still coming in ... we've quickly exhausted the parts for the first run of 100 Fireball 40 kits and ALREADY have another set of parts coming from the suppliers!  We should have these kitted over the holidays and to you in the mail by the end of this month. The response to this kit has been phenomenal and much more/quicker response than we anticipated.  Thank you all!  

Now, if you haven't yet placed your order for an FB40 please feel free to do so ... you'll be pleasantly surprised when you receive the "rev B" circuit board.  We made some improvements to make it even easier to construct.  

Thanks to Doug Hendricks for the nice review of the "tech manual" for the Fireball 40!  We think you all will be quite happy with the information presented in the document.

To let a little cat out of the bag, we're looking to put together a FB40 sprint after the holidays leading up to the Atlanticon QRP conference, with some interesting operating twists and goals.  (Think "miles per watt".)  Should be great fun and we've got some neat prizes lined up.  More later ...  

Now, for the little SNAFU (every project has at least one snafu, right?)  In our kitting excitement, we forgot to place a part into the bag ... just one little part: the LM78L05Z voltage regulator!  The little bag of TO-92 parts just never made it to the kit assembly line table.  Ohhhh noooooo!  Well, this little device will be coming to you early next week in a standard envelope with an apology for the omission.  Please hang in there!  

Again, thanks so much for all your orders.  And if you haven't yet sent in an order for the FB40, please do so at your *earliest* convenience because these little kits are going like ... well, like fireballs :-)  And when the kit availability is made known in QRPp, QQ, SPRAT, CQ, WorldRadio, and a few other widely distributed ham publications, we expect the orders to sky rocket (or at least we hope they will) and we wanted everyone on QRP-L to have a shot at getting theirs before the fire storm hits.  

Stay tuned for some detailed photos and step-by-step Fireball 40 construction and operating pictorials coming soon on our Jersey QRP website. We think all owners will be pleased to see additional detail on putting all the optional/accessory components on the board.   For more information on the "Jersey Fireball 40" QRPp transmitter, please visit our website at:  

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Fireball 40 Schematic & Photo Assembly Guide Online ... Dec 24

The Jersey QRP Club has updated the web pages for its "Fireball 40" kit in a big way. Here are the quick details:

Many people have requested to see the schematic for the Jersey Fireball 40 QRPp Transmitter Kit, and we've now put the entire manual on the website so you can view and download the schematic, parts layout, technical description ... everything!  (Note: you'll need to be able to read PDF files, but most of us can do this already. But if not, visit the website for your free reader.)

Additionally, we now have COMPLETE PHOTO COVERAGE of the kit assembly steps! Take a look at these to compare your kit construction or to help identify the parts supplied in your kit.  We also assembled one of our prototypes into an Altoids tin (of course!) and you can see this photo too in the web pages.

The web pages for the "Jersey Fireball 40" can be found at

For those of you not able to surf the website, we will provide the Photo Assembly Guide and a copy of the Technical Manual (schematics, description, et al) by mail for a modest cost reimbursement (for copying & mailing) ... contact us if interested.

Some people have contacted us requesting built-up FB40s ... although we only supply the FB40 as a kit, we are having a "kit construction seminar" at our January meeting of the NJ-QRP Club, and we'll be using the FB40 as the basis for our instruction.  If you are interested in receiving an assembled and tested FB40 for only a little more than the cost of the kit, please contact us!

Response continues to be great as orders are still piling up in the club mailbox.  Hang in there and we'll soon be able to send out our next run of 200 kits in the first week of January.

Thanks for all your support and the kind notes being sent with the orders! This group is so great, and we're very pleased to be able to supply this FUN kit to all you folks *first* before the advertisement is spread to a much wider audience.

Don't forget the awards mentioned last week for each of the first 2-way FB40 contacts on 80, 40, 20 and 10 ... should be fun getting these coordinated and QSOs confirmed!

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FB40 Built w/RF Amp ... also as Marker Generator

... by Paul Harden NA5N, Dec 25

Yup, great little kit, high quality board, excellent manual, and far beyond what you'd expect for $10.  Built mine for 40M with the 1W 2N2222 (running at 850mW on mine) and clean output.  Now here in NM, I figure it takes a watt just to get signals across the state line, and nobody in NM I want to QSO with anyway (oops, sorry Jay, and Tim in Las Cruces darn near counts for TX anyway!) so one watt it has to be here.  Then the thought hit me ... what an excellent marker generator this would make.  So came into the lab at work, scrounged around for awhile, and darn if I didn't finally find a 28.000 MHz TTL oscillator can.  Plugged it in, and makes beautiful band-edge markers at 7.00, 14.00 and 28.00 MHz.  And you don't even need the 1W PA for that.  So next step is to mount it in an Altoids can (I think it will fit), small rotary switch, and BNC.  Gonna add a 50 ohm linear taper pot and calibrate the output in dBm/mW.  That way, have a nice little pocket sized signal generator for a QRP marker/calibrate the tuning dial thing, and a ball park check of receiver sensitivity (MDS).  Then, a small collapsable whip antenna on a BNC connector, you got yourself a carry around generator for making antenna field strength measurements, etc.  Leave it on in the kitchen and call it a "far field" test range!

So if you're not crazy about the Fireball as a QRP transmitter, it's the cheapest signal generator/marker generator you can build.

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Fireball 40 Technical Notes ... December 28

There have been real good responses from everyone building their "Jersey Fireball 40 QRPp Transmitters" (or FB40 for short) ... rigs are getting built on different bands, skeds are being attempted, etc. But no FB-to-FB contacts yet, huh? Remember: the Jersey QRP Club is sponsoring a prize for each of the players in the first FB-to-FB contacts on each bands. And there's a FB Sprint coming along in January ... So get those Fireball 40's ordered, built and on the air soon!

Okay, to help on the technical side, our club elmers have been busy with responses to the various technical questions being posed on the lists lately. Here's a collection of notes that might help all you Fireballers:

1) GROUNDING -- Don't forget to bend over the leads and solder to the bottom-side ground plane on a couple of the components. As noted in the manual, you should do this at least on the DC input, the ground-side of the output filters, and the RF output connection too. This establishes a good ground for the important areas of the circuit and electrically ties in the entire bottom-side ground plane to give some good shielding. (The 'rev B' version of the kit will handle this grounding automatically.)

2) LOW POWER & DC DECOUPLING -- In the original 'rev A' FB 40 kit, there is no dc decoupling for the oscillator or 74LS74 TTL divider chips to the output filter and antenna. This means that there is an average 2.5 volt dc signal connected between antenna and ground through the output filter. With simple dipoles or other antennas with no dc continuity this is not immediately a problem. But if folks use antennas with dc connections (like many mulitband verticals) or a link-coupled tuner, the oscillator or divider section selected will see a dc short circuit. We doubt that there will be any damage, but the harmonic content may suffer or the chip may not produce the correct output. A simple fix would be to replace the BAND selection jumper with a 0.1 uF disc capacitor. With the optional amplifier in line there *is* dc isolation so this is not an issue.

3) OUTPUT FILTER VALUES -- Some builders have questioned how we obtained the output filter component values for operation on the different bands. The computer program used is one called "L.exe - Low Pass / High Pass Filters, version 1.50", a Wes Hayward program supplied by the ARRL. This is a neat program that automates one of the standard filter calculations in the Handbook to provide all sorts of filters with varying parameters: Butterworth, Chebyshev, Elliptical, variable number of elements, cut-off frequencies, and maximum ripple values. In each case, we chose a 5-element Chebyshev low pass filter with 50-ohm input and output impedance, with 1 dB maximum ripple, and a cut-off frequency at the next higher megahertz value from where we were operating. [e.g., a cut-off frequency of 4 MHz was selected for the 80m filter, etc.] Shown below is a complete listing of the component values for each of the bands. (Note: We had forgotten to list the 20m and 160m band components in the manual. And view the table with a proportional font like Courier to have the columns line up.)

  C4 L1 C6 L2 C5
160m 3400pF 4.3uH 4770pF 4.3uH 3397pF
80m 1700pF 2.2uH 2400pF 2.2uH 1700pF
40m 820pF 1.1uH 1000pF 1.1uH 820pF
20m 450pF 0.6uH 630pF 0.6uH 450pF
10m 230pF 0.3uH 330pF 0.3uH 230pF

4) FILTER CAP QUALITY AT 20m & 10m -- You might need better quality capacitors when attempting to build your output filters for the higher frequencies. At 14 MHz and 28 MHz, the el cheapo disc capacitors are quite lossy and results in a low Q filter. Try using some silver mica caps (or equivalent) and your output power at the higher frequencies might improve.

5) OUTPUT FILTER TYPE -- For the purists among us ... the manual states in a couple of places that the output filter is an "elliptical filter". We originally used this kind of filter in our prototypes but later found just as good results using a 5-element Chebyshev low pass filter. Thus we were able to do away with the extra capacitors in parallel with the inductors (which is the characteristic configuration for an elliptical filter).

6) TOROIDS -- Some questions had come up as to the turns calculation for the L1 and L2 inductors used in the output filter. The equation used in the manual is the standard one for determining the required number of turns around a specific type of toroid core:

N = 100 * SQRT (Ldesired / AL)

This equation is stated in an excellent reference book: "The Electronic Data Book for Homebrewers and QRPers", by Paul Harden, NA5N (ISBN 0-913945-57-9), as well as in the ARRL Handbook (my 1996 version has it on page 6.25 ... check the index for "toroid" in other versions).

In order to accommodate the greatly varying core permeabilities at different frequencies of use, each core has an inductance index, or "AL". Thus looking up the T37-2 core used in the FB40, you'll find its AL = 40 uH per 100 turns.

So if we wanted the 1.1uH value for our filter inductor, the equation computes to:

N = 100 * SQRT (1.1 / 40) = 16.58 Turns

And since we can't have fractional windings with toroidal inductors, we rounded this to 16 Turns. Close enough!

7) YET MORE POWER -- One of the builders notes that by using "Advanced CMOS" TTL devices instead of the "Low-power Schottky" ones we used for U2 and U3 (74LS74), we could get effective power transfer from the chips. The AC devices provide an output impedance much closer to the 50-ohms that the output filter was designed for, thus providing a better match and more power to the antenna. If we can find these AC devices at a reasonable price, we may try using them in 'rev C' of the FB40 project.

8) 160M OPERATION -- An alert builder spotted another capability of the FB40: 160m operation! In the interest of time and board space, we decided not to use the second flip-flop gate in U3. If it were connected as in U2b, you could bring the 80m signal out to the unused 5th BAND jumper pads and get your 160m signal out! Note that the 160m filter component values are provided in the table above. Also, note that you'll have to use a higher oscillator frequency (e.g., above 28.800 MHz) in order to operate with the 160m amateur band when it's divided in half 4 times!

Okay, we hope these these technical tips will help you Fireballers in getting your rigs on the air. Remember that you can visit the Fireball website for a complete listing of all news, announcements and ordering information. We've placed the manual on the website, available for the viewing or download (includes schematic and parts layout). And we've recently added a step-by-step photographic documentation section to help you compare your construction to that of a typical unit. The website is at

Hope you all enjoy this $10 marvel! And hope to hear lots of Fireball40's on the air soon!

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Last Modified: Dec 28, 1998