TEN TEC Argonaut 509 and a DDS vfo. Now working and on the air. March
1 -2011...A written report
1 -2011...A written report
The Argonaut 505 and 509 were ground breakers back in 1973/74. I bought
a brand new one back then: a 505. I did have a problem with the Reed Relay
sticking but the distributor sent me a new circuit board and the problem
was resolved. I can remember back in 74, I was invited out to the OVMRC
radio club in Ottawa to put on a presentation about the Argonaut. I brought
it to one of the club meetings at the Science Museum and the hams who
looked it over with the manual..were quite impressed. At that time, many
hams were still using Heathkit tube transceivers. We had a Heathkit store
in Ottawa (north of upper NY state by about 70 miles).
I just went searching around the web for material for writing this article and
checked out eham reviews. The rating on the Argonaut 509 is a rather high
4.8 out of 5. It is still a popular radio. Much of it has to do with sentimental
value.
Ten Tec support is still available for these older products. The parts are
fairly generic/standard and easy to get discrete components such as
MC1496P Double Balanced Mixer IC, ua723 voltage regualator IC..(has been
around for a long long time now (ASTRON power LINEARsupplies use them
as well).
The PTOs of the Ten Tec Rigs do tend to get stiff with age and they seize
up eventually. Before that, you can have some erratic jumping as you tune
the band.
I had one seize up on me. Rather than try and rebuild the PTO..I decided to
replace the PTO with a DDS vfo. I chose the N3ZI version 2 dds vfo. I found
..by luck..that the circuit board fit very nicely into the cavity left behind
when I removed the old PTO.
a brand new one back then: a 505. I did have a problem with the Reed Relay
sticking but the distributor sent me a new circuit board and the problem
was resolved. I can remember back in 74, I was invited out to the OVMRC
radio club in Ottawa to put on a presentation about the Argonaut. I brought
it to one of the club meetings at the Science Museum and the hams who
looked it over with the manual..were quite impressed. At that time, many
hams were still using Heathkit tube transceivers. We had a Heathkit store
in Ottawa (north of upper NY state by about 70 miles).
I just went searching around the web for material for writing this article and
checked out eham reviews. The rating on the Argonaut 509 is a rather high
4.8 out of 5. It is still a popular radio. Much of it has to do with sentimental
value.
Ten Tec support is still available for these older products. The parts are
fairly generic/standard and easy to get discrete components such as
MC1496P Double Balanced Mixer IC, ua723 voltage regualator IC..(has been
around for a long long time now (ASTRON power LINEARsupplies use them
as well).
The PTOs of the Ten Tec Rigs do tend to get stiff with age and they seize
up eventually. Before that, you can have some erratic jumping as you tune
the band.
I had one seize up on me. Rather than try and rebuild the PTO..I decided to
replace the PTO with a DDS vfo. I chose the N3ZI version 2 dds vfo. I found
..by luck..that the circuit board fit very nicely into the cavity left behind
when I removed the old PTO.
Right now, Feb 14, 2011 The front panel looks like this. It is a working
prototype. I was using it last night to do some receiving on 80 meters.
It receives very well. I was listening to some interesting cw on the low end
of 80. Again tonight..Feb 15 I am hearing another wild cw pileup on the
lower part of 80!
I am now starting to use it on the air in the testing stage. IM IN NO RUSH. It
is not a production item. So I will be playing around with it in its prototype
form for several months. It is butt ugly (like the military people say)! But it
does seem to work fairly well.
One thing I will be looking for..is harmonics on both transmit and receive
and birdies and spurious emissions and that kind of thing. I am using a dds
amplifier to boost the output of the dds vfo to a useable level. I have not
added filtering (YET).
When I do put it on the air..I am going to use a quality low pass filter on the
output of the radio. I will be switching back and forth on the bench
between my unmodified original 509 and this newer modified argonaut.
If it works out..I will be trying to repackage all the circuity back into the
original 509 chasis format. The front panel..will have to be changed though
to accomodate the new controls and buttons
prototype. I was using it last night to do some receiving on 80 meters.
It receives very well. I was listening to some interesting cw on the low end
of 80. Again tonight..Feb 15 I am hearing another wild cw pileup on the
lower part of 80!
I am now starting to use it on the air in the testing stage. IM IN NO RUSH. It
is not a production item. So I will be playing around with it in its prototype
form for several months. It is butt ugly (like the military people say)! But it
does seem to work fairly well.
One thing I will be looking for..is harmonics on both transmit and receive
and birdies and spurious emissions and that kind of thing. I am using a dds
amplifier to boost the output of the dds vfo to a useable level. I have not
added filtering (YET).
When I do put it on the air..I am going to use a quality low pass filter on the
output of the radio. I will be switching back and forth on the bench
between my unmodified original 509 and this newer modified argonaut.
If it works out..I will be trying to repackage all the circuity back into the
original 509 chasis format. The front panel..will have to be changed though
to accomodate the new controls and buttons
| Supports IF+VFO, IF-VFO, and VFO-IF radios. . ((note: the argonaut VFO runs at a different frequency range for each band and (as well) there are multiplications (except on 20 meters). For 4 bands (80,40,15 and 10) there is a mulitplier stage and this produces the "INJECTION FREQUENCY" -- Other radios that do this scheme are Swan and Atlas. THIS DOES MAKE IT A BIT DIFFICULT TO FILTER THE OUTPUT OF THE DDS (and DDS amp) in order to produce a ""filtered"" injection frequency. I am working on this challenge now. ID LOVE TO HEAR from anyone who suceeds with a DDS vfo for the Argonaut that is ""clean"". I use memory banks 0 through 9 and each memory bank (as well as VFO A and VFO B) can be programmed with an IF offset. Expands the frequency coverage of many radios. -- Can be useful. Only 1 surface mount part, 20 Pin TSSOP (AD9834) Solder it yourself, it's easier than you think. (( my special note: Yes..IF YOU HAVE SOLDER FLUX, A GOOD 15 watt (or maybe 25 watt grounded tip soldering iron). A good magnifying glass with plenty of light. I successfully did it. I used a high magnification light for working with small components. I carefully lined up the leads and used a wee piece of scotch tape to hold the little chip in place. I used tiny diameter solder and a 15 watt grounded tip soldering iron (from radio shack) -- and desoldering braid and solder flux. I did bridge a couple of leads with solder but I sucked away the solder with some flux to aid the flow..and the DDS worked fine!! Kitbuilders will do it for $10 Requires 9 to 15 volt DC supply, approx. 50mA, more if a backlit display is used. 10 Memories plus A/B VFO all with their own IF offset setting. ---> the 10 memories will be allocated for each band. For 80 meters two memory registers..channel 0 and 1 will be 3.560 and 3.755 mhz. Separate A/B VFO input signal line. Separate RIT memory & control IF offsets settable via RS-232 or LCD/Button/Dial I set my IF OFFSETS by dialing up the actual injection frequency for the argonaut..ie 12.500 mhz for 3.5 mhz and then I go in and set the frequency STEP for something large like 200khz (fast dial) and then I dialed up -9 mhz for the IF offset and then when all was well..I set the tuning step back to 25 hz (very slow tuning). Easy to set RIT from tuing knob (I havent done this yet. The original RIT for the Ten TEc argonaut is now non operational). Normal range +/-9.999KHz (1Hz steps) But can be set up +/-9.999MHz for special applications Non volatile memory storage of last operating frequency and all memories/IF's Yes it is non volitile. Hopefully for a very long time. When you are first learning to use this dds vfo and you are getting used to it...it takes a bit longer to set up each band with the proper IF offsets ect. Front Panel components can be remoted (LCD, Rotary Encoder, Buttons) I did remove mount the LCD, Rotary Encoder and Buttons on a front sub panel. It is a temporary arrangement. IF I like the way this DDS and Argonaut plays..(and it certainly looks promising at this point)-- I will be creating a new front panel, side panels ect. Top quaility commercial PCB with Separate Analog and Digital ground planes for best output purity |
| Information ((below)) with some commentary from myself . This is from the N3ZI (ponderance) web site concerning the N3ZI ver 2 DDS VFO --- I have added some commentary with regard to using this dds vfo (or perhaps any dds vfo) with a Ten Tec Argonaut. It will require a bit more thought and work and circuitry (perhaps) because the Argonaut uses a freqency multiplication scheme rather than a straight 5 to 5.5 mhz (vfo) and heterodyne oscillator -- as used by other rigs with a 9 mhz IF. |
The DDS vfo output was too low to be of any use with the Argonaut 509.
I built this 2 stage buffer amplifier. It made all the difference in the world.
Before, when using the DDS vfo output to directly drive circuitry in the
Argonaut, there was very low transmitter output and very low receive signals.
Now with this circuit being used to boost up the level..the Argonaut is back to
sounding (and transmitting) like the old Argonaut 509.
I built this 2 stage buffer amplifier. It made all the difference in the world.
Before, when using the DDS vfo output to directly drive circuitry in the
Argonaut, there was very low transmitter output and very low receive signals.
Now with this circuit being used to boost up the level..the Argonaut is back to
sounding (and transmitting) like the old Argonaut 509.
Above is a table of frequencies for the argonaut. The BASIC
frequency changes from band to band to produce the injection
frequency.
There are no heterodyne oscillator crystals to produce the mixing
frequency. The INJECTION frequency is mixed with the 9MHZ IF
frequency to produce the fundamental frequency (on transmit).
On receive: the fundamental frequency is mixed with the injection
frequency to produce the IF frequency which is filtered and
demodulated and audio results.
It is certainly not impossible to create a DDS version of the Argonaut.
But for me..I have decided to move the N3ZI version 2 DDS unit over
to the FT301 and create a stable transceiver with reliable readout.
Right now..the 301 unit has no display. I have been borrowing its TIL
306s and TIL308s as spares for myself and other hams. I was going to
buy an AADE digital display but now..if I use the N3ZI vfo to this 301, I
will have accomplished the goal of a new display.
Speaking of displays, I have ordered some green backlit 2 line
displays from ebay and I plan to change the display to a backlit one.
frequency changes from band to band to produce the injection
frequency.
There are no heterodyne oscillator crystals to produce the mixing
frequency. The INJECTION frequency is mixed with the 9MHZ IF
frequency to produce the fundamental frequency (on transmit).
On receive: the fundamental frequency is mixed with the injection
frequency to produce the IF frequency which is filtered and
demodulated and audio results.
It is certainly not impossible to create a DDS version of the Argonaut.
But for me..I have decided to move the N3ZI version 2 DDS unit over
to the FT301 and create a stable transceiver with reliable readout.
Right now..the 301 unit has no display. I have been borrowing its TIL
306s and TIL308s as spares for myself and other hams. I was going to
buy an AADE digital display but now..if I use the N3ZI vfo to this 301, I
will have accomplished the goal of a new display.
Speaking of displays, I have ordered some green backlit 2 line
displays from ebay and I plan to change the display to a backlit one.
Above is a schematic of a 10 mhz Band Pass filter. I will likely do a couple of things with the DDS unit after I place it in the FT301. First..I will
have a DDS amplifier that has some means of controlling the gain. I dont want to overdrive the mixer of the FT301. I will perhaps build a
variable pad attenuator. I will also build a band pass filter for the 5 to 5.5 mhz range. It will be fairly simple, something along the lines of the
schematic here. This one appeared on the web site QRP pops, QRP builder.
have a DDS amplifier that has some means of controlling the gain. I dont want to overdrive the mixer of the FT301. I will perhaps build a
variable pad attenuator. I will also build a band pass filter for the 5 to 5.5 mhz range. It will be fairly simple, something along the lines of the
schematic here. This one appeared on the web site QRP pops, QRP builder.
The information on this page is for reference. I
am putting this project ---ON HOLD--- until I do
more work and research on how to best filter the
injection frequency.
I am going to try the N3ZI dds vfo in an old
FT301D. THIS WILL BE AN EXTERNAL VFO
along the lines of the FV 301 vfo..only a DDS
homebrew version.
BEING EXTERNAL VFO ..it can be tried on a
number of other rigs as well..including the
Argonaut 509 in an experimental vien.
I would be interested in hearing from anyone
that goes ahead and fully implements a DDS vfo
in the Argonaut.
One fellow in USA did write me about "where to
tap in to the Argonaut 509 circuitry" so ..I think
there is interest. I see on YOU TUBE videos of of
a fellow who nicely implemented a digital
frequency display for his 509. ---->>> this is the
direction I may head. I will be ordering a PTO
rebuild kit from Ten Ten and restore the old PTO
into this rig.
am putting this project ---ON HOLD--- until I do
more work and research on how to best filter the
injection frequency.
I am going to try the N3ZI dds vfo in an old
FT301D. THIS WILL BE AN EXTERNAL VFO
along the lines of the FV 301 vfo..only a DDS
homebrew version.
BEING EXTERNAL VFO ..it can be tried on a
number of other rigs as well..including the
Argonaut 509 in an experimental vien.
I would be interested in hearing from anyone
that goes ahead and fully implements a DDS vfo
in the Argonaut.
One fellow in USA did write me about "where to
tap in to the Argonaut 509 circuitry" so ..I think
there is interest. I see on YOU TUBE videos of of
a fellow who nicely implemented a digital
frequency display for his 509. ---->>> this is the
direction I may head. I will be ordering a PTO
rebuild kit from Ten Ten and restore the old PTO
into this rig.
Today, I just read where KANGA USA is carrying a new kit. It is a DDS type vfo developed using a different chip from the N3ZI ver 2 that I am using. It is
about $85 for the complete kit. The output is higher than the N3ZI one. Output max around 1.5 v p to p which might be enough to drive the dual gate mosfet
mixer of the Argonaut 509. More importantly, this newer dds is advertised not to have SPURs like other DDS units.
Technology is advancing. I may end up trying another DDS vfo in the argonaut in the near future. Perhaps even this one that Kanga is offering. When I do
build it and try it; I will be writing up my experiences.
Below are some notes from Craig Johnson AA0ZZ. This is from his web site *you can google it. He has other projects and has a PDF file which specifically
deals with topics such as "what happens when you amplify a dds signal"..the concern being SPURS. He claims his DDS unit..is a "clean" running dds
without a problem with spurs. My Argonaut (when tuning certain bands) had birdies and spurs. I am not blaming the N3ZI dds vfo. I think I was using
perhaps too much amplification..(overdriving) with my 2 transistor amplifier. NOTE: I did not build a bandpass filter for the Argonaut DDS vfo because the
vfo frequencies change from band to band. Because of the complexity..I have decided to abandon the Argonaut 509 DDS control and go back to the old
PTO (after I rebuild it). The PTO had frozen.
I had thought that a DDS vfo for the Argonaut was a good idea ..and it still might be..BUT..I have decided against it. If you are considering trying this
yourself..you can use some of my ideas but be prepared to do some serious building and modification. Still..it was quite a thrill to make some contacts with
this butt ugly breadboard kind of radio. Just like the old golden age of radio back in the good old days!! You cobble up something and try to make it work.
Its not perfect. It has harmonics and birdies and there is qrm and all that..but the qso really stands out because you made it using your own hand built
gear. Gear you understand. Gear you can work on. Gear you can actually repair yourself. I can work on this gear. The FT817 would be a real challenge to fix.
I guess board level repairs would be possible..but you would have to have a set of spare boards.
The FT301 is the next victim of my soldering iron. It is an old unit. It works but the display is not working properly. A DDS display will fix that. The finals are
fried in the FT301. NO PROBLEM either. I will use it at the 10 watt level as a QRP DDS controlled rig. Certainly not a small portable neat little unit..but
something to work on.
about $85 for the complete kit. The output is higher than the N3ZI one. Output max around 1.5 v p to p which might be enough to drive the dual gate mosfet
mixer of the Argonaut 509. More importantly, this newer dds is advertised not to have SPURs like other DDS units.
Technology is advancing. I may end up trying another DDS vfo in the argonaut in the near future. Perhaps even this one that Kanga is offering. When I do
build it and try it; I will be writing up my experiences.
Below are some notes from Craig Johnson AA0ZZ. This is from his web site *you can google it. He has other projects and has a PDF file which specifically
deals with topics such as "what happens when you amplify a dds signal"..the concern being SPURS. He claims his DDS unit..is a "clean" running dds
without a problem with spurs. My Argonaut (when tuning certain bands) had birdies and spurs. I am not blaming the N3ZI dds vfo. I think I was using
perhaps too much amplification..(overdriving) with my 2 transistor amplifier. NOTE: I did not build a bandpass filter for the Argonaut DDS vfo because the
vfo frequencies change from band to band. Because of the complexity..I have decided to abandon the Argonaut 509 DDS control and go back to the old
PTO (after I rebuild it). The PTO had frozen.
I had thought that a DDS vfo for the Argonaut was a good idea ..and it still might be..BUT..I have decided against it. If you are considering trying this
yourself..you can use some of my ideas but be prepared to do some serious building and modification. Still..it was quite a thrill to make some contacts with
this butt ugly breadboard kind of radio. Just like the old golden age of radio back in the good old days!! You cobble up something and try to make it work.
Its not perfect. It has harmonics and birdies and there is qrm and all that..but the qso really stands out because you made it using your own hand built
gear. Gear you understand. Gear you can work on. Gear you can actually repair yourself. I can work on this gear. The FT817 would be a real challenge to fix.
I guess board level repairs would be possible..but you would have to have a set of spare boards.
The FT301 is the next victim of my soldering iron. It is an old unit. It works but the display is not working properly. A DDS display will fix that. The finals are
fried in the FT301. NO PROBLEM either. I will use it at the 10 watt level as a QRP DDS controlled rig. Certainly not a small portable neat little unit..but
something to work on.
NOTES ON THE ARGONAUT 509 WITH N3ZI DDS VFO.
Just because I changed my mind about using a DDS vfo with the
Argonaut 509..does not mean..it cannot be done.
It certainly can be done. In my case..I had an FT301 transceiver
that had a few problems and I decided to rebuild it with the N3ZI
version 2 vfo (removing it from my argonaut). The Argonaut 509
will now have a rebuilt PTO..(I have one now) which will go back
inside the spot where the DDS used to be.
The N3ZI dds board fit perfectly in the cavity where the 509 PTO
used to be. I built a spacer board using blank fiberglass circuit
board and 4 standoffs to mount it..as per the picture (LEFT).
I had a few qsos with the Argonaut dds as well. I did have spurs. I
used an amplifer (see schematic near top of page). I did not try to
match the impedances nor did I tailor the drive level to the circuity
of the Argonaut mixers.
I tried patching in to the argonaut circuitry and use the mulitplier
stages to produce the injection frequency BUT..the digital readout
would then not display the proper frequency. It would be skewed.
Im hoping to have better sucess trying this N3ZI unit with the
FT301. The FT301 has a 5 to 5.5 mhz vfo and i can use a bandpass
fillter after the dds vfo and amplifier to cut down on
spurs..(hopefully). The same thing could be done with the
Argonaut but would require 5 separate bandpass filters for each
set of injection frequencies. IT GOT TOO COMPLEX and I decided
not to go ahead with it.
IF YOU DECIDE TO TRY THIS PROJECT in some form or other..I'd
really like to hear from you. I can even write up your sucess story
in an article for this magazine.
Remember..we are amateurs and this is a hobby. We are not all
professional engineers. I am a technician by training and I don't
have a sophisticated machine shop or anything at my disposal.
Sometimes I don't always get professional results!
Just because I changed my mind about using a DDS vfo with the
Argonaut 509..does not mean..it cannot be done.
It certainly can be done. In my case..I had an FT301 transceiver
that had a few problems and I decided to rebuild it with the N3ZI
version 2 vfo (removing it from my argonaut). The Argonaut 509
will now have a rebuilt PTO..(I have one now) which will go back
inside the spot where the DDS used to be.
The N3ZI dds board fit perfectly in the cavity where the 509 PTO
used to be. I built a spacer board using blank fiberglass circuit
board and 4 standoffs to mount it..as per the picture (LEFT).
I had a few qsos with the Argonaut dds as well. I did have spurs. I
used an amplifer (see schematic near top of page). I did not try to
match the impedances nor did I tailor the drive level to the circuity
of the Argonaut mixers.
I tried patching in to the argonaut circuitry and use the mulitplier
stages to produce the injection frequency BUT..the digital readout
would then not display the proper frequency. It would be skewed.
Im hoping to have better sucess trying this N3ZI unit with the
FT301. The FT301 has a 5 to 5.5 mhz vfo and i can use a bandpass
fillter after the dds vfo and amplifier to cut down on
spurs..(hopefully). The same thing could be done with the
Argonaut but would require 5 separate bandpass filters for each
set of injection frequencies. IT GOT TOO COMPLEX and I decided
not to go ahead with it.
IF YOU DECIDE TO TRY THIS PROJECT in some form or other..I'd
really like to hear from you. I can even write up your sucess story
in an article for this magazine.
Remember..we are amateurs and this is a hobby. We are not all
professional engineers. I am a technician by training and I don't
have a sophisticated machine shop or anything at my disposal.
Sometimes I don't always get professional results!
The FT301 is larger and will allow more room for shielding and additional circuitry. It will not be a portable UNIT. but a stay at home radio. I may not fix the final output
circuit as the replacement transistors are costly..BUT RATHER..i CAN use it as a 10 watt qrp radio. With the 301 ..it is a simple matter to convert it to a full time qrp rig.
It was made with a detachable 100 watt heatsink and you can wire the driver circuit with a coax jumper cable to bypass the final PA stage. Yaesu did make a qrp
version of the FT301D that was the FT301SD. Same basic circuitry and layout but the PA stage was not included.
Above another schematic and some information from the AADE Almost All Digital Electronics web site. This might be a good amplifier for the DDS vfo.
I dont have any of these parts yet..but I will be trying to buy some LT1252s ..looks like a good circuit.
I dont have any of these parts yet..but I will be trying to buy some LT1252s ..looks like a good circuit.
PROTOTYPE: test unit.."an experiment"
ABOVE: A working FT301D with issues. 100 watt PA stage will
be removed (easy to do with the 301 modules) and it will be
turned into a 10 watt rig with the N3ZI DDSversion 2 vfo which will
also cure the burned readout problem it has.
be removed (easy to do with the 301 modules) and it will be
turned into a 10 watt rig with the N3ZI DDSversion 2 vfo which will
also cure the burned readout problem it has.
| IF....you happen to rebuild your Argonaut 509 with a dds vfo..I'd like to hear from you. If you send pictures and give a bit of information..I will write it up for you..or you can write the article and I will feature it in my magazine. NOTE: Some Argonaut owners and QRPers have written me that they think I am committing a big sin by so drastically altering or modifying the Argonaut. The early Argonauts have a great deal of sentimental value and memories. The Argonauts came into ham radio and QRP back in the early 70s and Ten Tec was just a small wee outfit manufacturing items such as the Power Mites and their modules to build similar radios. ...Then..the ARGONAUT 505 and 509 came along. A nice little superhet rcvr and sensitive and SSB and Full Break in CW. I bought my first Argonaut new in 1974. Long LIVE THE ARGONAUT! I wish some company would build a similar (simple) perhaps a bit physically smaller but good Argonaut with a bit more modern circuitry but no real complex ICs or microprocessors or PLLs. A kit form would be good. One fellow called the K2 the mother of all kits! I think a simpler rig qrp but all the bands..would definitely be welcome. And American Made like the old Drakes and Heathkits that so once dominated our hobby. |
| To the left is a homebrew digital frequency readout for an Argonaut 509. You can easily find this movie on YOU TUBE. A real neat job was done of it. Some of these hams with pictures and videos on the internet...put my homebrew projects and experiments into shame. THESE GUYS ARE REAL CRAFTSMEN! -- My efforts end up looking like trash!!! OH WELL!!! It is not a beauty contest. The main thing is to learn and enjoy and get satisfaction out of your projects. |
This homely argonaut 509 dds prototype is being boxed up
for awhile and I will try plan B ..implementing a DDS vfo the
FT301D pictured beside it.
I may..in the future..buy another DDS vfo and try the
experiment again with the Argonaut 509.
There are newer DDS vfos comming out now and they
claim to be cleaner and higher power output. Perhaps then...
????
for awhile and I will try plan B ..implementing a DDS vfo the
FT301D pictured beside it.
I may..in the future..buy another DDS vfo and try the
experiment again with the Argonaut 509.
There are newer DDS vfos comming out now and they
claim to be cleaner and higher power output. Perhaps then...
????
Below: the schematic of the Argonaut VFO (a Permeability Tuned Oscillator) with multiplication scheme to provide the "injection
frequencies" to be heterodyned to a 9 mhz IF. At the very output ..a 47 pf capacitor will sample some of the injection frequency
and display it on a digital display. This is from the AADE web site. Almost all digital electronics. (easy to find with google!).
frequencies" to be heterodyned to a 9 mhz IF. At the very output ..a 47 pf capacitor will sample some of the injection frequency
and display it on a digital display. This is from the AADE web site. Almost all digital electronics. (easy to find with google!).
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_____ a FREE on line ham radio/electronics magazine-- for the hands on ham who enjoys
tinkering..or even just reading about tinkering!!!
click here to visit the ham magazine home page