Transmitter Dreamin........

[W7SOE]

Be warned, some of this may be sacrilege...........   

I am a digital guy, just barely dabbling in the tube world.

I am gathering the components needed to build my first HB rig, a plate modulated transmitter.  Given my other obligations I think I am on the five year plan.

This I like:

http://www.wb4gwa.netfirms.com/pagethree.html

It is just big/small enough and I seem to have a fondness for the 813.

Here comes the sacrilege.  Imagine the same rig but instead of the Millen exciter there is a HB exciter.  The HB exciter may use a 6146 as a final.  The frequency source would be a DDS type IC.  There would be a cool graphics LCD that would display the frequency.  The display could also display plate voltages, grid current etc.

So the rig would look old school but I would still be able to throw in a micro and write some code.  I have a tendency to do this whenever possible.    This would also allow some cool things like automatic current limiting or whatever.

It is sort of a Steampunk type idea but with real functionality.

http://en.wikipedia.org/wiki/File:Steamtop.jpg

Rich

[flintstone mop]

Far from sacrilege.
Sacrilege is when Hammy Hambones changes a nice reliable design into something ugly with holes in the cabinet for gross modifications.
Nothing wrong at all with a mixture of various technolgies. New and old to make an A.M. transmitter.
The 813 is a nice performer.

Fred

[ka3zlr]

Well Done, I wish you all the luck in finding Good Iron for yer rig....it can be a pain....


73
Jack.

[W1RKW]

Rich,
Don't overlook this 813 rig: http://www.amwindow.org/tech/htm/813/813.htm
I considered WB4GWA's xmitter but found K1JJ's 813 Maul the way to go, less complex.

I built it and it works good.  I had some trouble but the designer (Tom/K1JJ) and other experts who live on this forum were at the ready when it came to troubleshooting.

About 95% of the rig is built according to plan.  I added a few liberties of my own. For example, rather than using an outboard audio amp I designed my own solid state audio amp and incorporated it into the modulator deck.  My screen and plate supply isn't according plan either  because of hardware but some compensation and modification got both supplies working and stable.

The input tuning network works good as well. I had some trouble with it at first but it turned out to be a defective tuning cap.

As far as exciting it, this rig is flexible.  I'm driving it with an FT-102 which allows me to use the receive section of the FT-102 so the whole setup is essentially a transceiver but I can quickly change it to any other 10 to 30 watt transmitter and use it as an exciter. If it were me, I'd scrap the idea of driving it with a homebrewed exciter and just drive it with something already built.  You can certainly feed that exciter with a DDS device for frequency stability.

Don't feel bad about it taking 5 years to build it.  It took me over 7 years to complete my Maul. There were alot of distractions involved that slowed construction. But I had most of the critical components already on hand which were easy to come by. I just needed the time to sit down and build.

Just so you know this is my first big homebrewed rig. From a construction and mechanical stand point, I'm OK with building stuff but this project was a different avenue for me.  I was taking a design, building not 100% to plan and working out bugs.  But even if at 100% to plan there maybe some bugs to work out.  The point is, the guys here were so helpful in getting it going.

Go for it!!

[W7SOE]

Don't overlook this 813 rig: http://www.amwindow.org/tech/htm/813/813.htm
I considered WB4GWA's xmitter but found K1JJ's 813 Maul the way to go, less complex.

Yea!  I had forgotten that one!  That may be the ticket.  Yea, gathering the iron is a sticking point......

Rich

[w4bfs]

the only bad idea is the unexplored idea  .... hybrid designs are way cool but present their own challenges ... 73 ...John

[Opcom]

All those designs are great. I like the WB4GWA just fine. As for steampunk, many neoclassical designs are appealing. The onlything missing from the steamputer is a pair of pneumatic mechanical larynxes for speakers. Gothic styles are also interesting.

[WBear2GCR]

In my view it is preferable to run the modulator in AB2 or B2 nor AB1 or B1...

Ymmv.

             _-_-WBear2GCR

[W1RKW]

Hook up with Skip/K7YOO. He may have some iron.

Yea!  I had forgotten that one!  That may be the ticket.  Yea, gathering the iron is a sticking point......
Rich