LOOK WHAT BORGI-K9YQQ HAS BEEN UP TO!

Borgi loves to build high quality transmitters

and has constructed some amazing and

beautiful ones for some very happy hams.


   
   

LOU, W9LRS- 4-1000 plate modulated by a pair of 4-400s in class AB1. Excited by a Johnson Navigator. 160, 80 and 40. Lou calls it the BTA 1000 T (Borgi Transmitting Apparatus) 


   

 
ROB, K5UJ- 4-1000 plate modulated by a pair of 4-400s in class AB1. Exciter TBA. 160 only. 
 


 

 

   
 

RON, K4JEE- A pair of 813s plate modulated by a pair of triode connected 813s in class AB2. Exciter is a Collins 32V2 providing RF drive and audio drive. 80 and 40. Ron says: Thank you Borgi for the AM build. You really made my collins 32v3 sing on the air with your build.  For those of you out there Borgi installed the WA1HLR audio mod in the 32v3 to round out the audio.  The 32v3 is being operated in the split exciter mode rather than as a stand alone AM transmitter. The 500 ohm audio output from the 32v3 modulation transformer is being used to drive the high power modulator and the RF output is being used to drive the high power RF final.  Terminals on the back of the 32v3 allows for the B+ to the 4d32 RF final to be broken and a resistor inserted to drop the B+ and therefore the power output .   A combination of a 3K 50 watt and 20k 20 watt resistor in parallel provides the correct voltage drop for about 25 watts of RF out of the 32v3 .   Fine adjustment of the actual driving power to the high power RF final is accomplished with the loading control on the 32v3 .   Below the 32v3 is the 4 foot rack that Borgi did his build in. 2x813 in RF deck modulated by 2x813 .   In the mod deck is a 1 Kilowatt mod transformer that came out of a commercial AM broadcast transmitter.

         Plate voltage comes from two transformers 2200 volts.  The full wave rectifier is a string of 1KV diodes that form a bridge rectifier .  The input choke is 10 HY. The filter capacitor is 10UF @ 3KV. The plate on contactor coil is fed from the control deck via the normally closed contacts of the overload relays in the RF and MOD decks as well as the HV enable switch on the front panel.   Any overload will open the plate on the contactor coil and dump the high voltage.   Circuit breakers for the 240 vac are on the front panel.”



  GERRY, KC8ZUL- A single 4-400 plate modulated by a pair of 4-250s in class AB1. excited by a FLEX-3000. 160-40. (old hill-jerk rig). 



 

  JERRY, WA4JK- A pair of 813s plate modulated by a pair of Russian GI7Bs in class AB2. Exciter is an Adventurer with a DDS VFO. 160, 80 and 40. 



   
 

TIM, KC9QJE- A 4-1000 plate modulated by a pair of 833s in class AB2. Exciter is an Adventurer with a DDS VFO. 160, 80 and 40. Tim calls his TX “Mr. Lincoln” and tells us:This is my main AM transmitter.  This transmitter started life out as an RCA  BTA-1R1  AM broadcast transmitter in Chillicothe, Ohio. The transmitter originally ran a pair of 4-400's modulating another pair of 4-400's. The RCA transmitter was disassembled and a new cabinet was built that would fit into my very small ham shack. The cabinet is now 2'x2'x6' and weighs 500-600 lbs. This transmitter's tube complement is now a single 4-1000a plate modulated by a pair of 833's. The transmitter is band switching for 40,80, and 160. 

The RF excition is coming from the Viking Adventurer which now uses a 6146 output tube and has 160 meters added. The Adventurer feeds 20 watts of RF to grid of the 4-1000a tube and uses a DDS VFO for frequency stability. The audio comes from the CRL audio rack which feeds the Crown D-150A audio amplifier. The output from the Crown D-150 feeds the grids of the 833's.The high voltage was dropped on the plate of the 4-1000a to allow the transmitter to run at legal limit 24-7! The hose and blower on the wall is the exhaust system for the transmitter it vents thru a dedicated dryer vent to get the heat out of the shack. Borgi completely documented this transmitter so if I ever need to work on it it will be very easy to do. A HUGE HUGE THANK YOU  goes out to Borgi for everything he did in this project!”

 
 


  LOU, N9GTO- A 4-1000 plate modulated by a pair of 4-400s in class AB1. Excited by a DX40 with a DDS VFO. 160, 80 and 40. 
  A PAIR OF 4-400s SCREEN MODULATED BY A SINGLE 6L6. DDS EXCITER. 80-10 



   
 

AA9JC- A 4-1000 plate modulated by a pair of 4-400s in class AB1. Excited by an IC-718. 160, 80 and 40. Currently under construction.

 

 



And some handcrafted rigs from Borgi's private collection:

  Neutered Ruskie started off as a pair of GI7Bs modulated by another pair. Ended up as a pair of 813s plate modulated by a pair of 4-250s in class AB1. 80-20. 
 

  A single 4-1000 plate modulated by a pair of 4-400s in class AB1. 80-20. 
 


 

A pair of 4CX250Bs screen modulated by a single 6L6. 80-10.

All above rigs are excited by an IC-718.

 
 


  A pair of 304THs in push-pull plate modulated by a pair if 304TLs in class AB1. Plug in coils for 160, 80 and 40. Swinging link output coupling. excited by a DX-100 with a DDS VFO. 
  This transmitter also can incorporate a single 833 in the final RF stage with a band switching pi-net. 160-40. RF decks roll out and in. 


 

 

 

 

A single 5762 (7C24) grid modulated with a 5 volt filament transformer and a Crown D-150 audio amp. Excited by a DX-100 and stock VFO. 160-40.



 

A single 4-400 plate modulated by a pair of triode connected 813s in class AB2. 160, 80 and 40.