Edited by author 07-08-2003 02:38 PM
Could you elaborate a bit on the winding of T2? I see the Secondary and Sense winding shown on the drawing, but not the Primary. The instructions say to wind the secondary first and mount it to the PCB. That's the last mention of it I could find. Thanks.
   Steve

Steve,
T2 is formed with 2 ferrite cores with brass tubes inside. These tubes form the primary. The tubes are soldered to PC Boards at each end. On one end the etch is separated to form the two ends of the primary. On the other end the etch is joined to complete the path between the tubes and to provide the center tap.

See the images: http://www.rfparts.com/combiner.html#Broadband

On inspecting my FAR Circuits boards, I found a problem with the Filter board.

On the component side ground plane, the etch is not relieved for clearance around the Input side of the 30m (D) filter connections for Relay K6 Common, C1 and L1.

These need to fixed with a Dremel or a knife.

Also there is superfluous clearance around Out Relay K1 N.C. which is grounded.

-Duncan

P.S. No response to my query about choke RFC1.

I have 3 questions:
1) Should the #18 and #24 teflon wire be solid or stranded?
2) Where can you get just a foot of each size. Every place I've tried sells it by the hundred feet and the #18 is over $100.00 for 100 feet.
3) What gauge wire do you recommend for the rest of the hook up wire...#22 or #24 solid copper.
I'v been successful in getting everything else except for the teflon wire.
Thank you.

1)Has there been a value for the capacitor (TBD) located on the component layout between Q3&4 and the pads below T1, or is this capacitor needed?
2)There are two R14 resistor shown on the schmatic. One near Q2 and on by the light emitting diode D10. I assune the R14 near Q2 should be 4.7K as shown and not as listed in the component list as 3.3K.
Pete
AB2kg

The TBD capacitor is not used.

The values shown in the schematic are correct. They are not critical, a 3.3K or 4.7 K should work OK for both.

Jim

Jim,
Thanks.
So far so good. I have the amp board completed.
I'm going to use power poles for my power commection and will mount them with the two BNC's on the back side. Note: You get two wire sizes with the inductor package. I guess you use the 24 ga on 160 and 80, and 22 ga on the rest. Also the spacers spec'd out are too short. It looks like you need 1" and not 1/4" as spec'd in the article. Also can you give instructions on how the heat sink material and isolation kits are installed for Q3&4. What goes againt the cabinet? Thanks.
Pete
AB2KG

Pete .. use 5430-2205 for the standoffs, they are 1 inch.
I don't have the instructions for WA2EBY's filter board handy but what you suggest sounds OK as the 160 & 80 have the most turns. I installed the thermo pads against the cabinet and used the isolation hardware from the mounting kit. The mounting screws should be isolated from the transistor tab.
Jim

I need help.
1)I have completed assembly of both boards, and have mounted the HF amp board in the enclosure and connected the various cchassis components.I checked Q3&Q4 to make sure they were isolated.
2)I do not have access to a IFR - 1600S service monitor. I do have a radio shack SWR/Watt meter. I hooked up my Yasue FT817 and ran it on battery. When I transmitted a carrier with packet I read 1,2-1/2,and 5 watt on the meter when I was transmitting on 1 watt, 2-1/2, and 5.
3)I hooked up the amplifier as instructed in the instructions, applied 12.7 volt to the amp with a battery since I don't have a regulated 12 v source. Before I turned on the amp I checked the output through the amp in the off position with one watt and that is what showed on the watt meter.
4)I jumped out the PTT to ground and teh relay pulled in and the FT-817 stopped receiving indicating the relay did pull in. When I transmitted with 1 watt this time I got a blip on the watt meter and then NOTHING at all out of the amp. Note: I disconnected the PTT and tried it again and the green transmit light came on, the relay pulled in and I got the same blip on the watt meter and then nothing.
5) I did check the voltage regulator U1 with the unit on. In the grounded position it put out about 12.6 volt and when I turned pot on R15 the voltage dropped to around 7 volts. I did put the jumper between filter in and out.
6)Any suggestions. Could it be Q3 or Q4? The soldering looks OK but maybe I messed up some place.I looked very carefully to see if something was shorted but I couldn't see anything
Any help would be greatly appreciated.
Pete
AB2KG

Edited by author 08-26-2003 10:31 AM
LET'S SEE IF I CAN OFFER A FEW SUGGESTIONS...
I need help.
1)I have completed assembly of both boards, and have mounted the HF amp board in the enclosure and connected the various cchassis components.I checked Q3&Q4 to make sure they were isolated.
DOUBLE CHECK THE COLLECTORS TO SEE THEY ARE ISOLATED

2)I do not have access to a IFR - 1600S service monitor. I do have a radio shack SWR/Watt meter. I hooked up my Yasue FT817 and ran it on battery. When I transmitted a carrier with packet I read 1,2-1/2,and 5 watt on the meter when I was transmitting on 1 watt, 2-1/2, and 5.
OK
3)I hooked up the amplifier as instructed in the instructions, applied 12.7 volt to the amp with a battery since I don't have a regulated 12 v source. Before I turned on the amp I checked the output through the amp in the off position with one watt and that is what showed on the watt meter.
OK ... TRY TO FIND A POWER SUPPLY WITH METERS, BEING ABLE TO SEE THE VOLTAGE AND CURRENT BEING DRAWN IS HELPFUL. A BATTERY IS OK, BUT IT NEEDS TO SUPPLY 7 AMPS OR SO CURRENT
4)I jumped out the PTT to ground and teh relay pulled in and the FT-817 stopped receiving indicating the relay did pull in. When I transmitted with 1 watt this time I got a blip on the watt meter and then NOTHING at all out of the amp. Note: I disconnected the PTT and tried it again and the green transmit light came on, the relay pulled in and I got the same blip on the watt meter and then nothing.
OK ... THE T/R SWITCH SEEMS TO BE WORKING, DOES THE RELAY REMAIN ACTIVATED WHILE YOU HAVE DRIVE APPLIED OR DOES IT DROP OUT? MAKE THIS CHECK WITHOUT THE FILTER CARD IN PLACE, USE A DUMMY LOAD. WHAT IS THE BATTERY VOLTAGE UNDER LOAD? HOW MUCH CURRENT IS BEING DRAWN FROM THE BATTERY?
5) I did check the voltage regulator U1 with the unit on. In the grounded position it put out about 12.6 volt and when I turned pot on R15 the voltage dropped to around 7 volts. I did put the jumper between filter in and out.
JUMPER THE PTT LINE TO GROUND, WHAT VOLTAGE DO YOU MEASURE
AT THE CENTER TAP OF T1 (Q3&4 BASE)??
6)Any suggestions. Could it be Q3 or Q4? The soldering looks OK but maybe I messed up some place.I looked very carefully to see if something was shorted but I couldn't see anything
Any help would be greatly appreciated.
DID YOU INSTALL THE GROUND STRAP IN THE EMITTERS OF Q3&4? CHECK TO SEE THE EMITTERS ARE GROUNDED.
Pete
AB2KG
IF YOUR ABLE TO MEASURE CURRENT THAT SHOULD PROVIDE AN INDICATION IF THE AMPLIFIER IS BEING DRIVEN. IF THERE'S NO DRIVE WORK FROM THE INPUT TO THE OUTPUT. CHECK T1.

GOOD LUCK.
JIM

I printed out the chassis and heatsink drilling templates from the binaries at the ARRL website. However, when I went to lay the template over the heatsink, I noticed that the markings did not line up with the notches in the side of the heatsink. I got out my ruler and discovered that the dimensions on the printout do not match the indicated measurements. The templates print about 5 to 10 percent to smaller. I tried downloading again and reprinting, but got the same results. My software tells me that I'm printing at 100 percent of the original document size, so I'm wondering if the templates on the ARRL website are slightly reduced from the original size.
Has anybody else had this problem? Could anybody share templates that print at full size?

I haven't downloaded the ARRL template file. I have the templates as a PDF file, send me your email address and I’ll forward them to you.

Jim

Thanks, Jim. My email is dswain100@netscape.net.

I have a few more questions that someone may be able to answer:
1) I have assembled the parts for the optional RF activated PTT switching circuitry on the PC board. Can I still test and use the amp by simply grounding the PTT line?
2) On the RF amplifier schematic, the values for the amp input attenuator at 2 watts for R2 and R3 are dashes. Does this mean that R2 and R3 are not used, or does it mean that the value of 300 ohms from the row above is to be repeated.
3) In the QST article, page 39, is it correct to assume that the tune-up and testing power levels specified are for an amp built with an input attenuator for 2 watts.
I know that the answer to some of these questions must seem obvious to the more experienced builders, but I'm fairly new at this and I'd hate to damage any amp components by making a bad assumption.
Thanks in advance for your help,
David

David,
I’ll forward the PDFs to you soon.
A few answers to your questions …
1. Yes, the PTT line can be grounded manually even with the RF switch circuitry in place.
2. With 2 watts drive omit R2 & R3 (schematic) –DON’T OVERDRIVE THE AMP WITH 5 WATTS and no attenuator.
3. The tune up drive actually refers to what the input to the input of T1 ‘sees’. Maximum drive to the input of the RF stage (at T1) should be limited to 2.5 watts. The tune up instructions actually refer to this point. R1, 2,&R3 form a –3dB pad, that is half of the input power is dissipated in this network resulting in about 2 watts drive with the maximum 5 watts output from the FT-817. SORRY FOR THE CONFUSION.

Jim

Jim,
I received the PDF files -- thanks! They printed to proper scale when I used my work computer and printer. I then tried the ARRL PDF files from work, and they also printed to scale, so obviously I have some software/printer configuration issue at home.
Also, thanks very much for the clarifications on resistor values, grounding PTT, and testing. This is a great project and I'm really enjoying the learning experience.
Thanks again for your help!
David

Can anyone tell me if an IFR 1600S communications service monitor will work for testing amateur radios in the UHF anf VHF range. Does it have a spectrum analyzer, can it read deviation, can it read sinad, eetc. Is it as good as an IFR 1200S?
Sid KN4EW