Well, here's the latest... found a wrong mica cap in the output of the Pi-Network (coupling switch; Should be 300 pf, was 500pf) Installed a 330 that was on-hand and the tuning got better. I'm up to almost 30 Watts on 6 Meters. (using SS HV rectifiers, tube LV).

And yes the tuning is a bit fussy and requires a bit of retouch as you go for maximum power.

Also squashed the 6 Meter coil together for better performance on the low end of the band.

I have re-capped the rig and added an NTC thermister w/SS circuit breaker.

The audio sounds much better than my Valiant (using a dynamic mic) but sounds terrific with a new xtal element in the D-104 housing.

So thanks for the ideas and help. Three heads are better than one

73,
Tom

I should have said multiplier and driver...

Swapped the osc and driver from a known good rig with no change.

Since this was a kit build, with unknown quality but nice  looks, I'm wondering if there is a wiring error? I may have to do a point by point comparison between the two rigs.

My rig has good output on 160 - 10 Meters but only a few Watts from 6 Meters (via Xtal or VFO). Any thoughts?

NO MORE INFO NEEDED

With some of the list help, I measured the band data from the transceiver and drew a data table. Found another's effort (http://www.k0lee.com/ft100faq.html#banddata) that provided a table to check against.

Turns out my table and the other are the same. My conclusion is the band data is good from my transceiver and CT-118 cable, so the error in band follow of the Quadra is a Quadra problem.

Thanks to all
73
Tom

ADDITIONAL INFORMATION:

1) Used w/FT-450

2) Have already reset the transceiver and amp

Does anyone have information on the band change function, ie: levels, timing etc?

Hi,

Seems my "almost new" Quadra (Yaesu VL-1000) doesn't follow the band changes for 10, 14, 18, 21 MHz. No change at 10 and 1.8, 3.5 and 7.2 respectively for the 14, 18, 21.

The F-Set seems to work OK on any band

Using a CT-118 Yaesu cable(appeared to Ohm out OK...)

Any thoughts? (reset(s), Yaesu were no help....)

73,
Tom tsiglin@yahoo.com

MORE ON MY MEASUREMENTS

After calibrating and checking the setup here's the operating conditions:

CW:

Plate B+ 630 Volts, 450 MA = 283 input Watts
Bird WM with a 45 Ohm load = 190 output Watts

Scope 380 VPP across 45 Ohm load

380 VPP/2 *.707 squared and divided by 45 Ohm load= 399 PEP Watts?

AM UnModulated:

B+ 660 Volts, 330 MA = 218 Input Watts
Bird WM with a 45 Ohm load = 150 output Watts

Scope 330 VPP across 45 Ohm load

330/2 * .707 squared and divided by 45 Ohm load=
299 PEP Watts

AM Modulated:

Scope 620 VPP/2 * .707 squared and divided by 45 Ohm=
= 1065 PEP Watts?

(I don't have a peak reading Watt meter...)

Equipment: Fluke DVM, TEK 100 MHz Scope w /10 probe-100 Mhz, Transmitter set to 7.2 MHz, MFJ Dummy load, Bird Watt meter. (I calibrated the Valiant's meter for plate current and tested the scope/probe against the AC power line voltage, ref the fluke DVM))

QUESTION: Why does the scope and calculation show more power than the actual measurements? Is this a 3db increase because of the FCC method of power measurement?

73, and thanks to all for their input.
Tom - WA2LTD

My Johnson Valiant is 275 Watt input for about 165 out. On AM it is rated for 200 in (carrier) and at 60% eff, about 120 out (X4 for peak w/100% modulation?).

When I look at the transmitter CW output across the dummy load with a scope, I see 370 V p-p. that devided by 2 for peak, *.707 for RMS, squared and divided by the 50 Ohm load = 334 PEP Watts?

Is that 334 Watts suposed to be ~3 DB higher than the original figure of 180 for CW output?

It gets worse when I modulate the AM carrier...and get 540 PP Volts from + crest to - crest. That would indicate a PEP output of over 700 Watts!

Am I thinking right here?

73,
Tom  

My Johnson Valiant is 275 Watt input for about 165 out. On AM it is rated for 200 in (carrier) and at 60% eff, about 120 out (X4 for peak w/100% modulation).

When I look at the output across the dummy load with a scope, I see 370 V p-p. that devided by 2 for peak, *.707 for RMS, squared and divided by the 50 Ohm load = 334 PEP Watts?

Is that 334 Watts suposed to be ~3 DB higher than the original figure of 180?

It gets worse when I modulate the AM carrier... 540 PP Volts from + crest to - crest. That would indicate a PEP output of over 700 Watts!

Am I thinking rigt here?

73,
Tom

My Johnson Valiant is 275 Watt input for about 165 out. On AM it is rated for 200 in (carrier) and at 60% eff, about 120 out (X4 for peak w/100% modulation).

When I look at the output across the dummy load with a scope, I see 370 V p-p. that devided by 2 for peak, *.707 for RMS, squared and divided by the 50 Ohm load = 334 PEP Watts?

Is that 334 Watts suposed to be ~3 DB higher than the original figure of 180?

It gets worse when I modulate the AM carrier... 540 PP Volts from + crest to - crest. That would indicate a PEP output of over 700 Watts!

Am I thinking rigt here?

73,
Tom

Hi All,

I find myself also working on a Johnson Valiant.. When I felt the low voltage transformer was too hot, I measured the AC side and found the current running about 1.5 amps. This rig had a 2 Amp fuse installed for the low voltage side, instead of the recommended 1.5 Amp.

I decided to make an effort to lower this current and did the following:

  1)replaced the LV B+ rectifier with silicon diodes

  2)replaced the bias rectifier with diodes

  3)installed a 220 Ohm, 3 Amp NTC thermister in
    the AC input side of the power line

  4)used the now, not needed 5 Volt secondary of the
    low voltage transformer to buck the AC input
    voltage.

These changes brought my low voltage AC input to 1.25 Amps and the LV transformer runs cooler! My B+ under transmit conditions perfect.

73,
Tom