Anan 7000dle and pure signal setting

ik7ytt
Posts: 46
Joined: Tue Mar 12, 2019 11:48 am

Anan 7000dle and pure signal setting

Postby ik7ytt » Fri Jul 19, 2019 10:42 am

Hello
trying to set anan 7000dle with expert 1,3k and Xtronic XDC-1

i'm setting the xpert at low-mid level for now that shuld have 600 to 800kw outut power.
with input power of 5w. With 10w in will give more then 1kw. but for the moment i don't have an attenuator pad. so will not try for the moment
From my calculations the only Xtronic should be ok for this level for in power and output. But i think there is something wrong

Result are this:
5w only of anan - ATT is 5

test2 5in.jpg
test2 5in.jpg (129.71 KiB) Viewed 1713 times



5w in / LOW 600w out ATT 26 .

test 5in-800w.jpg
test 5in-800w.jpg (128.36 KiB) Viewed 1713 times
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DL2XY
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Re: Anan 7000dle and pure signal setting

Postby DL2XY » Sat Jul 20, 2019 7:24 pm

The amplifier is clearly overdriven (clipping), look at Mag AMP (blue Line). It touches 1 on Y axis at X=0.9.
In the higher part the blue line is widened, an indicator for a weak power supply.

I think you cannot expect 600W output in "LOW" setting at only 32V drain voltage.

This is how it should look, 600W and 1000W output of an ACOM 1200S (50V Vd):

AV ACOM 600W.jpg
AV ACOM 600W.jpg (78.69 KiB) Viewed 1674 times


AV ACOM 1000W.jpg
AV ACOM 1000W.jpg (78.45 KiB) Viewed 1674 times


73 Walter
w3ub
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Location: Lunenburg, NS/Florida

Re: Anan 7000dle and pure signal setting

Postby w3ub » Sun Jul 21, 2019 12:46 pm

The 1.3 is a good amplifier (I have one), but the top end characteristics are soft, what you are seeing is the way it is, you should probably back it off a bit, although the PS can do a good job of linearization, you gain nothing in terms of output power and are completely dependent on PS to keep things in check.

Doug
ik7ytt
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Re: Anan 7000dle and pure signal setting

Postby ik7ytt » Sat Jul 27, 2019 4:24 am

now i have all hardware set.

Xtronic XDC-4so
-20dbpad from Forward port to bypass port

TX with 10w
out 1200w

ATT now goes on 10

but wave form i think is still not correct

test 5in-1300w.jpg
test 5in-1300w.jpg (49.2 KiB) Viewed 1561 times
I4LEC
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Joined: Sun Apr 09, 2017 2:58 pm

Re: Anan 7000dle and pure signal setting

Postby I4LEC » Sun Jul 28, 2019 8:09 am

Andy,
I am afraid Doug is pretty much right in what he is saying, I have experienced more or less the same behavior, to less extent on the latest 1.5K-FA MK2, which uses the 1K8 module, redesign output transformer and improved cooling system, see pick attached.
At the same rated power, I compared the Titan 425, as you can tell, the outcome is rather different
73, Clay

Pre-1_5K MK2.jpg
Expert 1K5
Pre-1_5K MK2.jpg (57.33 KiB) Viewed 1522 times

55dB vs 40dB.jpg
Titan 425
55dB vs 40dB.jpg (53.54 KiB) Viewed 1522 times

Expert-Titan.jpg
Expert vs Titan
Expert-Titan.jpg (164.73 KiB) Viewed 1522 times
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w-u-2-o
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Re: Anan 7000dle and pure signal setting

Postby w-u-2-o » Sun Jul 28, 2019 12:04 pm

ik7ytt wrote:now i have all hardware set.

Xtronic XDC-4so
-20dbpad from Forward port to bypass port

TX with 10w
out 1200w

ATT now goes on 10

but wave form i think is still not correct

test 5in-1300w.jpg
Everything appears to be working correctly with the radio and coupler but you are VERY BADLY over-driving your amplifier, and there may be a problem with the amplifier input circuitry.

First, with the step attenuator at 10 that means you have a level of -1dB at the Bypass input connector (see this link for how that is calculated). That means +19 at the output of the coupler, and given a coupling factor of 44dB for that coupler, that means 63dBm at the amplifier output, or 2KW. That is much higher than the rated output of that amplifier and it clearly has to be in a fully saturated, badly compressed state.

Second, look at your AmpView results. The blue line is COMPLETELY flat (horizontal) at the top. Where it becomes flat is where the amplifier simply has no more power to deliver. Again, this shows the amplifier in a badly over-driven, completely saturated state. And you continue to drive the input level higher WELL BEYOND that point. You are absolutely hammering that poor thing. I've never seen anyone over-drive an amp that hard! :o Bad, bad, bad, and I can't believe the amplifier input over-drive protection circuits have not tripped the amp into a fault/standby condition.

There is no way that only 10W should drive the amplifier that hard unless the amplifier input attenuator has been removed, modified, or damaged. And the amplifier input protection circuitry should have tripped. This further implies that the amp is damaged in some way. And 1200W output is definitely wrong. The power meter that you are using (maybe it is the one in the amp) also has problems. The output is definitely higher than that.

You must reduce your maximum drive level into that amplifier, or get the amplifier repaired.
Joe-W4WT
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Location: Cumming, GA

Re: Anan 7000dle and pure signal setting

Postby Joe-W4WT » Mon Jul 29, 2019 4:13 am

I assume this amp uses an LDMOS chip and if so, 10 watts is WAY too much drive. LDMOS chips run 28 to 30db of "amplification". That means at 30db one watt of input produces 1000 watts out.

I have a homebrew amp that uses two LDMOS chips and the maximum drive it takes to produce 2K out is 4.5 watts on 6m. On the HF bands it takes less than one (160m) and maybe 2.5/3 watts on 10m.

With this high amplification, you NEED an input attenuator or you will likely blow the chip. It is very difficult to set power out in tenths of a watt which is what you need to do. I run a 10db pad on the input of my amp which means I run somewhere between about 8 and 45 watts drive depending on band. Much more manageable than trying to output 0.8 to 4.5 watts! I would urge you not to use this amp until you get an attenuator on the input.

As Scott mentions, it looks like you have a metering problem in measuring power. I would suggest you watch your current and do not add any more input power once the current drawn by the amplifier stops increasing linearly with more drive. At that point it is doing all it is going to do. Back off a bit from there and it should be close.

Joe W4WT
ik7ytt
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Re: Anan 7000dle and pure signal setting

Postby ik7ytt » Mon Jul 29, 2019 12:19 pm

the expert 1,3k i'm using need little more then 10w to gave max power. that is 1300w/1400w.
so the driving power in normal condition is correct.
i remove the att and bypass cable and i use the software PS-A as in the beginning and have this results that i think are correct

software ps-a.jpg
software ps-a.jpg (45.13 KiB) Viewed 1464 times


with this setting i have

6w in 1kw out ATT=3
9/10W in 1,2 /1,3w out att=5

i can also increase power a bit wihtout any distortion from above setting.

then if i add the coupler we had the result like this with no distortion if i keep the power at 6w, with att still high.
if i increase the power as i usually was driving the amp at 10w we have the distortion as the previous picticure.

test new settings.jpg
test new settings.jpg (53.5 KiB) Viewed 1464 times


from the calculations

Step 1--calculate peak RF power in dBm. Power in dBm = 10log(1200)+30 = 61.14dBm.

Step 2--calculate output power level of the coupler at peak RF power input. 61.14dBm - 44dB = 17.14dBm.

Step 3--calculate required input power to the step attenuator to obtain -17dBm at the output of the step attenuator at your desired step attenuator setpoint. -17dBm + 25dB = 8dBm (assumes any radio except the 7000 or 8000, just change -17 to -11 for those radios).

-11dBm + 25dB = 14dBm

Step 4--calculate the additional external attenuation required between the coupler output level determined in (2) above and the rear panel input to obtain the feedback level determined in (3) above. 17.76dBm - 8dBm = 9.76dB.

17.14-14=3.14

but i'm using 20db on the bypass.....can be this the problem? 20db is too much?
i was thinking was the opposit
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w-u-2-o
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Re: Anan 7000dle and pure signal setting

Postby w-u-2-o » Mon Jul 29, 2019 2:30 pm

For a 7000 or 8000, a 1500W amplifier, and an Xtronic coupler, 3dB is the optimum attenuator value. However that was not the problem. The 20dB attenuator configuration will also work. That is not the problem, although I would recommend using a 3dB attenuator instead of 20dB.

The problem is that while 6W of drive is fine, 10W is way too much. You were driving the amplifier much too hard. As you yourself wrote:
then if i add the coupler we had the result like this with no distortion if i keep the power at 6w, with att still high.
if i increase the power as i usually was driving the amp at 10w we have the distortion as the previous picticure.
If you have an amplifier that has a lot of gain, as apparently that one does, then it can be difficult to make fine adjustments in drive level because the amount of control that you have over the output of the 7000 from 1 to 6 or 7 Watts is not very precise. I would buy a 3 or 6dB 100W rated attenuator and place that in between the 7000 and the amplifier. That way you can double or quadruple your allowable output power range and achieve much more precise control over your drive levels.

At any rate, the bottom line is that at drive levels over 6W your amplifier starts to be over-driven, regardless of what your power meter says. The AmpView display doesn't lie. And if you don't believe that or the power meter, get out an oscilloscope and set up a station monitor display. You will clearly see the distortion that occurs.
w3ub
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Re: Anan 7000dle and pure signal setting

Postby w3ub » Mon Jul 29, 2019 4:45 pm

What can help with more resolution for lower only output powers on the 7000 is to possibly re-calibrate the transmitter, concentrating only on generating a lower maximum power. I think ...

The export versions of the SPE amps have great gain, but are a real pain to use with most 100W transceivers.

Doug
ik7ytt
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Re: Anan 7000dle and pure signal setting

Postby ik7ytt » Thu Aug 01, 2019 9:21 am

I have done few considerations and tests following previous suggestions

1) i have recalibrated the max power to 20w as 100 level in Thetis scale.Then reduced to 80 level to have 15W as maximum power
Consideration: this will let lose linearity to the PA stage? is correct? or the correct way is to use a 100w attenuator?

Consideration: i have noticed that if i set any power valute to 100. decreasing the level below 80 the power reduction is not linear any more.
that means if i set 100 as 20w. on 50 i have only 5w!!!! if i set 100 as 100w at 50 i have only 40w. i feel this little stange.

2) i get 3 and 6 db attenuator as for the calculations done before. When i have used only 6db the S-ATT jumped to 20. then i tried to use 6+20 and get S-ATT=2. this is normal as for the filed results but not for the calculations.
also with 15w and 6 or 20 or 26 the result is still overdriving. to have good result i still have to reduce power.

3) i never have used the expert 1,3k with 100w rig. i always have used with k3/10 - KX3- sunsdr - elad fmduo. so all the previous rtx never gave me problems of overdrive the 1,3k or have the necessity to use ALC. so this is the first time. i think that can be a problem also with linearity of the anan to have low range 6-10w output. so next test as suggest will be buy a 6dB 100W rated attenuator and check what will happen.

Unfortunately i don't have other PA to try now.

all other other ideas/suggestions are always welcome
w3ub
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Re: Anan 7000dle and pure signal setting

Postby w3ub » Thu Aug 01, 2019 12:38 pm

Yes, you must reduce power for sure. I don't think the recalibration to lower powers will change the linearity, it is just the TX chain gain you are lowering.

The only problem with an external attenuator is how to remove it from the RX path, assuming you put one in line with the amp input.

Doug
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w-u-2-o
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Re: Anan 7000dle and pure signal setting

Postby w-u-2-o » Thu Aug 01, 2019 1:00 pm

ik7ytt wrote:I have done few considerations and tests following previous suggestions

1) i have recalibrated the max power to 20w as 100 level in Thetis scale.Then reduced to 80 level to have 15W as maximum power
Consideration: this will let lose linearity to the PA stage? is correct? or the correct way is to use a 100w attenuator?
The linearity will be terrible either way. This is an unhappy result of the poor gain linearity of the RF sections of the design. However, if you use a 100W attenuator, you will have more precise control because you are adjusting the output of the radio over a much greater range. For instance, 1 to 10W is a 10dB range, 1 to 50W is a 17dB range.
Consideration: i have noticed that if i set any power valute to 100. decreasing the level below 80 the power reduction is not linear any more. that means if i set 100 as 20w. on 50 i have only 5w!!!! if i set 100 as 100w at 50 i have only 40w. i feel this little stange.
The way the RF drive is controlled is as follows: there is a 31dB step attenuator on the output of the DAC. Gross changes in drive are made with that, fractional dB changes are made by adjusting the DAC reference voltage level. This latter adjustment is done by low pass filtering a PWM waveform output by the FPGA. I have never measured it myself, but I have been told that the resulting linearity at that point is near perfect. Unfortunately, the gain linearity of the following amplifier stages, and its gain flatness over frequency, is not very good. This is why the linearity of the RF Drive control is also not very good. There is nothing you can do about this. I have proposed a software equalizer function to solve the problem, but no developer has bit off on that idea yet.
2) i get 3 and 6 db attenuator as for the calculations done before. When i have used only 6db the S-ATT jumped to 20. then i tried to use 6+20 and get S-ATT=2. this is normal as for the filed results but not for the calculations.
That is exactly right, well within probable margin of error for how accurately your hardware measures power.
also with 15w and 6 or 20 or 26 the result is still overdriving. to have good result i still have to reduce power.
No surprise there. Changing the attenuator value has absolutely no bearing on this problem.
3) i never have used the expert 1,3k with 100w rig. i always have used with k3/10 - KX3- sunsdr - elad fmduo. so all the previous rtx never gave me problems of overdrive the 1,3k or have the necessity to use ALC. so this is the first time. i think that can be a problem also with linearity of the anan to have low range 6-10w output. so next test as suggest will be buy a 6dB 100W rated attenuator and check what will happen.
Using the attenuator will make it easier to adjust drive levels, but it will NOT prevent you from over-driving the amplifier. You must maintain drive levels at an appropriate level.

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