Something strange is a foot with PGXL

Wayne Westfield

Last week I received an LP-700 for my birthday ( http://www.telepostinc.com/ ), today I am noticing that when attempting to drive the PGXL to 1000 watts the PGXL utility would show peaks at or near 1K however the LP-700 shows me peaking at 2400 watts.  Now I do not recall this happening yesterday.  I am reaching out to TelePost as well.

I have two samplers, one before the amp and one after the amp, I have switched them around and have the same result.

Has any one here seen this?

Wayne - KG5MGN

David-N5PSM

I also have an LP-700 with calibrated sensors as well as the PGXL......I will start looking this weekend...

Bob- W5TX

Probably a time constant difference between sensors.  One reading peak differently.
Bob

KF4HR

I also have the PG-XL and LP-700.  I've been told both the power display on on the PG-XL and the PG-XL Utility are providing Average power readings, although it seems the readings are even lower than Average power readings.  Perhaps it has something to do with communications latency, not sure.  In any case, both the average and peak readings on my LP-700 always read higher than the PG-XL screen or PG-XL Utility, so I rely on my LP-700 for its accuracy.  From what I understand 403A knows about the power reading discrepancy problem and is working the issue.

By the way, I have two sets of Telepost Sensors and both sensors sets read the same.

HCampbell WB4IVF

When I first got my LP-700 I noticed readings were higher than on my LP-100.  This problem (which is mentioned in the user manual) turned out to be the chassis bonding (my early production LP-700 does not have a ground lug).  I switched from the station PS to a Triad wall wart listed in the manual and the problem has not reoccurred.

Howard

Wayne Westfield

Thanks everyone,
 @Howard,  I read that two and bonded my equipment, I guess I can try and switch to a wall wart.   

I can understand reading high but when I think I should be putting out 1K and the meter shows 2.5K that's a huge discrepancy, isn't it?

HCampbell WB4IVF

Yes, your readings show more of a discrepancy than what I had noticed, and if your LP700 is properly bonded I doubt that it is the problem.  Have you tried checking output with another meter? 

Howard

Wayne Westfield

I have to check on Saturday at the club breakfast, I don't have one so will have see if can barrow.

Wayne Westfield

Some additional information, if I switch mode from Phone to FT8, the meter appears to be spot on, this leads me to believe that the Amp is overshooting on peaks.

I have my Mic gain set to peak about -8db
I do not have ALC checked in band settings

anything I might have missed?

Mark_WS7M

I don't op voice hardly at all.  Either CW or FT8.  I don't have a PGXL but I do have an SPE 2K-FA.

My LP-700 was spot on with a Bird Watt meter I borrowed but no longer have.   Of course on CW it was a little hard to see exactly but we connected a straight key and on key down read the values and they were virtually spot on.

Currently my LP-700 case is NOT bonded.   Shack redesign this spring will change that.

Wayne Westfield

Okay so new information;
Doing key down test at various RF settings with the amp on the meter is reading pretty much on the mark.

So why am I overshooting so much that Peaks are in the 2K range?

Using Heil PR781
Processing is disabled
DEXP is on set to around 86
TX EQ - on or of did not matter, from left to right 0db, -2db, -4db, -6db, -6db, -4db, -2db, 0db
ALC off
Mic gain set to peak -8db

Tim - W4TME

Turn PROC on (you should always use it for voice modes).

And make sure that your radio's power supply is not surging when under load.  If you have a different p/s try it.

Wayne Westfield

Thanks Tim for Weighing, I had turned it off at the direction Larry creator of the LP-700, but will turn it on.  I do not have another PS but maybe a good excuse to get one.  will look into surging, wouldn't that also show up with key down testing?

Again thanks.

KI4P

Always use processer on SSB?

Tim - W4TME

@KI4P - Yes.  It is a CESSB processor (not a compressor) and increases talk power by 3 dB.

KI4P

OK, I'll try that, seemed to make it a raspy sound when I recorded and played it back. I'll experiment, thanks

Bill -VA3WTB

KI4P, If you sound a little raspy sounding with the PROC on then make sure your not hitting the mic level to hard. And try bringing down some of your EQ sliders in the higher freq, such as the 1K, 2K, and 4K. This will make you sound much smoother.

Tim - W4TME

That is a good point.  If you are boosting the EQ much over 4 dB, then you are not using the EQ properly.  A properly set EQ is used to REDUCE frequencies that are overbearing in the audio mix.  It is not intended to add high-frequency content that is not in the original source material (aka "your voice).

Check out this HelpDesk article, Rules for EQing Voice for Optimal Phone Operation. The golden rule of EQing is to cut before boosting.

Wayne Westfield

These were my EQ settings;

TX EQ - on or of did not matter, from left to right 0db, -2db, -4db, -6db, -6db, -4db, -2db, 0db

Wayne Westfield

Checked P/S incoming was 14.4 dropping when calling CQ to 13.9 no surging however

Wayne Westfield

Wayne Westfield

Tim - W4TME

Due to low resolution, I can't tell from the video exactly how many amps are being drawn when transmitting (Peak Id) but it looks like it is in the neighborhood of 20.  At that Pleak Id, there is no way the amp is generating in excess of 1000W.

To even approach 2400W, your SWR would have to be low and your Peak Id would be in excess of 50A and the amp would fault.

And your SWR is indicating that it is high.

Trust the amp.

I'd move the LP to a different point in the coax run to the antenna, preferably a 1/8 of a wavelength on the transmitting frequency.