Low Power Output? 6300 or 6500

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With  both my 6300 and 6500 they struggle to produce over 85 watts. 
Using the same DC supply and watt meter my other rigs easily do 100 watts. 
So am I the only one or have others noticed this?

I'm not interested in how small the DB difference is either. I just want to know.
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Steve N4LQ

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Posted 4 years ago

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Jim Gilliam

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if you have a calculator it is 10*log80/100. This will be a negative number and the number of dB down it would be. My calculator gives -.969 dB. almost 1 dB down.
(Edited)
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Jim Gilliam

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My 6500 reads 105 Watts out. My Bird Watt meter reads 108 Watts forward and about 5 Watts reflected which means the output power of the transmitter is 103 Watts. This is without the tuner.


Jim

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KY6LA - Howard, Elmer

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Steve:

I easily get 100W out of my 6700 but I use a 50A power supply and very short 8 gauge power cables.

Have you measured the voltage at the INPUT to your 6500 under transmit conditions.

I suspect that you have too low a supply voltage at the input and/or your voltage drop in your cables is causing your issue.
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Barry Isseks

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My 6300 and 6500 both put out full power.. 100w+/-  into low SWR loads.
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Steve N4LQ

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I'm measuring 13.55 volts at the rig, key down at full output, 88 watts. Shouldn't that be enough? 
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KY6LA - Howard, Elmer

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12V DC is usually defined as meaning actually 13.8V
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Duane, AC5AA

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Steve, my readings checked tonight with 6500 -> PowerMaster -> Palstar HF-Auto (bypassed) -> Dummy load:

A = PowerMaster reading (set for full forward power reading), 
B = Palstar HF-Auto power meter:

Band        A          B     
--------     -----     ------
160m     98.3      90
  80m     98.9      92
  40m     95.0      89
  30m   101         92
  20m     97.7      92
  17m   103       101
  15m     88.6      87
  12m     96.6      99
  10m    92.3       89
    6m     n/a      104*

* probably inaccurate at this freq.

Hope this helps. My 6500 is almost exactly a year old.

   73, Duane
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W5XZ - dan

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you're not the only one, my 6500 is a little soft of 100w also, w a 35 amp pwr supply..

seems odd, since the rd100's are good for 100 w a piece...and there's a pair, in push pull..

i know there's hardware rf negative feedback, but suspect the calibration routine..

I'd be a happy camper if mine put out 125 w easy, all bands..
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k3Tim

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The DC power spec says:
  • Power Supply Requirements:  +13.8V DC nominal ±15%
At this station we run 14.0V with a 8" pigtail (12 gauge) and see 100 watts consistently on the meter.
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Burt Fisher

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"we?"
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Steve N4LQ

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I can just see me chopping off my power lead to 8". 
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Pat - WH6HI

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Queation:  Are these measurements being done with a good Resistive Load or antenna?  No antenna is purely resistive and the reactive parts have a bearing on the output of the transmitter. 
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Steve N4LQ

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Doesn't matter. 50 ohm resistive or reactive, it's always low. 
No it's not the power supply....Same one for other rigs.
No it's not the cable....Checked with DVM
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k3Tim

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Hi Burt,

"we"

Yes - the plural -  The?/My? XYL just passed General Class exam.  Extremely proud of her as she is Business Major in College and by profession.  She passed Tech with a lot of study but seems over the basics now and passed General w/o as much effort it seems (although a lot of study non the less).  97% passing score on both exams.  She's now going for Extra Class....

Sharing the station (6500) with her, of course, hence "we".  Maybe time for a 6700 with dial receiver.  

Best Regards,
Tim
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DrTeeth

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Tim,

Mni congrats to the XYL. Sharing a rig won't last for long...then there will be the mutual RFI/QRM. Opened a can of worms, Hi hi?
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Burt Fisher

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You are really into saying hi hi. Are we on CW?
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DrTeeth

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You sound like a broken record, 'click,' you sound like a broken record, 'click' etc ad infinitum.
(Edited)
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Ed, K0KC

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"Record" ??? I think I remember those things! :)
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DrTeeth

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Ed, a few years ago my daughter asked me, "Daddy, in the old days when everything was in black and white...". She had seen some old films and came to the only logical conclusion a cute youngster could. She's now grown up and a teenager, :-(, hi hi.
(Edited)
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Ed, K0KC

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When measuring the DC at the input to the radio, it is difficult to make contact with the PowerPole connectors with DMM probes. My solution was to use a couple of sewing needles to make contact and then touching the needles with the DMM probes.

It is hard to believe, but I will have had my 6700 for two years next month (probably means I will experience a non-warranty failure this summer). I noticed the low power output issue early on and it was cured by a short vacation in Austin for a re-calibration.

The length and gauge of the power cables are certainly important, but another factor to consider is the resistance of a PowerPole connector; it is even worse if you use some distribution system such as a RigRunner.

Ed, K0KC
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Steve N4LQ

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So we're "calibrating" rigs now so we can get rated power? 
Can't it calibrate itself? I claims to be doing that when I turn it on. 
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Ed, K0KC

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Steve,

The "calibration" that I mentioned above was completed at the Flex facility in Austin after several conversations with Dudley in Technical Support. The calibration that the radio performs on startup is something different as far as I know.

Ed, K0KC
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Joe, KQ1Q

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BTW, Fluke has fine-tip test probes which can easily get inside a Power Pole connector: http://www.amazon.com/Fluke-TL910-Electronic-Test-Probes/dp/B000VRJH0G
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Al / NN4ZZ

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Another option is to make your own.....using a straight pin or snip off a section from a safety pin.   I have a set of alligator leads with pin tips in the drawer and they work fine for this.

Regards, Al / NN4ZZ  
al (at) nn4zz (dot) com

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Greg Leber. (K9ON)

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Had the same problem with a different rig found there was a voltage drop in my MFJ power strip. Connected straight to power supply an back to full power!
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wb4dwd

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80-82 watts is all my 6300 will do.  Tried every band and a 20 and a 45 amp power supply and a dummy load. .   My ACOM amp can't tolerate more than 30-50 watts, so I haven't bothered with it. 
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DrTeeth

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Similar here. Never seen 100W even with 14v when txing, into a 1:1 swr antenna.
(Edited)
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George Molnar, KF2T, Elmer

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Did some experimenting. Yes, the input voltage is the culprit (at least here). If at all possible, shorten your leads as much as you can. Check connectors. With a single cleanup of one not-so-expertly installed PowerPole, I came back up to 100w on the button.
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Bill -VA3WTB

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George, it must be something like what you say, most people are getting 100W   I am
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Steve N4LQ

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I'm using the power cable that came with the 6500. Before that I used the power cable that came with the 6300. Both have low power. At one point Flex stated that a firmware update would cure the problem. It helped a little but not much. Again. I'm getting 13.55v at the radio. I might be able to adjust the PSU up to 13.8. Is it really that critical on these rigs?  You would think there would be some wiggle room.
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DrTeeth

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Changing the supplied voltage a few 1/10V does not change anything much. I just experiemneted for those who mentioned the voltage drop on key down condx.
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Reggie-k6xr

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I have 14.0 volts delivered to the connector on back of flex 6500. 80 to15 is 85 watts. 17=100,  21 to 28=95. into dummy load and on air.
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Steve N4LQ

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From reading these post I now believe there must be at least 50% out there with low power. 
Wonder what the problem really is? Can it be fixed in software? What is "calibration"? 
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DrTeeth

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Let's hope that the 'calibration' is not keeping the output the same but making the meter read 100W, hi hi.

FWIW, I use the voltage readout from DDUtil which takes into account cable length and resistive connections.
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Jim Gilliam

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Have you double checked your power output with an external power meter? It could be the readings on the internal meter are software-driven and could be giving erroneous readings. Also, the tuner will exhibit some loss. Remember if you have an SWR that the power delivered by the source (transmitter) is the forward power minus the reflected power.


Jim, K6QE

(Edited)
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Steve N4LQ

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Jim
Believe us. It's low. 
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Steve K9ZW, Elmer

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Early on with the Flex-6700 I found unexplained lower output times.  The power supply "should" have not been the issue, as it was above spec and metering didn't indicate it as the issue.

Switching to a slightly larger power supply 100% corrected the issue.  Suspicion centers on the apparently marginal power supply slightly dropping voltage - drooping if you prefer - at the key up moment, which the radio was sensitive to enough to limit output.

The oversized power supply corrected low output of the Flex-6700.

Mobile with the Flex-6300 I have used another oversized power supply with no noted issues.

73

Steve

K9ZW

 

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DrTeeth

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Steve,

Are you saying that the input voltage reading from DDUtil is not reliable? AIUI, and am happy to be proven wrong, it gets its info from my 6300 itself. Plus, I do not see any significant increase in power by changing my key-down voltage from its dropped value to 14.0v.

73.
(Edited)
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Steve K9ZW, Elmer

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Hi Guy

I cannot say, as the versions of the software was pre-release program software, I don't think I even had DDUTIL at the time, and the power supply swap was intuitively in keeping with reduced output from other radios I had experienced. 

Was annoying as I had to change the power supply end of the beautifully done power cable to suit the larger supply.

The only generalization I should make is "It is worth trying another, preferably larger power supply and checking all aspects of your power-supply into the radio cabling before sending your radio in for a checkup."  Of course YMMV.

73

Steve

K9ZW

(Edited)
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W5XZ - dan

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I need to look up one of the local guys who has an LP-100.  I THINK that thing has traceable NIST
accuracy...if calibrated from the factory...before i can say with some confidence of accuracy that
my Pout is low...don't have one in my shack...yet...  

OTOH, i'm checking with a buddy for a simple, but reasonably accurate way to measure r.f. voltage around the 100 watt level...looks like 70.7 volts = 100w, to me..
(Edited)
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AA0KM

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Steve K9ZW, Elmer

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Is there a similar guide for connector contact surface area & connector conductor sizes? 

I've long wondered if the massive reduction from a nice cable to a small ring or a single clamp/crimp plays a role?

73

Steve

K9ZW

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Ken - NM9P, Employee

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I don't know, But I would love to convert my old backup Pyramid power supply from posts to Power Pole connectors, if not only for convenience!
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Joe, KQ1Q

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My 6300 puts out from 97-100 watts into a dummy load as measured by a LP-100A. That's on 80, 40, 20 and 10m. Tested using 9-inch long 12 gauge cables from a switching 30 amp supply. Voltage under load as measured by Fluke DVM was 13.8 volts.

As already mentioned, RF power output is very sensitive to DC supply voltage at the input terminals. If voltage sags to only about 12.8 volts, RF power out diminishes several watts, in some cases down to the high 80s. The spec in the ver. 1.4.0 Flex 6000 hardware Reference Manual states 100 watts CW out *at* 13.8 volts DC supply. If you don't measure 13.8 volts at the radio DC input terminals under load, it's not getting the specified voltage for full power RF output.
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Paul Christensen, W9AC, Elmer

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I ran into this issue a few months ago and it turned out to be slight loss through a PL-259 connector. 

I run my supply at +14.5V using the Flex-supplied cable with Powepoles.  This results in better than +14V at the Flex 6700.  The power connection is fastened right on to the supply's 1/4-inch bolts.  If a RigRunner or similar DC manifold is used to distribute +12V power through the shack, I strongly encourage folks to connect their transceivers direct to the power supply and not through the RigRunner. 

Cascading Anderson Powerpoles can result in losses that quickly add up.  When we're asking near 20A of current through them, even very small resistance affects voltage at the transceiver.  I won't get into a philosophical diatribe about Powerpoles, but I do wish transceiver manufacturers would parallel these with a real power connector, like a pair of 1/4-inch bolts. 

Next, when these power issues come up, it's important to measure power right at the output of the transceiver into a known 50-ohm load.  When a wattmeter is inserted after filters and complex switch arrangements, one can easily see the accumulated loss through the coaxial distribution.  That's what was happening here.  I was seeing 85W after the switches and filters, but >95W at the output of the Flex 6700. 

Any time a wattmeter's calibration is suspect, an easy way to verify the result is to measure RF voltage with a sufficiently-high-bandwidth oscilloscope at the 50-ohm load.  Going one step further toward calibration, one can calibrate the scope against a known AC voltage.     

Paul, W9AC
(Edited)
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Steve N4LQ

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Official Response
Ok. I chopped my DC power lead down to 16" and soldered a pair of heavy duty lugs on the end. The PSU is an Astron 35m, fairly new. I adjusted its voltage for 14.0 as measured at the terminals. Then, with the DVM probes jammed into the Anderson PP on the 6500 I measured exactly 13.96v, key down. Not bad! 
Power output now at 95 watts max, any band. I also used a different, shorter coax jumper to the meter and dummy load. 
I hated to shorten my cord. Now I need to order another one in case I want to relocate the rig. 
So by increasing my voltage and shortening the cord I gained about 3 watts maybe. It's still low in my book. 
BTW: Both my external watt-meter and the one in SmartSDR read nearly the same.....>Low

As for those Anderson Ppoles, I think they are dinky. The tiny strip of metal inside them seems inadequate ....What is the part number for those so I can order more? 
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Joe, KQ1Q

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There are three sizes of Power Pole connectors, for 15 amp, 30 amp and 45 amps, each requiring unique contacts and wire gauges. Scroll down this page to see the options: http://www.powerwerx.com/anderson-powerpoles/powerpole-sets/45-amp-permanently-bonded-red-black-ande...

I personally use 45 amp Power Poles and 10 gauge wires for the main DC supply to a 100 watt radio, but I guess technically 30 amp Power Poles and 12-14 ga. might work if very short.

Re Flex 6000 RF output power, ideally everyone testing should use the same procedure, whatever that is. E.g, do you test the initial power, or after 30 sec, on every band, etc? Into a dummy load? How much degradation is expected after 30 sec or 60 sec?

Personally I'd suggest only testing into a 50 ohm dummy load, only with very short heavy gauge DC cables, and only after verifying the DC supply can maintain 13.8 volts at the radio input terminals. Further I'd suggest everybody standardize on some to-be-determined timing such as take the RF output measurement after 15 seconds or 30 seconds of key down, and test multiple bands not just one.

Since the final amp is a linear device and must dissipate significant heat, part of meeting the spec is how the PA handles temperature compensation under load. For that reason it seems appropriate to test after x number of seconds, maybe with some recovery time or duty cycle spec between repeated tests, but I don't know what fair numbers would be or what the common industry practice is for such testing.

Unfortunately the hardware reference manual just states 100 watts, with no +/- percentage or any other qualifying info except 13.8 volts DC.
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Steve N4LQ

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So what size is on the Flex 6000? 30 Amp?
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Joe, KQ1Q

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I haven't measured it but I think it ships with 45 amp Power Poles and 10 gauge cable. That's just what it feels like.