6500 power

W9OY

Ill let flex speak to absolute voltage limits but I run a 6300 6500 and 670voltagehigh quality regulated power supplies at 14.5 no problem.

KC2QMA_John

Yes lets see what FRS says about running the radios at 14.5v. 

W9OY

I already know what the limits are because I made it a point to find out, but I'm just not speaking for Flex.  14.5v no load, set on a reliable PS with a quality meter, by someone who knows what he is doing twiddling the VR pots inside a PS, is my compromise.  It gives me 13.8V to 13.9V at peak current as read by the API from my particular PS dynamics.  Each radio has it's own PS (same brand) and is set up like this and everything behaves with perfect consistency. I take no responsibility for anyone else, and it's probably not in Flex's interest to say.

73  W9OY

KC2QMA_John

My question is will running the radio over the FRS recommended voltage spec of 13.6vdc

1. Void the warranty?

2.Shorten the life of the electronic components in the radio.?

So lets see what FRS says about running the radios at 14.5v.

If they say it's OK I will go to 14.5v.

K4MT

My Flex 6300 manual says voltage range is 13.8 +/- 15%.  Based on that you can go up to 15.7 volts and be within the plus 15%.  14.5 would only be 5% over.

KC2QMA_John

OK that sounds good. But I would still like to see what FRS says about this.

Mike NN9DD

Say it one more time 7th time is a charm Mike

KC2QMA_John

OK Mike just for you."Lets see what FRS says about running the radios at 14.5v."

Gerald-K5SDR

Not a problem to run at up to 15% over 13.8V.  The internal over voltage diode on the input to the PA is 16V.  I run my Astron supply at it's max which I think is close to 15V.  Linearity improves with the higher voltage as well.  Maximum power increases or decreases with the square of the voltage divided by the impedance (P=E^2/R).  Not sure if they still teach that on the ham radio exams anymore since it was a long time ago when I took the test.  I will comment on the main thread as well.

KC2QMA_John

Thanks for the Official response Gerald. I just wanted to make sure that it was not going to shorten the life of the radios components or void's the warranty.

OK I will adjust my voltage up to compensate for the voltage drop.

K4MT

John did not know you were a flex user. Have checked in with you on TenTec net when I had my TenTec station. Nice to see you here

Javi LU5FF

Salvador nunca pude lograr mas de 85w en cualquier banda.. acorte el cable, levante la tensión de la fuente para que cuando caiga quede en 13,8v y ni asi.. en 20 mts con una roe en antena de 1.2 logro sacar casi 80w

KY6LA_Howard

Suggest you open a Help Desk Ticket

KC2QMA_John

Hey Gary, Yes the TT net is still going strong. Good to see you here as well. Other than the occasional bump in the road I am really enjoying my 6500.

K4MT

I too enjoy my 5000A and now my 6000 series. Miss my Tentec gear.  I worked for tentec  for several years and hope they can recover.

KC2QMA_John

They are back in biz and have a new Version of the Omni VII coming and future plans for an Orion III and a few other new products. Mike from Dishtronix bought TT. They are still making most of their money with Gov contract radios.

Gerald-K5SDR

Let me first address how we calibrate our radios at the factory.  The entire process is automated and cannot be bypassed by the factory operator or test technician.  It is not possible for a radio to complete the test process without PA calibration over its linear power range on all all bands.  After the automated calibration and 24 hour burn in we perform a 100% QA using the SmartSDR GUI and run the power up to manually confirm 100W on the center of each band before shipment.

All power calibration is performed with the voltage set to 13.8V under full load at the DC terminals on the back of the radio.  We use a 40 dB precision power attenuator connected to a Mini-Circuits PWR-4GHS Power Sensor to precisely measure the power during both the automated test and the final QA.  The measurement accuracy of this test station is significantly better than virtually all ham measurement equipment on the market including the popular Bird "slug" watt-meters.  

MOSFETs used in HF power amplifiers are effectively variable resistors where the resistance will increase as they heat.  As the resistance goes up with heat, the power will decrease (P = E^2/R).  If the voltage on the input terminals decreases the power will go down proportional to the square of the voltage.  

Not all dummy loads are 50 ohms.  Not all ham dummy loads are still (or were ever) good.  Cables don't have 0 dB loss.  Not all connectors are good.  DC connector crimps and connections are not 0 Ohms.  What is the absolute accuracy of the power meter at the frequency of measurement?

Let's say we have a peak current of 20A and a series resistance of 0.1 Ohm in the DC cable and connector.  P = I^2 * R = 20^2 * 0.1 = 40W  That means that the cable and connector will dissipate 40W before you get to the back of the radio.  The voltage drop at 20A will be 20 * 0.1 = 2V.  It all makes a difference.

Now let's look at the effect of a simple change in impedance of the RF load.  Let's say that the load is 55 Ohms instead of 50 Ohms.  100W is 70.7 Vrms into 50 Ohms.  Since P = E^2/R then P = 70.7^2/55 = 90.88W.  A 5 Ohm (10%) increase in the load drops the power to ~91W.   55 Ohms is a SWR of 1.1:1.  You can experience that SWR on a cable, connectors and ham shack dummy load fairly commonly.  Drop the impedance to 45 Ohms at the same voltage and you get 111W.  Same 1.1:1 SWR!  

Finally, in the 90.88W example the power output difference from 100W is only 0.4 dB, which is totally imperceptible on the other end of the contact.  

73,
Gerald

K4MT

Thank you for all the specs and this is all true.  

I do however have to ask why my other radios to include a 5000A put out 100 watts or more with my power supply set to 13.8 VDC at the supply with the standard 5-6 foot power cable.  

I have other equip connected to my shack supply that do not have +- 15% range allowance and I can not turn the supply voltage up to achieve 13.8 at the back of the radio and I feel I should not have to buy a different power supply for each rig I own when I have a 70 amp supply that can run everything.. Therefore as I believe most hams do, I use one supply for everything.  

When I worked for another ham manufacturer we tested the radios with 13.8 VDC at the power supply using the same power cable supplied to the customer and set the radios to 100 watts.  

I do not mind seeing a few watts either way from specs (and yes I understand it makes no difference at the receive end) but I never have owned a radio that is 15 watts shy as mentioned by others on this discussion.  Maybe the power spec should be redone to say 100 watts +- 15%.

Before the fan club chimes in I am not trying to bash the product.  I simply cant see why a 100 watt radio does not put out 100 watts with a normal ham power supply that are all set for 13.8 VDC.

Stefano - W2WTZ

Lee, you are an enthusiast, so not impartial in technical evaluations. You should consider  the second number and not the first becouse the output power drops down after 1-2 seconds. Second value is after 5 seconds and the voltage INSIDE Flex is 13,8V under load. From a practical point of view 85 of 100W is not apreciable in a dx communications, you are right but Flex advertised 6500 as 100W, not 100W in 6m and 85W in 40m. Following yr reasoning even 75W changes nothing so maybe Flex will produce next SDR at 75W in 40m... Sorry but I disagree, tehchnical specification should be respected.Dan, I don't suspect to have a hardware issue, I suspect that simply 6500 is "constipated" about output power. I asked you to explain to the community how were solved same type of complaints that other guys made on the forum in the past years where yr reply were to open a ticked. I suspect that now with some tricks as overvoltage, tolerance and so on Flex search to consider normal the missing W becouse there is not a zero costo solution as the RF part of 6500 is hardware. If you insist that I have to open a ticket becouse my 6500 has to arrive to 100W in low bands too I will do and I will keep the community informed about results, positive or negative. Next week I will go on holidays, when back home I will open the ticket but it's evident that there is a general problem. What is yr comment on ARRL Lab measures (very close to mine)?
Gerald, thank you very much for yr technical explanation, I think it should be published on FAQ too. I'm sure about the product quality and the way it's produced and calibrated. I'm also sure you use high level lab precision instruments, no discussion and I am ABSOLUTELY VERY GLAD of my 6500, but...
 - I supplied INSIDE the Flex 13,8V under load, so the voltage drop problem doesn't apply to my specifi case.
- I know that 0.4 dB is an imperceptible difference, but you sold me and I purchased from you a radio that has 100W in all bands at 13,8v (pls see your catalogues), not a radio 0.4 dB below the declared values by Flex.
My dummy load is Ericcson, SWR measured is 1.01:1 so the problem is not swr.
Gerald, this situation seems what happens with Xerox technician when comes to repair  my printing machine. These are the steps:
1 - negate the problem, even if evident
2 - admit the problem but minimizing it
3 - put the blame on someone else (in my case to the paper quality, here is the voltage or the lab inbstrumens)
4 - it's not a defect it's a characteristic but within tolerance
5 - at this point I get ****, the technician opens the machine and he repair it with success...
In the same testing conditions but with 13,8v at the power supply (that means 13,3 inside the radio) Yaesu 991 gives:
6m 95W
10m 99W
12m 97W
15m 98W
17m 97W
20m 97W
30m 99W
40m 97W
80m 104W
160m 99W
Increasing the voltage at 14,3V nothing changes, maybe there is inside 991 a voltage stabilizer, but I think inside 6500 too. 
Gerald, 6500 is within the elite group of top radios, pls  evaluate if Isn't better for your image a different approach, as to use in the next release a Mosfet with 120W, so even with 13,8v at power supply, without cutting the original power cord, without space age  voltage sensors, in the worst band, you provide 100W? How much will be the extra cost considerning the product level?
I think it's time to stop with this disussion, all participants have enough informations in order to have an own idea of the situation, I don't want that a technical discussion could be interpreted as an attack against Flex Radio. I'm in love of my Flex 6500 but I think that Flex made false step on power output matter and there is none so deaf as he who will not hear.

sorry for my long post

Bill -VA3WTB

Gerald has explained this well. The Flex is a 100W radio. And he explained some of the things in the shack that could effect power output.  As he states, that the power MOSFETs used change as they heat up.

From Gerald.
Let me first address how we calibrate our radios at the factory.  The entire process is automated and cannot be bypassed by the factory operator or test technician.  It is not possible for a radio to complete the test process without PA calibration over its linear power range on all all bands.  After the automated calibration and 24 hour burn in we perform a 100% QA using the SmartSDR GUI and run the power up to manually confirm 100W on the center of each band before shipment.

I see nothing misleading in the Flex specs.

Gerald-K5SDR

I want to say that I respect everything being said here and believe that I can shed some additional light here.  Our calibration philosophy has been to calibrate to 100W when the slider is set to 100 in the factory as I stated in my earlier post.  The Japanese manufacturers have chosen to set the power output higher than 100W when their control is set to 100%.  Here is an example I copied from a recent ICOM service manual.  You can see that they calibrate to 105W at 100% on the slider.  That way you can be low by 10W and still show 95W.  

I am told that some of the guitar amplifiers have volume controls that go to "11" instead of "10." at maximum.  Maybe we should do the same.



The down side to calibrating at 105W is that intermodulation distortion gets worse the more you drive the amplifier into compression.  If we relaxed our maximum compression limits in the calibration we could let the radio pass test with higher distortion.  On SSB, you are a better neighbor if you run a 13.8V PA at 80W to 90W for best linearity.  CW and RTTY are not linear modes so it doesn't matter.

Now it is always possible that there was a problem with the test stand when a specific radio went through the line.  It is totally impossible to know without putting my hands on the radio and validating the test environment.  If you are truly concerned, you can open a help desk ticket and get a RMA.  I will look at it personally.

I would be curious to know how many customers would like us to allow the power slider to go to "11?"  That would be just a simple software change but would increase splatter on SSB.  We could also keep it at 100% and tweak the internal gain so that it is really ~105% and you don't know it just as with the ICOM.

By the way, the same discussion can be had on S meter calibration but that is the subject for another time.

73,
Gerald

Walt

I vote to leave it as it is. Your QA is fine with me. Cheers

G8ZPX

Gerald, to be honest I had assumed that you would be tweaking the gain for the next release to avoid this kind of misunderstanding and bad PR.

I drive an Alpha 8100 so really don't care about +/-10W, but others clearly do.

I guess if you only ran 100W max all the time then being down 10-15% is a painful pill to swallow. I can certainly understand the frustration when the spec advertises 100W output for 13.8v at the terminals, yet that is near impossible to achieve outside of the test lab. The end result is that the radio fails to meet customer expectation.

Customers have the legal right to expect the radio to perform according to the specifications being claimed in the real-world. I think the diesel car emissions fiasco has proven to the world that the spec is the spec and no amount of marketing talk can detract from the end-user expectation of conformance and transparency of the specification.

My suggestion would be that the slider should represent the actual output, not just an arbitrary scale from 0-100W. In other words if we read 100W on the F6k slider then we should be able to measure 100W of output. If that means the PA is too close for comfort then the scale needs re-labeling to match the actual achievable output, not a theoretical one, and the spec downgrading to what can be sensibly achieved.

If you can't get a good clean all-band 100W from the F6k then it's time to decide which marketing position is best: a clean sub-100W TCVR, or a slightly less-clean 100W. Either way the spec has to reflect the real-world and also be honest with the customer.

73 de Steve G!XOW

Gerald-K5SDR

The reason I run higher voltage is because I know it improves linearity of the amplifier vs 13.8V.  

Gerald-K5SDR

Luca, 12.56V is way to low at the back panel to get full output.  That is more than 1V lower than nominal.

Bill -VA3WTB

I don't think Flex Is doing anything ilegal. Gerald has answered all this. He explained the reasons for not showing a 100 watts all the time. My radio is 100W on some bands. If I had a choice, I would chose a cleaner transmission then running very close to distortion. And I don't think just because a few take Flex to task over a few watts is bad PR. This is a matter of education, I'm glad Gerald cleared this up.

Peter Bentley

Thank you  Gerald, I'm with you.

These guys just don't 'get it'.

G8ZPX

Bill,

Gerald is asking for feedback. Nobody said that this IS illegal, simply that the customer does have a legal right of conformance against specification. Understand the difference please. EU advertising standards authorities have levied big fines and/or import embargoes where claims cannot be achieved in a real-world scenario.

The technical solution is easy: a selector box in the Transmit setup menu :-

TX output ultra-clean (10% lower TX power) choices: on/off.

Obviously this would be a non-issue for everyone if we could get pre-distortion released.

Gerald-K5SDR

Steve,

I forgot to mention in an earlier post that we heat and hold our PA transistor temperature to 45C during calibration.

We use exactly the same transistors in our 13.8V PA as the other manufacturers (RD100HHF1).  There is not much variance in the PA designs from manufacturer to manufacturer.  The transistors can put out over 100W at 13.8V at the expense of increased distortion.  There is a direct trade off between the two that is due to increasing compression in the amplifier as you get closer to drain saturation.  

Our competitors opt for higher distortion.  100W is a nominal power specification because so many things are not under the manufacurer's control.  As I said, +/- 5 Ohms at the load can make a 10W difference.  A 1V drop from nominal at the back panel connector could cost over 20W according to my calculations.

Maybe we should say the heck with distortion and calibration and just turn up the gain in the software.  I can make the amp (and have) put out at least 150W but the output starts to look like a square wave. The only technical way I know of to guarantee at least 100W it to increase distortion.  Some bands will be worse or better than others due to the inherent impedance variation in the output transformer and low pass filters.

Now it is always possible that an individual radio could have either a hardware problem or a faulty calibration.  Test stands can fail as well.  The only way to tell is to physically examine the radio in a controlled environment with calibrated test equipment.

Steve, I am being 100% transparent yet conflicted on what to do.  We are **** if we do and **** if we don't turn up the gain.  Maybe more splatter with a power control that goes to 110% is the way to go.  That is what the other guys do but they probably won't tell you that it increases splatter.

73,
Gerald

Bill -VA3WTB

Gerald, the Flex is about the cleanest transmit in the industry, I for one like that.

Steve, as mentioned, many people do get 100W on some bands, I do. Is that not conforming to specs?