6500 and low output

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  • Updated 3 years ago
I see a number of posts about low power output. I too can get 80w and no more out of the flex 6500. Before all the PS suggestions are posted. I have an Astron 35A supply. The power leads are not over two feet long and my elecraft hits 100w no problem. go.......
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Mike

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Posted 3 years ago

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George Molnar, KF2T, Elmer

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I had a bad Powerpole connection (my low quality work!) that did the same. Re-termination and solder fixed it right up.
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Tim - W4TME, Customer Experience Manager

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Mike - just because you have an Astron doesn't mean that there is 13.8V at the radio.  On my Astron RS-35M, I have to set the output voltage to 14.4 VDC to compensate for the IR drop through the DC power cables, fuses, and voltage distribution panel.
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Mike

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True but it seems to me if one radio puts out 100w so should the Flex. I have 14.0v on the back end of the radio.
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Tim - W4TME, Customer Experience Manager

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Some radio manufacturers calibrate their radios to put out more than 100W to compensate for low power conditions.  They do this at the expense of spectral purity.  We have decided to do it differently and not add in the additional headroom to ensure spectral purity of our transmitters.

If you have the proper voltage at the connector of the radio and your power is still below 90W, then, by all means open a HelpDesk support ticket so we can investigate further.
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N9VC

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I, too, had low output when I would transmit. I, also,
tried to compensate with raising the voltage. I had 14.5
at the terminals, but when I would transmit, it would
drop to 12.2, hence low output. Turned out, the voltage drop
was due to running it through a Rigrunner. Changed to a
different fuse and things improved. Eliminated the Rigrunner
altogether and fed with short cable and everything was great.
Do not overlook how it is fed.

73, Jim N9VC

I had a similar, comparable, situation because same power supply
and Rigrunner feeding a Yaesu FTdx3k and it ran 100 watts.
But the fuse was in the Rigrunner was causing a voltage
drop. The fuses were obtained from an un-named big box
store. The power supply was an Astron RS-35A.
(Edited)
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Bill -VA3WTB

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If power out drops to much, I don't think you are getting 14V at the pins on the radio. I think the voltage is dropping on transmit.

I had a Flex 3000 that was wired to a power strip I made, there are several things also connected to the strip. all heavy duty. My voltage would drop many volts on transmit. I changed the wiring to go direct to the power supply and connected the power strip also to the same terminals on the power supply. I always had 14v after that on the radio. So yea, if there is anything between the radio and the power supply, than?
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Jay / NO5J

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Agreed
The only voltages that matter are the ones at the radio termials, which can be seen using FlexMeter, as has been mentioned in other threads. I'm also using a homebrewed DC power strip to power meter lamps, etc. it's wired in parallel, with the 10 inch Flex Power cord, which is connected directly to the power supply terminals. I still see a little voltage sag on TX, but I set the voltage to read 14.4 v during TX, which reads as 14.7 v during RX.

My Diamond GVZ4000 power supply is front panel adjustable. It's also rated for 40 amp continuous, yet it still sags @ .3 v on TX. I've never noticed any troublesome birdies caused by it, even though its a switcher.

14.7 v in Flexmeter, = 95+ watts on most of the bands.

Adjusting the voltage any higher doesn't gain any additional wattage with my 6500.  
   
 SDRgadgets

73, Jay - NO5J

(Edited)
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Rory - N6OIL

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Wow! So last night after reading this thread I figured I should not have any issues since I have 50 amp Astron linear supply. I download the FlexMeter app and flip on my WSJT-X software and hit the tune button for 100 watts and it looks like I'm dropping almost half volt or more. I'm using the supplied power cable but it's hooked to a RigRunner but I think my feeder to the RigRunner might be 12ga wire. Something to look at tonight when I get home. But even with the I/R drop I was still able to 100 watts. I'll take more measurements tonight. 
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Jay / NO5J

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Additionally
Flexmeter's FWDPWR readings vary depending on the SWR match seen at the radio's antenna jack. My current dummy load, is often not, (never) a perfect match, sometimes the best it provides is 1.5:1, with the ATU bypassed. After a tune cycle with the ATU engaged it's usually,still not a perfect match (1.1+:1). Full power in SmartSDR will read lower in Flexmeter when connected to my dummy load, with the ATU match (bypassed), it usually ranges from 84 - 90 watts. When matched at 1.1:1 when fed to my antenna and externally matched, it's usually 95+ watts, so the match matters. Not seeing a perfect 100 watts, doesn't bother me. Full power, just is what it is. 1 - 5 watts difference, doesn't make any detectable difference in SSB, mike placement has a larger effect, IMHO. I can always manage legal limit, with my amp turned on anyway. 
 
 SDRgadgets

73, Jay - NO5J

(Edited)
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Rory - N6OIL

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Ok, here are my results into a dummy load on 10m

Before Fuse
13.66 Idle
12.71 50w
12.17 100w
So I'll be upgrading the supply cable to largest I can fit on a 45 amp PowerPole then test again. I might need to bump up PS voltage, what do you guys think?
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k3Tim

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I am running an Astron 50A linear supply also. With an 8" long 10# cable the V drops from 14.14 to 13.98 on transmit. I had to reseat the powerpole connector on the radio to achieve this low drop. Xmit power = 96 on 15 meters.
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Mike

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Flex meter?
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Mike

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Flex meter?
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Jay / NO5J

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Mike

Flexmeter.exe v1.1.0.1 is available from either ...

http://wiki.sdrgadgets.com/index.php/FlexMeter
 or
https://www.dropbox.com/s/igsnaxr91y8lhga/FlexMeter.zip?dl=0

Both are identical.

Not sure we need two download locations, but I like having alternatives. Give it a try, you may find it useful. There isn't much in the way of documentation. But Ham's don't need documentation, do we? We learn by doing.

Flexmeter has been being discussed here in the Community ever since Denley W3XY, wrote it and released it, Even though the Community Search appears to have not, noticed. Both Flex, and meter, are so prevalent in the posts in the Community that they aren't really useful as search terms. 

I figured out a better search term for use with the Community Search. Searching on "Denley", takes you right to it (this morning).

https://community.flexradio.com/flexradio/topics/a-small-utility-to-read-smartsdr-radio-metering-points-with-ethernet-api

A thread, that explains a lot.  

 SDRgadgets

73, Jay - NO5J

(Edited)
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Rick Hadley - W0FG

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Bump the PS voltage to 14.1 or so in front of the fuse.
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Rory - N6OIL

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Hi Rick, yup thinking of doing it first since I don't have power leads to make up. Now to get the beast out of it's hiding spot and pop the top, I should put it on slide out rails.
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Sergey, R5AU

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Hi All, after a couple of years usage of my F6700 I recognized some issue with PS cables circuit on read panel
of my Radio. Connection not so fixed and after sometime on air necessary a bit shake/plug out - plug in PS cable .
Very visible with DDutil voltage monitor.
BTW, similar issue on many radios with similar circuit type, ex.: on my Ic-7600(with stable line of dust. :-). , must be sold asap, but just have no time due Flex very magic to spend time with this radio)

73!