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Author Topic: E6AF Niue  (Read 538 times)

WO7R

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Re: E6AF Niue
« Reply #15 on: March 29, 2023, 07:59:52 AM »

I think E6 is a nice surrogate for world-wide conditions, at least as far as travel goes.

I worked E6 nearly every year from 2019 going backwards as far as I cared to look.

Nothing since. . .2020, the magic virus disruptor year.

Maybe activity here is another sign that travel has gone back to normal?  In which case, we can expect more of this one.
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K6OK

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Re: E6AF Niue
« Reply #16 on: March 29, 2023, 09:26:53 AM »

I talked to an amp guy a month ago or so and he said he can't keep up with amp and power supply repairs... Straight from the horses mouth, "FT8 is an amp killer".

Not really.  Modes don't kill amps, operators do.  FT8 is 12.6 seconds transmit and 17.4 seconds receive, which is a 42% duty cycle over time.  Notice that the cooling off period is longer than the key down period.  All you have to do is monitor the heat buildup on your finals and transformer. With a 17.4 second cooloff period there's no reason you can't run FT8 continuously.  For a single 3-500z amp 500 watts is about right, I've done that for 24 hours in the WW DIGI contest with no damage to tube or transformer.  I find that running stations in RTTY contests to be tougher on my amp than FT-8.

So I'd re-phrase it as, "Operators who don't pay attention to heat dissipation while using digi modes are amp killers."  I mean, you can kill an amp with CW if you're careless enough...

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KD6KVL

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Re: E6AF Niue
« Reply #17 on: March 29, 2023, 10:13:29 AM »

I always get a laugh out of antennas rated for 5KW SSB/CW, 600 wats rtty.....Kind of a big difference there.
Frank KG6N
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Frank KG6N

VE3VEE

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Re: E6AF Niue
« Reply #18 on: March 29, 2023, 01:50:15 PM »


Last E6 in the log was....E6AF, almost four years ago to the day.


Yes, since the start of Covid, this is the first E6 for me, too.

Marvin VE3VEE
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KD8MJR

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Re: E6AF Niue
« Reply #19 on: March 29, 2023, 02:07:29 PM »

Probably running that lazy, scripted computer automated text messaging thingy.

I talked to an amp guy a month ago or so and he said he can't keep up with amp and power supply repairs, specifically internal amp power supply and final transistor repairs.  Burned'm up.  Straight from the horses mouth, "FT8 is an amp killer". He's turning them away faster than he can take them in.  When I said I thought they said it was a "low power, below the noise mode", his reply, "yeah, right".

I think that is very Valid.  MY THP 2.5KFX gets hot even at 200W of power.  I have tried 1KW and the Amps temp shoots up from 40C to 60C within the 15 seconds.   I think a lot of people are damaging their Finals and don't even know it.  Transistors can get slowly burned out as damage progresses in the junctions.

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Tell ya' the truth I'm afraid what would happen if I bricked for 12-15 seconds straight over and over, and over (and over) again with 15 seconds "off" time at full power while I went to the gym, ate lunch, took a shower and came back to see how my computer did.  Things might get a little more toastier than usual, bwahahahahaha.

I have had FT8 signals from Dx stations that will not decode until I followed a trick a friend told me and put on 6-12db of attenuation.  People keep thinking that more and more power will make the contact but all it does is distort the signal or overload the Rx stations front end.

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I suppose some folks (maybe most folks) run them low power, but there's always those that think "all knobs to the right" is better.  I did notice the new Mercury LUX 1.5kW amp only has an 800 watt rating for "digital".  Can't imagine ya' need more - but hey, when Crozet and Bouvet turn up I'm sure folks were doing all the pushin' they could muster (what's duty cycle mean? lol).

During my testing phase I was easily able to work Sri Lanka and Asiatic Russia with just 70 Watts from the radio and these were stations with Wire Antennas and 100W.
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Never understood why some put a minimal amperage MFJ power supply on a $4,000 radio either. It is what it is I guess.

Hope he gets it's fixed, I love chasing DX on human modes...

 :)

NØUN


---

I don't know why anyone uses a switching power supply in the first place.  My Astron Linear Power Supplies are over 20 years old and never given me a problem.  You just never know when the Capacitors in a Switching Power supply will take a dump or when one of the Mosfets or PWM will quit.  An Astron Linear Supply will outlive the owner.
« Last Edit: March 29, 2023, 02:10:48 PM by KD8MJR »
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“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)

WO7R

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Re: E6AF Niue
« Reply #20 on: March 29, 2023, 02:43:09 PM »

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I don't know why anyone uses a switching power supply in the first place

For DXpeditioning?  Weight.  If you take a station, any station, overseas, you rapidly learn to obsess about weight.

There are surcharges in some cases.  In others, especially the "American Eagle" style puddle jumpers that are often the last leg of these things, there can be absolute weight limits as well. 

It isn't always a question of surcharges (which can be hefty enough).  Sometimes, if you are overlimit, you just don't fly.  Those smaller planes need to have the weight in the belly balanced out.

When I traveled to Placentia, Belize, I literally flew on a Cessna.  Commercial grade, all weather instrumented, larger than a pleasure craft version, but it was actually a Cessna.

I also helped a friend take his immensely clever 2m EME station overseas a couple of times.  The antenna system, rig, and amp was very carefully divided into three major duffel bags (which also had to meet various limits about dimensions also).  A lot of stuff was done for the sake of weight -- and everything had to break down to a maximum length as well.

The three bags clocked in at 49.5 pounds or so each.  By very careful design.  You also had to make the kilo limit (I think it was 22 or 23) in this otherwise metric world.  In any case, we flew in just under the limit (weight, height) in all three bags and had to put an exact inventory of parts in each one.

BTW, commercial antennas for 2m EME just don't fit these dimensions.  He had a lot of custom aluminum in that antenna.


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NU1O

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Re: E6AF Niue
« Reply #21 on: March 29, 2023, 05:52:46 PM »


I don't know why anyone uses a switching power supply in the first place.  My Astron Linear Power Supplies are over 20 years old and never given me a problem.  You just never know when the Capacitors in a Switching Power supply will take a dump or when one of the Mosfets or PWM will quit.  An Astron Linear Supply will outlive the owner.

I've had two Astron 35 amp supplies die on me after about 10 years for each.  I could've likely repaired them but I'd have to get the parts and it was easier to just call HRO and get a new one in 2 days.  I have two switching supplies for stuff like meters and an antenna tuner.  I think the largest is 7 or 10 amps.  I wouldn't use one for a rig.
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KC0W

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Re: E6AF Niue
« Reply #22 on: March 29, 2023, 06:16:28 PM »

Quote
I don't know why anyone uses a switching power supply in the first place

For DXpeditioning?  Weight.  If you take a station, any station, overseas, you rapidly learn to obsess about weight.

There are surcharges in some cases.  In others, especially the "American Eagle" style puddle jumpers that are often the last leg of these things, there can be absolute weight limits as well. 

It isn't always a question of surcharges (which can be hefty enough).  Sometimes, if you are overlimit, you just don't fly.  Those smaller planes need to have the weight in the belly balanced out.


  A 21 pound 1 kW DXpedition station:

        Juma PA1000     12 pounds
        KX3                  1.5 pounds
        17' MFJ 1979     .75 pound
        Laptop                3 pounds
        Radial wire         .50 pound
        100' RG8X           3 pounds
 
 


 

 This is the EXACT setup I used in KHØ (before the Yagi) Guatemala, Hong Kong, Haiti, Philippines & Canada.

 The holy grail of 1kW DXpeditioning setups might be getting the weight to 15 pounds or under. Using a tablet instead of a laptop would shave 2 pounds off. Using 30' of coax would be another 2 pounds..............There you go, a PROVEN & reliable 1,000 Watt station weighing 15 pounds.

                                                                Tom KH0/KC0W
                                                                   KH0W.com
       
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N4NYY

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Re: E6AF Niue
« Reply #23 on: March 29, 2023, 06:52:04 PM »


I don't know why anyone uses a switching power supply in the first place.  My Astron Linear Power Supplies are over 20 years old and never given me a problem.  You just never know when the Capacitors in a Switching Power supply will take a dump or when one of the Mosfets or PWM will quit.  An Astron Linear Supply will outlive the owner.

I took a lightning hit on my RM-35. The filter caps and bridges were cooked. I replaced the PCB, pass transistors, and the emitter resistors. Basically everything outside the transformer, Bridges, and Caps. Cost $60 (pre-covid). Took it to HRO to test and worked like a charm. Sold it to a ham and told him the history, and offered money back if it failed. Never heard back. Love their ease to repair, and cheap price to overhaul. BTW, the reason I sold it is I bought a new one, and then later decided to give it a shot at repair. And it ended up working.

I've had two Astron 35 amp supplies die on me after about 10 years for each.  I could've likely repaired them but I'd have to get the parts and it was easier to just call HRO and get a new one in 2 days.  I have two switching supplies for stuff like meters and an antenna tuner.  I think the largest is 7 or 10 amps.  I wouldn't use one for a rig.
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