ECO-4, am I reading this correctly?

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abwdvm
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ECO-4, am I reading this correctly?

Post by abwdvm »

ports.jpg
VSWR.jpg
VSWR of almost 2?
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Re: ECO-4, am I reading this correctly?

Post by RGORJANCE »

The meter is punched--depressed---in the FORWARD position and it is showing over 1kw xmttr output.

The overall efficiency of the xmttr is very poor, as I see it on the metering. It calculates out to 34.5%. Definitely waaaay low.

For one thing, the plate voltage is way too high for 1000-1500 watts Tpo. The power xfmr needs to be tapped to produce the lowest secondary voltage you can obtain. If that won't get it down, try to locate a power xfmr out of a 1-2.5kw xmttr and use that to obtain a lower Ep. I think you should have a plate voltage value of under 3,000 volts to get it at 1-1.5kw watts output. While I never worked on that rig, i would think that you should be seeing over 60% efficiency at that power level.....maybe even higher.

Anybody currently running a 1-2.5kw tube rig that could tell us what Ep/Ip/Tpo you are running.

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Re: ECO-4, am I reading this correctly?

Post by abwdvm »

Once we get it moved and set, I will go through the tuning procedure in the manual
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Re: ECO-4, am I reading this correctly?

Post by Deep Thought »

On that transmitter the power output is directly controlled by the IPA power output driving the tube. The PA voltage does not change (much) from zero to full power output. What is the plate current on the PA?

Edit: found the Ip on your earlier post. Check the IPA output power. ALSO...check the fingerstock on the deck which slides over the tube to make sure it isn't burned off. I ran into an ECO6 which was pulling full plate current with zero output and had a PA cavity vent stack which was blowing ridiculously hot air...the tube had no RF connection to the output network but still had "normal" Ep and Ip readings and the IPA output varied the plate current like it was supposed to. I found this inside:
IMG_20160921_171613.jpg
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Re: ECO-4, am I reading this correctly?

Post by RGORJANCE »

Deep-----it looks like about 0.750 amps of Ip.

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Re: ECO-4, am I reading this correctly?

Post by abwdvm »

So the hose clamp is not factory? Ours has one too....
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Re: ECO-4, am I reading this correctly?

Post by Deep Thought »

The hose clamp is standard equipment. The lack of fingerstock around the tube in the space between it and the deck is not.
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Re: ECO-4, am I reading this correctly?

Post by ncradioeng »

What is your transmitter output power supposed to be?
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Re: ECO-4, am I reading this correctly?

Post by abwdvm »

3600 ERP
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Re: ECO-4, am I reading this correctly?

Post by Deep Thought »

That's not the transmitter power. It should be on the license.
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Re: ECO-4, am I reading this correctly?

Post by kkiddkkidd »

RGORJANCE wrote: Thu Jun 28, 2018 12:51 pm Deep-----it looks like about 0.750 amps of Ip.

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Where, pray do tell, are you devining an Ip reading from? Admittedly it is 1:15am, I am sitting in a hotel room, in a town that I didn't mean to be spending the night in, but I ain't saw a Plate Current meter yet...
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Re: ECO-4, am I reading this correctly?

Post by Shane »

It’s in the picture of the transmitter in the OTHER thread on transmission line.

We’ll have to hear your story later. :shock:
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Re: ECO-4, am I reading this correctly?

Post by Nathaniel Steele »

Aren't tube transmitters less efficient when operated at lower than rated power? of course 35% is still way low.
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Re: I ain't saw a Plate Current meter yet...

Post by RGORJANCE »

I have exceptional powers.......I know all, I see all........(I enlarged the picture showing the meters) :lol: .

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Re: ECO-4, am I reading this correctly?

Post by TPT »

I'm confused- ERP of 3600? Let's back up and start from the beginning, several questions:

1. Licensed ERP of 3600?

2. How many antenna bays? Can you tell who made them? (shot a picture)

3. How many feet of coax from the base of the tower to where it goes into the antenna?

4. How many feet of coax from the base of the tower into the shack and to the transmitter?

We can do the calculation and figure out what transmitter power output you should have. As I noted in the feedline thread--the output meter on these transmitters are "gee--It's there." Also, you will find the efficiency numbers in your manual are examples of great fiction writing.

I have one of these things--like you--got the transmitter with the station when we bought it. Also take care of an ECO-6 at the local college. I would check the tube socket as suggested above. I would also check the tuning and loading controls. These are nothing more than a sliding short on a threaded rod between two bars..they can get dirty, and--problem with my ECO-4--the tiny little hex-head screws loosen up in the plastic block connecting the front panel crank to the slider. You turn and turn and turn --and nothing happens.

These transmitter tune differently than you might expect. Some of the problem was bad 3CX3000A7 tubes out of Econoco a couple years back. After being bought by CPI (Eimac) rebuild quality has increased substantially. Often you have to do a lot of cranking to get the output up.

The IPA metering is dependent upon the last tech who touched that IPA...I have one transmitter where the IPA output meter is pegged, the other where it reads half scale. Only way to know for sure how much drive you have is to insert a Bird watt meter between the IPA and the grid. Probably not worth the effort--either the IPA works or it doesn't. You can drive the final with an outside amplifier, but the match is touchy. Had to run my 802B in directly one time, got about a kilowatt out.
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