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Author Topic: Another Astron question.  (Read 406 times)
KD5TOS
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Posts: 14




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« on: April 20, 2004, 08:08:12 PM »

I'm getting set to buy an Astron and would like to hear some opinions on the metered vs. unmetered versions of the RS35.

I can imagine the meters being useful at times.  I can also imagine that I'd not really look at them much.  Then again..I like the idea of meters,...then again,  why bother?

Any opinions, Reasons ?

RS35A or RS35M?
Thanks in advance
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K5LXP
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« Reply #1 on: April 20, 2004, 08:17:47 PM »

Meters have a limited usefulness on a supply that will likely be stashed behind or underneath the operating position.  Even if within sight, they offer little more than eye candy during typical operation.  Having meters on a bench supply that is constantly adjusted and monitored during operation is definite plus, however.

Mark K5LXP
Albuquerque, NM

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KA5N
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« Reply #2 on: April 20, 2004, 09:17:55 PM »

It is quite simple to add a current meter to any Astron supply.  In the 35 amp unit there are four 0.05 ohm resistors which are used to balance the load on the series transistors (output stage).  Simply rig a microamp meter to read the voltage across one of these resistors and divide by 0.05 to get the current and multiply by four to get the total current.  You can remote the meter and put it where you want it.  If you are not sure how to do this any ARRL handbook has the information on meters and how to calculate the needed series resistor.  I did this with a RS-20 when I wanted to make sure and not draw too much current on a TenTec 405 amplifier.  If you have a meter with a scale that doesn't lend itself to be easily read you can make your own scale (use a computer drawing program) and install it.  Makes a good easy project.
Gud luck Allen KA5N
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KB1GTX
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« Reply #3 on: April 20, 2004, 09:34:07 PM »

I have the vs35 and both the meters,voltage
adjustment and current limmiting is really quite usefull.

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W5ONV
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« Reply #4 on: April 21, 2004, 12:31:44 AM »

 I have the SS-30 M . I like having the current meter to look at and monitor the current drawn while operating SSB. Actually I look at the current meter more than the power meter on the rig. I can tell about how much power is going out by the fluctuations on the current meter. I don't look at the voltage meter very often as it is always constant. 73,Jim
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W4TME
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Posts: 299




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« Reply #5 on: April 21, 2004, 07:06:47 PM »

I have to agree with Jim, W5ONV.  I do the same thing a lot, just to make sure I an not drawing too much current. Since I power other things in my shack besides the rig with my RS-35M, I could exceed my current budget if everything was powered on and operating at the same time (which I don't do, but you never know, especially after contesting for several days...).  Meters are good.  Smoke is bad. Very bad.

-Tim
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KD5TOS
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Posts: 14




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« Reply #6 on: April 21, 2004, 09:57:21 PM »

Thanks for all of the great replies.  I had to ask.  I've  read quite a bit about these units on eHam and they seem to be the way to go (resale value seems good too).  

SSB power flucuations?  Now why didn't I think of that!
     Cool!

Remote meter mounting?  Now why didn't I think of that!
     Cool!

Thanks again
Karl KD5TOS
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WA9SVD
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« Reply #7 on: April 22, 2004, 02:45:14 AM »

Meters can be fun to watch, but they can also be added to a regular power supply!  It's what Ham Radio is all about, isn't it?
    If you have to troubleshoot, you'll still need a multimeter to check voltages, and a panel mounted meter is no help there.
    An Ammeter may be of some help, IF the power supply is easily visible from the operating position.

    Then again, if price is no object, get the supply with the meters.
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WB2WIK
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« Reply #8 on: April 22, 2004, 01:41:07 PM »

Astron offers the meters for such a reasonble cost -- much less than it would cost to buy meters and add them, yourself -- that the difference is well worth it, even if you look at the meters once a year.

However, it's true that: "I don't look at things I can't adjust," and observing load current on an ammeter while operating SSB is kind of meaningless.  Load current hasn't much to do with output power, at all.  My rigs run absolute max-out full PEP power while indicating practically nothing on the RS50M ammeter...the meter isn't nearly fast enough to respond.

WB2WIK/6
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NA9Q
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« Reply #9 on: April 22, 2004, 08:37:19 PM »

One major consideration.  I took an Astron SS30M on a Ham vacation to the island of Rhodes (SV5) a couple of years ago.  While the supply handled the trip quite well and was ideal in terms weight and compatibility with 230 VAC, 50 Hz, the meters were less than ideal.  Typical of most present day mechanical meters, they are taught-band movements and are quite sensitive to vibration and shock.  In my case the voltage meter arrived back home after the mini DXpedition with a stuck needle.  The meter had to be replaced.  So consider if you will be traveling with this unit or not as to the desirability of meters.  If you only use it at home, no problem.  If it must survive in checked baggage, I would recommend against them.  73, Mike, NA9Q
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KA5ROW
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« Reply #10 on: April 22, 2004, 08:49:58 PM »

I have a Astron RS70 and I use it to power a 400 watt TE-System amp and a 2 meter all mode rig. As I read earlier it is just eye candy I saved a few dollars and did not get the meters. But at times it would be nice to see how many amps you pull. Once you know it is not that important anymore.
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W5ONV
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« Reply #11 on: April 22, 2004, 11:30:20 PM »

The meter on my SS-30M is very accurate and fast acting. At 100 watts SSB,I can do a very short, fast whistle and show a full 20 amps on the Astron meter.At 100 watts FM it will show a full 21 amps. The meter is actually fast response and accurate.  73,Jim
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