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MY ANTENNA CAME DOWN DAMAGING MY PALOMAR 350Z

Sonar

Sr. Member
Apr 8, 2016
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70 mile an hour gusts of winds brought my antenna (Imax 2000) down. I keyed up my Madison and 350z for approximately a couple of minutes (in totality) without an antenna hooked up.
The pl259 into the antennas so 239 was ripped out of the coax (LMR 400.)
No smoke.
No popped or exploding capacitors.
No smell or anything out of the ordinary was noticed while operating the Madison and the 350Z basically without an antenna hooked up.
I hooked up the MFJ 1500 watt dummy load and to my pleasant surprise the Madison showed it's 2.5 watt DK and 13 watt pep (modulated.)
The 350z showed it's (normal) 125 watts DK and 500 watts pep (modulated.)

I let the Madison and 350z run for 45 minutes before I keyed and modulated them once again.
That's when I noticed I didn't get away without issue.
The Madison with the 350z in standby worked as it should.
Even after a 3 minute modulated key down it showed it's normal 2.5 DK and 13 pep watts with out any drop in output.
I took the amplifier out of standby and began to modulate.

After about 3 minutes (in totality) the amplifiers 125 DK and it 500 watt pep began to drop until the only output being shown on my MFJ 828 digital swr power meter was the Madison's 2.5 DK and 13 modulated (pep) watts.
I repeated the same test after shutting the Madison and 350z off for a half hour then turning them back on.
The results were the same.
The Madison shows no signs of damage no matter how long i key down and modulate.

On the other hand the Palomar 350z's 125 DK and 500 watt pep begins to drop down to zero output after modulating on and off for a few minutes.
I think it's important to mention that even when the amplifiers output reaches 0 and the only output shown on the MFJ 828 (swr/power meter) is the Madison's 2.5/13 Watts pep.
Even after the 350Z reaches 0 output it's relay is still activating when the microphone is keyed.

Those of you that are familiar with the Palomar 350Z know that there is a switch on the rear of the amplifier that allows the operator to switch between low (4 watts) and hi drive (50 through 100 Watts.) The switch bypasses the 350z's two driver tubes and uses the 50 through 100 Watts as the amplifiers driver.

Unfortunately the other two amplifiers I own are out for upgrades/repair.

From what I've written here in this post can anyone advise me as to whether they think it's the driver tubes that were damaged?
I was thinking about sending the amplifier out.

But after a bit of contemplating I thought I might save myself a few dollars by testing the 350Z with the switch in the high drive position.
The low position on the 300a which is one of the amps I sent out could easily be set for about 70 watts output.
If it is indeed the driver tubes I should see full output on the 350z with no drop down in the amplifiers output, correct?

If the problem still exists while driving it with 70 Watts what should I assume?
Could I have damaged all 6 tubes?
Or could I be actually looking in the wrong place when considering the damage to the amplifier?
If this test is not advisable please let me know?

I will wait until the 300a comes back and test the 350Z with the 70 watts driver unless those of you in the know advise against this testing.
Any ideas from my description about the way the amplifier quickly loses its output and eventually drops to zero output as to what damage could've been caused to the amplifier by operating it with no antenna?

Any information or advice as to what I should look for with the amplifiers covers (top and bottom) off that might coincide with the total loss of the amplifiers output after a couple of minutes of operation? Thanks.
73
PS. I do not have a tube tester.
 
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That is why people are using SWR meters prohibit transmit when SWR is over xxx value.
Better safe than sorry.
And to be clear, not your antenna damaged amplifier. It was you.
Mike
I didn't want to add to much info. I tend to go off topic.
My swr was 1.00 on the digital MFJ 828.
It normally reads 1.13. I thought the swr reading was something I should've payed attention too but since the swr was reading lower I wasn't that concerned.
 
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When I had an antenna come down from wind (Maco V5000), I couldn't hear much of anything and knew something was wrong, no way I was going to key up any amps. How was your receive?

That said, I know a local that has several Imax 2000 coming down / break, and still had a great SWR, I'm wanting to say even the base alone showed a pretty normal SWR, I know he ran one for a while with just a base and center or just the base section when one broke (he had a bunch of Imax 2000 and various problems).

Anytime I have high winds, I take a peak at the antenna to make sure nothing bad happened.
 
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I now run an cross needle SWR between the radio and my amp.. easy to see my radio swing and notice funky SWR before I kick on my amp.. and also kind of pass thru monitoring when the TS350 is on as well. Only gain is like a . with the amp on vs. off.

My A99 recently went up to 41' or so to the tip. So now I watch everything.. any change to anything, I just walk outside to check. Ain't worth frying crap for a downed antenna.
 
I tuned a pair of 8877s up into an open piece of coax once. Grid current was in check so they didn't seem to mind. :oops:

I would try replacing the plate blocking cap(s). The high voltage from the open circuit may have damaged it.
 
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When I had an antenna come down from wind (Maco V5000), I couldn't hear much of anything and knew something was wrong, no way I was going to key up any amps. How was your receive?

That said, I know a local that has several Imax 2000 coming down / break, and still had a great SWR, I'm wanting to say even the base alone showed a pretty normal SWR, I know he ran one for a while with just a base and center or just the base section when one broke (he had a bunch of Imax 2000 and various problems).

Anytime I have high winds, I take a peak at the antenna to make sure nothing bad happened.
I didn't look at the Madisons s-unit meter but two of my closest locals we're having a qso and sounded (DB wise) just as loud as they always do. Theses guys are about 10 miles away. I'm guessing that the 10' of the 125' of LMR 400 that was actually hanging up in the tree was acting like an antenna hence the negligibility of the RX once the Madison was turned on.
My swr was actually reading lower on the digital side of the 828.
I didn't look at the analog (cross needle) side of the meter. I'm sure it's also read lower then normal. Had it been higher especially astronomically it would have caught the corner of my eye.
The digital side normally reads 1.14. On that day it read 1.00.
If the loudness of those two stations was affected on the receive side it was initially negligible.
I had no reason to pay extra attention as to how they sounded.
Thinking back I'm sure those stations were lower DB wise (ever so slightly.) And had i looked at the Madisons s unit meter I probably would have noticed the two locals had a lower signal than normal. But I didn't. I can't go back and change the fact that it went down the way it did. By time I would've noticed I believe the damage was already done.
It doesn't bother me that some are going to blame me. I already blamed myself.

I hope like myself others can get passed pointing the finger and give me some ideas as to what possibly was damaged Indy amplifier using my description as to the way it's currently working (or in this case not working.)

I've heard and read stories about operators who've been on the air for 50 + years and forgotten to screw their pl259 into the back of their transmitter before operating.
How many times do we hear stories about people who reverse their pl259's while hooking up an amplifier?
It happens more than one could imagine.
We're only human and s*** happens.
I'm not embarrassed or ashamed to say that I should have noticed something wasn't right.
I should've heard or seen something that would've stopped me from keying up the microphone. But I didn't and it's not the end of the world.
I'm not going to beat myself up over it.

I hope that most reading this post can get past the fact that I made a mistake and caused unnecessary damage to a perfectly working amplifier. I have no doubt that the amplifier will be up and running to its 100% working condition within no time.
I'm just trying to get some ideas as to what the damage could possibly could be.

I'd like to get some input before I get the amplifier to my technician. It will probably take him less than 10 minutes to tell me exactly what the damage is.
My curiosity is definitely peaked and the thought of waiting a week or two to find out exactly what happened and the damage that's causing the amplifier to act the way it is might drive me close to insanity
LOL!
I jest of course but it certainly would be nice to get some serious input as to the possible damage.

I think the information I described to you should lead several members to hit the nail on the head as far as exactly what happened to the amplifier and what will need to be repaired.
Thanks to all who reply.
73
 
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We all have " Senior " moments . My drill daily before I " Key " is check ! I got up one morning , took the dog for his walk to find the top section of my A-99 unscrewed & lying on the ground lock washer and all ! Whipping back& forth w/ the winds on this hill caused it ( I assume ) now Loctite ! Good or Not ! Swr is fine ! But like said I check daily before keying .
 
I've been adjusting and changing my 3 antennas here since I moved in last week.

Today was take the 'choke' off the A99 day and see if I get and stray RF at gound level or in the house day. But guessing since the antenna is like 20+ feet above the roof I should be fine even when I was pushing 300w. I checked the coax twice before getting down..

On the end-fed for HF same thing.. added said choke (and later removed again..

Then inside the shack I keyed up my CB in AM mode.and the TS350 was in SSB mode and made a horrible clicking.. Thankfully it was a single second to check SWR and it didn't kill the TS350 or the CB..

So yes we all make mistakes. Sorry about your amp..
 
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I've been adjusting and changing my 3 antennas here since I moved in last week.

Today was take the 'choke' off the A99 day and see if I get and stray RF at gound level or in the house day. But guessing since the antenna is like 20+ feet above the roof I should be fine even when I was pushing 300w. I checked the coax twice before getting down..

On the end-fed for HF same thing.. added said choke (and later removed again..

Then inside the shack I keyed up my CB in AM mode.and the TS350 was in SSB mode and made a horrible clicking.. Thankfully it was a single second to check SWR and it didn't kill the TS350 or the CB..

So yes we all make mistakes. Sorry about your amp..
I'm glad to hear that there was no damage to your equipment. It's obvious that almost all who've been on the air long enough will inevitably make a mistake (if they haven't already.)
I'm sure there were those who've ruined thousands of dollars in equipment in the blink of eye (literally and figuratively.) The lesson I've learned is priceless. Well not exactly priceless. $60 round trip shipping and the price to repair the amp. I'm guessing the cost should'nt exceed $200. Some might think $200 exceeds the worth of the amp. This amp and some other equipment I own and operate were given to me by a friend who's no longer with us. I refuse to turn anything he's given me into a paper wheight. If it can be repaired (and I'm positive the 350z can be) then it shall be. I've decided to have the amp packed up and sent out to my tech.
Even though my knowledge of amps and diagnosing the damage I caused is low on the technical side, the testing I did after my faux pas I believe that the issue is tube related. It's unfortunate the sweep tubes my amps (and most base craze era amps) use are so damn expensive!!
My mistake caused me $. Live and learn. It could've been worse. The Madison got away unscaved. Thanks to all who have replied. 73.
5200-1507945963-a7242cd1c7259320f9c184dbd68967ce.jpg
 

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