[ICOM] IC756 Pro III Filters

Phil Krichbaum vailphil at sopris.net
Sun Oct 2 06:33:49 EDT 2016 

Ron,

     Colorado is Nr 2 to FL in lightening strikes and they rarely happen 
in the winter. 15,000 on a summer afternoon is not unusual! I sit on a 
high spot in the middle of a large valley in western CO and am about 700 
ft higher than the Colorado river about 5 miles to my north. I'm right 
at 6000 ft ASL and can see mountains of 10,000 to 12000 ft within 15 to 
20 miles. I have 9 towers with none over 75 ft. My effective height is 
more like 150 to 250 ft in many directions as it slopes gently downhill 
for up to 7 miles in some directions and I get some nice ground gain 
from my mesa location. I have no trees over 25 ft as it is quite dry. 
After my first event with a strike coming in the neutral and taking out 
the TV, answering machine and 756 PRO II and a few other items, I had 
the power company install a "Meter Treater" on both my meters (one for 
my well, 1/4 mile from the house) and I've not lost anything else except 
an answering machine and two well relays that I can replace myself for 
about $50 even though I've seen lightening strike the 40 ft power pole 
50 ft from the house 3 different times. It is interesting to see, hear 
and smell it at the same time. Last summer a strike blew the lightening 
arrestor oft the transformer and took out a noisey xfmr at my neighbors 
so cured that problem. I have a 70 ft tower about 100 ft from the power 
pole and no problems with that tower.. As far as I know my antennas have 
never been struck and I ground all my antennas at the bottom of each 
tower plus put in a 3 turns coil of coax 3 ft in Dia (almost infinite 
impedance to lightening) at the bottom of each tower before the coaxes 
go to an antenna switching and lightening arrestor location 100 ft out 
from the house.  From there two buried hardlines carry signals to the 
shack. These Meter Treaters cost about $75 each to be installed and are 
guaranteed to cover something like $400K in damages. Apparently they 
cost the power company around $350 each and apparently are 3 big MOVs. 
One of our local hams used to work for the power company and he said he 
never had seen one go out! I have switched over to a K3 for my go to rig 
and can hear a relay kicking in and out when storms are close or if 
someone is TXing on a 2nd rig in a contest.. Blowing snow or rain is 
enough to take out the Icom rigs as they are so poorly designed. If you 
use a beverage RX ant thru the RX antenna jack on the Icom, it is still 
connected to the RX when you TX which takes out some grain of wheat 
sized FETs in the tuner. Icoms are not the only rigs built this way but 
K3s seem to survive. Anytime I see a storm or leave during lightening 
season, I disconnect the two coaxes to the rig and pull the power strips 
out of the wall plugs. I've got 3 KW amps running off 235VAC and can 
unplug one cable to isolate those. On the first instance with the TV, my 
insurance company wanted me to get a TV shop to say lightening caused 
the damage. There are two TV repair shops within 75 miles and one only 
does big home entertainment centers and the other one doesn't answer 
their phone! You do not fix modern regular TVs as it is cheaper to buy a 
new one. My neighbors like my antennas as they have not had any 
lightening strikes since I moved here. Most of the properties are over 
100 acres except for my little 8 acre piece so neighbors are far enough 
I usually drive over for a visit. Obviously no local antenna 
restrictions and I'm my own HOA.

  73   Phil N0KE


On 10/1/2016 2:17 PM, Ron via Icom wrote:
> Hi Phil. Same here. A couple of years ago, a lightning strike on the Neutral leg of my power line took out a LOT of things in my house. The PRO was off and antennas grounded. Luckily, the radio and Astron (also off) were an easy fix. The TVs, DVD, etc, not so lucky.......
> Having two 100 foot + towers, I was fortunate. However, they are well grounded.
>
> Ah Florida, the lightning strike capitol of the USA.......
>
> ron
> N4ue
>
>
>
> -----Original Message-----
> From: Phil Krichbaum <vailphil at sopris.net>
> To: ICOM Reflector <icom at mailman.qth.net>
> Sent: Sat, Oct 1, 2016 4:08 am
> Subject: Re: [ICOM] IC756 Pro III Filters
>
> The Icom 756 PRO II and III rigs are very poorly protected against ESD
> as even with antennas disconnected and power off it can come in the
> neutral side of the power cord. You need to not only disconnect antennas
> but remove the power cord from any connection to power system. It is
> likely that turning the power strip off left the neutral connected to
> the PS and rig. I had a 756PROII destroyed when the antennas were
> removed from the radio and the Icom PS was off but the rig was toast and
> it (nearby lightening) came thru the neutral side as the power cord from
> the Icom PS was off but plugged into the wall outlet. The Icom PS
> survived and it is still in use with a 756PROIII yet today, some years
> later. If you are using two rigs on different bands at the same time in
> the same station, you could toast a 756 PRO II or III even with the
> other rig at the 100w level. Been there, done that too. Icom doesn't
> seem to think it is an issue? My 756PROIII is now a backup rig.
>
>       Phil N0KE
>
>
> On 9/30/2016 9:21 AM, Mike McCarthy, W1NR wrote:
>> Clear the twin passband tuning? (PBT Clear)
>>
>> Mike, W1NR
>>
>> On 09/30/2016 10:54 AM, Mark K3MSB wrote:
>>> Hello
>>>
>>> I've owned my radio for quite a few years (purchased new) and it's worked
>>> without issue.
>>>
>>> Recently, I noticed that when I go to the 500 and 250 Hz filter settings on
>>> CW,  the audio is like what you'd hear in the bottom of a barrel.
>>>
>>> Prior to this, when switching between the 1.2 Khz,  500, and 250 Hz filter
>>> settings while copying a signal,  the signal was always centered.   Now,
>>> for the 500 and 250 positions I have to adjust the main tuning slightly,
>>> and the signal is not sharp and distinct.
>>>
>>> I've performed a reset on the radio which did nothing.
>>>
>>> Now, a few weeks ago during an electrical storm I heard a "pop" from the
>>> radio bench.   All antennas were (of course) physically disconnected.   I
>>> forgot to remove the power plug from the outlet strip, but the strip was
>>> turned off.     Afterwards, as is currently the case,  aside from the
>>> filter issue,  the radio works fine.
>>>
>>> Any ideas?
>>>
>>> Thank you
>>>
>>> Mark K3MSB
>>> ----
>>> Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
>>> Icom Users Net: Sundays, 1700Z, 14.316 MHz
>>> Icom FAQ: http://www.qsl.net/icom/
>>> To support QSL/QTH.net: http://www.qsl.net/donate.html
>>>
>> ----
>> Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
>> Icom Users Net: Sundays, 1700Z, 14.316 MHz
>> Icom FAQ: http://www.qsl.net/icom/
>> To support QSL/QTH.net: http://www.qsl.net/donate.html
>>
> ----
> Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/
> To support QSL/QTH.net: http://www.qsl.net/donate.html
>
> ----
> Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/
> To support QSL/QTH.net: http://www.qsl.net/donate.html
>

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