Off Air for 50 Years. Now Need System Configuration Feedback

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  • Updated 6 months ago
Hello, Flex community.  I have been off the air since 1971 and am now awaiting delivery of a Flex 8600.  I am constrained on antennas and transceiver location so that the Flex will blend right in.  I am not familiar with all of the new modes and digital stuff but will be learning on the job.
The purpose of this post is to describe my configuration and ask for feedback on potential problems/improvements.  I have read a lot of posts and Flex Help Desk documents, so feel I have addressed most of the common issues.

First, the configuration:

Flex 6400 
Astron RS-35 DC power supply

80-10 Meters

20 Foot Offset Feed Flagpole Antenna, 80-10 meters
1:1 Current Balun
LDG RT-600 Remote Antenna Tuner
ATD-1 Remote Antenna Disconnect / Lighting Protection
125 Feet 400 MAX Coax 

2 Meters

Down East L144-28HP75 Transvertor
Hustler G7-144 Vertical Antenna
DX Engineering DXE-ISFL1-NF2K Lighting Arrestor
100 Feet 400 Max Coax

Questions

1- Equipment Grounding. The Astron power supply schematic shows two ground points.  First, the NEC required equipment ground to the metal case back to the utility equipment ground.  And second, the 12 volt minus is grounded to the metal case.  The internal step-down transformer provides internal isolation of the 120 VAC, so I was surprised to see the 12 VDC is ground to the same case, tying the negative terminal to the utility equipment ground.   This path provides a path for fault current and utility originated lighting strike currents to flow thru the Astron power supply then to the FLEX 8600.  Should I open up the power supply and break the negative post to the metal case bond?  This prevent any utility originated fault currents from flowing thru the Flex.   And, may also eliminate a “ghost” RF circuit path from the Flex back through the power supply.

2 - Floating Earth Ground for OCV Vertical Antenna.  

The Flagpole OCF antenna must float above the earth ground.  This requirement precludes the use of lighting arrestors, so a remote antenna disconnect is used when the Flex is not in use to open up the shield and conductor, then bond each to a remote earth ground.  To keep the OCF antenna floating, if I do not provide an RF ground at the FLEX, will that be an RF leakage problem?  Will providing an RF ground at the FLEX downstream of the tuner and 125 feet of coax, impact the performance of the Flagpole?  

I will also be working two meters.  Even if I do not directly provide an RF ground directly at the FLEX, the coax for the 2-meter antenna will be grounded at the lightning arrestor and provide an RF path from the FLEX through the transvertor chassis to the lightning arrestor.  Will this be an RF problem?  Will it affect the performance of the OCF Antenna, as this would be a bonding point to earth ground?

For now, I plan to provide an RF ground at the Flex directly.  Probably a design compromise, but it seems to eliminating RF in the shack takes priority over OCF antenna performance.

3- Lighting Protection and Equipment Grounding Effect on OCF RF Performance

I have an auxiliary grounding system at my home.  The National Electric Code requires the auxiliary ground system to connect all earth grounds and bond to the utility system at one location, the utility entrance earth ground.  Now, back to the OCF antenna which floats above the ground.  For lightning protection, I am using a remote disconnect and driving an earth ground remotely at the antenna, which the disconnect will tie the shield and conductor of the antenna to when not in use.   National Electric Code says this remote earth ground must be bonded together with my other earth grounds as described earlier.  So, I am running 100 feet of #6 copper to this remote earth ground for bonding purposes.  When in service, the copper will be disconnected at the antenna end and will remain bonded to an earth ground near my shack.  Question, when transmitting on HF, could the 100 feet of the copper act in any way as a near resonate device to mess up the OCF antenna performance or provide eeard RF paths?

Thanks, everyone for your feedback on my configuration and any of the questions.
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Alan

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Posted 6 months ago

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Photo of Mark - WS7M

Mark - WS7M

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Hi Alan,

Welcome back and wow!  You are jumping back in big time!

First, your configuration sounds wonderful but it will be complex.   I suggest you start small.  IE don't try to learn to operate everything the first weekend.

The Flex Radios are a different paradigm than radios from the big three.  You will control your radio (I didn't see a Maestro in your list) completely from your computer.  So this implies for relatively trouble free operation:

1) A good network
2) A reasonably powerful computer
3) The patience to learn to control your radio via the computer

Just getting your station working on HF will be some work.  You will have to get used to the remote tuner and I question if it will be able to tune a 20 ft pole on 80m or not.  I'm not personally familiar with the 20' OCF configuration.  But hopefully it works for you. 

As you mention the grounding will be tricky and because of this you might have to deal with some RFI issues.   I would add to your list a bunch of snap on RFI cores to put on your network cables and other cables in/out of the radio.  

We have had quite a few people here that say had an Icom radio, then they change to a Flex Radio and suddenly have an RFI problem when TX at full power.   Some say the Flex is not well protected against RFI.  I beg to differ and rather think that their RFI problem was there all along and they just didn't see it in the same way with the Icom.

Remote Antenna Disconnect - I hope this works for you.  The idea is sound but every lightening expert I've talked said that if you receive a strike pretty much anywhere on your property these remote disconnects do not have enough gap to do much good.  And certainly on a direct strike it is unlikely to protect your gear.  In addition, the lightening can do just as much damage coming in over the power lines as it can over the coax.

In my humble opinion the only way(s) to protect your station/gear from lightening is to physically be there and remove all cabling from the units during the storm AND carry a lightening insurance policy if you can get it.

I live in Colorado and I carry lightening insurance and I try very hard to simply disconnect everything when a big storm looks to be in the area.  It is a pain.

Anyway, welcome to the Flex.  I think with some patience you will be very happy.
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Alan

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Thanks, Mark

Thanks for the ideas and feedback.  Agree on taking it one step at a time.  I do tend to overthink before I act.

Alan
Photo of Al / NN4ZZ

Al / NN4ZZ

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Hi Alan,
Here are a few links to my Flex 6700 web page that may be of interest.   The links are to notes on RFI, grounding, lightning protection, Ethernet and USB protection I've employed on my 6700. 

http://www.nn4zz.com/FLEX6700.htm#RF_issues_and_solutions

http://www.nn4zz.com/FLEX6700.htm#Ethernet_Lightning_Protection

http://www.nn4zz.com/FLEX6700.htm#USB_Port_protection_

And other notes, links, etc

http://www.nn4zz.com/FLEX6700.htm

I'm sure you will enjoy your 6400!

Al / NN4ZZ  
al (at) nn4zz (dot) com
6700 & SSDR-W  V 2.4.9
Win10

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Alan

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Thanks, Al

I had seen portions of your articles in other posts.  Lots of good information.  Thanks.

One question.  I am looking for a "feed thru" for the outside to inside cables.  I noticed on in your grounding article.  Can you tell me the make and model?

Alan

 
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Al / NN4ZZ

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Hi Alan,
The feed thru is homebrew.  I just used some electrical boxes, conduit, and waterproof covers I got from Home Depot. 

I mounted an electrical box on the outside wall.    Then drilled through the wall to locate where to mount another box on the inside wall.    There is a piece of conduit between the boxes.  I mounted the covers on both the outside and inside. 

To keep out the bugs, I stuff some foam in the conduit around the cables.  The covers hide the foam but it's easy to pull it out if you need to add or remove a cable.  Just use a good size diameter piece of conduit between the boxes.

Al / NN4ZZ  
al (at) nn4zz (dot) com
6700 & SSDR-W  V 2.4.9
Win10


 
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Ed, K6VMV

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Hi Alan,
I read your post with great interest as you and I have a lot in common.  I've been a ham for many years , licensed in 1956 as KN6VMV when I was 13.  I didn't have a clue about SDR radios but  I took the plunge and bought a Flex 6300.  Best radio I've ever owned and I've owned a lot of rigs over the years.  I like to keep things simple and easy.  I haven't had one single problem with my 6300 and current setup.  I don't want to take up space here but I would like to share some of my thoughts and info with you. I would greatly appreciate it if you please send me your email address, and/or mailing address.  My email address is edk6vmv@gmail.com.  All my info, and pics, are good on qrz.com.  Welcome back Alan. 73, Ed K6VMV