Ground requirements for Flex 6500? (2nd floor shack)

Jeff Shelton

I am considering the purchase of a 6500. My shack is on the second floor of my house, and I can't change this.

By liberal use of common mode chokes, burial of coax lead-ins, and proper grounding at the ground level entrance point of all coax, I've been able to get with by a 18 foot long lead from my operating position to the entrance panel ground point, using conventional rigs, without apparent problems. These included a TS-590S, a TenTec Argonaut VI, and a IC-7200. None seem to have issues.

My question is, is a Flex 6500 significantly more likely to have problems from my less-than-ideal ground than conventional rigs?

David

I have the same second floor shack issue and the Flex works great not difference between it and the old Icom IC-725. I don't have a separate run of a ground to the panel or to an earth ground. Not ideal but it works and have not encountered any issues. You should have a great time with the 6000 series.

WA2SQQ

Nothing special here either. Much better than 5000 was.

George KF2T

Also on the 2nd floor. No special issues.

K0UNX

Agreed.  No problems with grounding.  As long as your cables come through a COMMON ground somewhere, the long cable inside the house shouldn't present any sort of problem.  Note that I live in an area with abundant lightning in the summer, so when I erected my tower 42 years ago, I had a caisson driller drill me a 24" diameter hole, TWENTY FEET DOWN and I buried two sections of Rohn 25 underground before erecting the above-ground portion.  I've been struck by lightning MANY times with no damage to anything.  INSIDE the house, I have a common ground with an 8' ground rod bonded to water and electrical at a common point, and all COAX mounted on a copper plate using SO238 "feed-throughs" through that copper plate.  AND I always disconnect the radios when not in use.  By using "slip-on" rather than "****-on" PL259's, I can just "yank it off" at the first rumble of thunder.

K0UNX
Jim Flannery
Littleton, Colorado

Jeff Shelton

Excellent information, thank you all - Jeff N3JS

jim

A good friend has a 5000 and tried everything to get rid of problems.  He ended up getting the MFJ-931 artificial ground and his problems are now gone.

KY6LA_Howard

Suggest you read Hiow to Build a Quiet Station https://community.flexradio.com/flexradio/topics/how-to-build-a-quiet-station

Bob K4RLC

Guess I'm the outlier, as I had significant RF problems with the 6500 on a second floor shack...and none of the other rigs in the same operating position.
Tim sent an article on grounding that really helped (I'm out of town and don't have access) but it basically has modifications that I didn't need for the 706, 746, 756, FT-1000 or any other rig.
Liberal use of toroids is needed, including mic cables...After trying several spkr combos, I ended up with the West Mountain Radio Spkrs. These spkrs are much cheaper than others and better shielded.
Hope this helps.
73  de K4RLC Bob Raleigh, NC

Jim

I have had many radio's 5 different Flex's and many more does matter what floor it now got to be grounded and  the antenna and the house. The link I have shows my ground system and there are 2 more links inside of the main link. A station ground will cost several hundred dollars  if done right.
http://w4wwj.org/house_and_station_grounding.htm

73 Jim W4WWJ

Jeff Shelton

Many thanks for the information. Some details on my station grounding: antennas are tree-mounted dipoles and a vertical. Common mode chokes are applied on the coax at the antenna feed point.  Coax runs are buried until they reach the KF7P entrance panel on the ground floor. I've bonded the entrance panel to the service ground and an an additional 8' driven ground rod. About the bottom four feet of this ground rod is in the water table here, which is brackish.

Coax coming in is mounted to Alpha-Delta gas tubes to connect to the coax running up to the second floor shack. Equipment in the shack is all bonded to a copper bar at the operating position. An 18' length of #4 copper wire connects that bar to the KF7P panel.

I would feel pretty good about the grounding setup were the shack not so far from the KF7P panel, but I can't change that.  Anyway, since getting all the other pieces in place, I've had no RF-in-the-shack issues, even running 500 watts.

If the 6500 is no more prone than legacy radios to RF feedback issues, I should be good. However, I've heard - possibly incorrectly - that the Flex rigs are much fussier about grounding and much more prone to RF feedback problems than legacy rigs, thus my question.

Again, many thanks - Jeff N3JS

George KF2T

The thing is that the 6000's have a network connection, which provides a ground loop possibility, or an additional path for RF ingress. Since the radio's performance is tied tightly to the network and client computer, anything that gets into those will adversely affect the 6000.

Al_NN4ZZ

The RFI ingress was one reason I added an optical link.  The other reason was lightning isolation.  (blowing out the ethernet interface in the radio would inconvenient)

More info on my web page on the ethernet optical link, RF blocking and grounding.

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

Regards, Al / NN4ZZ  
al (at) nn4zz (dot) com
6700 - HW.................... V 1.6.17.74
SSDR / DAX / CAT...... V 1.6.17.156
Win10

Jeff Shelton

Oh, that looks like it would do the trick.

WA2SQQ

Can you post the info on the optical converter you used? I was led to believe these were rather expensive.

Walt - KZ1F

That is awesome Al! I did a google on fiber media converter and Amazon actually has a bunch around $70. You'd need two I suspect, fiber to ethernet and ethernet to fiber. Al, you show a multinode one which is even better...add $19. I suspect it helps keep rf away from endpoints too.

Al, to your knowledge are there quality / performance differences varying by price or are they all coming out of the same factory, so to speak?

Prior to your post Al, I wouldn't have concluded that was the term to google.

Al_NN4ZZ

Here are the ones I used, all from Amazon.  Total cost was about $160 in 2013.  There are others that are as good or better but 100MB was all I needed.  I got the optical jumper so I wouldn't have to mess with adding the connectors.  The install was plug and play, wish everything was this easy.  It has been installed since August 2013 and never any problems.  

Regards, Al / NN4ZZ  
al (at) nn4zz (dot) com
6700 - HW.................... V 1.6.17.74
SSDR / DAX / CAT...... V 1.6.17.156
Win10








Either cable will work, I got 2 sizes but the short one is fine.

WA2SQQ

Just an FYI to all who might be thinking of purchasing these two items and feed your Flex (or shack) with a fiber isolated feed. The fiber cable you need MUST be a  MULTIMODE (orange) cable. I tried using the single mode (yellow) cable and the two units would not talk to each other. You also need to make sure that the TX on one unit is connected to the RX on the other unit, and vice versa, Now, all is working fine with absolutely no speed reduction.

Al_NN4ZZ

Yes, I'm also using the orange multimode cable. Never tried the other one so removed it from my list.

I would remove the yellow single mode cable picture from the post above but it can't be editted. Thanks for the note.

Regards, AL / NN4ZZ

Tim VE6SH

Thanks Al. I will try implementing this as I have some stray RF when I operate CW at HP. Your webpage also provides some valuable advice!

73

Tim VE6SH

Walt - KZ1F

A service ground is not an RF ground. Snake a copper ground wire (stranded 12-14 gauge through to your basement. Drill a 1" hole through the cement floor, drive an 8' copper ground rod and weld the ground wire to the ground rod.

Jeff Shelton

Already did that, save that I used much larger wire. Local code requires the driven ground rod to be bonded to the service ground, so it is. One bet I missed is that the connections are mechanical, not Cadweld, but I have no RF problems with my TS-590.

The 6500 is on order, once I've set it up I'll post here with the results.

Stan VA7NF

One additional step - seal the opening if there is any Radon or high water table.  On my previous shack I did the above but made it two 8ft separated ground rods through the concrete pad.  And yes also connected to the service ground to meet code.

Walt - KZ1F

Both excellent points Stan.

Jeff Shelton

Just thought I'd mention I've set my 6500 up and been using it for a few days. No apparent problems from the second floor location. Many thanks to all for the help and information.