A lot us are equipment junkies. Radios, antenna, accessories…how do you keep it all straight? How do you make sure you have the setup patched together that you want to be using without it affecting the received signals? Let’s see how some DXers handle this situation.

Rick Kenneally <woodlandview@yahoo.com>

I'd like a bit of advice from folks who manage a lot of radios & antennas. Right now I've got 2 longwires, a loop, a phaser, two 4-way antenna splitters, 4 receivers, and a web of patch cords and 2- pole antenna switches. When signal levels are low or high sensitivity is needed, I like to bypass the splitters and the phaser. But when I want to share the existing antenna across multiple receivers, or engage the phaser, I end up performing a series of switches and moving cables around. Now Kaz's success with the phased BOGs has me planning out another

pair of wire antennas. All of this calls for some kind of flexible, many-to-many patching solution.

I'm thinking of just building a patching box that has a bunch of SO-239 coax connectors on the back panel connected to a bunch of RCA phono jacks on the front panel. I would connect all radios, antennas, phaser, preselector, etc. to the back and just use a bunch of jumper cables to cross-connect things on the front.

My question is - how much do I have to worry about internal coupling between the different jacks? I plan on using a grounded, metal enclosure. I assume that shielded coax should be used for the internal wiring. Is shielded audio cable sufficient, or is there a better option?

Les Rayburn <lowga@hotmail.com>

Like yourself, I struggle to manage quite a few antennas here, including the air core loop, tuned active whip, EWE, TX Vertical, and others. I also have a phaser, so I wanted to be able to patch things in and out as needed.

I finally settled on using a window mounted Plexiglas piece that brings all antennas into the shack. Onto the glass I mounted female to female Type "F" connectors for feed-throughs.

Any radio that requires an S0-239 was fitted with a type F adapter, and I settled on using isolation transformers on both inputs to the phaser.

After labeling all the wires, I can now quickly swap things by simply screwing in the type F connectors.

It's not a perfect solution, but it's proven to be very workable so far.

Hope this helps.

Frederick R. Vobbe fredv@nrcdxas.org

Rick: Use "bulk head" BNC female-female connectors, and mount them on a steel panel. It's your option if you want the ground side of all the antenna common, or you can also get isolated BNCs. They are more expensive, but then you don't "share" a common ground. However, I have found that if the panel is grounded to say, a water pipe or other good ground, then the common ground system works flawlessly.

I use BNCs for anything 6-meters and below, F connectors for the FM/TV antennas, and type N for the 2-meter and above stuff.

Rick Kenneally <woodlandview@yahoo.com>

Thanks Fred, Is there any advantage of BNC over a plain old slip-on RCA phono plug for the front patch panel? I'll use SO-239 coax panel jacks for the rear, permanent connections.

One way or the other, the grounds will be connected, so I agree – might as well not bother with isolated jacks. The only issue with grounding is that my shack is on the 2nd story on the wrong side of the house, so the wire from shack to ground rod is about 25-30'.

The other thing I have to find is decent SO-239 panel jacks - the kind that mount with a big round hole and a locking nut (and NOT the kind that mount with 4 small screws). Somewhere I've got a manufacturer and part number from Gerry Thomas of just such a jack.

Charles Hutton <charlesh3@msn.com>

I also use bulkhead BNC's but instead of audio cable for connections I use miniature coax like RG187, RG188 or RG223(?). This is about the same diameter as audio cable so is very easy to work with and is the electronics industry's method of choice for internal connections at these type of frequencies.

I have no problem to find this stuff on ebay if you are interested in using it.

Frederick R. Vobbe <fredv@nrcdxas.org>

I like the BNC plugs as you push them on and give them a 1/4 twist to lock. They are the Aim p/n:27- 8470, and I've seen them as low as $1.27 in lots of 20. See: http://www.aimelectronics.com/productcatalog/aimbnc8b.htm

The bulkhead connectors are easy to mount in a hole, and tighten in with a small wrench. I use the Middle Atlantic panels, and drill them myself. See.... http://www.middleatlantic.com/rackac/panels/bpanels.htm

Some RCA jacks can be found at the Mouser site at; http://www.mouser.com/index.cfm?handler=fra_pdfset&dir=611&pdffile=384

The ones that seem to work well are the "D" variety as long as you terminate the antenna connections close to the jack. Also, it's a good idea to make a termination or shorting "male" RCA pin plug so antennas not used are not left open in the patch field.

(The length of the wire from shack to ground rod) *could* be a problem, but if you terminated each antenna with a 50-ohm resistor when not in use, you may be able to fake it out. I would try it and see what happens.

Check out http://www.aimelectronics.com/productcatalog/aimuhf14b.htm and see if some of those help you(to find decent SO-239 panel jacks).

By the way, I have seen a few guys selling the "nuts" that go on the 25-7351 style connectors in packages of 50, and there is no reason you can't thread them on the 25-7330 connectors. The only trick is to use some material like.375" thick Plexiglas to mount them in since you have the added space you need to make up.

Jim Bagge <K1ygg@aol.com>

Personally I have found that when all the antenna grounds are common, there is some interaction between the antennas that affects the directional properties on them. I use a 6 position switch that changes both the center conductor and ground shield on each antenna leaving the unused ones floating. I also do not ground the receiver and fortunately the noise level is quite low.

Rick Kenneally <woodlandview@yahoo.com

I can appreciate the desire to keep unused antennas isolated or independently grounded. But at the end of the day, I only have one ground wire running from my shack. And I feel it is necessary to ground the "shack" end of all antennas because my feedlines are so long (150'), and I've already had static damage to my phaser. Your comments do have me thinking about a way to add to my patch box a switch (or more likely a set of switches) that rapidly grounds out the center pole of every antenna for use during heavy weather or vacations.

What do people think about adding a Siemens gas-discharge tube between hot and ground of every antenna jack? On the surface, it seems that would provide some good protection against a static charge. But I'm a novice at electronics, and don't know if adding these would cause problems.

Big thanks to everyone who have responded to this with ideas and tips.

Charles Hutton <charlesh3@msn.com>

Rick: A lot of ham Beverage users in lightning-ish areas are very religious about putting gas discharge tubes on their Beverages. Were I to still have permanent Beverages, I'd use them.

Russ Edmunds <wb2bjh@nrcdxas.org>

Seems to me that it would be far less trouble to set it up so that any antenna not in use was automatically grounded. Whether you do that with switches, or set up one switch to simply ground all of them any time they're not in use is open to choice.

Frederick Vobbe <fredv@nrcdxas.org>

It can't hurt (to add a gas-discharge tube). Also, a Polyphaser in series with the antenna lead is good

as well.

But the thing that I have always stressed throughout the years is... if lightning can jump a mile or more across the sky, don't put a lot of faith into surge strips and small suppression devices. A discharge device, when hit by lighting will absorb only a small percentage of voltage.

Rick Kenneally <woodlandview@yahoo.com>

Yep, agreed Fred. I still rely on physical disconnection, via switch or actually disconnecting the cable, when weather gets threatening. It's the smaller, much more frequent static buildups on the Beverage and feedlines that the discharge tubes are meant to address.

I'm not sure what a polyphaser is, but I'm going to look it up.

Frederick Vobbe <fredv@nrcdxas.org>

Most of my antennas have an open frame relay on them that have to be energized for the antenna to work. Turning off the power (or a power loss) causes the center conductor to go to ground.

The (polyphasers) I use for critical communications are...

http://www.polyphaser.com/kommerce_productdetail.asp?item=IS-50NX-C1

Robert Foxworth <rfoxwor1@tampabay.rr.com>

Probably the ideal way to manage antenna patching would be to use a professional grade patch panel. You can get coaxial patches in both 50 and 75 ohm specs. The barrels are probably 3/8 to 1/2 inch diameter and about 6 inches long and have a screw flange to attach to a Bakelite patch strip. They fit in the same patch arrangement as the old style WE audio patch that used the double plug arrangement. We had them at ITT WorldCom when I was there. Trimm and Trompeter Electronics were two manufacturers I recall. Doing this would maintain total shield isolation. You can do things such as getting a signal splitter/combiner and patching it "across" the antenna line to allow injection of calibration signals, inserting inline pads or matching circuits, with each such device appearing on your patch strip at the input and output, or 3 patches for "Y" splitter/combiners etc.

In the absence of spending prof-grade dollars, the double-female BNC bulkhead connectors, on a Bakelite strip, would be my next choice. Then a crimp tool for Kings crimp-on BNC plugs becomes a desirable item to make up the patch cords you'll want. The coaxial jacks are all-solder items however. It's easier than it sounds, all solder points are on lugs.

You'd want every antenna lead-in, every pad-matcher-combiner lead, and every antenna receiver input, to appear at a female jack. Then every patch cord will be male on both ends.

Another thought - just pull out all the patch cords when away and you're covered. Have all antenna downleads on one row and receiver inputs on another row. You can have a row of _grounded_ connectors and patch all ant. lead-ins to them, when not being used. Or, all ants except the one in use.

If you get a _direct hit_ however it won't much matter what you did. But all your receiver inputs will be totally floating.

Russ Edmunds <wb2bjh@nrcdxas.org>

A direct hit will do what it's going to - whether you're connected or not. Lightning can fry your equipment if you're not disconnected, but I'm not sure what would happen with strong static charges built up from a nearby hit coming into the shack on several loose wires, ungrounded....

Frederick R. Vobbe <fredv@nrcdxas.org>

An insurance friend showed me pictures of claims made by hams and SWLs because of direct hits, and nearby hits.

One nearby hit, 8 houses from where the claim was taken, showed several dead items including a Sangean radio that was *next* to a lead in wire that was dangling.

Another claim was by a homeowner who had to take his dog to the vet, after the glass jar exploded into small bits after the neighbors light pole took a hit. The person making the claim had a 100 foot longwire stretched out in the backyard, and lead-in cable with PL-259 was put in a pickle jar after the owner disconnected it from his radio to protect it. He had heard that by putting the end of an antenna wire in a jar it would keep the antenna from being hit. The antenna was not hit, but the EMF was enough to shatter the jar as it sat 8" from a heating duct.

Again, when Zap, (the lightning god), pays a visit, his hand of friendship extends a long way! <grin> BTW, at WLIO I have several folded dipoles and a 10-15-40 dipole on the building. Each coax goes to ground level, then up into the building to the equipment. At ground level I transition through a "T" into and I have a banana plug that can be inserted into the T to short the center to ground. While this is a PITA when you want to operate, since you have to go outside and pull out the jumper, there have been times when the grounding "whisker" had to be replaced due to a hit that blew apart a #12 wire.

Dan Bellesfield <dsb013@ptd.net>

Hi All, OK, I was hesitant to ask this question for fear of sounding REALLY stupid, but Fred's post here makes me have to! As I am new to the "outside" antenna world, recently having strung a 72' longwire between some trees, followed by RG-6U quad shield from the tree to the house (shield at the tree end is grounded with #12 solid wire to a copper ground rod), I have been faithfully disconnecting the PL259 from the back of the radio, leaving the wire "dangling" about 2 inches from the top of the radio. Is this the safest thing to do, or do I run a risk of a lightning hit doing damage on the house end of the wire? Should I do something with the exposed end?

Sorry again for sounding stupid....

Russ Edmunds: <wb2bjh@nrcdxas.org>

Two thoughts - if either is off base, I'm sure I'll be corrected:-}

1) Get a jack for the plug, and tie the jack to ground at the nearest and safest place depending on where your shack is.

2) Get a jack, and short it - tie the two terminals together so as to send any voltage that might accumulate from static discharge back out to your ground rod. (This probably only works if there is no solid ground nearby the shack).

Dan Bellesfield <dsb013@ptd.net>

Russ, Thanks for the info. I was kind of thinking along the same lines, but wasn't quite sure. The only problem I possibly foresee, is since I inadvertently used RG6 quad shield, which uses aluminum (I think) for the shield, I am not fully confident in the ground to PL259 connection on my cable (since I couldn't solder it), so I would think that a jack inside at the shack, with the center conductor going to the water pipe in the basement (directly below the shack), would be the safest route.

Frederick Vobbe <fredv@nrcdxas.org>

It's not a stupid question. For years I did the same thing you did, and it was not till I took a job at WLIO, (which has a 500 foot lightning rod), that I started to get interested in what makes lightning tick.

Lightning will seek the best ground it can find. Along with lightning you have to be somewhat concerned about the EMF pulse that a metal object struck by lightning will give off. Two examples.

A direct hit on our tower may find its way into an antenna cable, such as a coax, and follow the center-conductor down to the radio. Such was the case when my 70 cm amateur radio repeater (GE Master II) died an early death.

However, most of the damage I sustain is EMF. The tower is hit, and the charge goes down the tower. In doing so a magnetic field is introduced into objects. In the building, computer monitors turn an ugly purple, and equipment with long runs of serial lines are damaged.

I think that the prudent thing to do is try and eliminate the things that can happen. In long wires this is keeping paths that can lead to grounds from being used, and make paths to grounds away from your equipment.

Dan Bellesfield <dsb013@ptd.net>

Fred, I am not quite sure I follow. Do you mean that I should not connect the shack end of my longwire to a ground, as Russ and I discussed, when the antenna is not connected to the radio (just let it sit there)?

Frederick Vobbe <fredv@nrcdxas.org>

It depends on the area around the outside antenna. If your antenna is attractive to lightning, by grounding the antenna you could be inviting it into your home. If there are other more likely places the lightning would land (local water towers, phone poles, cell towers), then I would leave the antenna disconnected.

You can't make a rule for lightning installations other than to understand that lightning will seek the best ground it finds. If it's your antenna, then you need to drain the voltage prior to entry into the house. If it's another structure, then limit the possibility of voltage entry through induction or EMF field from affecting your equipment.

Dan Bellesfield <dsb013@ptd.net>

OK, Thanks. I think that perhaps my best course is to just leave it disconnected.

Next time we’ll start to look at some detailed antenna information, as well as some other topics that will hopefully enlighten and entertain.