First Non-US Contact… Lots ‘a Listenin’, Some Talkin’ !

With filters and chokes hopefully doing their job, preventing interference with my neighbors on the other side of the steel and concrete wall of our condo, I made my first voice transmission at about one third RF power (~30 watts) with Mike (W2YP) in new Rochelle, NY, just north of New York City at 1059 EST on 14.200 Mhz (twenty meter) USB (upper sideband).

Mike is running a cubical quad antenna up a whopping 19 meters (62 feet), pushing just 80 watts of power.

My antenna was still parked at due north (sort of aimed at NY) at the time, although he was aimed at Europe, not Florida, and I was timidly running only about one-third power (~30W) for now, he still gave me a report of 3×3 (somewhat readable, not very strong). More importantly, I listened to him work many stations in Europe, learned a good bit about workin’ DX in the last half hour. Things that enabled him to achieve many long distance contacts in a fun and efficient manner. Great job, Mike!

His tag line, “a great pleasure to hear your booming signal this time, every time, and until next time, bye bye!”. Can’t wait to hear him say that about my signal one day soon! Maybe once I feel confident about crankin’ up my RF (radio frequency) output power and learn how to properly aim my beam!

Stations that I listened to Mike work (and could hear both sides of the conversation quite clearly), especially since I started easing the beam from due north to a more easterly direction (more toward Europe):

•  Several stations (individuals) in the U.K. (not too distinct since I was still aimed at the north pole at the time!)
• as I started swinging the beam more easterly, clearly heard (with a good deal of background noise):
  • Jean (F1DWI) in Eloyes, France
  • Rudolf (DK9VX) in Neunkirchen, Germany
  • Jean-Paul (ON4KBZ) in Molenstraat, Belgium
  • Eric (F5NBK) in ARTIGUELOUVE, France
  • AP (GI4VKS) from STRABANE, Northern Ireland, who did a fine job speaking through a voice box surgically implanted in his throat

With my antenna still aimed north, and power eased up to about 60% (60 whole watts! ), I just completed a solid and interesting contact with the Maritime Mobile Service Network (see www.mmsn.org for more info on this emergency communications organizations, specializing in serving maritime (offshore boat and ship) mobile and deployed military radio traffic. Connected with Tom (VE3II) in suburban Toronto, Ontario (grid location FN044) before he relinquished net control to Rooney in Portmore, Jamaica. Tom gave me a 5/7 to 5/9 signal report (best readability, almost best quality signal!) and asked if anyone had any traffic for Punta Gorda, Florida that I could relay. No traffic, but my first participant in a potential communication traffic relay at this QTH (radio station location) in Burnt Store Marina South Shore. On our way, kids!

I monitored a dozen or so other US and non-US contacts (both sides of each) before I needed to shut down the rig and move on to working on the boat (see www.oursojourn.wordpress.com if interested)

A humble start from this location to the fascinating DX side of amateur, but like any new tool, learning its proper use before plunging is the first significant & reasonable step.

So far, I’m quite impressed with this antenna and this location (near salt water shore, relatively clean elevation, a darn good signal launch platform!)

73

de Gene K0GKJ

Final Condo Antenna Tests Successful !

Antenna is now not only up, but leveled and debugged!

Took some effort to get to this point, however. You might find interesting what I found after initial installation…

Guess what… I put the MFJ-269 antenna analyzer on the station (“shack”) end of the feed line from the hexbeam antenna, and was shocked to watch the meter jump wildly in both SWR (standing wave ratio) and impedance (think “resistance”). it is supposed to be of certain values and rock steady. More on this later.

Hmmmm…

I emailed Leo Shoemaker (K4KI0), the supplier of the antenna whose reputation for supporting before and after the sale is stellar, and got an almost immediate response.

As expected he was very helpful with ideas and measurements I could take to zero in on the problem.

Thanks, Leo! Your reputation is well-deserved.

Sounded like a bad connection, Leo suggested, either in my solder joints installing connectors on the roof end of the feedline, or something in the center post of the antenna, very probably NOT anything to do with the wire elements or non-conductive spacers.

Back to the roof.

I first eliminated my feed line as the issue, with the antenna in place.

It did look like the center post of the antenna may indeed be the culprit after getting a few unexpected measurements with my trusty VOM (volt-ohm meter). Resistance (indicator of impedance) jumped around.

Yup, that would cause flakey and erratic SWRs, and weird impedances too!

After removing a couple of pinning bolts and lowering the antenna by manually lifting it and the upper four foot mast section off the top of the lower mast section, hossing it down just five feet (not heavy, just awkward) and temporarily securing it in parallel to the lower mast section (which is bolted to the mansard wall) with strong twine ,while I removed the center post (ugh! a pain, but doable in about five minutes once the antenna is lowered), I took the post down to my test bench.

Yup, the problem was somewhere in that center post. Found erratic continuity between the back of the SO-239 connector (where the feed line connects to the antenna) and the front!

Again, hmmmm…

The culprit: There’s a tiny screw that connects the post’s internal cable harness ground (coax harness shield) to this feedline connector’s outer conductor. That one tiny little screw wasn’t loose, but wasn’t tight either, causing an intermittent connection where a very solid connection is required!

Lesson? Check to ensure ALL connections are good ‘n tight, including the small but important ones like this one!

What’s wrong with this picture? (hex beam, but no center post!):

Checking center post continuity ‘in situ’:

Combined with these nums !! Major league YUCK !! If you don’t get it, read on…

Pulling the center post for further testing and resolution on the bench was not as difficult as I thought since the top of the post, to which all the Kevlar tensioning cords are affixed, comes off the top of the post with some pressure, and can stay connected and in place (whew):

Then it was just a matter of disconnecting each end of the wire elements, the pinning bolt in the baseplate flange, and loosening the two locking allen nuts from the post. Out she came. I did collect all the wire ends that I disconnected from the center post in a cable tie to prevent them from getting unruly in the wind while I was working on the post:

The post went back into the antenna quite painlessly, ALL connections rechecked and resealed (with Coax Seal).

This time I routed the feedline through the hole in the base plate as I should have done in the first place. Functionally, Leo tells me it doesn’t matter, but with the heavy RG-213 coax stuffed through there (and the hole IS large enough to pass the PL-259 connector), it acts as a nice feed line strain relief as the beam rotates.

Note the common mode choke above (for noise suppression), also known as a 1:1 current balun, composed of six Amidon FB-77-1024 ferrite beads available from Ron Mott (W4RDM) at www.hexkit.com at a competitive price. I installed an identical set at the other end of the feed line as well (just in case – as they say, ”can’t hurt!”. The rooftop set also has a couple more smaller Mix 77 (best for these HF frequencies) on each end of the six.

Note the generous loop of feedline to allow for 360 beam rotation:

Down in the station, part of the end-to-end “antenna system”, in addition to the antenna, the feedline, two common mode chokes, I’ve also installed a commercial low pass filter to prevent another type of interference called differential mode interference (don’t ask!). Suffice it to say that I’m going to great lengths to PREVENT interference BEFORE it happens. Lots of other common mode chokes on control lines, connecting cables, etc.

 with the bottom of the antenna literally less than a foot above the metal mansard wall (galvanized steel girders and powder-coated aluminum roof sheathing).

I knew the readings would not be good this close to the roof, and I was right, but wanted to see for myself.  Obviously (to other hams), lower SWR numbers (the three right-most columns below) are better, and anything above 2.0 is not good, with 1.0 ideal:

Band Name (wave length in meters)	Frequency Measured (Mhz)	Antenna down *	Antenna up **	Measurd in-station
20M	14.000	1.9	1.8	1.8
	14.350	1.7	1.5	1.5
17M	18.068	2.0	1.4	1.2
	18.168	2.0	1.5	1.2
15M	21.000	1.9	1.3	1.1
	21.450	3.1	1.8	1.9
10M	28.000	1.2	1.1	1.2
	29.700	5.5	3.4	2.8

Note from these measurements that proximity of the antenna to the metal roof (‘Antenna down’) does indeed impact antenna function – likely an undesirable phenomenon known as capacitative coupling (between roof and antenna) - however, this is a necessary compromise since going higher is simply not an option.

‘Antenna up’ = operating position with the bottom of the antenna just 57 inches above top of metal wall – about the absolute minimum height to get good but not optimal performance. Going higher for better performance is simply not an option here (aesthetically).

Height (AGL) measurements (higher is better):
			in feet:
Base plate to top of center post:			3.58
Top of mansard to base plate:			4.75
Top of mansard wall to flat roof:			4.25
Roof to 3rd floor deck:			10.33
3rd floor deck to 2nd floor deck:			10
2nd floor deck to parking lot:			11.5
Height of base plate AGL #			44.41
Height of top of antenna AGL			40.83
	# AGL = Above Ground Level

The good news is that the roof height at over thirty-five feet AGL will be a big advantage over something mounted closer to the ground, metal mansard wall notwithstanding.

Note from the numbers that elevating the bottom of the antenna just a few feet above the metal has dramatically improved SWR (over-simplified, “performance” readings), particularly for the higher frequencies, as I would expect (short distance = greatest influence over higher frequencies that have shorter wavelengths as measured in meters, in case you care!).

Also note that the in-station measurements, including the fifty foot low loss (RG-213) coax feedline, also had some effect on the total “antenna system” as expected, when measuring the entire antenna system end-to-end, with two sets of Mix 77 chokes (noise suppression beads) to suppress common mode interference, as well as a low pass filter to address differential mode interference:

For those of you who care and understand the following, note that undesirable reactance is thankfully very low! No doubt at all (setting aside all humility) because of a well-designed and carefully implemented installation, end-to-end! This is a sweet antenna, and the countless hams that have contributed to its design and refinements are to be complimented!

“The Sweet Spot” within Each of the Four Bands:
Band Name	Resonant Frequency	SWR	Rs	Lowest Xs
20M	14.205	1.3	37	5
17M	18.090	1.2	42	4
15M	21.095	1.1	45	5
10M	28.229	1.1	50	4
Rs = “real resistance” component of complex impedance (closer to 50 is better)
Xs = “imaginary” component of complex impedance (lower is usually better)

Not too bad considering the necessary installation compromises !

Oh yeah, check this out – is life good, or what! I’ve been waiting for four years to see this! I’m declarin’ this antenna now installed, tested and ready to get heated up!

Additionally, the height AGL (above ground level) that the roof provides is an advantage (higher is ALWAYS better), and the minimum elevation above the metallic roof appears to be a reasonable compromise between function and aesthetics from what I can see right now…

I have yet to hit transmit, however, since I’m learning the ins/outs and do’s/don’t’s of my new on-the-air “neighborhoods” by listening first, plus I wanted all filters and chokes installed and tested first (see below).

But even without aiming this antenna (still just pointed north, its home position), the few minutes I’ve spent just listening, I’m hearing stations from Jamaica to Ontario, from Indiana to Alaska, from Iowa to Colorado, mostly on the band I’m most familiar – twenty meter – a longer-range frequency. A

lso listening to more local transmissions from Cape Coral to Naples to Miami, loud and clear.  

This is gonna be good!

By the way, we had sustained twenty plus knot winds for over twenty-four hours, and while the antenna flex’d its muscle a bit, due to its somewhat flexible shock-absorber structure, she stayed right put! Good first test.

I’ll be contacting the local ARES team (Amateur Radio Emergency Service) once I get my two meter (VHF, i.e., very local) band (frequency range) completely operational. I’m already listening to the NOAA weather channels on VHF. Transmitting is next, once I’m sure my HF stuff (all of the above) is squared away. dont want to change too many variables in the equation all at once!  

FB! (fine business, or “awesome”!)

Next order of business – chasin’ a little DX (long distance contacts) to get my feet on the ground, and my ears and voice and brass on the air (‘poundin’ brass’ is what CW (“continuous wave”, or Morse Code) operators do when operating their keys!

I’m reving up for “straight key night” which is one twenty-four hour period each year, starting on New Year’s Eve, where CW operators communicate with each other using only a traditional Morse code key. Big fun after everyone else is done singing “Auld Lang Syne”, kissing everyone in sight, and its then that the real party reptiles spin up the rigs and start the waves hummin’ with dots and dashes (dits ‘n dahs).

I certainly won’t be viewed as a “legendary fist” (a really good CW operator) by then or anytime soon, but I’ll have some fun that too few people on the planet will ever enjoy! Neat connection with history too!

73 (warmest regards) , or dah-dah-di-di-dit  di-di-di-dah-dah, baby! (say that outloud to yourself real fast- wonderful rhythmic symmetry, no?)

de (this is) Gene (K0GKJ)

Condo Beam is Up! Testing Soon!

Well, long time comin’, but the antenna is on the roof !

Still some adjustments to element wire and cord tension, as well as plumbing to better vertical orientation, not as high above metal roof as I’d like, but the ole MFJ-269 antenna analyzer will determine whether I’m having a SWR nightmare or a wet dream!

Probably something between the two.

She’s as high above the roof line as I dare go, even though higher is always better.

Life is full of little (and some not so little) compromises, huh?

 

Visible (as I had warned our homeowner’s board when they approved this installation), but not obnoxiously so (at least that’s my view!)

A view from nearby on the roof. Today’s task, assuming it stops raining, is to level the entire affair.

Crooked looks like crap, although notice I do NOT have the problem of TOO much tension in the wire elements. Quite the contrary, but ran outa time yesterday:

Since we live in hurricane and tropical storm country, I took a precaution that I saw on the hex beam forum–drilled and inserted a couple of “anti-windmill” bolts through each flange above and below the base plate.

Notice one straight head and one phillips head stainless screws below) above and below the base plate (which is laying on its side on the bench).

Used the hardware I had on hand.

I’ll do the same between the two four foot fiberglass pole mast sections:

Since I have a flat roof with no easy vertical access from the ground (for hoisting an assembled hex beam), I decided to assemble and test on the roof, which had its own set of problems (AND advantages). Here’s my up-the-ladder kit.

From left to right below, my trusty hardware and tool shoulder bag, baseplate/rotator/topmast assembly, center post, secondary mast section and assembled spreaders.

Once on the roof and carried the sixty paces to the mounting location, I disassembled the spreaders again for attaching to the baseplate (after marking them with my own simpleton-oriented numbers and arrows): 

Once on location, I used the electronic compass in my portable GPS to find north, marked it on top of the roof wall:

My assembly and test “stand” comprised tying the upper mast section to the lower mast section that is firmly mounted to the roof.

After afixing the center post firmly to the base plate, I needed to allow the base plate to “free wheel” on the mast to allow assembly since, at any point in time, half the spreaders will be suspended in mid-air.

This was one of the complications of not assembling this baby on the ground.

No big deal. I just rotated the base so that each set of spreaders was accessible either by standing on the roof or on a step ladder (which I also had to hoss up to the roof).

Now for my simpleton markings.

With six spreader assemblies, comprising three sections of different diameters each, with four sets of wire element connectors and one tensioning cord connector at the end of each spreader assembly, I needed to mark which way was up so that all wire element connectors were of the same skyward orientation as I started bolting the spreaders to the base plate:

Spreaders in place, with careful focus on equally tensioning all bolts so as not to deform the hex shape of the antenna support system:

Tensioning cords laid out. These are made of Kevlar (like bullet-proof vests) with a UV resistant Dacron cover with at least 700# pull strength for high winds. They connect opposite spreader tips to the center post which creates the basic “upside-down umbrella frame shape”:

Outboard ends of the first two spreaders connected to the center post – see the shape coming together? Cool! Note the step ladder necessary to reach the top of the center post:

and so on… you can see that there are at least two reasons why the bottom of this antenna needs to be elevated well above the top of the 5 foot high mansard wall.

First, to avoid nasty capacitative coupling with the metal roof. Second, head room for rooftop maintenance and inspection

If you’re not aware, check out Leo’s (K4KIO) awesome storm warranty at http://k4kio.com/warranty.html

A good weather-tight connection between center post and feedline with Coax-Seal molded around the joint.

Have you ever tried to remove this stuff after its been there for awhile? Sticky mess, right?

A trick I read about somewhere…

I first wrapped the joint with a non-sticky silicone tape that only sticks to itself, similar to a sailboat rigger’s tape (no adhesive residue on the joint) before wrapping with Coax-Seal.

When I go to remove it, no residue left on either the SO-239 center post connector or its mate, the PL-259 feedline connector!

Notice in the pic above I also clearly numbered each spreader since spreaders 1 and 6 have special significance for threading and tensioning the director and reflector wire elements.

Here are the wire elements, still in bags, to be strung around the perimeter of the “upside-down umbrella frame:

The wire itself is really where the action is. The rest of this stuff just holds it in place in the proper orientation. The wire is very cool stuff – PVC-insulated 14 gauge 168 strand copper flexweave, making it easy to handle. The insulation provides these actual antenna elements protection against saltwater corrosion.

A close-up of the completed assembly with tensioning lines connecting the spreader ends and four sets of wire elements installed. I opted for four bands–10M, 15M, 17M & 20M–not five–eliminated 12 meter so as to really get clean signals on 10M as solar cycle 24 fires back up. Plus, I ran outa moolah!

The pic below shows the view of the antenna from the roof of the front of the same building. You can see the distance the antenna (and the tip of a six foot step ladder for reference) is set back from the front of the building (the side that faces the rest of the buildings in our condo association).

Also gives you an idea of how visible (or invisible) it is.

This is probably worst case since the afternoon sun is behind the antenna to the west and southwest, causing it to be silhouetted against the sky.

Today, weather permitting, I’ll level the antenna, bolt the mast in the appropriate orientation for accurate and consistent rotatation with respect to points of the compass, test for SWR (standing wave ratio) with my antenna analyzer and then firmly bolt mast sections together so as to retain the desired orientation.

This should complete the HF portion of my installation. For more of the techy info on this antenna, check out http://k4kio.com/whatisahexbeam.html

To see what other hams are saying about this antenna, if interested, see http://www.eham.net/reviews/detail/8150

Bad news is that the roof gables themselves (under the mansard walls) are constructed of galvanized steel beams and vertical galvanized sheathing (the silver stuff).

The better news is that all  the roofing material itself is non-magnetic painted aluminum (orange stuff). So hopefully (ALWAYS hopeful!), not quite as bad an issue with antenna interference as initially feared. Tests with confirm or refute!

I’m posting this for my condo neighbors as much (or more) than fellow hams to give them a sense of what the skyward end of their association’s communications command post looks like from a view most all of them will likely will never see (from the roof).

Dear friends and neighbors, YOUR community radio station antenna should be an awesome performer !

right now I’m resisting the temptation to solder the PL-259 connector to the shack end of the feedline and test the SWR at this height above the roof, and to fire up the Icom 746 transceiver to see some on-the-air results. I’ve got another set of feedline noise suppression beads for this end of the cable coming from Ron Mott, which probably aren’t necessary, but can’t hurt, before I solder the final connection. I also need to clean up my feedline entry point before getting too far down range.

But its FINALLY comin’ together, folks!

Watch this space…

de (Morse shorthand for “this is”) K0GKJ (my amateur radio call sign)

dit dit (Morse for “LATER, ‘GATORS!)

Feedline is IN !!

Ok, for those of you who live in a house in a non-deed restricted neighborhood, or have your own acreage with flexibility to put up whatever type of wet dream antenna farm you desire, as high and as bold as you please, this may not seem like a big deal.

If you’re living in a large condominium complex that is very conscientious about uniform, consistent and aesthetically appealing appearance, just running a feedline external to the building (which is “common grounds”) is a very big deal!

So I’m very proud to say that after one additional round of lobbying with a few board members and neighbors to address a few remaining concerns, and after modifying my plan for the antenna feedline conduit run and intended antenna location up top one more time in order to make both even less conspicuous to the casual observer, we’ve just finished installing the conduit, feeding one run of RG-213 coax for my HF feedline, a three-conductor rotator control line and three jet lines.

The last term above was new to me, and maybe new to you, although the concept is clear to anyone who has ever needed to plan for running additional feedlines after the initial set-up (as backup, for a different band (e.g., VHF), to add RFI noise suppression beads IF necessary, etc.). These are additional “pull” lines run through the conduit with the feedline, and stand ready to pull additional lines or to extract an existing line to add beads, etc. What I learned today was a fascinating and simple way to get the initial jet line through a 28 foot conduit with one right angle turn and two 7 inch offsets.

But I’m getting ahead of myself.

Indulge me – the last three and a half hours of effort, just completed by the endorsed association craftsman for such installations, with my help as a runner and grunt extraordinaire, represent the culmination of over four years of planning, lobbying, presenting, cajoling, compromising and finally, implementing a long-held dream I’ve had to establish a ‘new’ QTH in my retirement home, one thing I’ve truly missed about living in my own standalone house “up north”. Down here (in Southwest Florida), I’ve only been able to operate mobile so far.

I learned a few very interesting tricks today that might also be new to you, so here we go!

Below, piece-parts assembled at oh-dark thirty this morning. Supposed to be ready to rock with Todd by 7am. I was fortunate to catch him at all before he leaves on vacation later today for an extended period, so I let him dictate the time. Note the (previously gray PVC) conduit is all painted to color match the exterior color of our condo building:

Todd arrives with his mobile workshop, along with his intimate knowledge of the structure of our steel-reinforced concrete building and the rather elaborate category four hurricane-certified roof system that we’ll be leveraging. By the time we’re done, my antenna mount will be compliant with category four standards (able to withstand winds up to 155 MPH. So it will NOT be the mount that lets loose!

Is this guy equipped, or what!

Much of the morning was spent perched on some very tall ladders (by he-who-must-be-insured) to insall the conduit from roof to apartment:

Cutting just the right size hole in the underside of the eaves for the two inch diameter conduit…

This oughta do it…

With the upper offset connected to the straight-run conduit by just two dabs of PVC glue (so as to stay put, but be easy to pull apart with an aggressive twiest), and affixed to the wall with wrap-around brackets and tap-cons (screws) into the concrete and stucco, this conduit shouldn’t be too difficult to uninstall if/when we decide to relocate…

Tip number one: barbeque your conduit to form custom shapes.

We needed to fabricate a custom offset through the use of that highly specialized pipe-bender called a propane barbeque grill. Be sure to turn frequently to ensure uniform softness around the circumference of the PVC pipe for the two feet or so necessary to create the two offsetting bends.

Once softened, lay on a flat surface with the section intended to remain straight along a railing or something straight so you can more precisely plan and execute the two offsetting bends. Then once there, cool and stabilize with a soaking wet towel.

Done!

The result. A bit of touching up the paint and put ‘er into play!

Looking up the vertical run from the top floor eaves and the interior of the mansard (more on this later when we move to the roof):

Transitioning to the horizontal run straight into the shack with a ’sweep’ – a gentle curve which makes it easier to pull cables through and obviates the need for a bulkier LB fitting (elbow with a screw-on access plate). 

Todd drilled and punched through over a foot of concrete, trying to miss the steel rebars by offsetting a bit out from the corner. Took a few trial holes before hitting the sweet spot:

Hammer drilling and hammering through two layers of the tough stuff, and then the hole saw for the sheet rock inside:

After touching up the paint scratches on the conduit sections from teasing joints to fit (with a hammer), the twelve foot vertical run from the eves and the sixteen foot horizontal run into the radio room don’t look too bad, huh? Couldn’t have tucked them more neatly into vertical and horizontal corners! Good design, guys – thanks for the advice!

Unless you were specifically looking for it, probably not noticeable at all. Looks like it belongs…

Now on to the roof, requiring a ten foot (extension) ladder to get up there.

Todd popping the access panel to the innards of the mansard below.

Using a magnet, I determined that the vertical surfaces are galvanized steel, and the painted orange top and outer mansard roofing material is painted aluminum (non-magnetic). So much for using the top of the wall for a VHF ground plane!

 

Inside you can see TV cable & CAT-5 runs for some of the twelve units in our building:

The vertical aluminum box you see below is actually a structural brace to distribute load of the antenna to be mounted on the opposite side of this galvanized sheet metal wall below. The load, as you can see, gets distributed across several strong horizontal “top hat” beams. It also captures the stout double thick 3/4″ plywood backing plate (total 1.5″) between this dimensionally-stable brace and the outer galvanized steel sheathing…

Feedline and control line flaked (laid) out on the roof in preparation for pulling ‘em through the conduit:

You see the white lines layed out diagonally in the pic above? They get pulled easily off the spool in the box below. Todd calls this “jet line’, since it comes out of the box at the speed of a jet, if pulled quickly. 

Tip number two: duct-tape a shop vac to the shack end of a cable conduit. In the roof end, insert the jet line tied to a bit of foam to give the end of the line some volume for sucking. Turn on the shop vac in the shack, and in about 8 or 9 seconds, the jet line will magically show up in the shack!

From there, its a snap to pull the cables through, with someone attending them on the roof end.

This little tip resulted in the following rat’s nest in the shack. I photographed this mess immediately after the heat of the moment. I was wildly pulling all the excess feedline down from the roof.

I had two hundred feet. Now I only have 150 remaining, so I now know where to cut and install connectors to another fifty feet of coax which will become the VHF feedline. After drawing that line through, I’ll add add shack-end connectors and noise suppression beads to both (mix 77 on HF, mix 43 on VHF).

One of the cosmetic compromises caused my feedlines to enter the shack a good ten feet from the equipment and near the ceiling instead of lower and closer to the gear. Longer RF gr0und runs from each piece of equipment to this entry point (to ensure all at the same potential in case of a direct or near lightening strike). Oh well. As long as I get on the air!

One the vagaries of a second floor shack in a three story condo building with prestressed concrete floors above and below is an earth ground that doesn’t radiate RFI or create other common mode current issues. I’m still evaluating the wisdom of an earth ground this far up (I’m almost exactly 1/2 worst case wavelength away from the earth on at least one of my intended operational frequencies).

I’ll trim the conduit later and install an entry (RF ground) plate, although I probably won’t pursue an earth ground at this time, just a good RF ground, being a good half wavelength or more on some HF frequencies from Mother Earth.  This post, after all, is about the feedline portion of our station.

 

Total feedline length from shack entrance point to antenna mast = 16′ horizontal run + 12 foot vertical run + 24′ inside mansard and through vent to mast (allows some slack for rotation and running around inside mansard) = 50 feet (rounded up from 48 feet). My entry point is then another twelve feet to the rigs, but I’ll probably install an RF ground connector plate at the point of entry with another set of connectors from there to the rigs.

Now the feedline and control line exit the mansard at one of the drip-proof vents on the mansard wall and will then drape to the base of the mast.

Here you see the mast securely strapped and bolted to the mount/backing plate inside the mansard (not visible in this pic) through a set of pre-treated wood spacer blocks to enable the mast to plumb vertical for appropriate radiation angle as intended by the design of the antenna.

As Todd said, “this baby ain’t goin’ nowhere!”

Kay and I are taking off in the boat for a few days this weekend, which means antenna assembly and testing will have to wait until next week (arghhhh!!). The remainder of this week will be spent getting the boat ready (which is also big fun). Check out the boat at www.oursojourn.wordpress.com.

73

de K0GKJ

dit dit

Anatomy of an Antenna Feedline

Now that I have approval to install an antenna on the roof of our condo building, careful construction of the feedline(s) and control lines from roof to apartment should enable me to do this just once as access to the (~flat) roof is quite restricted – for good reasons.

By the way, since I’m expecting some non-hams to peruse this site, I’ve taken the trouble to explain some terms that many of you know all too well. Thanks for your patience!

Since we live at almost ground zero of the lightening capital of the world, I figure at least some reasonable measures of protection are warranted, without breaking the bank. First, as you all know, there is no complete protection against a direct strike. The objective is to minimize the likelihood by either disconnecting the path to the shack or providing a FAR easier low impedance path to ground than through your equipment. Since I have a second story shack, my strategy will be the former – disconnect – both at the antenna on the roof as well as in the shack.

On the roof, I’m installing “The Sheriff”, a gas tube lightening arrestor. 

 

Should a direct or near hit spike current on the feedline, a small gas tube (the cylindrical device in these pics) blows like a fuse…

The gas tube completes the circuit against a gold connector in the body of the arrestor. This disadvantage is that a trip to the roof will be necessary if this blows. The advantage is that it should keep the strike well away from shack and equipment. During times of high electrical activity in the atmosphere, I’ll also disconnect the antenna feedlines where they enter the shack. For now, that will entail unscrewing the antenna feedlines from the back of the transceivers. Later, perhaps a switch directly to ground during storms.

Next order of business – the prevention of RFI (radio frequency interference).

There are two primary types of RFI suppression that I’m designing this shack for. The first is called differential mode RFI. I’ve installed a “low pass filter”, which should only allow desired frequencies to pass, and not “harmonics” or undesirable “echoes” of different (multiples of) frequencies I WANT to pass through.

The second primary type of RFI suppression in this design is called common mode RFI. At the radio frequencies I’ll be transmitting (HF, or high frequency, i.e., 14 to 28 Mhz; and VHF, i.e., 144 to 444 Mhz), I want to prevent that RF energy from traveling down the OUTSIDE surface of my coax cable, where it can potentially radiate to nearby appliances, for example, and contain it to the INSIDE conductor of the (shielded) coaxial cable. That is achieved by employing “common mode chokes” or inhibitors of this undesirable energy radiation within the frequency ranges I’ll be operating.

RFI suppression is achieved by passing the conductors of this energy through a series of ferromagnetic cores called “toroids”, and there is a different “mix” (composition of materials with varying properties) depending on various operating frequencies. See the following resources for more info if desired:

• A great tutorial on common mode chokes at http://freepdfhosting.com/1e5c787453.pdf
• A good description of RFI suppression with respect to how it affects audio g(and video) gear: http://www.audiosystemsgroup.com/RFI-Ham.pdf
• High level description of “beads” for power lines, speaker cables, etc, see http://www.eham.net/reviews/detail/5334

In anticipation of AVOIDING common mode RFI problems, I’ve been accumulating a collection of toroids, beads and split beads of various sizes and mixes. Here’s my “kit”:

There is a confusing array of fairly standardized part numbers signifying various sizes (for different size cables) and mixes (for various frequencies). I was confused, so I created this “cheat sheet” on the inside lid of my RFI kit;

For my HF antenna feedline, I’ll be using RG-213 50Ω coax, which has an O.D. (outside diameter) of 0.405″. That means I’ll need beads that are of the FB-102 size designation (0.5″ hole). And for HF, I’ll use mix 77. That means if I were to order these babies (I use Palomar Engineering or http://hexkit.com/rfchoke.html), I would get the recommended minimum six FB102-77’s which look like this:

Slide ‘em onto the feedline cable and use shrink tube to hold ‘em in place

Unfortunately, my largest shrink tube on hand wasn’t quite large enough to go over the FB102’s, so, never-say-die, I used on smaller bead on each end of this string (F82-77’s) which just fit into my largest shrink tubing, using these as retainers (you can always use more beads for more protection – OR to hold the others in place!)

Before sliding the ‘82 onto the coax and shrinking, a nice tight fit (although this tubing is supposed to shrink to half its unshrunk size, which is quite a bit:

After shrinking with a heat gun – hair dryer would work too (nice, huh?):

The complete assembly. This will be immediately below the antenna up on the roof. If I experience any problems, I’ll first add another set where the feedline enters the shack. If any issues remain, I’ll add additional sets along the feedline at strategic locations (every 1/3 wavelength of my highest operating frequency):

Now the same routine for the VHF feedline, except for the “mix” of the toroids will be mix 43 for VHF frequencies instead of 77 for the HF frequencies. I just collected a bunch of 43’s from my kit with holes large enough to slide over the coax (another run of RG-213):

Assembled tools and materials. Note my heat gun is not in the pic – he’s shy because he’s so ugly from being so old and beaten up from hard shipboard use!

A clean coax cutter  (blue handles) is necessary for good operation of the DX Engineering cable trimmer (in red protective cover below):

This cool little cable trimmer tool really eases the job of attaching connectors to coax ends in a quality fashion. Just insert the end of the cable and turn in a clockwise direction. Worth the forty bucks, in my humble opinion. Cuts in two operations. First cut in one end, second cut in the other… this one is for larger diameter RG-213 or RG-8 coax cables:

The first cut trims away outer insulation, copper braid shield and inner insulation, just to the right point needed for the standard (PL-259) connector that I’ll be using: 

Here, the trimmer is trimming the second cut to bare the right amount of copper shield without cutting through it by trimming only the outer (black) insulation:

This is how the bared braid looks (nice cut that only requires a bit of further trimming, but for some reason, my first cut didn’t get all of the inner (white) insulation. i think I pushed the cable too aggressively into the end of the trimmer as it left the insulation around the inner conductor, and it should not have done so. The next one, with a little less pressure on the cable into the end of the device came out perfectly:

Then slide the barrel of the connector onto the cable, and then turn the other half of the PL-259 onto the cable end. When it got tight (a good thing), I needed to employ a pair of plyers and a golf club to get the right grip for completing the turning on process:

Before soldering (four holes in sides and pin at the end):

Below, after soldering (use thin resin-core solder, not acid-core).

The trick is to get the connector hot enough to encourage the solder to flow into the holes without melting the white insulation underneath the copper braid shield, which would have the undesirable effect of melting the outer shield to the inner conductor, creating a short!

Testing for a short – nope – guess I didn’t screw THIS one up, too badly, anyway!

The finished product (at least this end of the feedline). The other end of the feedline will receive no connector or beads until after run through the conduit:

Other control lines (this is for the antenna rotator) will get wrapped around the appropriate beads or toroids (more wraps = better RFI suppression) at both ends of their length as well:

And here’s the collection of wires and cables that will connect roof to shack:

• HF feedline (one line for four bands – 20, 17, 15 & 10 meter)
• VHF feedline (one line for 2M and 70cm)
• Rotator control line
• Antenna coupler control line (and spare feedline)
• Strong parachute cord for pulling additional wires back and forth through the conduit ”just in case” (for adding more RFI suppression if needed, for example).

Spools ready to lay out for installation, hopefully within the next couple of days:

The two inch conduit through which all this stuff must pass (including sufficient room for potentially adding more RFI suppression beads as required). Using elbows with opening access panels to ease cable runs. note all are painted to color-match the exterior paint on our building. Should be pretty “invisible”.

Well, that’s my prep for feedline installation. In future posts, I’ll add pics and descriptions for rooftop antenna installation and how all this stuff will then enter the shack.  

73 (best regards)

de (this is) K0GKJ (yours truly)

dit dit (traditional sign-off between CW (Morse Code) operators)

After Four Years, Condo Antenna Approved!

“This is the first such request to come before the Marina South Shore Condominium Association and to be approved since our inception in 1981, so there’ s not likely to be a ‘run on the bank’ for a proliferation of such requests in the future! “ 

 

 After four years of lobbying, I’m finally good to go! On to installation!

 Here were my remarks at this morning’s home owner’s board (HOB) meeting, with a couple dozen other owners present, some of whom asked questions, but not many after I addressed the following talking points: 

 “By way of brief background, not long after Hurricane Charley nailed our community in 2004, it was clear that South Shore would have benefited a great deal immediately after that disaster from communications capabilities that would have been independent of cell towers, telephone landlines and power lines that were not working. A close and well-practiced liaison on your behalf with emergency services organizations from our neighboring communities would also have been beneficial to our friends and neighbors within South Shore, some who were injured during the storm.

 As I seem to be the only skilled amateur radio operator within South Shore, I was approached by members of the board and reconstruction committee at that time to investigate and assemble a proposal for a South Shore communications command post so we’d never be stranded with virtually no communication out here at the end of the road again. Since that time, I have been working toward that end on your behalf.

 This July, our board voted & approved the installation of an antenna on the roof of building two. That decision was to be ratified at the October board meeting, but the final ratification was tabled until today’s meeting.

 I’ve been asked to briefly describe the station & its purpose with you today, as well as to attempt to anticipate any remaining questions about the antenna before the topic is closed.

 This antenna would complete the last component of our radio station & command post, to be used by the board & their delegates in times of emergency.

 First, the station is essentially now complete within our home. It will provide both local & long range communication capabilities, independent of land-line phones, cell towers, Internet access or power, by the way, since the entire station can run on a sizable bank of batteries, if necessary.

 Amateur radio, or ham radio as it is often called, is one of my passions, & I willingly offer to open up my station, once operational, to anyone either idly or passionately interested in this fascinating hobby.

 After receiving the board’s support this summer, I purchased the antenna described in my proposal, along with a good deal of additional equipment, all of which, except the antenna, is now installed.

 Antennas for this type of station are normally quite tall in height. A vertical antenna can easily be thirty feet tall or more. Knowing this would NOT be acceptable, I selected a very efficient & proven low profile design that is only a little over four feet tall, & is not very visible.

 In fact, not only does it not look like an antenna at all, rather more like just an inverted umbrella frame, IF you’d even notice it up there, set back from the front of the building as its components are very skinny, mostly just wire in fact, & should be quite hard to see from a distance, & virtually impossible to see from most locations on the ground.

 And it will use the exact same (board-approved) mount that existing satellite TV dishes use.

 But let me be clear – the bottom of this antenna does functionally need to be at least a few feet above the top of the mansard wall to be clear of the effects of that metal roof, which would interfere with, or more likely negate its intended function.

 This is a departure from the current board policy that nothing should extend above the mansard, & would take a board vote to create an exception for this specific installation.

 The decision the board will be ratifying is whether South Shore wants to have access to the kind of emergency communications command post that I’m offering, or not, which is entirely at my own considerable expense, & that comes with my expertise.

And potentially, this could be the genesis of a South Shore ARC, or amateur radio club if there were of interest to some of you.This would enable me to serve our South Shore community in a unique way, AND also enable me to pursue a hobby for which I’m passionate, while sustaining my proficiency with this gear, as well as to create an active liaison with Punta Gorda, Port Charlotte & Cape Coral emergency services organizations at the same time. 

These local & nationally-affiliated organizations known as ARES, or Amateur Radio Emergency Services, are well known for not only providing communication support in times of disaster, but also for methodically preparing for that eventuality with proficiency exercises periodically throughout the year.They did so immediately after Charley, for example, but we simply weren’t in the loop at that time.

Another one of my personal objectives would be to communicate with as many amateur radio operators as I’m able who also happen to be currently serving our nation’s armed forces in Iraq & Afghanistan who may be reaching out over the airwaves. There are many. I’d like to be listening and respond when they call.

Thank you.”

 

Another small victory for community-service-oriented ham radio! 

FB

de K0GKJ 

dit dit

 

 

Station Reconfigured, Antenna Setback

Rearranged shack for more efficient access to fronts and backs of all gear. Now have actually have a dedicated (albeit small) room for the station. Love it!

With an entirely separate space to leave all my “ugly stuff” out in the open (some XYLs are less tolerant than others), I’ve relegated the “hamoire” to my junk drawers and the ham library:

It now appears there’s an additional rub on my hex beam antenna on the condo building roof (three story building, second story shack).

The home owner’s board, despite the description in the presentation forwarded to them for approval, assumed that the antenna would not protrude above the top of the mansard wall surrounding the roof. Since that wall is solid metal, there would have been serious capacitative coupling isssues.

So ratification of the approval I received this summer has been tabled until the November board meeting. I plan to walk the intended installation around to each of the key board members (again) in hopes of resolving the remaining visibility issues.

I believe it will boil down to whether our community wants to have an emergency communication and command post for disaster preparedness and recovery, along with the ability to contact some of our troops abroad, OR NOT! (I’m the only ham in 123 units within our complex).

Watch this space!

de K0GKJ

dit dit

New Gear is Here!

Just received the shipment from Texas! Just like Christmas…

How’s this for a haul?

 

Here’s a better pic of the jewels of the collection:

Now I just need to move the shack to a large walk-in closet, mount the antenna on my (CCR) roof, run the feedline, solve any RFI problems as I get on the air, and away we go!

de Gene K0GKJ

dit dit

New (to me) Rig & Station Gear!

I’m sure some if not many of you who have been around ham radio for awhile have had that delightful experience of getting a whole box full of gear from someone who had left the hobby for whatever reason (hopefully, not a silent key). It’s like Christmas!

While visiting my brother-in-law in Texas, he made it known that he’d been out of the radio hobby for enough years to finally (emotionally) be ready to part with his box full of gear. And Mikey (AG1N) has some nice gear, despite the fact that he shed some of it before starting an almost four year full-time RV experience.

Now that they’re settled into a retirement community in Texas, and have moved on to other pursuits (sustained interest in anything is not one of Mikey’s attributes), he sold the entire boxed-up station (less antenna), books, filters, peripherals, digital interfaces, cables, etc., to me, all for an extremely reasonable price. Quite the package deal.

I’ll post a few pics once we return to our Florida QTH and receive the three large and heavy boxes (cost $190 to ship!!!!). As I get ready to hire a guy to install the mounting bracket on the roof for my hexbeam (gotta be Hurricane Category 4 (up to 140 MPH) certified, I’ll also be moving the shack to a more XYL-friendly location in the condo (a large walk-in closet with cable, power and an exterior wall). Then I’ll take a few pics of my more secluded (and private) shack, more suitable for 24×7 operation.

But here’s a short list of hardware goodies I scored this week:

• Icom 746 HF/VHF transceiver with optional CW & SSB filters – very good shape
• Icom SM-8 desk microphone with dual inputs (very nice unit – virtually never used)
• Diamond 40A (continuous) Switching Power Supply (GZV4000) with a plethora of output possibilities
• a low pass filter (by ParaDynamics)
• a large Pelican equipment case (APP-1550) that might make one heckuva “go box”!
• Rigblaster Plus for PSK31, etc.
• 300 watt dummy load
• a bag of split toroids for solving RFI issues
• an antique frequency counter
• an antique mil-spec field strength meter
• an excellent (reportedly) notch/peak filter for SSB/CW/Data by JPS (NRF-7)
• an old (hamfest-procured) Heathkit “reflected power and SWR bridge” (!)
• portable wall-wart style power adapter with various voltages and plugs
• headphones, connecting cables, spare coax cables with connectors, etc.

as well as the bulk of his ham radio library, at least the twenty or so books and a few software CDs that I didn’t already have. Cool stuff!

ARRL RFI Book   RF Exposure and You   The New Shortwave Propagation Handbook   Frequently Asked Questions   The ARRL Antenna Book, 19th Addition   Icom Amateur Radio Band Plan (2)   HF Antennas for All Locations, 2nd Edition   Ham Radio FAQ   Joe Carr’s Loop Antenna Handbook, First Edition   Where do we go Next?   The Amateur Radio Vertical Antenna Handbook, 2nd Edition   FCC US Amateur Part 97 Rules & Regulations, May 2001   Ham Desktop Reference, 7th Edition   Radio Amateurs World Atlas   Everything You Forgot to Ask About HF Mobileering, 3rd Edition   Worldwide Shortwave Listening Guide, 2001, 3rd Edition   The Modern Amateur’s Mobile Handbook, 19

Hamoire – Part Two

Remember my telling you I need to be extremely stealthy, both inside the condo as well as outside on the roof? Enter the armoire converted into a “hamoire”.

Well, I added another objective to this project. I want to rip the guts of this hidden station right out by the roots and take it on the road. Yeah, maybe for field day or mobile HF ops, but also to haul it down to the boat for a floating QTH. That meant this baby had to be “luggable”.

I might want to make it bang-around-proof too ultimately, but one step at a time.

I needed a main frame (pun intended, for you big-iron computer nerds like this ex-IBMer), so I built a small shelving unit approximately 26″ wide, 10″ deep and 15″ high. The bottom shelf is both a box bottom and a shelf. Actually, this thing started out as a shelf with legs on it, tipped it upside down and sawed off the legs to fit into the central shelf of the armoire.

All my station’s main components fit into this “frame”, including an MFJ-949E tuner, an MFJ-752C Signal Enhancer (a dual notch/peak filter). an MFJ-493 Super Menu Keyer with MFJ-79 Remote Controller, a West Mountain Rig Blaster Plus for digital ops, a low pass filter bolted onto the right side of the frame, and the Icom 706 MkII-G bolted onto the left side. There are a couple of other adapted components in there too, like an audio mixing board and a spectrum analyzer for audio interconnectivity convenience and sound quality (I’m an ex-studio engineer – what can I say?).

The “front end” for this mess is a an MFJ-299 desktop mic with integrated 4-band equalizer, an MFJ-422D Electronic Keyer/oscillator with a built-in Bencher iambic paddle (gosh, you’d think I was an MFJ guy – guess I am somewhat), and a sweet EFJ/Nye/Speed-X straight key (I think – bought it at a hamfest – no logo, but looks like an old E.F. Johnson model, maybe updated).

I mounted the 706’s faceplate on the front of the armoire’s (now ham junk) drawer for easy access.

So what do you guys think? I can pick the whole thing up, set it on the seat of the golf cart, and haul it down to the boat for the occasional CXpedition (get it? CW on the sea? Pun on DXpedition? Aw, never mind. Stupid attempt at humor! At any rate, the antenna on the boat is basically a longwire – one of the wires holding up the mast (the tall thingy on a sailboat) called a backstay – insulated, top and bottom, uses a copper foil strap connection to a sintered bronze block bolted to the outside bottom of the hull. Seawater makes a GREAT counterpoise! That QTH will come together after THIS one!

And being a boater, how will I keep stuff from sliding outa this contraption? Well, bungee cords, of course! Actually, I’ll solve that problem after a few quality QSOs. See you on the air…

Front:

Back (whole unit slid out of the “hamoire” for access to the backside (sans connections, so far):

Close-up left side:

Close-up right side:

Front-end (operator’s desk):

Well, you get the idea… kind of a fun project.

73 de k0gkj dit dit