Sunday, March 31, 2013

V8000 in F-150

Here are a couple pictures I promised on a recent 2m mobile installation in an F-150 -- from the post on eham here.

ICOM V8000 and Panavise Mount
Larsen NMO 5/8 wave 2m



Salt Water and Longwire Antennas

My family had the opportunity to visit our oldest son down at Embry-Riddle in Daytona Beach this past week while the kids here were out for Spring Break.  Although it was not the typical Florida weather with temps dipping into the 40's -- we managed to have a great time.  Fishing was fun, and Kennedy Space Center is just an amazing place.   I did manage to pack up the '706, some wire and an antenna tuner just in case.... and glad that I did!  Learned a few things in the process and had some fun when the weather was keeping us indoors.

Along with a manual antenna tuner, I opted for a longwire antenna (spool of stealthy black 22 gauge stranded hookup wire) since it was unknown what kind of access and arrangements would be allowed at the hotel.  As it turns out, we ended up in an end unit on the top floor (6th) -- about 55' or so above the parking lot facing the Atlantic.  

The building curves around north to east and another condo complex next door pretty much blocked views to the south; but that just increased the challenge a bit to get a decent signal launched.  The salt water 250 yards distant certainly can help, right?

The spool of Radio Shack hook up wire (maybe $7 ?!) was 95' feet long, but I quickly found it presented some high reactance on several bands at that length -- a bit more than the MFJ Versa Tuner II liked, so I trimmed 6' off of it that first night, and that seemed to do the trick on most of the bands to keep the tuner within its range.   The wire ran directly from the upper rail of our balcony down at about a 40 degree angle to a fence that went toward the beach, east-southeast direction; installing this at dusk several evenings prompted a few funny looks, but it was essentially invisible and well above any passerby's heads.  Using a couple "figure 9" carabiners on each end of the wire and some braided nylon line to tie off made the job a simple under 10 minute process each evening.

A loop in the wire up near the balcony hooked to the carabiner, allowed the slack "feedline" to make its way to the tuner.  A short 4' piece of RG8X with alligator clips was used to connect the longwire to the tuner and to ground the braid near the feedpoint on the metal balcony.  (I could have used the balanced high impedance input and some ladder line, but didn't bring any on the trip...so I was stuck with the 50 ohm coax connection...probably would have loaded better with that approach.)


I loaded it up on 20m the first evening, and although the tuner was a little touchy finding the right capacitor combinations -- a 1.2:1 match was obtained in fairly short order.  I answered a couple CQ's using 100w and was receiving very mediocre reports;  for example a loud W5 running 100w and solid 59 at my QTH, gave me a "weak" signal report of 53, just above his local noise.  Other QSO's were similar.  Why the report mismatch? What about the theory of antenna TX/RX reciprocity? Antenna Reciprocity  Well -- its is still there of course -- all day long -- but power losses on the transmit side in the form of lossy components and/or ground losses don't really impact the S/N ratio on the receive side the same way (try to transmit with a Beverage for example) .......soooooooo...... Where is the transmit power going?   It is either going to radiate or heat something up.  Pretty sure I was heating something up the hard way (tuner, coax, chassis, etc...).

As it turns out, the RF Ground (aka counterpoise) for the longwire and other unbalanced antennas is crucial, despite me and generations of other radio amateurs wishing otherwise.  A poor ground means that the return current faces real resistance (Rg) which ends up consuming,  and not radiating, power -- the better the ground plane / counterpoise, the less loss and the stronger transmit field strength. (A good description on the importance of minimizing Rg  is here)   I went back to work and made a solid ground connection from the braid at the feedpoint to the all aluminum balcony and the doorframe -- and for good measure connected about 150' of excess wire and twin lead laying on the balcony floor to the same ground.  Readjusted the tuner to the new impedance, loaded the antenna, and boom -- excellent signal reports all around on 20m.  More importantly, the reports implied that the antenna efficiency had improved and a 59 that I handed out was returned with a 59, a 55 with a 55 and so on.  (It is instructive to again witness that SWR is never a complete measure of effective antenna performance, only how happy your transmitter will be; after all, a dummy load presents a 1:1 SWR -- but is about as inefficent a radiator as you'll find.)
W4QA/4 on 6th Floor - Daytona Beach 250 yds away

After these changes, results were above my expectations on most bands, with 40m and 30m being the most productive when I was QRV as W4QA/4 -- and no doubt the salt water proximity didn't hurt.    Several stations on 30m remarked how loud the signal was and wanted the details of the antenna -- with more than one asking "only 100 watts?".  On these two bands I managed to log about a hundred contacts into maybe 30 countries with some casual operating in the evenings and early morning hours.  More than anything it was good fun, and I "relearned" my counterpoise lesson from my Novice days after getting more than one RF burn on my HW-101 due to RF in the shack from lack of a good ground.   It's also motivated me to learn more about Maxwell's concept of displacement current (i.e. the "imaginary current" running through the air between poles of an antenna, or the radiating element and ground) and why, after about 140 years, there is still a debate on what this actually is -- but that's a whole other story.....

The longwire hasn't been held up in amateur circles as a great antenna for a number of reasons, and I suspect much of its reputation has been due to the kinds of ground problems experienced here.  Reports of RF in the shack, poor efficiency, combined with unpredictable (well, without software at least) radiation patterns probably pushes away a lot of folks before they actually try it.  ("Hey, I've got a great SWR, can hear all kinds of stations, but just can't 'get out' ")    Also, antenna manufacturers don't exactly see the profit in selling you a spool of random length wire --- now tuner manufacturers, that's another story.  Focus on providing a decent ground and putting the wire up a significant height above ground however, and you've got something that can perform well on multiple bands (with gain in certain directions (!) ), costs very little, and is simple to install --- ideal for portable operations or limited space / budget QTHs.   I'll be doing it again next time and may just have to put one up at the home shack for some more experiments.


73,
Rush, W4QA

Wednesday, March 13, 2013

A New One....

My DXCC totals have inched up over the years and usually take bigger lurches forward whenever I make a substantial change to the station (i.e. New Amplifier, better / higher antennas, more time to operate, etc..).  As such, I'm at the point now where the "All Time New Ones" -- we'll call it ATNO now just to invent a new acronym -- are few and far between.  Long gone are the days where I might add 3 or 4 new ones over a weekend -- now its more like a new one over months, maybe years of effort!  I know a few DXers that are down to the last one -- say North Korea for example -- and can't wait for the day to join that epic sized pileup.

So -- its really exciting when I am able to snag the proverbial ATNO, especially when it is pretty much unanticipated.  This happened to me last night after coming home late from a business trip and turning on the rig to listen to 30m while I wound down.  The band was solid into Europe and I quickly worked a string of stations.  I copied a 9X0 prefix on 10.105 -- couldn't believe it -- and rotated the antenna a bit farther to the east to peak the signal...solid 579.  Nick, 9X0NH, was on simplex for the first few contacts, and I snagged him early with a quick exchange; the pileup instantly went ballistic, and he then switched to split.   Awesome to get him in the log!   I'll get a direct card in the mail to him at his home base in the UK as he's leaving Rwanda very soon.

Although Rwanda is not considered super-rare -- it's just never been one that has been active when I was also active.  It also helps to have entities active on a band like 30m, where the competition is just not nearly as fierce as on a band like 20 or 40.  A little luck, patience, and decent antennas come together in a nice way every now and then!

73,
Rush, W4QA

Sunday, March 10, 2013

A Timeline Chart of the DXCC Program

I've been looking for a succinct timeline of the DXCC program that shows the additions / subtractions of countries and entities over the years, and I found a great one created here on the KY6R blog.  You can download and print this out -- it's a super way to see how things have changed with the program since the beginning.

Saturday, March 9, 2013

Visiting the Charlotte Hamfest 2013


Getting connected w/ PowerPoles

Glad that I made the time to visit the Charlotte (Concord) Hamfest today, about a 45 minute drive from the house.  Pete was kind enough to pick up Mary Elizabeth from her horseback riding lessons this afternoon, and I took the chance to see some old friends, make a few new ones and kick around with some radios and antennas.   It was great to see some of the manufacturers invest the time and effort to make it here the past two days; the internet can be a wonderful time saver to buy that new rig, but lets face it there is really nothing quite like getting your hands on a radio, spinning the knobs, and maybe getting a peek under the hood at just what it is making it tick.  Yaesu had almost their full array of HF/VHF/UHF radios on display in their booth, as did the folks from FlexRadio, and MFJ.  The accessories dealers that made the trip were very welcomed -- I saw a LOT of connectors, antennas, cables, heat shrink, books, and keyers go out the door.

Goodies at the Yaesu booth
As for me -- I did have to bring home a couple items on the needed list, including a new 2m/440 duplexer for my Icom 821H, a simple 2 position coax switch, and some study cards for my sons who have shown some interest in getting their ticket.  Its the last item that I think I'm the happiest about -- we'll see what happens!

I learned about Indexa (International DX Association) today in a delightful conversation with the organization's President - Gary Dixon, K4MQG .  These guys are really doing all of us DXer's a wonderful service by helping sponsor many of the DXpeditions that we all love to hear on the air.  Ask him about the story around activating South Sudan via ST0R when it first became a new DXCC entity -- it is really a good story, a laid out well in one of their newsletters that Gary gave me.  Happy to join and support this group -- maybe one day I can fulfill a bucket list goal and be a part of one of those DXpeditions!

2kw Eimac Tubes - Medical Surplus
 The flea market has changed a bit over the years from what I could tell -- definitely not as much of the military surplus radios that were common in earlier decades -- and actually fewer computer and software folks on had.  One of the vacuum tube vendors that was up from Orlando remarked that the demand for tubes had shifted pretty dramatically from N. America to Asia and Russia -- much of their business is therefore export oriented, and just not as much here.  Like anything markets change over time -- and our hobby is no exception.

A nice bright spot was the number of really young, new hams that were at the hamfest -- many young enough to have to be with Mom and Dad!  This new generation will experience radio in a different way than many of us have and no doubt will spark new ideas around communications and technology that we'll need.  Great to see that ham spirit getting passed down....  Thanks W4BFB for helping make this happen!

73, Rush



Thursday, March 7, 2013

A Little Fun with EchoLink

I'd heard about Echolink through QST and some of the online forums -- had even listened to a couple of folks every now and then pop on the local .94 machine from places that would have otherwise required impossibly rare 2m propagation.  That caught my attention.  Despite the crowd that says internet linking is not "real radio" -- gotta admit its a very cool concept.

I downloaded the (free) software last night, went through the license validation process ensuring that I hold a valid FCC license, and after a little tweaking of my cheap computer mic was "linking" to repeaters all over.  My first QSO was with a KL7 in a small town 400 miles from Anchorage; he was on his 2m handheld to the local repeater, and I was connecting to his repeater via my PC and "the cloud".  It was kind of a strange experience talking to my computer and hearing it come back with the familiar squelch tail.  We had a nice brief chat, said 73 and I linked and listened to a few more.  I'm sure I'll do it again...its a different approach to something very familiar to me.

For me this'll never be a real rival to an actual radio, feedline, and antenna -- but I can see the applications here, and it's fun to be able to "dial up" a particular site in a faraway place with the click of a mouse.   Wanna key up a 440 machine in downtown Tokyo during rush hour? No problem.  No doubt, its also an aspect that I'll show to any young ham prospect -- how radio and the internet can be fused into one system for certain applications.

Monday, March 4, 2013

It's About Time...

I'm almost embarrassed to say how long it has been since I've logged contacts in my trusted DX4WIN logging program -- suffice it to say years -- until just very recently.  Between raising kids, a consuming but rewarding career, and all the workaday effort that all entails, Amateur Radio has just taken a back seat for a while.  Like a good friend though, its always here, I'm happy to say.

For many years, the shack occupied a private, albeit shabby and humble corner in the unfinished basement (think cinder block walls, floor joists and insulation, and the occasional critter).  Although not the most comfortable spot, it did the trick so to speak.   When Cindi and I decided to finish the basement, the shack was broken down, the radios were boxed up, cables were coiled and put behind panels in the new drywall, and the space was turned into a "proper" finished basement -- ready for the family to enjoy.  And, bonus -- I got a new office in the process; Cindi insisted that I have a good spot to do my work -- I'm grateful for that!

With everything going on, the radios, the switches, headphones, keyers, and logs all found a new home in boxes in the corner of the basement.  Starting a new position at a new company took a great deal of my focus over the next few years, and so that's where the radios remained.   Through the next several years, the wire antennas eventually fell prey to the elements and came off the trees -- but the Rohn 45G and the yagis remained intact.  The Tailtwister (sans a connected rotor control box) stayed pointing west along with the HF yagis -- and I wondered often if everything would still work if I could find the time to set things back up.

Through a friend at work and the local Boy Scouts troop -- I found the time and inspiration to finally start getting W4QA QRV once again.  Jaymes had asked if I was interested in talking to some scouts about amateur radio -- and after some scheduling challenges -- I hosted about 7 young men and a couple Scout leaders over at the house in January this year.  It was this event that encouraged me to get my backup Icom 706mkii out of the box and onto the feedline. 

Fumbling through the menus trying to remember how to run the rig, I was on the air shortly thereafter and enjoying great 20m signal reports from W6 and W7 (no rotor, everything point west!)  The demonstration went well -- and two of the scouts are interested in pursuing a license.  (as an aside, I took a little joy in both of them saying "...Facebook is just so boring...!")  Amateur Radio has a lot of life left in it....we're just now getting warmed up!

It's a start -- hopefully this little corner of the desk will expand a good bit over the next several months...