Showing posts with label VHF. Show all posts
Showing posts with label VHF. Show all posts

Saturday, December 1, 2012

Ham Shack Update

Well, with the exception of finding a Kenwood SP-120 speaker, I have just about completed a station that any ham from the late 80's to early 90's would be proud to call their own!

Just to brag (or whine, depending on time of day, my mood, and your point of view) my collection contains:

HF:
Kenwood TS-440S/AT (with FM module, IC-10 kit, Voice Module, tuner, and ALL optional filters)
Kenwood PS-430 power supply
Kenwood SP-430 speaker
Kenwood AT-250 outboard tuner (for 160m)
Kenwood IF-232C computer interface
Kenwood MC-50 microphone

VHF:
Kenwood TR-9000 (with ComSpec SS-64 tone module) 2m All Mode radio
Kenwood PS-20 power supply
Kenwood SP-120 speaker
Kenwood BO-9 base shelf
Kenwood TR-7730 (2m FM for APRS)
Mirage B-34-G amplifier with GaAsFET per-amp

UHF:
Kenwood TR-9500 70cm All Mode radio
Kenwood PS-20 power supply
Kenwood BO-9A base shelf
NEED THE SPEAKER!  ;-)

MISC:
SignaLink USB soundcard interface
Homebrew soundcard interface (cost <$20 and works just as well as the Signalink)
Homebrew coax tester
Homebrew LED ambiance lights ;-)
Homebrew PTT mic to PC interface
Wouxon KG-UV3D dual-band HT
Heath bench variable power supply
Radio Shack SWR/power meter
MFJ-941D antenna tuner
Cheap CW key

MOBILE:
Yaesu FT-2900R
Galaxy DX959
Radio Shack HTX-10
Radio Shack PRO-2050 scanner
Homebrew radio console

ANTENNA:
RadioWavz G5RV Lite
Homebrew 2m moxon
Homebrew 2m 1/4 wave ground plane

While this may all seem like an impressive list of equipment, it can all be replaced with one radio these days.  The Kenwood TS-2000, the ICOM 7000, the Yaesu FT-857D will each do everything that this entire list does and take up less space and power in the process!  Plus the new radios have DSP to clean up those weak signals.  On the flip side, all of the equipment listed didn't cost me what a fully loaded TS-2000 would cost.  So, pros and cons to each approach.

Anyhow, here is a quick pic of my shack (ignore the ugly desk, its not finished, and I'm an engineer, not a skilled wood worker, although I generally enjoy trying).


So anywho, there you go.  A shadowy flight into the ham shack of a man who does not exist...  Sorry, couldn't resist the geeky Knight Rider reference.

73 and good night,

Richard, KK4JDO

Tuesday, November 6, 2012

Mobile Install

I drive a 2011 Ford F-150, which is not the most radio friendly of vehicles.  It's not the worst, but it is not the best either.  When I only had a single radio in the truck, it was fairly easy to accomplish a professional looking installation.  As I added an 11m radio, and then a scanner, things got more difficult.  I ended up deciding that I needed to build a console in place to house these additional radios.


Yaesu FT-2900R


The first radio that I put into the truck was a Yaesu FT-2900R, which is a 2m mono-band ham radio.  This F-150 has a cubby hole at the bottom of the dash under the climate controls, which fit this radio like a glove while conveniently allowing plenty of air circulation to help cool this 75W solid aluminium beast.  I took out the cubby hole section, removed the back of it with a dremel, mounted the radio inside, and *bam*, it looked like original equipment (of course, that was before this blog, so no pictures).  The only downside was that it was a little difficult to see the top of the display on the FT-2900R to see if the offsets and tones were on at a glance.  This worked fine and dandy for months...


Galaxy DX-959

Enter a Galaxy DX-959 CB radio (if you're a ham and hate on CB'ers, keep it to yourself, I like to be able to talk to the truckers while making long trips, and sometimes it's just fun).  There is a world of difference between the way that a lot of CBs are built, versus the way that a lot of ham radios are built.  First off, they tend to be bulkier and flashier.  Needless to say, this wasn't going to fit in some handy preexisting pocket...


Radio Shack PRO-2050

Then along comes a scanner that I had originally purchased for use inside, then got into the whole scanner thing and decided that I wanted more features available in the house.  This makes for an interesting mounting challenge since there are no built-in mounting options on this scanner!  This brings us back to the whole idea of building a console for this all to fit into.

I decided that if I built a console, it would need to house all three radios, not just the two additions.  It would also need to look as stock as possible.  And lastly, it needed to be cheap!  I have seen some awesome custom professional installs but I have also seen some amazing price tags on them.  Since I'm not on an episode of "Pimp My Ride", I had to have an affordable solution.  I went through several iterations of the design, with the biggest issues being how to physically mount the radios in a small location.  My final solution was to build a box that fit between the vertical trim pieces on the dash, and angle back to the seat.  Originally, the radios were to be flush mounted, but to better make use of space I ended up angling the radios inside the new box.  Additionally, the original though was to have the box be independent of radios so that I could remove them individually for service.  However, space constraints dictated otherwise.

The end result was achieved by mocking up the sides of the box using cardboard to create a template, which was then cleaned up and copied to 11/32" plywood.  Once this was done, I was able to start finalizing the placement of the radios that I had mocked up earlier on the cardboard.  I ended up connecting the Galaxy radio directly to the plywood due to the space constraints mentioned earlier.  So much for a modular design.  

Since the scanner and the Galaxy radios were of similar size, they became the top and bottom spacers for the console.  I then used some scrap 1"x 2" to secure the two pieces of plywood together front and rear.  I used some scrap plywood to build a set of rails to hold the scanner in place, since it doesn't have a mobile mounting option.  The Yaesu presented a problem, since it was over two inches narrower than the other radios!  I ended up building spacers out of the 1" x 2", and mounting the 2m radio to them.

I then bought two $5 black rugs from Wal-Mart that closely resembled the carpet in my truck, and used a combination of 3M spray adhesive and carpet tacks to cover the sides of this contraction that I was putting together.  

Once all this was done, I had to take the whole thing apart to install it into the truck.  That turned out to be a pain in the rear!  Things that line up easily on the bench sometimes don't work so well in real life.  Such was the case with this console.  No tweaking was needed, but maneuvering around in the confines of the pick-up when I'm decidedly in the fat-boy club was a challenge indeed!  After much cussing and ill-will, things finally lined up properly and I was able to see my handy work:


As you can see, the radios are held securely, but it definitely needed a top!  This became in interesting problem.  How to come up with something that would fit?  Measuring would have been a major pain and I always mess that up anyway.  So back to the cardboard!  A snip here and a snip there, crumble it up, start over, and eventually, poof, a template is born!  I then transferred that to some 1/4" plywood that I had laying around and got busy with the jigsaw.  Eventually (and a few broken parts later) I had a top for the console!


But that's ugly, who wants to look at wood all day in a pickup?  So how to finish it?  I could paint it, but that would look funky.  I could stain it, but again, wood...  So I decided to cover it in vinyl.  A local upholstery shop was nice enough to give me enough material to take care of it, after declining to do it for me (they were afraid of breaking it, which I understand since I broke a few).  Again, the dilemma, how to actually do it?  The final decision was to use the spray adhesive again, and just razor blade the holes for the radios.  It actually turned out pretty well!  The only downside was that the end-grain was exposed, but a handy sharpie marker took care of that...LOL!

The finished product turned out like this:



Please no comments about the state of the dirt on my floorboard.  Consider it an experiment to see how long carpet survives without cleaning!

If I had it to do over again, I would try to cut the holes a little straighter with the jigsaw, and I would probably use some flat bar stock and build cradles for the radios to allow them to be serviced individually without massive effort and potentially marriage shattering language.

I'll attach a few more pictures, just because I can, and I am proud of this lash-up for some reason.  ;-)



Eventually, I intend to add an Icom IC-7000 to the mix.  I'm not sure whether I'll replace the Yaesu with it, or if I'll keep it so that I can monitor 2m or run APRS from the truck.  What do you think I should do?  Anyhow, if you've made it this far, you should be ready for bed, your insomnia has been cured!

73,

Richard, KK4JDO

Saturday, November 3, 2012

Quarter Wave Ground-Plane Scanner Antenna (and 2m ham antenna)

One of the purchases that I got via eBay is a Radio Shack PRO-2050 police/fire/etc scanner.  I've never had a scanner before, and this was a cheap way to check it out.  I didn't get a pick of it before I ended up moving it from the shack to the truck, so I nabbed a picture of the internet.  Here is what my scanner looks like for those that haven't seen one:



Of course, since I had a scanner, I needed an antenna.  I'm just getting into the whole scanner thing, so I didn't want to spend too much on the antenna since I didn't pay much for the scanner (which is several years old).  One of the cheapest and easiest antennas to build is the quarter-wave ground plane.  I had some #8 ground wire laying around, as well as an SO-239 connector, so I was off to the races.

There are several good calculators out there to help get the proper dimensions, however, the math is fairly simple:

468 divided by Frequency in MHz gives you the half-wave element length in feet.
The quotient from above divided by 2 gives you the quarter-wave element length in feet.
Take the quotient from the last problem and multiply it by 12, the product is the length of element in inches.

For example, if you want an antenna for the middle of the 2m ham band: 

(468/146) / 2 x 12 = 19.23" which roughly equals 19 1/4" (since tape measures are in fractions of an inch).

It helps if you cut it a little long to allow you to tune to your specific location.  I actually cut mine for resonance on the public services band (~150MHz) since that is what is in use in my area, however, I get acceptable performance on the 2m band as well (about 1.7:1 VSWR).

Bending the ground plane elements down to 45 degrees brings the resistance of the antenna closer to 50 Ohms.  I'm not sure how this works exactly, maybe someone could drop a post and let me know why this works.

Here is a quick pic of the completed antenna.  The ground plane elements sag a bit with they are supporting the weight of the antenna.  They are straight when the antenna is suspended properly.



I also added vertical stubs for the 440MHz band as well as the 800MHz bands.  I didn't add ground plane elements for them as I'm not sure that I would see any benefit from doing so since I have the 2m elements.  Here is a close up of the verticals.


The last thing that I did was to seal the top of the connector with some silicone caulking.  This will help to keep water out of the coax, which would degrade the metal over time.  I would have used coax-seal, but I ran out and didn't feel like spending the money on this antenna.


And the final thing that I need to do, as you can tell from the background of the picture above, is clean my work bench!  It is getting crazy in there, so hopefully I can get that squared away soon.

My Parts List:

  • 1 x SO-239 connector
  • 8' of #8 grounding wire
  • 4 x little screws
  • Caulking
Time to Completion:
  • About one hour for this one, mainly getting the jig built to solder the pieces together.

Next time I'll work on getting better pictures.  I tend to feel my way through some of these projects and don't think to document as I fumble along.

73,

Richard, KK4JDO