More station work gets done!

Over the last two weeks I’ve gotten a lot of station work done.  I’ve put up the new 15M 2 element beam and I’ve done more work on the single point ground box project.

When I got the 15M beam up, I checked it with the antenna analyzer.  Much to my dismay, it didn’t tune anywhere.  A quick e-mail to the YCCC reflector revealed that what I was probably seeing was bad coax – most likely a short between the shield and center conductor.  When i got around to checking things out a few days later, I realized that I had not connected the balun to the antenna correctly, and had accidentally created a short (there are 2 sets of leads from the balun – the 2nd would be used for the original 12/17M element and the way I had dressed them they were shorting to the boom).  Fixing this fixed the issues and the antenna now tunes nicely in the 15M band.  Unfortunately, it tunes also around 30MHz.  It would be nice if that 2nd resonant point were in the 10M band, but oh well.

I also got a lot more work done on the NEMA box this weekend.  I drilled all the holes for the connectors.  This went very smoothly as the box has a removeable “entrance panel” on the bottom.  This connects securely to the box with 10 screws and a gasket.  I used a 5/8″ hole saw for the coax connector holes and drills of appropriate size for the rest.  This went very smoothly.

I also realized that I cannot get away with only 2 Polyphaser suppressors.  The antenna must connect to the side of the suppressor that passes through the bulkhead.  So I’ve ordred 3 more suppressors from DX Engineering.  These should be in later this week and I can finish this project.

Here are some pictures of the NEMA box work that got done this weekend.

The RCS8V switches are connected to the backplate of the NEMA box with machine screws through their plastic cases.

The NEMA box with 2 of the 5 Polyphaser suppressors installed and the two antenna switches installed. There will be a lot more cable when everything is in place.

Two of the five Polyphaser surge suppressors installed on the NEMA box. The polyphaser suppressors bring each antenna feedline into the box, and the two bulkhead connectors at the left connect to the two lines that enter the house for the left and right rigs. The single hole to the left of the two bulkhead connectors is for the switch control lines.

Here is a view of the bottom of the box. It was easy to drill the holes because the box had a removable panel on the bottom. I used a 5/8" hole saw for the coax connector holes. The three empty large holes on the right are for the remaining Polyphaser suppressors (you can see their matching machine screw holes above each one). The large hole on the left is for the switch control lines. The two small holes at the top left and right are vent holes and will get covered with screen on the inside. The box will be grounded by running copper strap, heavy wire or braid from under two of the screws that mount the panel to the main box.

More Lightning Project Work

Today I was able to spend about an hour doing more work on the entrance panel project.  The antenna switches are moving farther away from the shack, so I needed to install new control lines.  I also ran the coax from where the NEMA box will be mounted into the shack.  There was also a fair amount of labelling that I did tonight.  Here’s some pictures of that labelling.  I used a Brother P-Touch labeller for the labels.  The only downside of this unit is that the backing is very difficult to remove from the labels.  Here’s a few pictures of some of the labelling.

Start of Lightning Protection Project

Over the last couple of days many of the parts for my lightning protection project have arrived.  All I’m waiting for at this point is the NEMA enclosure which I orderd from Electrical Replacement Parts (an ebay seller).  It seemed like it had shipped, but then the tracking number was coming up as invalid on the UPS site.  An e-mail to the seller revealed that they had started the process, but the package was not ready when their daily pickup occured.  I was told it would ship yesterday, but I have yet to see a new tracking number.  Hopefully it gets on the road soon.

Tonight I started prepping my SO2R antenna switching to move from the basement to the new enclosure just outisde the house where the coax comes in.  The switching uses two Ameritron RCS8V switches and a modified control box in the shack.  Each antenna will come into the entrance enclosure through a bulkhead connector, and then be divided with one lead going to each switch.  Here’s a picture with only one of the “dividers” attached for clarity.

These switches are quite old.  The one on the left has some damage from when I first installed it on a crank-up tower about 15 years ago (and I got it used from another ham then).  When I first cranked up the

tower one of the coax cables got caught on the base of the tower and ripped the connector off the switch.  I have the ability to connect an antenna to this broken port, but have not since only 1 of my 2 amplifiers is capable of 160M operation, I just use port 5 for that band.  The switch on the right was acquired from KV1W along with the control unit.  He had built this switch up very early on in the SO2R days and upgraded to a SixPac or similar later, then sold one RCS8V and the control head to me.   To the left is a picture of the control head.  It’s a modified RCS8V control box.  The rotary switch has been replaced by a power on lamp.  The selected antenna leds have been replaced with dpst switches.  Throwing a switch to the left connects the antenna with the left radio – throwing a switch to the right connects the antenna to the right radio.  The only way both transcievers could be attached to the same antenna would be through a circuit failure of some sort.  The switch works very well for my purposes, and could be automated if I so desired using band decoders and source driver boards.

I’ll be using PolyPhaser IS-B50LU-C0 surge suppressors to keep the lightning outside the house.   These will be inserted in the line after the switches, just before the coax enters the house.  Eventually I’d like to add 3 more of these supressors and put them in the line before the antennas get to the switches, but due to funding for this project, there are only 2 suppressors, and they’ll go between the switches and the radios.

Again due to cost, I ordered all my coax jumpers from R&L Electronics.  They have a “house brand” called Jetstream, and have many legnths of pre-made coax jumpers.  Since all my connections will occur inside a 16×16x8 enclosure, I choose 2 foot jumpers so there would be no tight connections.  These jumpers were 6.95 each with nickel Amphenol pl-259’s.  For a couple of bucks more I could have had silver plated connectors, but since I wasn’t soldering them, and they were all going to be inside an enclosure, I choose to go with the nickel plated ones.  Here are some pictures of the cables.  All the solder joints look good, and I’m very happy with the quality I see – time will tell how well they hold up.  As you can see, these jumpers are RG-8X.  I use mostly 8X throughout my station.  I run 1000 watts max, and my coax runs are short due to my small lot.  I’ve found the price for 8X to be good (especially through R&L) and the quality has been good as well.  I’m willing to deal with the loss associated with this type of coax in my situation.

I hope to sepnd a good portion of Monday working on putting up my newly modified MA5B 15M beam, and then some time in succeeding days finishing this lightning project – once the NEMA enclosure arrives.

Keep watching for more updates.

73 de Al, KE1FO

Antenna work – finally!

So I’ve finally gotten around to some of the antenna work I’ve been planning since the spring.  Today I worked on modifying the MA5B.  I had ordered 4 6 foot pieces of the appropriate diameter aluminimum from Texas Towers back in the spring.  This replaced the section just out from the middle of each element (the piece that connects to the “traps”).  I’ll have to re-measure so I can post some accurate measurements, but basically I did the “cut and test” method to find the right spot.  For better or worse, the reflector is 5% longer than the dimension I ended up wtih for the driven element.  This should at least give me some foward gain.  I was able to get the antenna to tune well on on 10 or 15 meters (this was 10 feet off the ground on a mast).  If it’s tuned for 10M, it resonates at 17M as well.  If it’s tuned for 15M, it resonates at about 30.5mhz.  Since we’re at the sunspot minimum and 10 is a dream, I tuned the beam for 15M, that way I can always be on two bands when contesting (using the tribander on 10 or 20 and this new antenna on 15).   On the 13th I hope to get the antenna up in the air.

It has become clear that I’m not going to get the tower moved over to a permenant base this year.  Say a prayer that the rope guys hold through the winter.  Next spring I’ll have to get the base dug and poured.  Oh well – like I said, hopefully the rope guys hold up through the winter.

Another project that I’ve decided I’ve got the money for is to install a single point ground where all the coax lines enter the house.  I’ve got a 16×16x8 NEMA 4 box on order from Electrical Replacement Parts (an ebay seller).  My local distributor wanted about $175, I was able to get one for $110 with shipping.  It should arrive in a week.  I’ve also ordered 2 polyphaser bulkhead surge supressors, 5 bulkhead so-239 connectors, a bunch of coax jumpers and a K5FD SP12 Surge Protector to put into the box.  The box will hold my two RCS8V coax switches as well as all this stuff.  The Polyphaser protectors will be in line after the switches.  If I had to replace those two switches due to lightning damage, I’d be fine with that.  They’re both at least 15 years old.

I’ve also orderd an EZ Hang.  I’ve had many hours of frustration getting one end of my 40M diople up.  Hopefully with the EZ Hang I can get it up in the top of the tree at around 50 feet instead of at 30 feet where it is now.  If I can get it up that high, I plan to install it as an inverted V with the apex up in the tree rather than a flat top like it is now.  I hope to get this done on the 13th as well.

Obviously, I’ll have another update after the 13th.  Hopefully with some pictures.

Until then,

73 de Al, KE1FO