Staycation, Part II

Back to the 9913. Once it was down, I put the multimeter to it and found that it was shorted. That's a problem obviously. I put I cut off the connector in preparation for putting on a new one, thinking that was the issue. I used my DXEngineering prep tool and discovered that the center conductor was an odd shade of black. OK, so this *is* a water incursion problem. I wonder? I cut off 6" and blew into the end. Lo and behold, a drop of water.

That makes this section of feedline toast, but what about the section connected to the D-56?

I put the multimeter and analyzer on that section - no short, but some resistance and SWR to dummy load was 3:1 instead of 1:1. Looks like I need *two* new sections of coax.

Fortunately for me, I had acquired a spool of LMR400 from a previous employer (yes, I did get permission!) so I cut new lengths for both antennas. While I was at it, I cut a slightly longer piece for the 10-m dipole.

Once up on the roof, I found out that the piece attached to the D-56 had good reason to have high SWR - in several places, the cable was chafed down into the dielectric! The way the cable runs, it comes down straight to the roof ... where the asphalt shingles abrade it as it moves with the wind. I have yet to solve this issue. The 40/80 could also potentially suffer from the same issue, but we solved it by moving the antenna closer to the NE end which allowed the cable to hang away from the roof.

With new cable in place on both antennas, SWR was now where it was supposed to be!

Wires were now down so it was on to the mast. The new anchors had set so it was time to prep the antennas. Got the cables secured and made sure that the wouldn't bind when rotated 360 degrees. Pushed the first section up and attached the 6-m loop. Got the whole thing up in the
air and attached the new guys.

Sounds simple, but took place over a couple of days. Temps were in the 90s and being on the asphalt roof did not help!

Even got the 6-m loop connected to the switch so that all four ports are now in use. This came in handy the following week during a 6 meter opening where I was able to switch between the loop and the 40-80 dipole, which is, oddly, resonant on 6 as well.

Staycation, Part I

I took a week-and-a-bit off from work and traveled to ... home. Loved the accommodations and the meal package! I also made a pretty big dent in the to-do list, mostly on the antenna section.

The antenna to-do list was a little longer than before due to the recent "wind storm". In addition to a number trees (most already dead), the wobble-stack took a bit of a hit. This was due, undoubtedly, to the crappy guying job that was in place prior to May 10. In addition to resurrecting the VHF antennas and making the wobble-stack decidedly less wobbly, the wire antennas were worked on as well.





In the case of the wire antennas, one of the dead trees that came down ended up leaning against a live tree that supported the Spi-Ro D-52 40-80 dipole, so we started there. The tree that fell, or tried to fall, was where the support rope for the dipole terminated. The tree it fell into is the one whose crown supports the rope that supports both the 40-80 and WARC-band dipoles.

We thought it best to lower the antenna (from the other end) lest too much tension snap something especially during the tree removal process. Since the 40-80 crosses the 80-10, we lowered that, too. The 10-m dipole has been supported at one end by the wobble-stack, so that was already down. At this point, the WARC-band dipole was still up.

We borrowed the neighbor's tractor (and the neighbor) and got the dead tree moved to a safer horizontal axis. That done, we got the 40-80 and the 80-10 back in the air. I still saw SWR issues on the 40-80, though, which I thought I'd blogged about but haven't. So a little diversion.

I started having trouble with the Spi-Ro D-56 (5-band trap dipole) back in 2008. See here and here. Basically, one of the traps that makes it resonant on the 10-meter band is dead so I needed a new antenna. Having had good service from it and the Spi-Ro D-314 WARC dipole, I thought I'd get another Spi-Ro. Unfortunately, they neither answered the phone nor email. They did have an eBay site (through a third party, as far as I can tell) so it appeared that they still sold antennas. Looking at their site, they had a D-52 trap dipole that promised coverage from 80 through 10 with only two traps and 20 or so more feet of copper. So I ordered one.

Well, it seems they were WAY optimistic on covering 20-15-10 meters. I eventually put up a home-brew dipole for 10 and continued to use the D-56 for 15 and 20.

With that many antennas, switching bands was becoming a hassle, so I acquired an Ameritron RCS4 switch. Within a few months, I had trouble, namely weird SWR issues that I initially blamed on the switch. It wasn't the switch.

Anyway, back to the story. SWR was wonky on the 40/80. Worse, it was really bad on the 80-10. OK, but I had other things to do.

With the 40-80 and 80-10 back up, I got the 10-m dipole off the ground (it had been supported at one end by the aforementioned wobble-stack) and supported by the Davis weather station's tripod on the roof. This meant that 1) the antenna was now higher leading to better signal reports on the weekly 10-m net and 2) it needed more that the 25' of feedline that it had so that it wasn't pulled horizontally. I left the latter for another day.

While we were tying the ribbons on having the 3 wires back in the air ... the WARC-band dipole fell down! Upon inspection of the support rope, we found fraying. This was undoubtedly due to the movement of the Sycamore tree used as one of the supports. Look back and you'll see that this was not totally unanticipated. Something else to leave to another day.

In thinking about the SWR issue on the 40-80 antenna, it occurred to me (finally!) that maybe it wasn't the switch and that maybe it was the coax. Since this was partially-air-dielectric Belden 9913, that was a distinct possibility. It's well known in the amateur radio community that 9913 has to be really well sealed at the connector ends lest water accumulate in that dielectric space. Even if you're careful, you may still get condensation.

To test, I substituted 68' of LMR-400 for the 40 or so feet of 9913. Initial tests were good so I left it for a few days.

On a subsequent day, though not sure which, I mounted the 2-m loop, the 2-m beam, and the rotator on the top of the mast. I had already prepared a new set of guys, ones that I hope will prevent a repeat of the wind-driven collapse of the VHF mast. Not only are the guys themselves better, but so are the anchors.


We also got the WARC-band dipole out of the tree. We debated whether or not to move the anchor from the Sycamore, but decided to leave that until another time. There are other candidate trees near the Sycamore that don't sway as much.

Next, the saga of 9913 and the VHF stuff ...

Current balun

For the time-being, I've decided to leave the D-56 in the air. It still works FB on the other bands, and, judging from the 60 QSOs I made in the 10-m contest, the 10-m dipole works FB as well.

I did, however, order a current balun kit from Palomar Engineers. Recall that I have RFI issues on the low bands. I worked around it by ignoring the rig interface connection during Sweepstakes, but I'd really rather not do that for the upcoming RTTY Roundup since, you know, the computer is a key part of modern RTTY.

Anyway, that should be here in time for me to build it and get it installed. If it cures the RFI issues, I'll be ahead of the game even if that trap is broken.

Antenna saga, part 42

Got an offer of a B&W broad-banded, folded dipole. Took the offer but changed my mind and re-installed the D-56 with the broken trap.

I emailed the vendor and have heard exactly nothing from him or the manufacturer.

Not sure where I'm going from here. The D-52 works great on 40 and 80, but I need 15 and 20, as well, and I'm running out of convenient trees. :-)

No one else seems to make a straight, 80-10, trap dipole.

Alpha Delta Communications has a 80-40 model with parallel wires for 10 and 20 (15 is a harmonic of 40 even if it's not on the D-52) but I'm not sure I want to experiment - that D-56 just worked on 5 bands (before the trap went).

No happy

Got the Spi-Ro D-52 the other day. It got to 60 F here today, so I left work early and put it up, as always with a ton of help from Spouse.

The D-56 cover 5 bands with 6 traps and is 82' long. The D-52 is said to cover 5 bands with 2 traps and is 105' long.

The D-56 was easy enough to explain - inner traps made it look like a 10-m dipole, next set like a 20-m dipole, third set like a 15/40-m dipole and on 80 m, no traps were visible.

But how would that work with only 2 traps?

So far, not so good. Dips are as follows:

MHz     SWR

3.84    1.2:1
7.24    1.6:1
15.00   3.8:1
22.7    2.3:1
32.65   2.7:1

Kindly note that only two of those are within the amateur bands. :-(

There are tuning instructions which, interestingly, only mention 40 and 80 for the D-52.

I'll see if I can do anything by adjusting element length but the ol' D-56 might end up back in the air ... or I'll buy/make something for 15/20.

More on 10 m

I was NCS for the local 10-m net tonight. By all accounts, the new 10-m slopey dipole works into town a lot better than the D-56 did.

Given that we're only about 8 radio miles east of the center of town you wouldn't think that there'd be much difference between a (roughly) NW-SE dipole and an N-S dipole ... but there clearly is.

Since the D-56 is still up, I could do A/B comparisons. Only two stations were better on the old antenna, one of which is only about 1/2 mile due south of me.

Interesting all around.

The new D-52 (5 bands, 2 traps, and about 23' longer than the D-56) has been ordered and should be here any day now. That, too, should be interesting.

Yep, need a new antenna

Well, actually, it still works from 80 - 15, and I do have a 10-m dipole ready to put up.

Last night on the local 10-m net, I managed to tune up OK before the net, and even chatted briefly with some locals, pre-net. It's a roll-call net (though we take check-ins as well) and when it was my turn, I launched into a monologue.

About a minute or 2 in, clink, off went the tuner. A ha. I was able to tune up again, but I kept transmissions short after that.

I gather that there is a heat sensor or something in the ATU of the IC-746Pro that kicks it off if it's working too hard. Evidently, 8.5:1 SWR is too much for it to digest, at least for very long.

What I'd really like to do is replace the D-56 with the D-52. Same 80-10 coverage, but with only 2 traps. About 23 extra feet of copper, but I have the trees to do that. Problem is, Spi-Ro Manufacturing seems to have gone out of business.

BULLETIN!! Just checked the site and it's been updated with an eBay store link. Great - I might be able to order the antenna after all!

Might need a new skywire

Well, I might have blown a trap on the 5-band Trap Dipole. It's a 15-year-old Spi-Ro D-56 and, pending confirmation tonight, it appears one of the 10-m traps has died. The SWR was never flat across all of 10 meters, but it was never > 6:1 over any of it that I recall. If I recheck and it really is that high on 10, I may not even be able to check in on the local weekly 10-m net. As the immortal Roseanne Roseannadanna used to say, "Well it just goes to show you, it's always something." I'll spare you the rest.