Friday, July 22, 2016

Chasing DX = A great view

I've been so swamped with school and work, and playing with the rapidly growing kiddo, I have let my radio pursuits slide a bit this summer. I've read on Twitter there's been some great new ops showing up on SO50, in rare grids. I've really been meaning to get out and work more of them, it just hasn't happened. Yesterday though, I resolved to chase some DX. 

Esteban, HC1JB, has shown up from time to time on SO50 recently, and he's worked some folks in the southern part of the US. It's always late in the pass, but after running the numbers I figured we should have a window. Emails exchanged, we settled on a descending SO50 pass with TCA's of around 50° for both of us. We'd have a 3 minute window as SO50 set for me, and was rising for him. He warned me though that from his QTH in Quito, Ecuador, he would be fighting mountains and volcanos for a clear view. I assured him that I could go all the way to the horizon, so I'd try and spot him as much elevation as I could. For this particular angle, I chose a hill in West Little Rock about 10 minutes from the house.. it's not as high as my 'mountain' is, but it gives me a wide angle to work with, and has a great uninterrupted horizon from about 150° to about 270°

The pass just happened to be a few minutes before sunset too, so while the bird streaked across the sky from AOS at 340° to LOS at about 160° I was treated to a great picture of the sun sinking over the distant sky. Esteban called me right on que with about 45 seconds to go, when I was down to 4° of elevation left. We quickly exchanged reports and said our 73s. The voices on the transponder all switched from English to Spanish, as US operators went LOS, and Latin American hams took over.

Satellite DXCC Entity #38, Oscar Century #95, and grid #422 in the log. Thanks my friend.. hope your view was as good as mine.

Thursday, July 21, 2016

Battery Powered

I have always taken a unique approach to powering my radios, compared to the rest of the hobby. I have never *once* made a QSO with my own gear on anything that wasn't battery powered. I simply don't own any power supplies, and have never had the need or desire to get one. Now obviously I use AC power to charge my batteries, and I have tapped into the big battery on my Jeep (even going to so far as to run powerpoles to two different place in it) but the fact remains that when it's time to actually turn electricity into RF, it has always been a battery that is providing the juice to do it.

I've got several different versions, for depending on what I'm up to. For 'normal' everyday usage on HF with my 857 I've got a pair of Werker 35AH Deep Cycle lead batteries (left most in the picture). They work well, and I can use the 857 at the full 100W on one or both of these for a day's worth of contacts. Next I've got a smaller Werker Deep Cycle, rated at 12AH (furthest to the right) that I use for slightly smaller jobs. It doesn't quite have the capacity to handle a full 100W HF load (on especially something like 6m) on the 857, but at lower levels < 50W it works well. This battery is nice for quick "hamming in the park" or NPOTA application where I'll only be on the air for a few hours, and don't necessarily need full power. The SLABs (Sealed Lead Acid) are my workhorses, and do most of the heavy lifting when it comes to powering my different rigs.

Finally, I've got the sports car of the bunch - my Zippy 8.4AH LiFePo4 Battery Pack (The blue battery in the middle). This thing is stripped down with no fanciness, but weighs about 1/4 of what the SLABs do for equal power, and the Lithium chemistry will hold full voltage even under the full load of 100W 6M FM from the 857. It is what I find myself using more and more of these days, because it's just so light and powerful. When it goes dead though, you REALLY have to watch it, cause voltage will fall from 13.2V to < 12V in a matter of minutes - and when it does, the battery is dead and it's time for a recharge.  

Downside of the LiFePo4 pack, is while it's stripped down and efficient, it's made up of multiple cells that have to be kept relatively close in voltage or else bad things will happen. This requires a special charger. Luckily they're pretty cheap, and are adaptable. Here I've got it hooked up to the powerpoles in the Jeep, so it's slurping juice from the alternator and the starting battery. The LiFePo4 chemistry in addition to dumping it's juice quickly, will also accept a charge very quickly as well. My particular charger will do up to 7A of DC charging ability (while keeping the cells balanced) which means I can get the battery back up to full power from near dead in just over an hour. When on the road and navigating summit to summit, this is a huge bonus.

Since power is a consumable quantity in my trade, knowing how much you've used, and how much you have left is huge... especially on the little lithium. That's why these inline power meters are practically essential. They give you current voltage, amperage use, and how many AH you've used since you plugged in. It's a great way to watch how much juice different modes and styles of operating pull as well. I highly recommend them when you're a battery only ham like I am. 

Tuesday, July 5, 2016

Pinnacle Mountain - SOTA, AMSAT and Observations

I am lucky to live in a state like Arkansas. It's one of the few places in the US where cost of living is cheap, the people are great, geography is varied, and we have State Parks that rival the best in the country. One such State Park is Pinnacle Mountain, and only being 15 minutes from the house, I consider it (along with Shinall, which I can drive up) *my* mountain.

This particular Sunday, I was in a mood to go run up my mountain, and I realized that I hadn't done a SOTA activation in nearly a month. I will sometimes just grab my HT and head to the top of the peak and call out on simplex, but it seems as if it's been getting tougher all the time to find customers there.. so, with the impending CM93 trip coming up - I decided it might be time for a dry run with some gear I don't normally use for the birds. I grabbed my 857d and my FT60, 2 pieces of LMR240, my trusty LiFePo4 battery pack, adapters for everything, and my arrow. I checked to make sure there was a pass coming - and indeed SO50 would be overhead in about 2 hours. That was all I needed.. I tossed everything in my backpack, made sure my camel-back bladder was full of water, and hit the road. 15 minutes later I was in the parking lot, and on my way up to the top. 

As you can probably tell from pictures, Pinnacle is basically just a big hill rising straight up out of the Arkansas River Valley. There's very little approach, you just get on the trail, and start climbing. I made pretty good time getting to the top, especially considering I was hauling 30 pounds of radio gear, first aid, and water with me. I'll have to do at least one hike roughly double the elevation of this out on Santa Rosa with a similar amount of gear.. and we've allowed 2 hours for that hike, so I think I'm on pace to where I should be.  

Once I got on top I went out to the 'West Summit' which is just a few foot lower than the 'East Summit' but a bit more isolated by 50 yards or so of scrambling over some boulders. It's also a bit further away from the trees, and has a better 360° view of the horizon, which is always important for Satellites. I set my gear up and called CQ on 146.520 for a bit, hoping to find some local folks before the pass at 2016UTC. To my surprise, I had quite a few takers. A little bit of power and a 3 element beam makes things much much better than a 5W HT and a whip. 

After I made a bunch of simplex contacts, I got setup for SO50. I would transmit with 10W on the 857 and receive on my FT60. I'd used this combination before, but it had a while. This is where I ran into some issues.

First - you have to set a 67hz PL tone to get into SO50's transponder. This is no biggie on an 857, you go into the menu, scroll down with the coarse adjustment knob til you find the PL tone setting, then use the big knob to select the PL tone setting.. save this, go back to the VFO, and then enable the tone on the frequency. Everything went fine until I tried to scroll with the big knob... no such luck.. I could scroll UP - but whenever I'd spin the wheel counter-clockwise.. nothing happened. This seemed to be happening on all menus and all bands. The more coarse step knob worked to scroll down, but the big dial simply wasn't responding. Well this sucks.. especially since this is the ONLY way to get the proper PL tone assigned, and unfortunately the menu doesn't start over at the bottom when you go to the top. I had run into this before, when my 857 is sitting in the sun, and it gets hot - and for some crazy reason the big knob doesn't scroll down anymore... No idea why, just does. It usually calms down in a few minutes after getting it back in the shade, but here I was at AOS for a pass lasting 12 minutes, on a frigging mountain with no shade. I covered the rig with my backpack to get it cooling off and went to improvising.

I quickly reconfigured... I'll use my FT60 to TX and my 857 to receive.. 5W uplink on a sunday afternoon is not optimal on SO50, but I'll give it a shot. I was able to work W5PFG/P in DM66 quickly - but after that I couldn't get in. To further complicate matters since I was now receiving with the 857, I had to adjust doppler there by, you guessed it, dialing DOWN - which I couldn't do. No problem, I can use the coarse control for this. Oh but wait, there's more! By default the 857 does 25khz steps on the coarse dial on 70cm, you have to change it to 5khz step in the menu by <drumroll> scrolling down with the big knob. If there is any problem with the 857's design, it's the extremely menu based options that requires every single setting to be controlled from there as a dial option. When something happens to your dial, you're basically hosed.

Around TCA of SO50 I got the 857 cool enough in the shade, that the down dial finally started responding, so I reconfigured back to my initial setup - TX on 857, RX on FT60. I got PL tone set, got TX freq set, and now I should be in business. However, this is where I ran into issue 2.

When I keyed up on the 857 I noticed I wasn't hearing myself (or ANYTHING) on the downlink. Once again, something wasn't right.. One of the more interesting phenomenon Satellite operators experience, that isn't that common the other parts of ham radio, is the concept of 'de-sense'. Since we're almost always cross-banded, you have to keep all of your TX power out of the front-end of your RX box. When you don't, it wipes out what you're receiving, and you lose your ability to be full duplex. This was now happening to me. Keep in mind that I normally am working Satellites with my Icom 821. It's a great rig, dual independent VFOs, extremely sensitive and good power levels. It also seems to be extremely resistant to desensing. I can't really explain why - perhaps the two independent VFOs are shielded a bit better, who knows, but with the 857 and ft60 combo though, some serious desense was happening.

In the past when I've had issues with desense, it's typically because something is not tuned right. The arrow is a nice hardy antenna that has a well built gamma matching device and I've always tuned all of my antennae as best as I can out of the box. I hadn't checked the tuning on my arrow in a while though, but it's been working well, so I haven't bothered.. well, until now. One of the other differences between my 821 and my 857, is that the 857 has a built in SWR meter, while my 821 doesn't. So even if it was getting out of tune, I was using a rig that is resistant to desense, and I'd have no built in methods for checking - unless I felt like putting a meter in line. So, at this point I keyed up, glanced at the SWR meter on the face of the 857, and saw it about halfway up - indicating an SWR in the range of 3:1. That's no bueno.

Lacking the time (and a Phillips screwdriver) to do anything about it, I just decided to finish the pass as is, and transmitted in the blind when I thought I had an opening. Half-Duplex is not how I like to operate, but it will get the job done. I managed 3 more contacts in the last 10 degrees of the pass, and had enough to call the activation complete. Phew.

I grabbed some video before packing my stuff up:

And headed back down the peak. I had come dangerously to borking the activation, but got it done. I was glad, but I had to some work to do in the shack later on. That said, still a great afternoon on my mountain.