ND2E's Blog

Since we moved here I have wanted to make the station or at least the radio, solar powered. I have been collecting the bits and pieces since we moved here. Originally I had been using a 7 AH gel battery to float across the 12 volt bus but it was charged by the Kenwood 25 amp power supply that I generally use for the radios. I contemplated eventually buying one of the little 1 or 2 watt solar chargers to keep the battery topped up but never seemed to get around to it.

Last winter, Harbor Freight had their 5 Watt solar module on sale. I jumped at it since it was relatively inexpensive … made in China! They captioned it as a battery charger but I suspect that it is too big for my 7 AH battery since the rule of thumb is 3.5 Watts of solar power for each 100 AH of battery. The 5 Watt solar charger definitely would be overkill for a 7 AH battery.

Over last summer I went searching for a small charge controller since the charger was too big for most any battery I would likely buy, I found a small 3A solar controller at All Electronics. It was cheap enough and it would ease my mind about overcharging a small battery.

In the mean time the 7 AH battery died as did my 3.5 AH battery so I had an unmounted solar charger and no batteries to charge.

Last week, I decided to just do it and went on line to see what batteries were available. I had in mind a gel battery of about 15 AH. After looking through pages and pages of battery specs and costs I went to Batteries Plus and looked at their stock. I found a AGM battery 35 AH for a reasonable price. My math indicates that I should meet my objectives of 2 hours per day running 25 Watts PEP as in PSK. That means roughly 2 amps during transmit and .84 amps during receive. Using these figures I believe the weighted agerage is somewhere around 1 amp assuming 40 minutes of receive for every 20 minutes of transmit. At 1 amp / hour, I need 2 AH of battery for my nightly session. In fact, it should be sufficient for running all day and night during an emergency or for Field Day.

I did not find this solar system calculator until after I had purchased everything. It shows that I am not in good shape on the solar side of the power system. To recharge the battery in one day I need to replace almost 25 Watt Hours of energy. At 15 Watt Hours per day during the winter (3 good sun hours at 5 Watts or some combination of sun equaling 15 Watts) I can expect to recharge the battery in a little less than a day and a half. To recharge the system in one day, I will need roughly two 5 Watt solar panel or one 10 Watt array. So when I find a sale on a 15 or 30 watt arrays I will look into upgrading the solar side of the system otherwise for each day I use the system I need to recharge using the Kenwood power supply and can only expect the solar charger to work as a float charger on the days I do not ue the radio. Evidently the 3.5 watts per 100AH of battery is for float service only; We will see what happens. I have the battery on the solar charger now and am waiting to see how long it takes to bring it up to 13.2 volts, my estimate of the float voltage. I had it on the float charger last night but it never came up to 13.2 Volts … so we will see what happens.

I don’t know if anyone reads this blog but I have turned the comments back on. If I start getting Spam here I will turn the comments off again…I really don’t want to do that.

For those folks selling SEO services, you really need to understand that this is not a commercial station…So don’t try to sell me SEO services.

Stan was a amateur radio operator and a friend. He died early in November of complications from pneumonia. Stan was a prime member of the Plano Amateur Radio Klub, he was active in his church, his city, and in amateur radio. Stan was there to help, to greet, and do what was needed. Stan was a good friend and will be missed by all who knew him.

The Plano Amateur Radio Klub has a Good News Net Memorial for Stan

Thanks Stan – You wil be missed

Even after I bonded the antenna and house grounds together, I suspect that there will still be a significant voltage spike on the ground during a lightning event. There are only a couple of ways to isolate the computer from the radio and in most cases it is not real isolation but using something that is relatively cheap as a consumable to isolate the spike effects.

So I had originally decided to use external usb to serial converters and cheap passive hubs to isolate the equipment. A little testing yesterday showed me that (at least using the PCMCIA card as a USB source) the USB ports can not provide enough power for the USB-Serial interface and a hard drive. Once the Gx270 is finished I will see if it can source enough current to handle the drives, USB adapters, and soundcard. If not I will have to introduce yet another variable-a powered USB hub. Who knows how that will affect the isolation.

Life is just not fair…it keeps getting in the way of play time. I’ve actually been on the air a couple of times since the last post but only long enough to make a couple of QSOs before I had to do something else.

I have replaced the Dell Dimension 8400 that died. I have a new used Optiplex GX270 that I picked up from one of the refurb dealers. Back in the day we would have called them salvage dealers but I guess that isn’t PC anymore.

In any case, I am waiting on PATA to SATA power connector adapters before I add the big disks to the system. It came with a 40 Gig hard drive and 512 M of RAM. I purchased another 1 Gig stick from Crucial so I should have enough RAM for radio and server operations. The GX270 is evidently 2003 vintage because it uses DDR not DDR2 sticks. That caught me by surprise, especially since I didn’t have DDR memory in stock…I completely skipped that era.

The new computer should be on line sometime late next week after I install the SATA drives, operating system, and programs.

I will install HRD V5 (I will keep V4 on my laptop) as well as a host of other programs including Dx Keeper and all of its subprograms. Others will include:
• XAMPP so I can have a test machine for the web sites I control
• Firefox
• GIMP
• OpenOffice
• Eraser
• CCleaner
• AdAware
• PDF Maker

Oh yes, I almost forgot, I need Creative’s package since I use an external soundcard.

In an effort to keep the system from being destroyed again, I have tied the antenna and house ground systems together. I really don’t think that it will actually do any good because the two ground points are about 100 feet apart. My understanding is that 35 feet of just about any economic size of copper wire will have enough inductance to make the two grounds appear to be separate during a lightning event. (The rise time of the lightning pulse being so quick that the inductance plays a significant role in the voltage difference.)

I am hoping that the big UFER otherwise known as the patio will help but I really don’t know nor do I know of any tool that might model the effect. So to meet code I have bonded the grounds.

So hopefully I will get some operating time this weekend and next week.