Posted: 3/18/2015 1:10:32 PM EDT
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My 40 meter QRP rig from Turkey as mentioned in THIS THREAD is either waiting on my porch, or waiting at the post office. Life has been coming at me at mach speeds, so I have not yet procured a microphone yet.
That won't be a problem though. The problem will be finding an antenna that will give me the most gain, and allow me to best use my whole 5 watts. I think I am going to whip up a Zepp. http://www.westmountainradio.com/antenna_calculator_zepp.php It appears that it will give me 3db of gain. The goal is to be able to put an antenna up in a tree, and go QRP, powered by one of these: antigravity battery I use one now to power an ic-2300h. I monitor for about 10 hours with it, and ragchew for about 3 hours with a full charge. Any other antenna ideas you guys can think of that would be relevant to this project? |
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I've had both the regular LNR Precision 10/20/40 and the trail friendly version, have had good results at 5w SSB. Here's a cheaper single band: http://www.ebay.com/itm/LnR-Precision-EndFedz-40-Meter-Dipole-Antenna-Model-EF-40-/181685767068?pt=US_Radio_Comm_Antennas&hash=item2a4d50cb9c |
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I own that battery.
I have used it to a small extent to power a radio (KX1) but didn't use it long enough to tell you how long it will last. I have used it to jump start a diesel engine several times however. I am excited to use that battery to power a small digital station. I am thinking the FT-817 with a Raspberry Pi. It is cool that it has jacks on it for both 12 volts and USB. |
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Quoted:
I own that battery. I have used it to a small extent to power a radio (KX1) but didn't use it long enough to tell you how long it will last. I have used it to jump start a diesel engine several times however. I am excited to use that battery to power a small digital station. I am thinking the FT-817 with a Raspberry Pi. It is cool that it has jacks on it for both 12 volts and USB. You going to run fldigi off that pi? Been using DroidPsk for awhile on various devices. |
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I think the most efficient small antenna is still going to be the half wave dipole. Unless you mean DBi gain, I don't think you will get any gain, DBd without being at least a half wave high.
For portable, NVIS antenna will probably be just as efficient as anything else and you can raise it for DX to use as a traditional dipole. Also easy load on the transmitter. |
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Quoted:
Isn't a magnetic loop antenna for 40m or shorter wavelength and portable ops the ideal solution? Yet no one has suggested it yet. What am I missing? Loops work great all the way down to 160m... but you still won't get any gain improvement until it's a half wave or more above ground. Below that it will just act as a NVIS. Also twice as much wire and support points as a dipole. Not really ideal for portable. IMO. |
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Quoted:
I know that endfed antennas aren't the best for QRP, but for portable ops I've had great luck with my EndFedz Trail Friendly. It is small and works well. I've tried a lot of different portable antennas but EndFedz 10/20/40 beats them all. It's small, easy to deploy and requires no tuner. A+ So far BuddiPole antennas have been my least favorite. They are a pure pain in the ass to tune properly. You definitely need an antenna analyzer every time you deploy it or change bands. It's too time consuming. I can get EndFedz up and running within a few minutes and it fits into a pocket. |
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Quoted:
You going to run fldigi off that pi? Been using DroidPsk for awhile on various devices. Quoted:
Quoted:
I own that battery. I have used it to a small extent to power a radio (KX1) but didn't use it long enough to tell you how long it will last. I have used it to jump start a diesel engine several times however. I am excited to use that battery to power a small digital station. I am thinking the FT-817 with a Raspberry Pi. It is cool that it has jacks on it for both 12 volts and USB. You going to run fldigi off that pi? Been using DroidPsk for awhile on various devices. Yes, it works perfectly. I worked a half dozen stations on PSK the first day I had the Pi. Used an FT-817, Signalink, and a Pi 2. I also made a couple QSOs using the KX3, Signalink, and the Pi 2. |
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For an antenna, I am just going to use an Alpha Delta Model DELTA-C kit and a spool of wire that have been sitting in my pile. I am going to build a dipole for 40 meters, raise it up, hook up the Rig Expert, and tune the crap out of it to get the lowest SWR I can.
Per the chart on THIS page, it seems that I get the best "dbi bang per feet" with the dipole. Sure, the Zepp has 3 dbi gain over the dipole, but it seems I have to be 16 meters up to "gain" it. (Ham humor, get it?) Any other ideas for an antenna with low SWR, ideal for QRP, and can deploy it where I don't have access to a tower? |
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Quoted:
Loops work great all the way down to 160m... but you still won't get any gain improvement until it's a half wave or more above ground. Below that it will just act as a NVIS. Also twice as much wire and support points as a dipole. Not really ideal for portable. IMO. Quoted:
Quoted:
Isn't a magnetic loop antenna for 40m or shorter wavelength and portable ops the ideal solution? Yet no one has suggested it yet. What am I missing? Loops work great all the way down to 160m... but you still won't get any gain improvement until it's a half wave or more above ground. Below that it will just act as a NVIS. Also twice as much wire and support points as a dipole. Not really ideal for portable. IMO. The key word here is "magnetic". A magnetic loop is very small, but requires that you tune it for every band and, if I am not mistaken, are only good for 40m and shorter wavelength. Two brands on the market are the Alex Loop and the Alpha Loop Quoted:
My AlexLoop is a great car portable antenna that performs fairly well on 40m. However, it's too cumbersome for long hikes, and is pretty expensive. I live in a town home and it pulls double duty as an indoor antenna with very good result. Especially 20-10m. The Alpha loop is only about 15" in diameter deployed, and it's flexible. How is that more cumbersome? |