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Satellite Newbie: Omnidirectional vs. Directional

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W9DTC

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So common sense, and a bit of reading inform me that a directional antenna should perform better than an omnidirectional for the task of listening and transmitting to satellites.

I purchased a the Arrow II LEO Antenna (Arrow Antenna Hand Held Portable dual band 146 437 440 arrowii Yagi Satellite) specifically for this purpose.

Now, I can hear the satellites on my yeasu FT-7900r http://www.yaesu.com/indexVS.cfm?cmd=DisplayProducts&ProdCatID=106&encProdID=2804F70E1A8F3C4B638CB8E0F201158C&DivisionID=65&isArchived=0 with an omnidirectional dual band antenna (2m&70cm), but I haven't been able to try the yagi with that radio yet.

I have tried the yagi with my BCD396xt http://www.uniden.com/scanners/bcd396xt-compact-apco-25-handheld-scanner/invt/bcd396xtg/ scanner. I can hardly get any reception with that setup.

I compared selectivity specs between the two, is this my problem?
FT-7900r : 0.2 μV for 12 dB SINAD (420 - 520 MHz, FM)
BCD396XT: 0.3μV 380—512 MHz NFM


Any input would be GRATEFULLY appreciated!
 

home121

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spec's

So common sense, and a bit of reading inform me that a directional antenna should perform better than an omnidirectional for the task of listening and transmitting to satellites.

I purchased a the Arrow II LEO Antenna (Arrow Antenna Hand Held Portable dual band 146 437 440 arrowii Yagi Satellite) specifically for this purpose.

Now, I can hear the satellites on my yeasu FT-7900r Welcome to Yaesu.com with an omnidirectional dual band antenna (2m&70cm), but I haven't been able to try the yagi with that radio yet.

I have tried the yagi with my BCD396xt "Uniden" BCD396XT Compact APCO 25 Handheld Scanner at Uniden scanner. I can hardly get any reception with that setup.

I compared selectivity specs between the two, is this my problem?
FT-7900r : 0.2 μV for 12 dB SINAD (420 - 520 MHz, FM)
BCD396XT: 0.3μV 380—512 MHz NFM


Any input would be GRATEFULLY appreciated!
Those spec's look fine, 2 and 3 micro volts is very good. good luck.
 

W9DTC

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I'm pointing it in the direction I believe the satellite is and then rotating the arrow along that axis slowly trying to catch the signal. Occationally I'm getting the white noise to start to drop out, but not nearly as much as with the ft-7900r where I'm catching actually comms.
 

AK4GA

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I'm pointing it in the direction I believe the satellite is and then rotating the arrow along that axis slowly trying to catch the signal. Occationally I'm getting the white noise to start to drop out, but not nearly as much as with the ft-7900r where I'm catching actually comms.
I think your problem is that you believe the sat is somewhere but it isn't. The sky is a damn big place and you have to be pretty close with the yagi.
 

W9DTC

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Do you have any suggestions as to how I can get on target better. I'm using pocketsat3 for the iPhone with data about one week old. Assuming it is accurate, my biggest difficulty is estimation proper vertical angle. I believe I get the compass direction pretty good (though obviously not good enough)
 

JeremyB

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Another question is: What satellites?

The arrow2 sat antenna is a very good antenna and it should be able to let you hear almost any sat as long as its pointed in the right spot. And there is a third issue, polarization of the satellite's antenna- horizontal-vertical and all points in between. AO-51 has circularly polarized antennas but you still have to compensate some with the arrow sometimes to get full quieting.

Check the amsat.org pass predictions if you know your grid square/ lat/long and see how it compares to pocketsat. Any more, all I use is orbitron(website stoff.pl the last I knew)

If you are trying to listen to SO-50 it can be a problem because it only transmits when it receives, AO-51 and AO-27 transmit while they are on, but AO-27 is only on for ascending passes(south-north) at about the time it reaches 27 degrees north

Good luck and 73!
 

W9DTC

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Thanks for the info all. It has been a while since my schedule has coincided with a satellite pass.

Yesterday I was able to hear AO-51 full quiet. Sounded like mostly one station taking contacts from other stations. I did hear one mobile station get a couple of contacts in.

I tried one time to transmit, but didn't make contact. Will try again soon.

Thanks again!

73
 

JeremyB

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satellite

Thanks for the info all. It has been a while since my schedule has coincided with a satellite pass.

Yesterday I was able to hear AO-51 full quiet. Sounded like mostly one station taking contacts from other stations. I did hear one mobile station get a couple of contacts in.

I tried one time to transmit, but didn't make contact. Will try again soon.

Thanks again!

73
It looks like there was a special event station on AO-51 along with a couple stations operating from a portable location. W6F was the special event station and AA5CK and K0BAM were operating away from home. Here is a site to check to see if you got through: General Satellite Recordings

John doesn't record(or upload) every pass but if you tried on a pass on his website it will let you know if you made it through or not. Try to aim your antenna for the best signal, you may even have to twist your wrist to match polarity. Early morning passes are the easiest by far but you could end up talking to yourself if no one else is awake
 

W9DTC

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I didn't realize that AO-51 required a PL-tone, so I'm certain I didn't get through.

Also, I didn't know my grid square, so its probably for the best that I didn't transmit successfully.

At least I now know I can hear the birds... so I'm doing something right.
 

JeremyB

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I didn't realize that AO-51 required a PL-tone, so I'm certain I didn't get through.

Also, I didn't know my grid square, so its probably for the best that I didn't transmit successfully.

At least I now know I can hear the birds... so I'm doing something right.
I don't think AO-51 has needed a tone for quite some time now, nothing about it on the AO-51 control team page, 435.150 down and 145.880 up was the last I heard
 

W9DTC

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Well... I finally did it!

On the last day of my vacation, I set an alarm to catch an opportunity at SO-50 and AO-51. I had already missed an opportunity to make my first contact from inside the Rocky Mountain Nation Park (because I didn't take the cables with me, duh!). Anyhow, SO-50 was silent. At least I didn't hear it. But I was in the foothills and probably didn't have enough clearance over the hills. The AO-51 pass was directly overhead however. So my first contact was truely mobile, outside my home grid.

I made one full QSL and nearly finished another before losing the bird.

A special thanks to JeremyB, the links and info you provided were invaluable! I listened to my contact this evening. I couldn't hear all of my own transmissions, but my contact station could hear me (apparently better than the recording station)... He was the clearest on my end, so I found that interesting.

Anyhow, thanks again RR and especially JeremyB.
 
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