Morning,

From a technical standpoint, had the best pass ever here. AOS at 295

degrees, 12 degrees elevation, slant range 1000 miles (1600 km). LOS at 150 degrees, 6 degrees elevation, 1570 miles (2500 km). Both are at or near my local horizon. This pass was qualitatively different in that I did not notice a single dropout, and it required modest power even at extreme range. 100-200 watts ERP compared with the 2500 needed on some passes.

One thing I did was recheck the deviation of my transmitter yesterday. I had noticed in previous passes that when I spoke, I would _sometimes_ lose the downlink, and it came back when I stopped. That is indicative of over deviation, and/or a really marginal signal at the ISS. I had set the deviation years ago at 3.2 KHz, and have gotten nothing but good reports on terrestrial and satellite communications. Rechecking, I found that it had drifted up to 3.8 KHz. That is well within normal parameters, but I dialed it back to 3.2 KHz again. I did not have time to do any A/B testing, but at least what I did was not harmful.

From a communication standpoint, not so much. I did hear someone else bring

up the repeater, and caught "N5???" twice, but each time the repeater dropped after the first two syllables. N5UXT???

I have a couple of things to test should they do this again. My lessons learned are that:

(a) You MUST be on frequency, much closer than when operating through normal satellite repeaters. The usual manual tuning just does not work in practice. It is good to check the actual mode L output, however you get there, since 2-3 KHz error is critical. My TX transverter has a few KHz error in the LO, but I just put the measured numbers into SATPC32, and it does the correct tuning for me.

(b) Your deviation needs to be optimum, with less being better than more.

(c) You need significantly more power than the usual mode UV or VU, but not unreasonable ERP.

Thanks to NASA and the ARISS team. Lets do it again sometime.

Alan WA4SCA

Hi Curt.

Either way will work.

http://www.g6lvb.com/AO-40%2070cm%20uplink%20antenna.htm

I have had superb success with mine, in fact during the days of AO-40 I worked the world with it as an uplink antenna with 50W.

http://www.g6lvb.com/3A2%20ops.htm http://www.g6lvb.com/dayton_demo_2002.htm

73, Howard G6LVB

-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Curt Nixon Sent: 02 January 2009 15:19 To: AMSAT-BB Subject: [amsat-bb] Question adding RHCP to Cheap Yagi

Good Morning All:

I've been using a 10el version of Kent Britain's Cheap yagi for my 70cm downlink antenna. It suffers from deep fades so I am going to add the second yagi with physical offset to get to RHCP in the x config.

Question is:

normally I would reverse the coax connections to a dipole driver but this is a hairpin (half of a folded dipole. )

Do I reverse the connections as normal? Kents instructions just say offset the elements and feed in phase.

Thanks

Curt KU8L

_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

Hi Curt

There are several ways to skin the same cat.

Although they are fed in phase, they are orthogonally mounted and with their spatial separation a 90 degree phase delay is created, thus creating CP.

If the elements are still orthogonal but are at the same location along the boom, then the delay would need to be inserted electrically, with an electrical 1/4 wave section of 50 ohm coax. Some CP antennas use a combination of both spatial and electrical phase difference.

To switch RHCP to LHCP can be achived by any of the following three means:

O Insert an additional 180 degree electrical delay between one arm of the power splitter and the antenna, with an electrical lambda/2 50 ohm coax section;

O Physically move one set of elements 180 degrees forward or behind;

O Turn one of the driven elements 180 degrees so the loop is on the other side of the antenna, but maintain the same electrical connections.

This may (of may not!) help... http://www.g6lvb.com/remotepolarization.htm

It takes a bit of lateral thinking, but once you've figured it out it's a bit like learning to ride a bike in that you don't forget, although in later years I find one may become a little wobbly.

73, Howard G6LVB

-----Original Message----- From: Curt Nixon [mailto:cptcurt@flash.net] Sent: 02 January 2009 16:50 To: Howard Long Cc: 'AMSAT-BB' Subject: Re: [amsat-bb] Question adding RHCP to Cheap Yagi

Hi Howard:

Thanks..I've looked at alot of your info on-line--especially the sub-500GBP AO-40 setup.

I guess I still don't get it..if I just feed them in-phase with both connections same polarity, what controls RH v. LH?

Or is it RH if the front half loop is to the right and LH if the front half-loop is to the left?

Thanks

Curt

Too cold to not get it right on the first try!!

Howard Long wrote:

Hi Curt.

Either way will work.

http://www.g6lvb.com/AO-40%2070cm%20uplink%20antenna.htm

I have had superb success with mine, in fact during the days of AO-40 I worked the world with it as an uplink antenna with 50W.

http://www.g6lvb.com/3A2%20ops.htm http://www.g6lvb.com/dayton_demo_2002.htm

73, Howard G6LVB

-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Curt Nixon Sent: 02 January 2009 15:19 To: AMSAT-BB Subject: [amsat-bb] Question adding RHCP to Cheap Yagi

Good Morning All:

I've been using a 10el version of Kent Britain's Cheap yagi for my 70cm downlink antenna. It suffers from deep fades so I am going to add the second yagi with physical offset to get to RHCP in the x config.

Question is:

normally I would reverse the coax connections to a dipole driver but this is a hairpin (half of a folded dipole. )

Do I reverse the connections as normal? Kents instructions just say offset the elements and feed in phase.

Thanks

Curt KU8L

---

Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

OK..I think I have it..RH v. LH depends on which half loop is to the left or right--I just had the view from the wrong end. I'll do it like your pic.

Thanks Again

Curt

Howard Long wrote:

Hi Curt.

Either way will work.

http://www.g6lvb.com/AO-40%2070cm%20uplink%20antenna.htm

I have had superb success with mine, in fact during the days of AO-40 I worked the world with it as an uplink antenna with 50W.

http://www.g6lvb.com/3A2%20ops.htm http://www.g6lvb.com/dayton_demo_2002.htm

73, Howard G6LVB

-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Curt Nixon Sent: 02 January 2009 15:19 To: AMSAT-BB Subject: [amsat-bb] Question adding RHCP to Cheap Yagi

Good Morning All:

I've been using a 10el version of Kent Britain's Cheap yagi for my 70cm downlink antenna. It suffers from deep fades so I am going to add the second yagi with physical offset to get to RHCP in the x config.

Question is:

normally I would reverse the coax connections to a dipole driver but this is a hairpin (half of a folded dipole. )

Do I reverse the connections as normal? Kents instructions just say offset the elements and feed in phase.

Thanks

Curt KU8L

---

Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

Hi Greg:

Yes it would..These will use the physical offset fed without the delay section. My problem was getting my arms around the polarity direction--RH or LH. I have it figured out now so I'm finishing up the assembly.

Thanks Curt

Greg D. wrote:

Hi Curt,

For CP you would either have the elements offset and feed them in-phase, or have them not offset and feed them with the phase delay. You want to create a spin to the wave as it travels down the boom. I expect doing both would make a mess out of things.

Greg KO6TH

...

Date: Fri, 2 Jan 2009 10:19:23 -0500 From: cptcurt@flash.net To: amsat-bb@amsat.org Subject: [amsat-bb] Question adding RHCP to Cheap Yagi

Good Morning All:

I've been using a 10el version of Kent Britain's Cheap yagi for my 70cm downlink antenna. It suffers from deep fades so I am going to add the second yagi with physical offset to get to RHCP in the x config.

Question is:

normally I would reverse the coax connections to a dipole driver but this is a hairpin (half of a folded dipole. )

Do I reverse the connections as normal? Kents instructions just say offset the elements and feed in phase.

Thanks

Curt KU8L

---

Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite

program!

...

Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

---

Send e-mail faster without improving your typing skills. Get your Hotmail® account. http://windowslive.com/online/hotmail?ocid=TXT_TAGLM_WL_hotmail_acq_speed_122008