I recently moved back to Cloverdale and not seeing much in the way of Amatuer Radio activity.  Any active clubs and or repeaters in the area? I recently moved from Santa Claus IN.  Been licensed for about 9 years (Extra) and am addicted to CW.

Greg
KC9ERZ

Thanks for the information.  Sounds like I am using too much power.  I will try 5 watts my next opportunity.

73
Greg
KC9ERZ

I was wondering what the rule of thumb transmit power should be for working the FM SATs like AO-51 and SO-50?  I have a 50 watt FM rig that I am using into a pair of 2meter cross-yagis (4 elements each).  Is 50 watts too much?

Thanks,
Greg
KC9ERZ

Thanks for the info on the uplink....and sorry for the typo (should have typed doppler, not doplar)!

Greg

I am fairly new to working the FM LEO Sats.  I have no problem getting into AO51 with a fixed uplink freq of 145.920.  But on AO27 and SO50 I have a hard time.  Do I need to compensate for doplar shift on the uplink to AO27 and SO50?  Also I know that SO50 requires a PL tone of 67.  What kind of tone is this?

Thanks,
Greg
KC9ERZ

Andy, after studying your diagram further I have another question.  As I trim my 75ohm stub, I assume I am looking for a low SWR on the power meter?  Having the open stub seems strange to me?  Also if I am looking for a low SWR on the meter, what percentage of the power am I looking for?  In other words if I am putting 1 watt from my TX should I see 1/2 watt on the meter?

Thanks again,
Greg
KC9ERZ

Thanks Andy for all the pointers.  I will try this tomorrow after work.  Your testing method makes alot of sense, especially with the drawing!

Thanks again!

Greg
KC9ERZ

Your first sentence is exactly correct and what I am trying to do.  I am using an SWR meter to meaure the the entire system.  In other words I was measuring once I had the 50ohm cable connected to the two 75ohm legs, which were then soldered to the DEs of each antenna.

As I mentioned in my first post, the yagis are based on the "Cheap Yagi" design, where the DE is a folded element.  The coax is soldered directly to the DE.  So in my case, I have two antennas on the same boom.  I tested each antenna seperately by temporarily hooking a 50ohm cable to the DE through an SWR meter and measuring.  Each antenna was less than 1.5:1.  

Then I calculated the length of the two matching sections of 75 ohm coax.  I soldered these directly together along with the 50 ohm coax (kind of a home-made T-adapter).  Then finally I soldered each of the 75 ohm legs to the DEs.  This is the point I measured the SWR and found it 5:1+.

Upon further reading it was suggested to not solder the three coaxes together, but rather to use a T-connector.  Also, I read where you include tip-to-tip when calculating length.  So in other words if the length comes out to be 4.5 inches for 1/4wave, then that is the total length, including the PL259 connectors end to end.  In my case there would only be one PL259 connector per leg and I the other end is soldered directly to the DE.

I have not tried using the T-connector or including the connectors in the overall lengths.  So possibly by matching stubs were to long?

Not sure if any of the above makes sense.....any help you could provide would be greatly appreciated.  

Thanks,
Greg
KC9ERZ

Andy,

Thanks for the quick response.  I want to make sure I understand what you recommend:

1)  Connect an RF power source (e.g. transmitter) to the T-connector input.

2)  Connect one side of the T-connector to one of my antennas that I am trying to feed using the approximate length of 75ohm cable.

3)  Connect the other side of the T-connector to a meter (SWR meter???).

Is the above correct?  I assume I would need to connect the end to the SWR meter using the same length of 75ohm coax (1/4 wave) as what I have connected to the antenna?

If I am putting 10watts into the T-connector, I should see 5-watts on my meter?

Again, thanks for your help.....any further clarification you could provide would be great!

Thanks,
Greg
KC9ERZ

I have built two yagis for 70cm on the same boom (cross-yagis).  They are physically 90deg out of phase for circular-polarization purposes.  They were built using the "Cheap Yagi" design where you solder the coax directly to the driven-element.  Now I need to build a matching harness to feed both antennas.  I understand the formula for calulating the length for each side using 75 ohm cable.  I also understand that everyone recommends using a T-adapter instead of trying to splice two 75ohm cables to a 50ohm cable.  So my question is what do I include in the measurements?  So for example if each leg of my harness is supposed to be 4.5 inches long, do I include the T-adapter in the measurements.  What about the ends that connect directly to the driven element?  Do I measure to the very end of the center-conductor, or just to the point where the outer-jacket was stripped off?

I've tested each antenna seperately for a low SWR and both are under 1.5:1.  But my first attempt at the matching harness failed (SWR greater than 5:1).

Thanks in advance for your help.

Greg
KC9ERZ

Sorry for all the "typos" in the first post.  The following is an amended version.

I just purchased a Yaesu G5500 Az/El rotor and want to make a couple circular polarized Yagis for 2 meter and 70cm. I have attempted to make a cross yagi for 70 cm using the "cheap yagi" design. I've also tried mounting them 90deg out of phase on the same boom. I then tried creating the power-divider harness. I can never seem to get a low SWR. It seems that every 1/16 inch or so you are off really increases the SWR.

Anyone have an easily reproduced 70 cm antenna that is good for working the LEOs? I'd prefer something directional, since I have the Az/El rotator.

Thanks for your help!
Greg
KC9ERZ

I just purchased a Yaesu G5500 Az/El rotator and want to make a couple circular polarized Az/Ez Yagis for 2 meter and 70cm.  I have attempted to make a cross yagi for 70 cm using the "cheap yagi" design.  I've also tried mounting them 90deg out of face on the same boom.  I then tried creating the power-divider harness.  I can never seem to get a low SWR.  It seems that every 1/16 inch or so you are off really is compounded when you put everything together.  

Anyway have an easily reproduced 70 cm antenna that is good for working the LEOs?  I'd prefer something directional, since I have the Az/El rotator.

Thanks for your help!
Greg
KC9ERZ

I've been a Ham for 5 years now and do mostly CW.  However, I've always used a straight key.  I am now trying to learn how to use paddles with the built-in keyer on my rig.  I am also a "lefty".  Does anyone have any suggestions on the best way to learn?  Also, as a lefty should I attempt to learn to use my Right hand, or use my left-hand?  If I use my left hand, should I switch around the dashes and dits on the paddle (e.g. make the left paddle dashes and the right dits)?

Any help would be appreciated.

Thanks,
Greg
KC9ERZ

Thanks Marc.  I'd probably do it on Linux.

Greg

Thanks Marc.  Got both a Linux and Mac OS X box...I'll give CWIRC a try.

Greg