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RE: Beginner birds



Emily wrote:

since I don't have 10M capability myself I'm  only guessing that 10M doppler is about the same as 2m doppler.

Wayne replies:

Three things make Mode A easier for a beginner to use than Mode B (AO-7) or Mode J (FO-29).

First, Mode A has much less Doppler shift.  +/-600 Hz on the 10m downlink and +/-3 kHz on the 2m uplink.  I agree that LEO Doppler is very challenging on Mode B (AO-7) and Mode J (FO-29).  I was never able to make FO-29 contacts until I got computer-controlled Doppler tuning.

Second, Mode A transponders are typically non-inverting, which makes tuning much more intuitive for a beginner.  Up is up.  Down is down.  Always USB.  AO-7 (Mode B) and FO-29 both have inverting transponders which add another layer of confusion for a beginner.  The inverting transponder keeps the Doppler from being quite so ornery, but it makes tuning much less intuitive.

Third, Mode A is viable with omnidirectional antennas because the path loss is low.  You can use a 10m inverted Vee and a 2m 1/4 wave ground plane antenna.  No need to mess with any kind of antenna pointing (manual or motorized).  Both antennas are extremely easy and cheap to homebrew.

Emily wrote:

The other objection is HF antennas are huge by today's entry level housing 
standards.  If you live in an apartment, condo or townhouse, you will be 
lucky to have a 3 meter wide balcony. Mine is 3.5m x 3.5m, but still not 
big enough to hide an efficient 10M HF antenna.  

Wayne replies:

A 10-meter inverted Vee would fit on your balcony.  The apex would ideally be 12 feet (3/8 wavelength) high, which is easy to accomplish with a temporary support.  If there is a balcony above you, the apex would have to be lower, but the antenna should still work.  The total length of the wire is 16 feet, but it's only 11-12 feet wide after bending it into an inverted Vee.  The wire can be almost invisible, and it can be homebrewed practically for free.  For instance use buttons as the center and end insulators.  A 10m inverted Vee is less visible and easier/cheaper to make than a 2m yagi.

Wayne Estes W9AE
Mundelein, IL, USA

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