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Re: Tune the uplink or downlink?



Hi Ciemon

Answer for FM sats (data & voice) is to tune both! (The 'One True Rule' also
states this for Transponder sats too, although this is rarely observed in my
experience). You can sometimes avoid tuning the 2m uplink as the doppler's
not as great on VHF, but it's worth being ready for it.

Assuming you're using your TH-D7E in full duplex (and headphones to stop AF
feedback), set up a set of memory channels for each band as follows (UO-14
example)

2m TX:
145.970
145.975
145.980.

70cm RX:
437.060
437.065
437.070
437.075
437.080

That way you can leave you D7 in 25kHz European channel spacing on the VFO,
and use memories on each band at 5kHz spacing.

At the start of a pass the RX is tuned at the high end, and you reduce the
frequency as it passes over.

On the other side of the coin, you _increase_ frequency from the lower end
to the higher end on the TX as the sat passes over.

Maplin has a large selection of Gel cells, if that's of any use. I think
you'll find it a bit easier to reach the sat with that bit more TX power
from you D7, especially with all the alligators about. But you can do it!
Especially in the very early hours, or during a weekday. I found the high
power battery pack on the D7 helped a bit in a similar (but more expensive!)
way.

The Arrow takes a bit of getting used to, as you have to twist and turn it
to get the right polarisation as well as the correct direction.

FWIW, it took a couple of weeks for me to get a downlink after hours and
hours of checking and double checking my configuration. It's a bit of a
technique to learn. But then isn't that what our hobby's all about? :-)

Having a headset/mic helps a bit too, so you don't have to hold another
piece of equipment.

73 Howard G6LVB

----- Original Message -----
From: "Ciemon G0TRT" <g0trt@AMSAT.Org>
To: <amsat-bb@AMSAT.Org>
Sent: Saturday, November 11, 2000 5:09 PM
Subject: [amsat-bb] Tune the uplink or downlink?


> After finally getting an Arrow antenna thanks to a very kind gentleman
here
> in the UK (I'll not give his callsign as he'd get swamped with requests)
I'm
> starting to have a go on the FM birds. The fabulous UK weather isn't
> helping, but the can of worms I need to re-open is, do I tune the uplink
or
> downlink? I seem to remember reading that's it's just the downlink.
>
> I'm also after a gel cell supplier in the UK, anyone?
> 73.....Ciemon Dunville G0TRT Sysop MB7UPG IGate
> email - g0trt@amsat.org
> ICQ - 6263612
> homepage - http://go.to/APRSUK
>
> ----
> Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>

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