[amsat-bb] Re: Best HT's for sats?

[Andrew Glasbrenner]

Bill,

The 530 lets you select one band as the transmit band, and the other as the 
band that the dial tunes. Simply set the 2m side to the 2m uplink, the 70cm 
to the downlink + expected doppler shift, set the sub band tune to tune the 
70cm side, and then when you push the ptt it will transmit on 2m. The only 
thing you'll need to touch during the pass is the main tuning knob, and the 
PTT. This feature is only on the 530, on the 470 you have to swap bands, 
tune, then swap back before transmitting. With the 470 figure on doing this 
5 times on a long pass, and I was always able to do it with one hand, even 
with gloves standing knee deep in snow in South Dakota.

To answer an earlier question (or to not answer it) I've never had the need 
or desire to operate a full duplex rig where the receive band mutes on tx. 
There are cheap earphones that work for full duplex just about everywhere. I 
still use a pair I picked up for free from JetBlue two years ago. If I'm 
doing a demo where I want others to hear, like at a hamfest, I have an 
extension speaker from MFJ (read CHEAP) that I screwed a belt clip from an 
old cell phone onto, so that it clips to the back of my belt facing the 
other way from me. This and careful volume control will normally prevent it 
from squealing due to feedback.

Think about this...full duplex means you can tweak your antenna orientation 
WHILE transmitting for max signal. All the FM microsats use a single whip 
for receive, meaning a linear yagi like the Arrow will have ~20db!!! of 
variation on the uplink due to cross polarization. If on your next 
dxpedition, would you bring along a 500w amp if it only had the size and 
weight of a pair of earbud headphones?

73, Drew KO4MA



----- Original Message ----- 
From: "Bill Dzurilla" <billdz.geo at yahoo.com>
To: <amsat-bb at amsat.org>
Sent: Friday, April 04, 2008 8:20 PM
Subject: [amsat-bb] Re: Best HT's for sats?


You mean you have to switch to the receive VFO and
then switch back to the uplink VFO every time we
need to make a Doppler correction?  It's not cold here
in Florida, but I can sure see how that would be
annoying.  Andrew said the FT-530 has a "subband
tune function," what about that?
73, Bill
> --- Dan O'Barr <kl7dr at yahoo.com> wrote:
>
> > Hi Rafael and Bill,
> >
> > That's the issue with the FT-530, and it's the
> same
> > with the Alinco DJ-580.
> > They are both very good radios for full duplex. If
> > you are in a warm climate,
> > and do not have to wear gloves, then all the
> button
> > pushing to change back and
> > forth between VHF for transmitting and then to UHF
> > for receiving and changing
> > frequencies for Doppler, then it's no big deal.
> > However, up here the ability to
> > just program 5 spit channels, like the VX-7R,
> makes
> > it a lot easier to work a
> > pass. I believe the FT-51 has the capability of
> > working full duplex with a
> > setting that allows the operator to transmit on
> one
> > band and receive and tune
> > on the other.



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