[amsat-bb] Re: HT supports full duplex satellite operation

[Michael Chen]

All,

Many thanks for those replies off the list.
Yes, just like Tim said, I am looking for HTs that are currently in
production. I am trying to get local high school club station to work
via the satellites. A true full-duplex HT can make this process easily
accepted by the students. At the same time, the school will always
require new HT purchase from the market.

It's sad that I can't find a good choice.  DJ-G7 does not seem to be
good enough.

I believe there will be a boost of satellite operation in China with
the launch of XW-1.

Michael Chen, BD5RV/4
Email: michael.bd5rv at gmail.com
MSN: bd5rv at jsdxc.org
Skype: michael-bd5rv



On Wed, Oct 21, 2009 at 12:57 AM, Tim - N3TL <n3tl at bellsouth.net> wrote:
> I intended to reply both to Michael and the BB, but I see that I simply
> responded to him and not to "all" in my earlier note.
>
> My sense from his original post is that he is looking only for
> current-production HTs, and I believe the Alinco is it when it comes to
> full-fuplex-capable HTs.
>
> That being said, I have been doing some related research over the past
> several months. Some BB readers may recall a post I made a few months ago
> about "the fully rechargeable satellite station." I have done some other
> things that I hope to include in an article for an upcoming issue of  "The
> AMSAT Journal," and I have discovered something that, I believe, could
> benefit all of us who enjoy using handheld stations.
>
> In addition to the TH-F6A HT from Kenwood, I have had an opportunity to use
> a Yaesu VR-500 handheld all-mode receiver. The general coverage receiver in
> the Kenwood is all-mode, as is the VR-500. Either also can serve as a
> receive radio for a station on the linear satellites, albeit with manual
> Doppler tuning.
>
> Most notable for those of us who enjoy using handheld stations for the FM
> satellites is the fact that the Kenwood's general coverage receiver and the
> Yaesu VR-500 each offer tuning steps down to 1 kHz and below, even in FM. As
> I recall, the Kenwood HT can tune as finely as 33 Hz. The VR-500 will tune
> as finely as 100 Hz. I routinely tune it in 1 kHz steps on the FM
> satellites. Doing so enables me to track Doppler on the UHF downlinks of our
> FM satellites much more accurately, and that has made a big difference in my
> ability to make handheld contacts. Those who choose to ignore the inarguable
> fact that high power isn't necessary for effective FM LEO satellite contacts
> still make things difficult for me and others who enjoy using handheld
> stations. I've accepted the fact that the situation won't ever change, which
> is disappointing.
>
> Nonetheless - from here, I believe that using a 2-radio full-duplex setup
> for the FM satellites that incorporates a receive radio capable of tuning in
> 1 kHz (or finer) steps actually represents the most effective option because
> of the improved receive capability the smaller tuning steps provide.
>
> Many of us would like to see more HT manufacturers adopt full-duplex as a
> feature on at least one current-production model. I also would like to cast
> my vote for (1) general coverage receivers that, like the TH-F6A, are
> all-mode, and (2) tuning steps finer than 5 kHz for FM that will work on
> both transmit AND receive.
>
> I am thrilled with the news that AMSAT is moving forward with plans to build
> and launch a 1U cub sat with a U/V (Mode B) transponder. However,
> consistently hitting the uplink with HTs that tune no finer than 5 kHz will
> be a challenge. I learned that last winter when the ISS repeater was active
> in Mode B. When I used my FT-817 as a transmit radio and could use the main
> tuning dial to infinitely fine-tune the uplink, I had much better - and more
> consistent - success hitting the uplink than with my HT, which will only
> tune in 5 kHz steps.
>
> 73 to all,
> Tim - N3TL
>
> 73 to all,
> Tim - N3TL
> Athens, Ga. - EM84ha
> ________________________________
> From: Alan P. Biddle <APBIDDLE at UNITED.NET>
> To: Michael Chen <michael.bd5rv at gmail.com>; amsat-bb at amsat.org
> Sent: Tuesday, October 20, 2009 12:02:14 PM
> Subject: [amsat-bb] Re: HT supports full duplex satellite operation
>
> Michael,
>
> That is a good reference from JoAnne.  Most on the list will work well,
> particularly the TH-D7 and the IC-W32A.  However, before you purchase one,
> be certain to research how well it actually works for satellite ops.  For
> instance, I have an Alinco DJ-G7 which has great specifications, but works
> very poorly for satellite ops, though it is a nice general purpose unit.
>
> Alan
> WA4SCA
>
>
> -----Original Message-----
> From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
> Behalf Of Michael Chen
> Sent: 20 October, 2009 09:12
> To: amsat-bb at amsat.org
> Subject: [amsat-bb] HT supports full duplex satellite operation
>
> All,
>
> Could anyone list the HT models (available today in the market) that
> support full duplex satellite operation?
> I know I can get connected with two HTs and portable cross Yagi. Just
> need a simpler solution.. IC-W23AT and TH-D7 are discontinued.
>
> Michael Chen, BD5RV/4
> Email: michael.bd5rv at gmail.com
> MSN: bd5rv at jsdxc.org
> Skype: michael-bd5rv
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>
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