Re: [amsat-bb] Icom 706

[tlang@xxxxxxxxxxxxxxxxxxxx (Tony Langdon)]

Hello Lee810@aol.com.

26 Mar 00 09:02, you wrote to All:

 L> I made a lot of contacts on AO27 using an Arrow and an FT50 which is
 L> not a full duplex HT.   However, after I got a full duplex HT (an
 L> FT51) I would never go back.  There are simply too many opportunities
 L> to get stepped on while using the FM birds and I know that when I hear
 L> others getting in while I'm trying to respond that I must try again.

And that's just one of the advantages of full duplex.  Another is the ability
to continuously monitor your own signal quality.  Not such a big issue if you
have 50 watts at your disposal, but very handy when you have only 2W, or as I
have done occasionally, 0.25W (into UO-14) or 0.5W (into SO-35).

 L> Secondly, a mobile rig with a vertical antenna makes a horrible
 L> combination for AO27.  You will miss a lot of calls because you'll
 L> only hear the downlink periodically, but your 50W will be stomping on
 L> others who can hear the downlink and you'll make yourself quite
 L> unpopular in a hurry.  Also, using an Arrow  handheld antenna with a

Sounds like the problems we get on UO-14 here...  However, something like a
small turnstile on the roof of the car might be interesting to experiment with,
especially as there's a ready made reflector.

I have had some success with UO-14 whilst mobile, but the resulting signals are
not for the faint hearted.  :-)  As for AO-27, there's a slight scheduling
problem there (read, I'm on the wrong side of the equator ;) ).

 L> rig mounted on your console will be difficult to tune while steering
 L> the antenna (i.e., one arm needs to be outside the car and the other
 L> arm inside the car).  You're right that the tuning on the 706 will be
 L> more precise, but you'll also find that the 5kHz steps for the Doppler
 L> correction on an HT is not a serious drawback on FM birds.

5 kHz is more than adequate spacing for Doppler correction on the FM birds.
That's never given me any trouble.  I use an Icom IC-T81A for 70cm downlinks
(at this stage, that means UO-14 only), because its Rx sensitivity is in the
order of 0.13 uV for 12dB SINAD (I've had my rig on a test set), and 70cm
downlinks require every bit of sensitivity you can muster. :-)

Tony

.. in theory!
--
|Fidonet:  Tony Langdon 3:633/284.18
|Internet: tlang@freeway.apana.org.au
|
| Standard disclaimer: The views of this user are strictly his own.


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