The3 Orion and Orion II have 2 hardware ALC circuits. One circuit lowers
drive when the ALC power output threshold is reached. The second circuit
lowers drive if the current in the finals exceeds 25 amps. When you lower
the power output on the radio, you are really just adjusting the ALC level
to cause it to reduce drive to the current setting. By setting the power
output to 40 watts, you guarantee the internal drive to the finals is set to
produce only 40 watts. This method is completely satisfactory to set the
drive level for any amplifier.
Carl Moreschi N4PY
121 Little Bell Mountain Dr
Hays, NC 28635
www.n4py.com
----- Original Message -----
From: "Ron Castro" <ronc@sonic.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Tuesday, February 09, 2010 12:09 PM
Subject: Re: [TenTec] Orion ALC and power output indication meter
andspeechprocessing
> Terry: All very interesting observations on the Orion! You mentioned
> that
> the radio shuts down when the current reaches a certain level, which I
> have
> seen my radio do on several occasions. Do you have any idea which circuit
> sets the 'trip level' for that shutdown and is there any way to adjust it?
> My guess is that it's something controlling the main power relay on the A0
> board near the DC power connector.
>
>>From what I'm able to tell, the Orions have two ALC circuits: one is a
> software derived system that also sets the audio for a very wide range of
> input levels and operates the ALC light on the front panel, and the other
> is
> a fairly standard hardware circuit. The hardware system only seems to
> operate when the power is near the maximum set by the internal ALC level
> control and there appears to be a "voting' circuit on the A5 board that
> controls the power, based on which ALC is demanding power reduction.
> Unless
> you are running near 100%, that will always be the software derived
> signal.
> When the power is set below 100%, the SSB peaks bob around wildly, never
> reaching the CW level, however when running 100%, the peaks stay 'nailed'
> at
> 100 Watts, as shown on my N8LP LP-100 Wattmeter.
>
> That means that in order to drive a linear that requires 40 Watts of drive
> and have both internal ALC's properly controlling peaks, you would need to
> put a 4 dB attenuator on the output of the Orion and run it at 100 Watts,
> or
> reset the ALC level for 40 Watts of output power. Neither seems like a
> great prospect!
>
> Ron N6IE
> www.N6IE.com
>
> ----- Original Message -----
> From: "Zivney, Terry L." <00tlzivney@bsu.edu>
> To: <tentec@contesting.com>
> Sent: Tuesday, February 09, 2010 7:22 AM
> Subject: [TenTec] Orion ALC and power output indication meter and
> speechprocessing
>
>
>> Earlier Ten-Tec rigs I have owned, such as the Delta, the Corsair II, and
>> the Omni VI+ all
>> have wattmeters which attempt to show the actual amount of RF output and
>> reflected power
>> on a Bruene-type circuit. The Orion does not seem to indicate the
>> actual
>> level of RF output
>> on the meter; rather it seems to show the percentage of full power the
>> operator sets - that is,
>> 100 indicates 100% of full power as set by the internal ALC pot, which
>> could be more or
>> less than 100 watts. My experience with two Orions is that the factory
>> sets this level to be
>> 100 watts.
>>
>> The purpose of ALC in the Ten-Tec radios appears to be to hold the peak
>> forward power
>> at the level selected by the operator regardless of the SWR. So, while
>> most JA rigs, and
>> apparently the West Coast "competition" turn back the peak forward power
>> under high
>> SWR conditions, the Ten-Tec radios historically have maintained the peak
>> power set until
>> the rig draws overcurrent which then powers the entire radio down. If
>> you
>> take a look at
>> the classical Motorola RF power transistor data sheets, they are
>> specified
>> to provide that
>> power under 30:1 SWRs; there should be no need to reduce forward power in
>> a properly
>> designed solid state amplifier. The key is to maintain the peak power at
>> the desired limit
>> (100 watts forward power in this case); this means the ALC circuit will
>> need to change
>> the drive level to maintain that desired forward power as the load SWR
>> changes.
>>
>> This is an issue for the WRTC-2010 competitors as noted on their
>> reflector. If the antenna
>> has a high SWR, the forward power may increase over the 100 watt limit
>> while maintaining
>> 100 watts net power (forward minus reflected). I measured the foward
>> power of both
>> my two Orions and my remaining Omni VI+ as staying within a needle's
>> width
>> of the set
>> forward power while the SWR went from 1:1 to over 10:1 (using monoband
>> antennas
>> on the "wrong" bands). Thus, the Ten-Tec radios met the WRTC-2010 spec
>> while other
>> radios may have to incorporate an external antenna tuner to avoid rules
>> violations. (See
>> the WRTC-2010 rules for additional information on this point about why
>> internal tuners
>> are not useful for this contest.)
>>
>> There were some posts a few years back about the speech processing on the
>> Orion
>> v1 versus v2 and the effictiveness of that processing. My personal
>> experience has been
>> that while I definitely needed the external Ten-Tec RF speech processor
>> on
>> the Omni VI
>> to be contest competitive, the internal firmware speech processing on the
>> Orion (level
>> 6 or 7) has been equally effective in practice for me. I have not tried
>> my external processor
>> on the Orion, as it is waaaaay down on the list of things to do here.
>>
>> Terry Zivney, N4TZ/9,
>> still trying to figure out the best way to get an Orion to Russia with
>> love...
>> _______________________________________________
>> TenTec mailing list
>> TenTec@contesting.com
>> http://lists.contesting.com/mailman/listinfo/tentec
>>
>
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|