An alternative is the DX-Engineering Engineering TVSU-1 Time Variable
Sequencer Unit which is a microprocessor-based transmit/receive control
signal delay unit and provides 0-30 ms of delay programmable in 2 ms
steps to as many as five outputs tied to the CW keying or push-to-talk
(PTT) lines.
By controlling the receive-to-transmit (and back) timing of linear
amplifiers, pre-amplifiers, and other sensitive equipment, damage caused
by improper switching can be eliminated. This sequencer improves CW
performance by eliminating annoying leading edge chopping or truncating
of Morse characters. This is especially important in contests or pileups
where sending accuracy is critical.
http://www.dxengineering.com/Products.asp?ID=214&SecID=79&DeptID=12
No argument... just an alternative. I do not opine on which is better.
=================== K8JHR ===============================
On 1/11/2010 3:09 PM, Ron Castro wrote:
> Doug:
>
> Looking at the schematic of the A0 board where the switching and QSK
> blocking is done, I can't see that there is any special protection. All
> inputs have a gas tube and parallel RF choke to discharge static, but the
> main two antenna connections have a diode network that builds voltage to
> back-bias a pair of diodes in the RX line to protect the RX front end when
> TX RF is present. I suspect that a very strong external signal from another
> transceiver in the shack would be blocked by the biased diodes on the two
> main inputs from wrecking the O II receiver, but when the input is switched
> to the AUX (RX only) input there is little else to stop extremely strong
> signals that could damage the front end.
>
> If I was going to use a long wire RX antenna in the area of a QRO transmit
> antenna, I would use the ICE limiter/protector model 197 at the RX input, or
> home-brew something similar.
>
> Ron N6IE
> www.N6IE.com
>
> ----- Original Message -----
> From: "Speer, Doug"<Doug.Speer@FairbanksMorse.com>
> To:<tentec@contesting.com>
> Sent: Monday, January 11, 2010 11:06 AM
> Subject: [TenTec] Orion II receive antenna input
>
>
>> I am away from my QTH& Orion II manual. Maybe some of you know the
>> answers to my questions. I would like to use the receive antenna input for
>> a 160/80m low noise receive antenna input. How much built in RF protection
>> / switching does the Orion II have on this input? In other words how much
>> input protection do I need on the receive only antenna to prevent RF damage
>> to the Orion due to RF energy from my transmitting antenna feeding back
>> into the receiver via the receive antenna input? How is the use of a
>> separate receive antenna best handled with a single Orion II station?
>>
>>
>> Doug, W9PN
>> Janesville, WI
>>
>>
>>
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