[CQ-Contest] LP SO2R with no filters?

[Joe]

I'm curious,
This conversation has been interesting for sure. But I wonder if the 
risk of damage has or is being exaggerated some. Reason thinking this is 
for one thing. What is gonna happen in a little over a week. Field Day.

Field Day, pushes the damage potential to the extreme far more than SO2R 
could ever be. And in many instances filters are not even an option for 
protection. As in the case of a say 40 meter phone station, CW station, 
and ex Novice Station ( Now the GOTA Station ) all on 40 meters at the 
same time.

Yet I have been doing Field Day since 1975, from simple 1A efforts to 
2A   or 5A and even up to once a 12A group. Yet I have not in my mind 
ever known of any damage that has ever happened to any of the rigs. Even 
one group one year was a 3 A Operation and all they had were multi band 
verticals for each station and they were all mounted on the same barb 
wire fence than was their ground system. and the 3 antennas were at the 
most maybe 100 feet apart MAX. Granted in this setup they were not able 
to operate all 3 on the same band, the overload desence was terrible. 
sounded like a big vacuum cleaner on the band sucking up all the 
signals, but no damage happened.

Hmmmm?

Joe WB9SBD
Sig
The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com
On 6/16/2015 5:14 PM, Jeff AC0C wrote:
> The amount of work a guy may want to put into checking out the setup 
> for isolation is in direct proportion to the cost of getting a 
> potentially expensive RX repaired.  My view is that until you have 
> TESTED to BE SURE the isolation exists, you have to assume it's going 
> to fry gear.
>
> And don't let the thought that "I'm only running 100W" be of any 
> consideration.  That's +50 dBm and you want to be very much under +20 
> dBm to avoid damage - and less than that in some cases.  I think W2VJN 
> recommends 0 dBm as the damage threshold target.  That means you need 
> 30-50 dB of isolation, on every band and directional combo - something 
> which takes time to check out.   The isolation is easy to achieve with 
> natural coupling loss and a stub.
>
> You really will probably not be happy if you just try it, trusting 
> luck alone, only to find out luck ends up against you.
>
> 73/jeff/ac0c
> www.ac0c.com
> alpha-charlie-zero-charlie
>
> -----Original Message----- From: Jeff Stai
> Sent: Tuesday, June 16, 2015 12:31 PM
> To: Mike Smith VE9AA
> Cc: cq-contest
> Subject: Re: [CQ-Contest] LP SO2R with no filters?
>
> On Mon, Jun 15, 2015 at 2:53 PM, Mike Smith VE9AA <ve9aa at nbnet.nb.ca> 
> wrote:
>
>> Has anyone ever done SO2R with no bandpass filters?
>
>
> Buy the W2VJN book from Inrad. It will explain everything:
>
> http://www.qth.com/inrad/book.htm
>
> But in a nutshell, just try it. It sounds like you have both 
> horizontal and
> vertical antennas, which will give you 20dB of separation at the outset.
> That could very well be enough for your conditions. If you need more, 
> stub
> filters can be very effective for the cost of some scrap coax.
>
> 73 jeff wk6i
>