[CQ-Contest] 10/15 interaction

Steve Lott lottsphoto at gmail.com
Sat Nov 8 08:24:11 EST 2014


what u are recommending will not work on a transmit port......

The DX Engineering
Receiver Guard
should be used
on any radio
*receive only antenna *
for low

They do work well for rcv antenna ports (I have one of each of my rigs rcv
port jacks)

My Ham Radio Friends

On Thu, Nov 6, 2014 at 11:15 AM, Joe <nss at mwt.net> wrote:

> How about using one of these?
> http://www.dxengineering.com/search/department/antennas/
> product-line/dx-engineering-receiver-guard-5000-electronic-rf-limiters?
> autoview=SKU&N=4294953330&sortby=Default&sortorder=Ascending
> Then you are good on any band too?
> Joe WB9SBD
> Sig
> The Original Rolling Ball Clock
> Idle Tyme
> Idle-Tyme.com
> http://www.idle-tyme.com
> On 11/6/2014 9:18 AM, Randall K Martin wrote:
>> Over the years, I've managed to clean up most of the cross band
>> interference that occurs when I operate my SO2R station running high power.
>> The one exception is that I cannot use my 10M monobander to transmit while
>> receiving on my 15M monobander. This is not surprising, since they are only
>> separated vertically by about 8 feet. Transmitting on 10M must be dumping
>> significant power back into the 15M transmitter (an elecraft K-3) since it
>> causes the COR relays to click and I get the "HI RFI" error. When this
>> happens, I immediately stop transmitting and flip the 15M rig over to a
>> tribander on a second tower. Normally, I'm able to remember not to do this,
>> but in the heat of a contest, I forget. What I find odd is that I can
>> transmit on the 15M monobander while the second radio is connected to the
>> 10M monobander and there is no "HI RFI" problem. In fact, very little
>> interference.
>> Here's my question. I'm contemplating purchasing a high power band pass
>> filter (4O3A) to prevent the interaction. I'd prefer not to buy both a 10M
>> and a 15M filter if I don't have to. My intuition tells me that I should be
>> able to add the filter to the 10M transmitter. Any thoughts on this? Is
>> there some other path in which the RF could be reaching the 15M rig that
>> would render the band pass filters ineffective?
>> I have dunestar 100W band pass filters on both rigs, placed between the
>> rig and the amp. I know that adding separation between the monobanders
>> would help, but my tower configuration isn't really amenable to adding more
>> separation.
>> 73
>> Randy K0EU
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