[600MRG] LF: Receiver protection - FOLLOW UP

[N1BUG]

Thanks for the excellent information, Roger!

I was not aware of the ARRL review of the DXE devices. That was
published before I started experimenting on 2200 and 630 meters and
it hadn't caught my attention. I also failed to notice the second
device which limits to a slightly lower output level.

With your permission, I would like to forward this to the 2200 meter
related mailing lists.

73,
Paul N1BUG


On 07/13/2018 11:40 AM, Roger Rehr W3SZ wrote:
> Thanks for an excellent summary, Paul!
> 
> I have a few additions to your comments on the DXE device, which I've
> used here on 630M with no problems and with excellent results, with
> transmitter outputs on the order of 200 watts and with only 20 ft of
> separation between the bottom of my inverted L transmit antenna and the
> feedpoint of my 500 ft beverage receive antenna.  The device is also
> "inline" on my 2200M receive system, but because I haven't transmitted
> on 137 kHz I can't comment on it protectional efficacy on that band.
> 
> First of all, there are TWO DXE devices, the RG-5000 and the RG-5000HD. 
> These have different power-out vs power-in curves at input levels above
> -10 dBm. For both of them, however, when tested by the ARRL, it took 10
> watts of RF AT THE BNC INPUT CONNECTOR TO THE RG-5000 or RG-5000HD to
> produce an output of +13.2 to +13.3 dBm, depending on which of the two
> units was being tested.  Below 10 watts of RF power AT THE BNC INPUT
> CONNECTOR TO THE RG-5000 or RG-5000HD the output level from the device
> is of course less than +13.2 to +13.3 dBm.
> 
> Second, although the devices are specified for use at 0.5-150 MHz, the
> insertion loss of these devices at 137 kHz may be acceptable for many
> users.  The loss is 0.85 dB at 137 kHz for the RG-5000 and 0.81 dB for
> the RG5000-HD.  I did not notice a change in my receive performance on
> 137 kHz from before to after I installed the RG5000-HD.  And "during the
> season", I DO monitor my receive performance on both 2200M and 630M in a
> quantitative way by examining the previous night's data pretty much
> every morning in the manner shown at the URL below.  So I think I would
> be more likely than many stations to notice an important change in
> receive performance.
> http://w3sz.x10.mx/wp/2017/12/13/12-13-17-lf-blog/
> 
> The entire ARRL review of these devices, which provides data in both
> graphical and tabular forms, is here:
> https://static.dxengineering.com/global/images/technicalarticles/dxe-rg-5000_sn.pdf
> 
> The excellent 16-page manual for these devices is here:
> https://static.dxengineering.com/global/images/instructions/dxe-rg-5000.pdf
> 
> I am posting this because I was concerned that some folks who could
> really benefit from one of these devices on either the 630M or the 2200M
> band might mistakenly discard consideration of them unless they were
> aware of the information provided above.
> 
> I am very happy with my RF-5000HD and consider the $89.99 I spent on it
> to be one of the best purchases I made when setting up my below-500 kHz
> stations.
> 
> 73,
> 
> Roger Rehr
> W3SZ