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Rec antenna protection

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Nr4c

Rec antenna protection

I'm looking for a device to protect my K3S front end when using a RX antenna. As I key my rig I can hear the COR clicking and it's making me nervous.

I have seen the AS-RXFEP review by W1ZR in QST. I have also seen devices with reed relays on the web. What are you using or am I just foolish to worry about this?

Sent from my iPhone
...nr4c. bill

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James Bennett

Re: Rec antenna protection

Bill,

I use that AS-RXFEP device and am 100% satisfied with it. I have run 550 watts from my K-line system, through 110 feet of 600-ohm ladder line feeder to an 88 foot long doublet at 45 feet. My diversity receive antenna is a ground mounted Hustler 5BTV (with radials) that is only 25 feet from the doublet. The COR clicking is a thing of the past for me. I also installed an MFJ dual-position coax switch in that line so that I could transmit (bare foot) into the Hustler, if so desired. The switch allows me to bypass the RXFEP when I transmit into the vertical. Anyway, I think you'll be quite satisfied with that Array Solutions device.

73, Jim

Jim Bennett / W6JHB
Folsom, CA

> On Aug 6, 2015, at 9:40 AM, Nr4c <[hidden email]> wrote:
>
> I'm looking for a device to protect my K3S front end when using a RX antenna. As I key my rig I can hear the COR clicking and it's making me nervous.
>
> I have seen the AS-RXFEP review by W1ZR in QST. I have also seen devices with reed relays on the web. What are you using or am I just foolish to worry about this?
>
>
> Sent from my iPhone
> ...nr4c. bill
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
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> Please help support this email list: http://www.qsl.net/donate.html
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Ken G Kopp

Re: Rec antenna protection

In reply to this post by Nr4c

Bill,

DX Engineering and Array Solutions both have protection devicees.

73!

Ken - K0PP
On Aug 6, 2015 10:43 AM, "Nr4c" <[hidden email]> wrote:

> I'm looking for a device to protect my K3S front end when using a RX
> antenna. As I key my rig I can hear the COR clicking and it's making me
> nervous.
>
> I have seen the AS-RXFEP review by W1ZR in QST. I have also seen devices
> with reed relays on the web. What are you using or am I just foolish to
> worry about this?
>
>
> Sent from my iPhone
> ...nr4c. bill
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

Chris Hallinan

Re: Rec antenna protection

In reply to this post by Nr4c

I''ve been somewhat frustrated with the same issue. I purchased the Array
Solutions (AS) Front End Protector, as you mention. When I first
connected it, I was treated with terrible noise and images all over the 20
meter and 40 meter bands. I returned the unit to AS, and they tested it
and found no problems. After further investigation, I discovered that the
RXFEP was being overloaded by broadcast signals, both from the US
Commercial AM broadcast band (550 to 1600KHz) as well as very strong
signals from some short wave broadcasters. These short wave stations are on
5 MHz and believe it or not, even one station in Alabama transmitting on
13.830, which pegs my K3's S-meter at +60dB over S9 at certain times of the
day depending on conditions and the orientation of my RX loop. All of
these together overload the RXFEP. Putting my antenna into a scope input,
I can see more than 2 volts p-p during the day, and up to 5 volts p-p at
night!!! If I did my calculations right, that's around +18 dBm!

So then I purchased the receive-only broadcast filter from AS, and that
improved my situation 95%. Now I need to eliminate the energy from the
other 5, 12 and 13 MHz broadcasters.

Even with the RXFEP installed, I still have COR clicking on 40 meters,
likely due to the proximity of my Rx Loop to my 40-meter vertical. I HATE
relay clicks, and LOVE the fact that the K3 is such a great CW rig with
silent TR switching. But...the only solution so far I've found is to
connect the K3 key out jack to the power tap from my Inlogis Rx Loop.
Unfortunately, that is a relay, and gives me audible clicks when I send CW.

I am in the process of further investigation/testing, and I'm going to try
some bandbass filters to see if I can alleviate the overloading issue. But
I might also be forced to relocate my loop or vertical to eliminate the
need to use a relay in the rx antenna circuit.

I would appreciate hearing about other's experiences.

73,

Chris
K1AY

disclaimer: I don't mean to bash Array Solutions. I think the AS-RXFEP is
a great product, and AS has other great products. Best money I ever spent
in amateur radio was my recent purchase of the AS AIM4300.

On Thu, Aug 6, 2015 at 12:40 PM, Nr4c <[hidden email]> wrote:

--
Life is like Linux - it never stands still.
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Re: Rec antenna protection

In reply to this post by James Bennett

The external reed relay /miniature relays are OK IF they are keyed by the
key line AND the RF is delayed a few ms from key line down.(K3 does this)
The diode limiter circuits like the AS and others like that don’t have this
limitation.

BUT I would be interested in the OFFICIAL Elecraft position on their COR

What bothers me about it is that if the internal relay is clicking , it has
to already have seen enough RF to be considered potentially damaging in
order for the K3 to decide the relay needs to be actuated . So the barn
door is closed after the RF has been applied for an unknown period but
surely a couple milliseconds.

I am a belt and suspenders type guy especially with expensive equipment -
and my feeling is that the K3 COR is telling me to DO SOMETHING ABOUT IT
NOW. I would never continue to operate with it actuating. I treat it as a
nice warning thing Mr. Elecraft has given me, not something to be used
continuously.

I made my own RX ant protector with a little DPDT miniature relay that has
gold plated contacts . It is wired so the rx ant line is opened and also the
K3 rx input is shorted. One could argue which should come first I guess but
I get over 100 dB isolation on 160 measured with VNA.

Hank K7HP

>
> I'm looking for a device to protect my K3S front end when using a RX
> antenna. As I key my rig I can hear the COR clicking and it's making me
> nervous.
>
> I have seen the AS-RXFEP review by W1ZR in QST. I have also seen devices
> with reed relays on the web. What are you using or am I just foolish to
> worry about this?
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Chris Hallinan

Re: Rec antenna protection

I couldn't agree more, Hank. That COR is a warning flag, and in my humble
opinion, not something I would consider for normal operation ;)

I'd also be interested in Elecraft's take on this. At what level does it
kick in? Also, what is the level of isolation between Aux RX In and the
main coax input/output?

-Chris

On Thu, Aug 6, 2015 at 1:47 PM, Hank P <[hidden email]> wrote:

> The external reed relay /miniature relays are OK IF they are keyed by the
> key line AND the RF is delayed a few ms from key line down.(K3 does this)
> The diode limiter circuits like the AS and others like that don’t have this
> limitation.
>
> BUT I would be interested in the OFFICIAL Elecraft position on their COR
>
> What bothers me about it is that if the internal relay is clicking , it
> has to already have seen enough RF to be considered potentially damaging in
> order for the K3 to decide the relay needs to be actuated . So the barn
> door is closed after the RF has been applied for an unknown period but
> surely a couple milliseconds.
>
> I am a belt and suspenders type guy especially with expensive equipment -
> and my feeling is that the K3 COR is telling me to DO SOMETHING ABOUT IT
> NOW. I would never continue to operate with it actuating. I treat it as a
> nice warning thing Mr. Elecraft has given me, not something to be used
> continuously.
>
> I made my own RX ant protector with a little DPDT miniature relay that
> has gold plated contacts . It is wired so the rx ant line is opened and
> also the K3 rx input is shorted. One could argue which should come first I
> guess but I get over 100 dB isolation on 160 measured with VNA.
>
> Hank K7HP
>
>
>> I'm looking for a device to protect my K3S front end when using a RX
>> antenna. As I key my rig I can hear the COR clicking and it's making me
>> nervous.
>>
>> I have seen the AS-RXFEP review by W1ZR in QST. I have also seen devices
>> with reed relays on the web. What are you using or am I just foolish to
>> worry about this?
>>
>>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

David Gimenez

Fwd: Rec antenna protection

In reply to this post by Nr4c

Bill you are not foolish...
I experienced the same, and measured 5 Watts using a dummy load at the end
of my K9AY when transmitting with my 40 m monopole (K3 + 1 kW amplifier)
The fix was adding a simple relay on the rx antenna path driven by the key
out signal of my K3. The NO contact of the relay was soldered to a 50 Ohm/5
W resistor. This additionally helps to protect my TS-830S, which is also
connected to the rx antenna..
Hope this helps

David
EA3FYZ

2015-08-06 18:40 GMT+02:00 Nr4c <[hidden email]>:

Petr, OK1RP/M0SIS

Re: Rec antenna protection

This post was updated on .

In reply to this post by Nr4c

Bill,

KD9SV Front-end saver is highly recommended. Never had any issue. Easy, cheap, reliable...

http://ok1rp.blogspot.cz/2015/03/front-end-saver-for-lb-antennas.html

No overloading, no noise issue, no filters, no problems.

73 - Petr, OK1RP

73 - Petr, OK1RP
"Apple & Elecraft freak"
B:http://ok1rp.blogspot.com
MeWe: https://bit.ly/2HGPoDx
MeWe: https://bit.ly/2FmwvDt