Nearby Ham Interference
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My neighbor is a ham, right now I set up a webpage for us to coordinate what band we are on so that we are not on the same band at the same time. I originally set this up for field day but it also works good for us. We are both CW ops and have not ran into issues yet but, there is always a but, we both want to make sure we do our best to protect our equipment which we both have K3's. I have a beverage that i use for 40 through 160 and i have a front end protector on my rx input but what about 10 theough 30? I have a beam and rotatable dipole for those bands so how do i protect my receiver better on those bands? Our tx antennas are roughly 300 feet apart, he has a vertical right now and i have both a vertical and a beam to switch between. He plans on a beam this summer and it will be the same distance apart. Thoughts... 73, Jeff K8KZB Sent from Outlook Mobile ______________________________________________________________ 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] |
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On Tue,1/19/2016 5:17 AM, [hidden email] wrote:
> Our tx antennas are roughly 300 feet apart, he has a vertical right now and i have both a vertical and a beam to switch between. He plans on a beam this summer and it will be the same distance apart. > > > Thoughts... For operation so close together, you really must view this as a multi-op station. :) Rules -- very practical ones. 1) Both stations must use rigs with excellent strong signal performance. 2) Both stations must use rigs with very clean TX performance, and operate them from supplies of at least 13.8V under load. 3) If using power amps, both stations must tune their amp very carefully. 4) Yes, antenna directivity matters. At county expeditions for the California QSO Party, we set up three stations -- two CW, one SSB, with antennas that are as widely separated as possible. Each station is a K3 with new synth board, a KPA500, and a KAT500. With 2-el Yagis spaced about 250 ft apart, we can operate CW and SSB on the same band with no QRM. The Yagis are carefully located and aimed so they are colinear when pointed 70 degrees azimuth (what works in W6 for US contests). Our wire antennas for 80 and 40 are about 300 ft apart, and we can operate CW and SSB on those bands too. 5) Bandpass filtering helps when you're NOT on the same band. We use TXBPF filter sets between the K3s and the KPA500s, and we have double-stub notch filters on the 40M and 80M CW feedlines to kill the second harmonic of the power amp. 6) Cross polarization can help. 7) Both stations need very good coax with well installed connectors. Coax shielding effectiveness depends on a shield with very low resistance and very good uniformity. THAT'S why there's no RG8X or RG58 in my station -- shield resistance is directly related to skin effect, and a larger diameter shield has less resistance than a small one. 8) Both stations need very good common mode chokes at the feedpoint of their antennas. This prevents radiation and reception by the feedlines. 9) Every little thing matters -- little things add up to a lot. I wasn't satisfied with the effectiveness of a 2-stub filter on my 40M antenna -- there was still too much second harmonic in my RX on 20M. Last fall, I bought some very good coax (Buryflex) and some Amphenol 83-1SP connectors and replaced every piece of coax inside my station. I have a lot of antenna switching, so that was nearly 100 ft of coax and 50 connectors. The second harmonic dropped by about 10 dB! Observations -- the only problem we've ever had with RX burnout was the first year we were there -- we strung two dipoles end to end with only a few feet between the ends and connected them to different K3s. 73, Jim K9YC ______________________________________________________________ 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] |
Re: Nearby Ham Interference
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I have seen how effecttive item #5 is on the previous post.
And if you don't follow all of Jim's advice then you are really missing out. I have seen companies spend thousands of dollars for advice that you just got for free. Nels Nelsen NE7LS n_n And I am still working on #9 (and the rest) ______________________________________________________________ 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] |
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In reply to this post by Jeff-2
If you're worried about burning out the receiver front end, why not test
it? Add a 20 dB (or more) attenuator in front of the receiver and have your neighbor try transmitting on all bands and antennas. The K3 S meter is pretty accurate. Just add 20 dB to the reading to see how much RF is coming down the coax. Alan N1AL On 01/19/2016 05:17 AM, [hidden email] wrote: > > > My neighbor is a ham, right now I set up a webpage for us to > coordinate what band we are on so that we are not on the same band at > the same time. I originally set this up for field day but it also > works good for us. > > > We are both CW ops and have not ran into issues yet but, there is > always a but, we both want to make sure we do our best to protect our > equipment which we both have K3's. > > > I have a beverage that i use for 40 through 160 and i have a front > end protector on my rx input but what about 10 theough 30? I have a > beam and rotatable dipole for those bands so how do i protect my > receiver better on those bands? > > > Our tx antennas are roughly 300 feet apart, he has a vertical right > now and i have both a vertical and a beam to switch between. He plans > on a beam this summer and it will be the same distance apart. > > > Thoughts... > > > 73, > > Jeff K8KZB > > > > Sent from Outlook Mobile > > > ______________________________________________________________ > 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] > 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] |
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This discussion has made me curious -- especially when I carry my KX3
around at field day -- how much signal is safe and how much can do physical front end damage? Brendon KK6AYI - Brendon On Tue, Jan 19, 2016 at 10:44 AM, Alan <[hidden email]> wrote: > If you're worried about burning out the receiver front end, why not test > it? Add a 20 dB (or more) attenuator in front of the receiver and have > your neighbor try transmitting on all bands and antennas. The K3 S meter > is pretty accurate. Just add 20 dB to the reading to see how much RF is > coming down the coax. > > Alan N1AL > > > > On 01/19/2016 05:17 AM, [hidden email] wrote: > >> >> >> My neighbor is a ham, right now I set up a webpage for us to >> coordinate what band we are on so that we are not on the same band at >> the same time. I originally set this up for field day but it also >> works good for us. >> >> >> We are both CW ops and have not ran into issues yet but, there is >> always a but, we both want to make sure we do our best to protect our >> equipment which we both have K3's. >> >> >> I have a beverage that i use for 40 through 160 and i have a front >> end protector on my rx input but what about 10 theough 30? I have a >> beam and rotatable dipole for those bands so how do i protect my >> receiver better on those bands? >> >> >> Our tx antennas are roughly 300 feet apart, he has a vertical right >> now and i have both a vertical and a beam to switch between. He plans >> on a beam this summer and it will be the same distance apart. >> >> >> Thoughts... >> >> >> 73, >> >> Jeff K8KZB >> >> >> >> Sent from Outlook Mobile >> >> >> ______________________________________________________________ >> 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] >> >> ______________________________________________________________ > 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] > 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] |
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In reply to this post by Jeff-2
Consider one of these: http://www.dxengineering.com/parts/dxe-rg5000hd
73, Ian N8IK -----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of [hidden email] Sent: Tuesday, January 19, 2016 08:17 To: 'Elecraft Reflector' <[hidden email]> Subject: [Elecraft] Nearby Ham Interference My neighbor is a ham, right now I set up a webpage for us to coordinate what band we are on so that we are not on the same band at the same time. I originally set this up for field day but it also works good for us. We are both CW ops and have not ran into issues yet but, there is always a but, we both want to make sure we do our best to protect our equipment which we both have K3's. I have a beverage that i use for 40 through 160 and i have a front end protector on my rx input but what about 10 theough 30? I have a beam and rotatable dipole for those bands so how do i protect my receiver better on those bands? Our tx antennas are roughly 300 feet apart, he has a vertical right now and i have both a vertical and a beam to switch between. He plans on a beam this summer and it will be the same distance apart. Thoughts... 73, Jeff K8KZB Sent from Outlook Mobile ______________________________________________________________ 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] ______________________________________________________________ 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] |
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On Tue,1/19/2016 3:05 PM, Ian wrote:
> Consider one of these:http://www.dxengineering.com/parts/dxe-rg5000hd > The K3 is pretty well protected -- if, for example, you hit it with too much signal, the attenuator will kick in and the preamp will turn off. And if that doesn't reduce the signal enough, you'll get a HIGH SIGNAL warning on your display. In addition to that, there's a diode on the front end. I'd verify that an RX is getting overloaded before spending dollars on this product. With antennas 300 ft apart, it's unlikely that you're going blow anything up unless the other station is running an amp. 73, Jim K9YC ______________________________________________________________ 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] |
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In reply to this post by Jeff-2
He said that he has a protector on the Beverage. The RG5000HD is for
receive antennas only so it will not work when he listens using his TX antenna on 10m-30m. John KK9A Ian ik7565 at verizon.net Tue Jan 19 18:05:07 EST 2016 Consider one of these: http://www.dxengineering.com/parts/dxe-rg5000hd 73, Ian N8IK -----Original Message----- From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of k8kzb at charter.net Sent: Tuesday, January 19, 2016 08:17 To: 'Elecraft Reflector' <elecraft at mailman.qth.net> Subject: [Elecraft] Nearby Ham Interference My neighbor is a ham, right now I set up a webpage for us to coordinate what band we are on so that we are not on the same band at the same time. I originally set this up for field day but it also works good for us. We are both CW ops and have not ran into issues yet but, there is always a but, we both want to make sure we do our best to protect our equipment which we both have K3's. I have a beverage that i use for 40 through 160 and i have a front end protector on my rx input but what about 10 theough 30? I have a beam and rotatable dipole for those bands so how do i protect my receiver better on those bands? Our tx antennas are roughly 300 feet apart, he has a vertical right now and i have both a vertical and a beam to switch between. He plans on a beam this summer and it will be the same distance apart. Thoughts... 73, Jeff K8KZB ______________________________________________________________ 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] |
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In reply to this post by Jim Brown-10
Hello Brendan, I have two ten meter 5 el yagi antenna arrays that are just under 300 ft apart. One is on a 70 ft tower and consists of three yagis. The other is a single yagi at 30 ft. If the two yagis are boresighted on each other, I see only 17 dB of attenuation between them. I checked the isolation with a signal generator and a crystal detector with an HP 415E meter. This can blow out a front end even running 100 watts. Each yagi has almost 9 dBd gain in free space. I guess it depends on what ur antenna is, but yagis on the higher bands can cause problems when aimed at each other. I did fry one K3 using an amp with this setup. I took out a diode. Be careful, and make a few checks to avoid surprises. Dave K1WHS ----- Original Message ----- From: "Jim Brown" <[hidden email]> To: <[hidden email]> Sent: Wednesday, January 20, 2016 12:30 AM Subject: Re: [Elecraft] Nearby Ham Interference > On Tue,1/19/2016 3:05 PM, Ian wrote: >> Consider one of these:http://www.dxengineering.com/parts/dxe-rg5000hd > > The K3 is pretty well protected -- if, for example, you hit it with too > much signal, the attenuator will kick in and the preamp will turn off. And > if that doesn't reduce the signal enough, you'll get a HIGH SIGNAL warning > on your display. In addition to that, there's a diode on the front end. > > I'd verify that an RX is getting overloaded before spending dollars on > this product. With antennas 300 ft apart, it's unlikely that you're going > blow anything up unless the other station is running an amp. > > 73, Jim K9YC > ______________________________________________________________ > 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] ______________________________________________________________ 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] |
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In a multi-transmitter setup, use a simple throwaway RF detector to test
for potentially damaging levels of RF *before* connecting the second radio. The simplest RF indicator consists of a 50-ohm resistor, one diode, one capacitor and an LED, haywired together on the rear of an SO-239. Sensitivity depends on the type of detector diode and LED, but typically the LED will begin to glow at RF levels above a few tens of milliwatts into 50 ohms. So if the LED shows anything more than a very dim glow, it would be risky to connect a radio. And if the detector burns out, well, that was the whole point of using a "throwaway" device - to take the bullet instead of your K3! Replace the damaged parts and carry on testing. (Obviously there's much more to say about this, but the details are currently buried in unsearchable Yahoo archives.) 73 from Ian GM3SEK >-----Original Message----- >From: Elecraft [mailto:[hidden email]] On Behalf Of >Dave Olean >Sent: 20 January 2016 06:36 >To: [hidden email] >Subject: Re: [Elecraft] Nearby Ham Interference > > >Hello Brendan, >I have two ten meter 5 el yagi antenna arrays that are just under 300 >apart. One is on a 70 ft tower and consists of three yagis. The other is a >single yagi at 30 ft. If the two yagis are boresighted on each other, I see >only 17 dB of attenuation between them. I checked the isolation with a >signal generator and a crystal detector with an HP 415E meter. This can >blow >out a front end even running 100 watts. Each yagi has almost 9 dBd gain in >free space. I guess it depends on what ur antenna is, but yagis on the >higher bands can cause problems when aimed at each other. I did fry one K3 >using an amp with this setup. I took out a diode. >Be careful, and make a few checks to avoid surprises. >Dave K1WHS >----- Original Message ----- >From: "Jim Brown" <[hidden email]> >To: <[hidden email]> >Sent: Wednesday, January 20, 2016 12:30 AM >Subject: Re: [Elecraft] Nearby Ham Interference > > >> On Tue,1/19/2016 3:05 PM, Ian wrote: >>> Consider one of these:http://www.dxengineering.com/parts/dxe- >rg5000hd >> >> The K3 is pretty well protected -- if, for example, you hit it with >> much signal, the attenuator will kick in and the preamp will turn off. And >> if that doesn't reduce the signal enough, you'll get a HIGH SIGNAL warning >> on your display. In addition to that, there's a diode on the front end. >> >> I'd verify that an RX is getting overloaded before spending dollars on >> this product. With antennas 300 ft apart, it's unlikely that you're going >> blow anything up unless the other station is running an amp. >> >> 73, Jim K9YC >> ______________________________________________________________ >> 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] > >______________________________________________________________ >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] ______________________________________________________________ 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] |
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In reply to this post by john@kk9a.com
With this device across the K3's RX in/out ports and RX ANT selected you can
use it with a single TX/RX antenna. See p.41 of the K3S owner manual. Works fb, very minimal insertion loss. 73, Ian N8IK -----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of [hidden email] Sent: Tuesday, January 19, 2016 21:58 To: [hidden email] Subject: Re: [Elecraft] Nearby Ham Interference He said that he has a protector on the Beverage. The RG5000HD is for receive antennas only so it will not work when he listens using his TX antenna on 10m-30m. John KK9A Ian ik7565 at verizon.net Tue Jan 19 18:05:07 EST 2016 Consider one of these: http://www.dxengineering.com/parts/dxe-rg5000hd 73, Ian N8IK -----Original Message----- From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of k8kzb at charter.net Sent: Tuesday, January 19, 2016 08:17 To: 'Elecraft Reflector' <elecraft at mailman.qth.net> Subject: [Elecraft] Nearby Ham Interference My neighbor is a ham, right now I set up a webpage for us to coordinate what band we are on so that we are not on the same band at the same time. I originally set this up for field day but it also works good for us. We are both CW ops and have not ran into issues yet but, there is always a but, we both want to make sure we do our best to protect our equipment which we both have K3's. I have a beverage that i use for 40 through 160 and i have a front end protector on my rx input but what about 10 theough 30? I have a beam and rotatable dipole for those bands so how do i protect my receiver better on those bands? Our tx antennas are roughly 300 feet apart, he has a vertical right now and i have both a vertical and a beam to switch between. He plans on a beam this summer and it will be the same distance apart. Thoughts... 73, Jeff K8KZB ______________________________________________________________ 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] ______________________________________________________________ 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] |
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In reply to this post by gm3sek
I've used a similar (simpler) test fixture which
consisted of a small "grain-of-wheat" bulb, probably a 5V @ 30 mA, (??) wired directly across the non-active antenna feed. A rule-of-thumb is if you see a glow, you're asking for trouble. Watching the bulb connected to a 600' Beveridge, which is about 50 feet from both a 20-10M Log Periodic and a 40/60/80/160M dipole, the bulb would glow at varying intensities when transmitting up to 100 W on all bands that the antennas are designed for. Some bands would show hardly any glow at 100W but others would light the lamp to full brightness at < 50 W with no rhyme or reason to which bands. It was enough to convince me to either NOT to leave the Beveridge connected or make sure I had some sort of protection. I use a commercial Collins "Receiver Protector" in line with the wire which seems to be adequate even running an amp. 73, Charlie k3ICH -----Original Message---- From: Elecraft [mailto:[hidden email]] On Behalf Of Ian White Sent: Wednesday, January 20, 2016 3:10 AM To: [hidden email] Subject: Re: [Elecraft] Nearby Ham Interference In a multi-transmitter setup, use a simple throwaway RF detector to test for potentially damaging levels of RF *before* connecting the second radio. The simplest RF indicator consists of a 50-ohm resistor, one diode, one capacitor and an LED, haywired together on the rear of an SO-239. Sensitivity depends on the type of detector diode and LED, but typically the LED will begin to glow at RF levels above a few tens of milliwatts into 50 ohms. So if the LED shows anything more than a very dim glow, it would be risky to connect a radio. And if the detector burns out, well, that was the whole point of using a "throwaway" device - to take the bullet instead of your K3! Replace the damaged parts and carry on testing. (Obviously there's much more to say about this, but the details are currently buried in unsearchable Yahoo archives.) 73 from Ian GM3SEK ______________________________________________________________ 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] |
Re: Nearby Ham Interference
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I have one special low band receive antenna that I need to
protect. I use a grain of wheat bulb in series with the antenna with two back-to-back 1N5818 Schottky Diodes (low Vf) to ground on the receiver side. You can use a receiver protector on the main TX antenna of a transceiver, but the protector has to go in the RX ANT OUT / RX ANT IN loop, and then you have to select RX ANT for receiving. Dave Hachadorian, K6LL Yuma, AZ ______________________________________________________________ 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] |
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