Re: Topband: Relay switching at the base on antenna
I use the "Key Out" line of my K3S to drive the base of a homebrew transistor switch that, in turn, drives a relay coil at the base of my antenna. There is an isolation diode between the K3S keying line and the switching transistor because I also use the same keying line to switch my AL-1200 QSK amp. I run full QSK with a Gigavac GH-1 vacuum relay as the switching relay at the antenna. I set the QSK delay in the K3S to 10 ms and the GH-1 has a closure time of 6 ms. It works fine. I've never had an issue with hot switching in full QSK. 73, John W1FV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of James Wolf Sent: Saturday, September 23, 2017 8:08 PM To: 'Richard (Rick) Karlquist'; 'MR TREVOR DUNNE'; topband@contesting.com Subject: Re: Topband: Relay switching at the base on antenna Trevor, I suspect you may be trying to detune the tower during receive, which I plan on doing here as well. Check your transceiver Amplifier Key Output line. That line should close about 10ms before any RF output from the radio occurs, for the very reason Rick mentions below. Any suggestions for the group on which relay to use for this? I don't want to give up my QSK. Jim - KR9U --- >There is nothing simple about this, because you need to avoid hot switching. This means that you need to start with the rig signal that is intended for use with QSK linears. This signal will change to the transmit state 10 ms before the transmitter actually starts putting out RF. The name of this signal will vary depending on the rig, and the "PTT" signal may or may not be the correct one. Additionally, in some rigs you may need to put a switch in the QSK position (such as the FT1000). >Once you have a 10 ms head start, you need a relay that will close in >less than 10 ms. If necessary, you can use speed up circuits that put a temporary overvoltage on the coil of the relay. This requires that the relay is energized on TX and non-energized on RX, rather than vice versa. >In keeping with the word "simple": a piece of hook up wire running to >the base of the antenna is much simpler than trying to send DC on the coax, depending on how hard it would be to install this wire. You can still use the shield of the coax as the return connection. >Rick N6RK On 9/23/2017 5:39 AM, MR TREVOR DUNNE wrote: >> Hi All > > >Can Anyone tell me a simple way to switch a 12v relay at the base of > >an antenna using the rigs ptt as the trigger?? _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Relay switching at the base on antenna
Trevor, I suspect you may be trying to detune the tower during receive, which I plan on doing here as well. Check your transceiver Amplifier Key Output line. That line should close about 10ms before any RF output from the radio occurs, for the very reason Rick mentions below. Any suggestions for the group on which relay to use for this? I don't want to give up my QSK. Jim - KR9U --- >There is nothing simple about this, because you need to avoid hot switching. This means that you need to start with the rig signal that is intended for use with QSK linears. This signal will change to the transmit state 10 ms before the transmitter actually starts putting out RF. The name of this signal will vary depending on the rig, and the "PTT" signal may or may not be the correct one. Additionally, in some rigs you may need to put a switch in the QSK position (such as the FT1000). >Once you have a 10 ms head start, you need a relay that will close in less than 10 ms. If necessary, you can use speed up circuits that put a temporary overvoltage on the coil of the relay. This requires that the relay is energized on TX and non-energized on RX, rather than vice versa. >In keeping with the word "simple": a piece of hook up wire running to the base of the antenna is much simpler than trying to send DC on the coax, depending on how hard it would be to install this wire. You can still use the shield of the coax as the return connection. >Rick N6RK On 9/23/2017 5:39 AM, MR TREVOR DUNNE wrote: >> Hi All > > >Can Anyone tell me a simple way to switch a 12v relay at the base of an antenna using the rigs ptt as the trigger?? _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Relay switching at the base on antenna
-Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Richard (Rick) Karlquist Sent: Saturday, September 23, 2017 5:42 PM To: MR TREVOR DUNNE ; topband@contesting.com Subject: Re: Topband: Relay switching at the base on antenna In keeping with the word "simple": a piece of hook up wire running to the base of the antenna is much simpler than trying to send DC on the coax, depending on how hard it would be to install this wire. You can still use the shield of the coax as the return connection. Rick N6RK That technique for me when I had a UHF pre-amp up at the antenna for ATV work. I used the coax shield as the DC return. 73 de Gene Smar AD3F _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Relay switching at the base on antenna
If you have a modern radio, there are connections on the back of radio that either go to ground when in TX mode or go high (+12Vdc) when in TX mode. Time to read up on all those connections. Kriss KA1GJU Sent from my iPad _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Relay switching at the base on antenna
There is nothing simple about this, because you need to avoid hot switching. This means that you need to start with the rig signal that is intended for use with QSK linears. This signal will change to the transmit state 10 ms before the transmitter actually starts putting out RF. The name of this signal will vary depending on the rig, and the "PTT" signal may or may not be the correct one. Additionally, in some rigs you may need to put a switch in the QSK position (such as the FT1000). Once you have a 10 ms head start, you need a relay that will close in less than 10 ms. If necessary, you can use speed up circuits that put a temporary overvoltage on the coil of the relay. This requires that the relay is energized on TX and non-energized on RX, rather than vice versa. In keeping with the word "simple": a piece of hook up wire running to the base of the antenna is much simpler than trying to send DC on the coax, depending on how hard it would be to install this wire. You can still use the shield of the coax as the return connection. Rick N6RK On 9/23/2017 5:39 AM, MR TREVOR DUNNE wrote: Hi All Can Anyone tell me a simple way to switch a 12v relay at the base of an antenna using the rigs ptt as the trigger?? Thanks Trevor EI2GLB _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Relay switching at the base on antenna
Thanks for all the info Guys, I have some multicore cable out to the base of the antenna, I will try using a relay keyed from the key out on my rig, and see how that works, I want to switch in and out my tx 160 and 80m tx antennas when I rx/tx depending on what band I'm on, Thanks Trevor EI2GLB - Original Message - From: Roger D Johnson To: MR TREVOR DUNNE Sent: Sat, 23 Sep 2017 21:15:09 +0100 (IST) Subject: Re: Topband: Relay switching at the base on antenna Just Google bias tee...there are many examples. The RF choke is easy. 100 uH and it doesn't have to handle much current. The cap is more of a problem. It needs to be about 0.1 uFd and it must handle the RF current which depends on how much power you're running. I think most peple just parallel a bunch of smaller caps. If there is no DC ground at the antenna. you will only need one tee. 73, Roger On 9/23/2017 1:32 PM, MR TREVOR DUNNE wrote: > Could you point me in the direction of a circuit for this I'm struggling to > visualise it, > > Thanks > Trevor > EI2GLB > - Original Message - > From: Roger D Johnson > To: MR TREVOR DUNNE > Sent: Sat, 23 Sep 2017 14:00:39 +0100 (IST) > Subject: Re: Topband: Relay switching at the base on antenna > > Sure! I'm doing it with a 24 volt vacuum relay at my antenna. Run 12 volts to > the antenna and through a series diode (for isolation) in the return line to > the > transceiver PTT. I have another diode in series with the amp keying circuit to > keep it from affecting the relay at the antenna and vice versa. > > > On 9/23/2017 8:39 AM, MR TREVOR DUNNE wrote: >> Hi All >> >> Can Anyone tell me a simple way to switch a 12v relay at the base of an >> antenna using the rigs ptt as the trigger?? >> >> Thanks >> Trevor >> EI2GLB >> _ >> Topband Reflector Archives - http://www.contesting.com/_topband >> > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Relay switching at the base on antenna
On 9/23/2017 6:39 AM, MR TREVOR DUNNE wrote: Can Anyone tell me a simple way to switch a 12v relay at the base of an antenna using the rigs ptt as the trigger?? If you're using a coaxial feed line, you could use a pair of "bias tee" devices, one on each end of the coax, to put 12 VDC on the line during transmit and 0 VDC during receive. Here is some info on bias tees. They are available commercially and can be home-brewed using readily available components. https://www.everythingrf.com/community/what-is-a-bias-tee If your rig has a key out connector it is likely providing a contact closure to ground during TX and open circuit during RX. Use that to switch 12 volts from the rig or a separate supply on during TX using an auxiliary relay or solid state switch, and feed that to the bias tee. Pick off that DC control voltage to activate the relay at the antenna end. NOTES: 1) The series capacitors go toward the transceiver and antenna respectively to pass RF while blocking the DC. The RFCs block RF but pass the DC control signal. 2) If you are going to use both positive and negative voltages as control signals for more complex switching over the coax be sure to use an isolated, separate power supply. Gus Hansen KB0YH _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Relay switching at the base on antenna
Could you point me in the direction of a circuit for this I'm struggling to visualise it, Thanks Trevor EI2GLB - Original Message - From: Roger D Johnson To: MR TREVOR DUNNE Sent: Sat, 23 Sep 2017 14:00:39 +0100 (IST) Subject: Re: Topband: Relay switching at the base on antenna Sure! I'm doing it with a 24 volt vacuum relay at my antenna. Run 12 volts to the antenna and through a series diode (for isolation) in the return line to the transceiver PTT. I have another diode in series with the amp keying circuit to keep it from affecting the relay at the antenna and vice versa. On 9/23/2017 8:39 AM, MR TREVOR DUNNE wrote: > Hi All > > Can Anyone tell me a simple way to switch a 12v relay at the base of an > antenna using the rigs ptt as the trigger?? > > Thanks > Trevor > EI2GLB > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Relay switching at the base on antenna
Hi All Can Anyone tell me a simple way to switch a 12v relay at the base of an antenna using the rigs ptt as the trigger?? Thanks Trevor EI2GLB _ Topband Reflector Archives - http://www.contesting.com/_topband
