Re: Topband: Receive ant question
for the years I used a TS-940S, which was prone to picking up RF on a Beverage plugged into the RX-only input, I used a simple $2.00 Radio Shack SPST reed relay to short out the coax at the back of the radio, through a 47-ohm resistor to ground. this solved the RF problems. the 940 was one of the first radios to produce a key-timed 12vdc output so this made it easy to power the relay. most newer radios have similar 12v keyed outputs (and many have improved RF protection). 73/Jon AA1K ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receive ant question
You can't beat Barry's 'front end saver' at http://n1eu.com for a combination of simplicity and effectiveness. Two back-to-back diode strings (four 1N914 diodes per string) and a series 22 ohm resistor. If the diodes should go into conduction due to excessive RF on the RX antenna, the resistor limits the current through them as well as the voltage across the RX input. I use something similar here, but with a small incandescent lamp (as a fuse) in place of the resistor, and just two 1N914/1N4148 diodes per string. 73, Mike http://www.w0btu.com/Beverage_antennas.html ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receive ant question
On 10/26/2011 09:27 AM, Mark Beckwith wrote: I think a front end protector is some good amount of insurance. I listen on other receivers while transmitting. I have cooked an IC746PRO doing this and it was quite annoying. It tricked me into thinking everything was fine because it worked okay for a good long while, but ultimately I cooked it and felt like an idiot. With the RX antenna a reasonable distance (100ft) away from the TX antenna, would an RF limiter (like the one ICE makes) be an acceptable substitute for a front end protector with relays? I am running 100W only here, no amp. -- All rights reversed. ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receive ant question
On Oct 26, 2011, at 2:32 PM, Rik van Riel wrote: With the RX antenna a reasonable distance (100ft) away from the TX antenna, would an RF limiter (like the one ICE makes) be an acceptable substitute for a front end protector with relays? I am running 100W only here, no amp. I run 1+ KW on 160/80 to a shunt fed tower that is 10 to 15 ft from an RX loop at its closest rotation. With an ICE 196 ahead of a preamp for the loop, I have had no problems over many years, first with an FT1000D (which I do not think grounded the RX only input during TX) and more recently a K3 which does have RF protection for the RX front end. YMWV but you're likely very safe. Note that the ICE 196 is no longer available from the new company http://www.morganmfg.us/radio-products/ Array solutions is planning a replacement but I have yet to see it on their website. 73 - Steve WB6RSE ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receive ant question
I think a front end protector is some good amount of insurance. I listen on other receivers while transmitting. I have cooked an IC746PRO doing this and it was quite annoying. It tricked me into thinking everything was fine because it worked okay for a good long while, but ultimately I cooked it and felt like an idiot. 73 - Mark, N5OT - Original Message - From: Its from Onion aredandg...@msn.com To: topband@contesting.com Sent: Tuesday, October 25, 2011 12:40 AM Subject: Topband: Receive ant question I'm looking to build and install my first beverage receive antenna. I use a 756 Pro and wondering a couple questions from folks who have been there. 1. Do I need a pre-amp and if yes your suggestion. 2. Do I need a front end saver and your thoughts again. Thank you and 73, Lee KE4VYN ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receive ant question
If the receive antenna is close to your transmit antenna then you will want to think about front end protection in a radio that has two receivers. Most single receiver radios should be shorting the receive line to ground during transmit or taking out out of line. I don't know with the Icom. You may or may not need a preamp. That is something you can add later. Mike W0MU J6/W0MU November 21 - December 1 2011 CQ WW DX CW W0MU-1 CC Cluster w0mu.net On 10/24/2011 11:40 PM, Its from Onion wrote: I'm looking to build and install my first beverage receive antenna. I use a 756 Pro and wondering a couple questions from folks who have been there. 1. Do I need a pre-amp and if yes your suggestion. 2. Do I need a front end saver and your thoughts again. Thank you and 73, Lee KE4VYN ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
