A little follow-up on the "relay bounce". It's certainly possible that I have mischaracterized the problem.
I have a newer version of the RCS-4. It has sealed, enclosed relays (P&B RTE24012F). There are no back-EMF diodes or capacitors across the relay coil. Unfortunately, the SO239's are riveted (not screwed) to the plate and they used a large blob of solder to connect each one to the board. Adding diodes/capacitors is not trivial. As an experiment, I bypassed the bias-T configuration and ran the control voltage on a separate wire. Alas, that reduced the switching spike by 90%. I think that does point to the relay coil back-EMF getting into the RF line.I will note that there is a 220 uF electrolytic across each relay coil. Thanks for all the suggestions. 73, Steve, N2IC On Wed, Feb 23, 2022 at 4:13 AM <ok...@post.cz> wrote: > Hello, > > > > I have been using FTR-K1 Series power relay for a years...see attached > document. > > > > > 73 from Vit, OK5MM > > > > > > ---------- Původní e-mail ---------- > Od: Allan Zadiraka <ajzadir...@gmail.com> > Komu: Grant Saviers <gran...@pacbell.net> > Datum: 23. 2. 2022 4:55:33 > Předmět: Re: Topband: Relay bounce > "While I totally agree with the comments on the poor performance and life > of > > the contacts on open frame relays, my experience with noise from relay > switching has been that it is usually a failed snubber capacitor or diode > across the relay coil. Occasionally, especially with rotary switches, the > cause has been arching on the switch contacts. > > > zeke ab8ou > > > On Tue, Feb 22, 2022 at 5:07 PM Grant Saviers <gran...@pacbell.net> > wrote: > > > Small signal, dry contact relays are made from different contact > > materials than power relays made for higher voltages and currents. Any > > fix that cleans them or removes the surface oxide that inhibits low > > voltage signal transmission will likely be temporary. Plus the high > > power relays are prone to generating noise and have a large bounce. > > Except for mercury wetted ones, bounce is common on all relays. > > > > Grant KZ1W > > > > On 2/22/2022 13:41, Michael Tope wrote: > > > Steve, > > > > > > Does the switch produce an S9 spike on any transition of the switch > > > (i.e. from position N to position N+/-1) or only on a certain subset > of > > > switch transitions? That might provide a clue as to whether there is a > > > problem with one of the relays or the power supply that energizes > them. > > > I am wondering if it could be a bad filter capacitor in the relay > > > control circuits or a bad DC blocking cap over on the switch end. > > > > > > I am not convinced that dirty relay contacts could cause the noise > > > spike, but it is probably agree to clean the relay contacts anyway > just > > > in case. W8JI recommended soaking a piece a paper in a liquid > > > hydrocarbon (I think he used Xylene) and then passing that paper > between > > > > the contacts of the relays in order to transfer any foreign material > to > > > the paper without causing undue abrasion to the relay contacts. I've > > > done this and it has fixed the problem of an RCS-4 going deaf on > receive > > > > despite still working for transmit. For receive only applications you > > > might have to do it more often. > > > > > > 73, Mike W4EF........... > > > > > > On 2/22/2022 10:04 AM, Steve London wrote: > > >> I am using an Ameritron RCS-4 antenna switch to select between > beverage > > > >> antennas. Recently, it has developed a bad case of relay bounce > > >> causing an > > >> S9 spike every time I switch between antennas. Any suggestions on how > to > > >> improve this ? Since it's only used for RX antenna selection, I'm > > >> amenable > > >> to replacing the relays with something else, although I have had > issues > > > >> before with other relays due to no current going through the > contacts. > > >> > > >> Thanks and 73, > > >> Steve, N2IC > > >> _____________ > > > > > > _________________ > > > Searchable Archives: http://www.contesting.com/_topband - Topband > > Reflector > > _________________ > > Searchable Archives: http://www.contesting.com/_topband - Topband > > Reflector > > > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector. > " > > > > > " > " > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector