RE: [dstar_digital] Noise/Desense and Loss Measurements - RP4000V Cables
Could somebody make similar measurements on a RP2000V? I don't have one... I made similar measurements on two RP4000V's here, and both had anywhere from .6 to 1dB of desense depending on how close the two cables were. Swapped inner cables with some made from RG142 and a pair of Delta Male/Female connectors and the units have zero desense now in the chassis. My testing was done with a General Dynamics service monitor and a Anritsu analyzer. Bottom line - 60% shielding on a cable (specs from the model # of cable in both of these RP4000's) when attached to a hi-q load is something you'd never find in higher quality gear. This is far from being a purist as someone else identified, this is simply good engineering practices. Regards, Dave KG4YZY -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.
[dstar_digital] Dongle
Thanks all, the Dongle has been sold. 73, Jeff KE9V
Re: RE: [dstar_digital] Noise/Desense and Loss Measurements - RP4000V Cables
Dave, One posting stated the rigs in the repeater were modified ID-1 and ID800s. Does this appear to be what is being used??? These rigs spec lower than typical good quality repeater rigs in spurious emmissions which can produce wide band noise affecting the performance using a duplexer. What duplexer did you use and was other filtering needed??? Most repeaters I've worked with (analog) usually require only a 4 cavity duplexer even when using a low noise pre-amp. Of course I am not running 100-250 watts, usually less than 40. 73, ron, n9ee/r From: Dave Anderson KG4YZY [EMAIL PROTECTED] Date: 2008/06/29 Sun AM 03:47:00 EDT To: dstar_digital@yahoogroups.com Subject: RE: [dstar_digital] Noise/Desense and Loss Measurements - RP4000V Cables
Re: Re: [dstar_digital] repeater mods
Most often a double shielded cable will have more loss than a single shielded. This can be seen with RG8 vs RG214 or the like. I am not saying use RG8, but loss is most often not the issue in this case. It is the radiation or leakage which even in RG8 with 60% shield the radiation loss at less than 1 GHz will be down 50 or more db or 10 micro W (.01 W) below 1 watt. This 50 db down of course is very noticable working with 0.3 uV receivers in the same box or room, but not to a watt meter or user. 73, ron, n9ee/r From: Nate Duehr [EMAIL PROTECTED] Date: 2008/06/29 Sun AM 04:07:20 EDT To: dstar_digital@yahoogroups.com Subject: Re: [dstar_digital] repeater mods
Re: Re: [dstar_digital] Noise/Desense and Loss Measurements - RP4000V Cables
Bob, Good repeater builders and engineers are often Purists. Some get real burned by not being one. I guess it is ok for some to just duck tape it and be done with it. I have been told so many times I know it don't meet spec, but it works. 6 months later they are reworking it to make it work. If one finds a manufacture supplied a defective, but to spec in their eyes cable or component it needs to be replaced. It is obvious the cables in the ICOM repeaters are defective from the factory. 73, ron, n9ee/r From: Bob Brown [EMAIL PROTECTED] Date: 2008/06/28 Sat PM 11:49:27 EDT To: dstar_digital@yahoogroups.com Subject: Re: [dstar_digital] Noise/Desense and Loss Measurements - RP4000V Cables
RE: [dstar_digital] Dongle
Jeff if i may ask did you get a web site wwhere you could buy one ? what i am finding are kit web site thanks gervais ve2ckn [ED - The DV Dongle can be purchased at HRO http://hamradio.com and AES http://aesham.com]
Re: [dstar_digital] Noise/Desense and Loss Measurements - RP4000V Cables
I wonder what the effect would be of having grommeted incoming coax into the repeater module and terminating; soldered direct to the chassis pcb(socket removed), such that all typical connector losses are eliminated in this relatively permanent installation, after initial metered tests are done? vk4tux [Non-text portions of this message have been removed]
Re: Re: [dstar_digital] Noise/Desense and Loss Measurements - RP4000V Cables
Adrian, Would reduce the losses some, but for maintance issues do like some connectors. Also getting inside some of these rigs is a chore, hi. I think repackaging the ICOM repeater would be good idea. That big box with the small rigs is such a waste. It does allow for a mobile duplexer which would make nice package with one RF connector on the rear. But if you gonna spend all that money with ICOM why not go for a large base type duplexer. It will make up for some of the ICOM DC to light front end and help keep some of the other UHF stuff out of your tx PA. 73, ron, n9ee/r Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
Re: Re: Re: [dstar_digital] Noise/Desense and Loss Measurements - RP4000V Cables
Adrian, From the front panel of the repeaters does not seem to be much there, power sw and cat5 conn. One could take the repeater and repackage doing as you said by mounting rigs as they are now close to front with connector and box short enought to have N conn coming out the back. Could make a nice package. Maintence would be an issue; being able to remove a rig for repair, etc. If mounted so connector would slide down into a U shaped hole instead of a round hole then could lift rig out. I really don't think anyone is going to this trouble, but would be improvement over what is there now. We are talking about a minor issue. However, the issue is really not loss. We are talking about very little loss with the cables now. The issue is desense and cable radiation. Replacing the cables with say RG142 would be one thing one could do. Might improve loss somewhat, but main issue is cable radiation. 73, ron, n9ee/r Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
Re: [dstar_digital] Noise/Desense and Loss Measurements - RP4000V Cables
Greg, One issue brought up by others is in your test you used a 50 Ohm dummy load which is good for testing in some environments. We all use good dummy loads for testing as we should. In real test one would like to test with actual loads. As in RF feedline 101 (that is Ohms Law 5000) a coaxial cable can radiate if terminated in a load with some LC and R something other than 50 such as with a duplexer and antenna connected. Since you got the good equipment might consider trying the test with these as the loads with rx and tx connected. I think all want to get info on how to put together the best system one can and for the high cost of $6k one really wants to know if performing the best one can get. 73, ron, n9ee/r Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
[dstar_digital] G2 alternative?
Hello all as we just sit and wait for our G2 to arrive and the only thing we can do is to ping D-Star controller over the Ubiquity PS5 Microwave link, I wonder if there is any alternative to the G2 soft or anything else we can try in the meantime. I am not a Linux gury but I have some experience over the last 10 years and I can follow installations either poor or well explained. So if someone has some ideas I would like to hear'm, By the way the system here is the UHF and SHF repeater. It is installed at a mountain overlooking Athens, at a hight of 1100m. The uhf antenna is on top of a 25m tower and the shf and 5 GHz antennas are on the same tower 15m high. When we proceed with the G2 we will bring up the SHF data system as well and although we have the 2m repeater too, I doubt if we can find a clear channel for 2m. Radio Amateur Assn of Greece will install another 7 or 8 systems in the next 4 years all over Greece. 73 Manos SV1IW RAAG President
[dstar_digital] Re: DPRS
http://www.aprs-is.net/DPRS.aspx Be sure you have the correct sentence in TX MSG C1...Steve --- In dstar_digital@yahoogroups.com, Gus [EMAIL PROTECTED] wrote: Hello all. I am having an interesting problem that I have not been able to figure out and would like to see if someone could point me in the direction for troubleshooting.
RE: [dstar_digital] Re: DPRS
Yes, I have this in the C1: LK *5A. Cut and past from dprs calc into the 800 program software. _ From: dstar_digital@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Steve Bosshard Sent: Sunday, June 29, 2008 10:13 PM To: dstar_digital@yahoogroups.com Subject: [dstar_digital] Re: DPRS http://www.aprs- http://www.aprs-is.net/DPRS.aspx is.net/DPRS.aspx Be sure you have the correct sentence in TX MSG C1...Steve --- In dstar_digital@ mailto:dstar_digital%40yahoogroups.com yahoogroups.com, Gus [EMAIL PROTECTED] wrote: Hello all. I am having an interesting problem that I have not been able to figure out and would like to see if someone could point me in the direction for troubleshooting. [Non-text portions of this message have been removed]
Re: {Disarmed} Re: RE: Re: [dstar_digital] Re: D-STAR Field Day Update
On Jun 28, 2008, at 2:38 PM, KE5KAF wrote: We have been listening and it sounds like the Dstar Field Day is dead.. No activity... Where is everyone hanging out on Dstar?? Our stack's (W0CDS) power supply was acting flakey and kicked its own breaker off (still investigating, but suspected to be a low-voltage dropout crowbar circuit) for most of this Field Day weekend. The power supply was replaced mid-day today (Sunday June 29th). Things should be stable now, but we did miss out on most opportunities to show a lot of people D-STAR during Field Day events all over the Front Range area. A bummer, but stuff happens. (The original supply was chosen because it had plenty of amps to spare, and was a nice rack-mount (Lambda), but it had three strikes against it in the last couple of weeks as the thunderstorms started rolling through in the afternoon, and it seemed to be misbehaving. The owner may or my not have time to debug, but a replacement with another known-good supply was in order. Sorry if we missed FD fun on D-STAR from Colorado... -- Nate Duehr, WY0X [EMAIL PROTECTED]
