[Repeater-Builder] Re: Repeaters and Water Towers
They paid for your losses and you (your club) accepted it??? I bet that gave them a warm and fuzzy feeling toward hams! Good advice about keeping up with what's happening, though. --- In Repeater-Builder@yahoogroups.com, Jim Brown w5...@... wrote: We put a repeater in the equipment room right under the water tank about 150 ft above the ground back in the 70's. It is a great environment since the water in the tank is a great heat sink. It assumes the average temp of the outside air (integrates the temp over months at a time) and keeps the air temp in the equipment room very cool in the summer and warm in the winter. The repeater is still operating on this tank. The only problem we had was when the city decided to sand blast the tank and did not let us know. The dust was over an inch thick on every horizontal part of the repeater, and was inside our shield boxes (tiny holes, but the crap sifted through). They bought us some new circuit board assemblies for the transmitter and receiver and we installed them in the old shielded boxes. We did manage to clean up the duplexer without having to tune it again. Be sure to keep up with any maintenance on the tank to make sure this does not happen to you - 73 - Jim W5ZIT --- On Thu, 8/20/09, kc8fwd kc8...@... wrote: From: kc8fwd kc8...@... Subject: [Repeater-Builder] Repeaters and Water Towers To: Repeater-Builder@yahoogroups.com Date: Thursday, August 20, 2009, 4:03 PM Hello, Has anyone had experience with repeaters at water tower sites now that homeland security is involved? I would like to hear your experience. Thanks Mike KC8FWD
Re: [Repeater-Builder] Talking about pdf and scanners what about microfiche??
try this http://www.princetonimaging.com/scanning/pdfservice.html -- From: mmoss111 mm...@mindspring.com Sent: Friday, August 21, 2009 6:46 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Talking about pdf and scanners what about microfiche?? I have some microfiche that I want to convert either to pdf or a 8 1/2 x 11 format but my scanner will not work on the tiny panels. I have a microfiche reader but the only thing I can think of is to take a digital picture of the screen. Getting the proper exposure might be tough though. Has anyone converted microfiche to usable pages that you can read? Any ideas? Thanks, Marvin Yahoo! Groups Links
[Repeater-Builder] Re: Sinclair UHF Receive Antenna Multicoupler Question
Thanks Eric and Walter. I just wanted to see what to expect when I hooked this up, and so far it does only show about 3db gain, which makes sense to overcome the splitter. I was able to adjust it using the couple of tuning screws to center on the 450 band. Has a very sharp tuning slope though since as a test I tried pushing a 460 and 440 signal through it at much reduced levels. Tony --- In Repeater-Builder@yahoogroups.com, kt...@... kt...@... wrote: Good Day everyone, Does anyone have experience or tuning info for a Sinclair UHF Antenna Multicoupler? The model on the rack panel is CR4-302CF and contains a power supply, pre-amp (or preselector) and BNC distribution box (1 to 12 outputs). Looks like 450-470 range. I haven't hooked this up yet, but wanted to see what to expect from it. Can such a device be used directly to receivers, or do you still need to add band-pass cavities between it and the receiver? Thanks for any information! Tony
RE: [Repeater-Builder] Talking about pdf and scanners what about microfiche??
There s an outfit on ebay that uses one of these http://www.nextscan.com/products/flexscan.html to scan microfiche to pdf for $33.00 a page... (ouch!) At 16:02 8/21/2009 -0700, you wrote: Marvin, I feel your pain. I have many GE manuals on microfiche, and I have been trying to find a way to convert them into PDF files. I, too, have a microfiche reader that I bought for reading census films (for genealogy), but the only way to get there from here is to use the microfiche reader-printer at the local Family History Center to get hard copy, and then scan it into PDF. Very time-consuming and inconvenient. I tried taking a digital picture of the reader's screen, but the results were unsatisfactory. The human eye ignores the bloom in the center of the screen image, but the camera doesn't. Since many building codes and manuals are on microfiche, you might try a commercial graphics shop that specializes in document and blueprint reproduction. The quality of microfiche images is already poor, and it is important to retain as much of the original detail as possible. That's why a one-step conversion (microfiche-to-PDF) is the ideal solution. I'm still looking for the best solution. 73, Eric Lemmon WB6FLY -Original Message- From: mailto:Repeater-Builder%40yahoogroups.comRepeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of mmoss111 Sent: Friday, August 21, 2009 3:47 PM To: mailto:Repeater-Builder%40yahoogroups.comRepeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Talking about pdf and scanners what about microfiche?? I have some microfiche that I want to convert either to pdf or a 8 1/2 x 11 format but my scanner will not work on the tiny panels. I have a microfiche reader but the only thing I can think of is to take a digital picture of the screen. Getting the proper exposure might be tough though. Has anyone converted microfiche to usable pages that you can read? Any ideas? Thanks, Marvin
[Repeater-Builder] isolation
Hope someone may have a program,commshop? What I need to know is what amount of isolation with duplexers that is required for a GE m2 reciever with .1...@12db and a m2 pll exciter,100 watt PA on vhf,600kc split?1/2in helix,with 4pole db224 antenna at 70 ft. thanks kj4si
Re: [Repeater-Builder] isolation
Hi You didn, say Freq. I picked 146.94-146.34 punched in your figures and Got 94.4 Wesley AB8KD - Original Message - From: kj4si To: Repeater-Builder@yahoogroups.com Sent: Saturday, August 22, 2009 9:54 AM Subject: [Repeater-Builder] isolation Hope someone may have a program,commshop? What I need to know is what amount of isolation with duplexers that is required for a GE m2 reciever with .1...@12db and a m2 pll exciter,100 watt PA on vhf,600kc split?1/2in helix,with 4pole db224 antenna at 70 ft. thanks kj4si
Fw: Re: [Repeater-Builder] Re: Squelch action on 10 m FM
Paul, 1) Yes, DSP-driven, adaptable squelch would be so excellent! Alas, I don't the the skills to program such a thing. I would probably be able to define the desired parameters operating modes and be glad to work with someone on that. What I need to do is hang an audio spectrum analyzer on my different FM radios' squelch amps to see what that spectrum looks like. I think there are vendor(s) still offering custom squelch boards using the Micor squelch chip. So who knows in what vault those chips now reside! 2) To address another message, on CTCSS falsing...that won't happen unless there's something not quite right about the decoder. PL was designed to NOT false, that's the whole point. If the PL decoder's bandpass is the wrong shape, e.g. too peaky, then yes, you could have falsing on random noise. It's Q is then too high it becomes prone to ringing on transients just like a vy narrow CW filter. Long live analog FM! Some of our ham radio club guys are all gung-ho on D-Star. I keep pointing out that its system developers are vy clear that it works properly when A) there's enuf SNR and B) there's no multipath! --John --- On Fri, 8/21/09, Paul Plack pl...@xmission.com wrote: From: Paul Plack pl...@xmission.com Subject: Re: [Repeater-Builder] Re: Squelch action on 10 m FM To: Repeater-Builder@yahoogroups.com Date: Friday, August 21, 2009, 5:27 PM Perhaps one the remaining contributions we could make as amateurs would be working with DSP to combine all these attributes in a standalone uP module. It would be great to have an adaptive squelch board for retrofit into repeaters which could account for multipath, propagation conditions, noise levels, and user priorities. It will probably fall to us to do it, because we'll no doubt be the last users of analog NBFM. Besides...those Micor squelch chips won't last forever! 73, Paul, AE4KR - Original Message - From: ka1jfy To: Repeater-Builder@ yahoogroups. com Sent: Friday, August 21, 2009 5:16 PM Subject: [Repeater-Builder] Re: Squelch action on 10 m FM Because CTCSS falses on the random noise. Been there, done that, gave away the t-shirt. WalterH --- In Repeater-Builder@ yahoogroups. com, n...@... wrote: At 8/20/2009 23:17, you wrote: John, how's this for an experiment.. . Configure a repeater with two receivers, one built for +/- 5 kHz deviation, the other for +/- 15, feed them from a splitter, use audio from the narrow one, but allow a DTMF command to select the wider receiver's COS when conditions warrant. (Obviously, those conditions would have to include no adjacent channel signal...) If noise squelch is so problematic in severe multipath conditions, why not do away with it entirely use straight CTCSS squelch? The GE decoders that use Versatone chips are fast enough that you can still almost eliminate the squelch tail with an ADM. Bob NO6B
Fw: [Repeater-Builder] Re: Sinclair UHF Receive Antenna Multicoupler Question
Let's never forget that ANY loss between the antenna and the receiver will degrade the rx's noise figure. That means feedline, duplexer, cavities, connectors, Polyphasers, etc. Noise figure degradation means less sensitivity, period. There's no way to make up for that EXCEPT with a preamp at the antenna. If that preamp's gain just equals the losses downstream from it, you've got a wash. However, you will lose on strong signal performance, IM, 3rd order intercept, etc., i.e. the preamp may be prone to overload by strong sigs. depending on its design. --John --- On Fri, 8/21/09, ka1jfy walter.howard...@gmail.com wrote: From: ka1jfy walter.howard...@gmail.com Subject: [Repeater-Builder] Re: Sinclair UHF Receive Antenna Multicoupler Question To: Repeater-Builder@yahoogroups.com Date: Friday, August 21, 2009, 5:31 PM Not quite the whole story Eric. If the original poster is trying to use this in the ham 440 band, then the preselector will most definitely need tuning before use. Sinclair says their standard preselector is +/- 5 MHz. And it should be mentioned that the gain of the amp is set to make up for the losses in the resistive dividers and nothing more. To get 'gain', you'll have to bypass one or more stages of the divider network. 2x divider gives you 3dB loss, and a 4x gives you 6dB. Remove one of those for corresponding 'gain'. Lastly, all unused outputs should have 50 ohm terminations. WalterH --- In Repeater-Builder@ yahoogroups. com, Eric Lemmon wb6...@... wrote: Tony, Those Sinclair multicouplers are intended to serve as many as 12 separate receivers from one antenna. Ideally, all receivers should be for frequencies that are clustered within a few MHz of each other, and the preselector will be tuned to pass a band that is perhaps 2-4 MHz wide. The splitter that follows the amplifier will provide sufficient isolation between receivers. No additional cavities are needed. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@ yahoogroups. com [mailto:Repeater-Builder@ yahoogroups. com] On Behalf Of kt...@... Sent: Friday, August 21, 2009 7:27 AM To: Repeater-Builder@ yahoogroups. com Subject: [Repeater-Builder] Sinclair UHF Receive Antenna Multicoupler Question Good Day everyone, Does anyone have experience or tuning info for a Sinclair UHF Antenna Multicoupler? The model on the rack panel is CR4-302CF and contains a power supply, pre-amp (or preselector) and BNC distribution box (1 to 12 outputs). Looks like 450-470 range. I haven't hooked this up yet, but wanted to see what to expect from it.. Can such a device be used directly to receivers, or do you still need to add band-pass cavities between it and the receiver? Thanks for any information! Tony
Re: [Repeater-Builder] PDF Page Scanner Choices?
At 8/21/2009 09:47, you wrote: Hi Skipp, For our Christmas present to us (my wife and myself), we purchased a Cannon CanoScan 8800F flatbed scanner. Works really well, and has a USB interface to our computer. There are buttons on the scanner that allows you to scan documents and convert to either color or black white pdf's. It also comes with ArcSoft photo Studio 5 software which allows one to copy 35 mm slides and import them to jpeg's. With a 35 mm library of well over 1,000 slides, I'm converting them to files to save for future viewing. A bit off topic, but as someone who's just wrapping up a 1000+ slide scanning project, I'd recommend a scanner with good dust removal. I use the Epson 4870 which has ICE. I forget what ICE stands for, but it's a hardware-based dust removal system that scans the slides with an infrared lamp. The idea is that infrared light will pass through the emulsion fairly evenly regardless of the image on the negative/slide, so that all that shows up is the dirt dust. The software then uses this as a mask for removing all the specs. Software only-based dust removal has to guess as to what's dust, sometimes gets it wrong. The only caveat with ICE is that it doesn't work well on certain films, reportedly Kodachrome. I've used it on 95% of my slides it does well on most of them; the ones that end up being a problem only show some very subtle blotchiness in dark uniform areas, kind of like what you get when you convert a picture to 256 colors without dithering. I suspect those were Kodachrome slides. Still a lot less trouble than having to manually PhotoShop out all the dust. The spec DMax is also important: it's dynamic range for scanners. To catch the full range of luminance in a 35mm slide you really need a DMax close to 4.0. I think my 4870 is around 3.8. Bob NO6B
RE: [Repeater-Builder] isolation
My CommShop calculates 99.65 dB is required. I'd definitely be looking at a six-cavity BpBr duplexer for this station. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of kj4si Sent: Saturday, August 22, 2009 6:55 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] isolation Hope someone may have a program,commshop? What I need to know is what amount of isolation with duplexers that is required for a GE m2 receiver with .1...@12db and a m2 pll exciter,100 watt PA on vhf,600kc split?1/2in helix,with 4pole db224 antenna at 70 ft. thanks kj4si
Re: [Repeater-Builder] isolation
H How about a mastr ii pll Vhf 147.225/147.825 with db224a @ 270' with 300' ldf7-50a and 110watts. I am running 45 watts right now. Thanks De N5NPO Norm - Original Message - From: Repeater-Builder@yahoogroups.com Repeater-Builder@yahoogroups.com To: Repeater-Builder@yahoogroups.com Repeater-Builder@yahoogroups.com Sent: Sat Aug 22 10:22:36 2009 Subject: RE: [Repeater-Builder] isolation My CommShop calculates 99.65 dB is required. I'd definitely be looking at a six-cavity BpBr duplexer for this station. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com ] On Behalf Of kj4si Sent: Saturday, August 22, 2009 6:55 AM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] isolation Hope someone may have a program,commshop? What I need to know is what amount of isolation with duplexers that is required for a GE m2 receiver with .1...@12db and a m2 pll exciter,100 watt PA on vhf,600kc split?1/2in helix,with 4pole db224 antenna at 70 ft. thanks kj4si
Re: [Repeater-Builder] isolation
Other than ordering the software, is there an old-school formula that can be used for this? I been using the decibel-wheel to convert from microvolts to dbm. NORM KNAPP wrote: H How about a mastr ii pll Vhf 147.225/147.825 with db224a @ 270' with 300' ldf7-50a and 110watts. I am running 45 watts right now. Thanks De N5NPO Norm - Original Message - From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Sat Aug 22 10:22:36 2009 Subject: RE: [Repeater-Builder] isolation My CommShop calculates 99.65 dB is required. I'd definitely be looking at a six-cavity BpBr duplexer for this station. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com ] On Behalf Of kj4si Sent: Saturday, August 22, 2009 6:55 AM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] isolation Hope someone may have a program,commshop? What I need to know is what amount of isolation with duplexers that is required for a GE m2 receiver with .1...@12db and a m2 pll exciter,100 watt PA on vhf,600kc split?1/2in helix,with 4pole db224 antenna at 70 ft. thanks kj4si
RE: [Repeater-Builder] Re: Repeater building
I don't know what band Nick is trying to operate on, but my suggestion would be to get a purpose-built vehicular repeater, like a Motorola PAC-RT, and operate that way. Maybe Uniden has something similar - I'm only familiar with Motorola... FWIW, Nick, the PAC-RT operates on a completely different band than the primary radio (for example, the primary is VHF and the PAC-RT is UHF), so you would need two antennas, but no duplexer. So your UHF portable would transmit to the car, which in turn would transmit on VHF. Mark - N9WYS -Original Message- From: Repeater-Builder@yahoogroups.com On Behalf Of agrimm0034 I have very little knowledge with Uniden but I am with Motorola. I don't know if this will help you any but you would definitely need a duplexer because at 50 watts tx on a repeater your antenna's would have to be separated vertically around 50 ft and horizontally as much as a mile to get the necessary separation. As far as linking them together I'd recommend having 2 Motorola type radio's, there easier to work with --- In Repeater-Builder@yahoogroups.com, flame05154 flame05...@... wrote: I have 2 mobile radio's and im very new at this but i was wondering if there was a way that i could make a reapeater out of them for my vechical. My goal is to be able to talk to my mobile repeater that will in turn transmit over the 50watt radio other than my portable which is 5watt. I have an older model uniden and older model motorola. i know i would need to purches a duplexer (at least i think i would unless i put 2 antennas on my truck) but anyway, if anyone has any ideas on making on that would be grand. Thanks, Nick
RE: [Repeater-Builder] isolation
Tony, I once chatted with the developer of CommShop for Windows, and learned that his formulae are based upon a number of assumptions- the most important being that the repeater is of commercial quality. This translates to GE Mastr II and Exec II, and Motorola Micor and Mitrek, for example. He gained a great deal of information from the GE Duplex Curves, all of which are available for download from the RBTIP. It is important to realize that the results provided by the CommShop program- or any similar software package- are ballpark estimates. A transmitter with a crystal oscillator or a PLL exciter will probably require less isolation than a synthesized unit, due to improved spectral purity. A receiver with poor selectivity or a barn door front end will probably require more isolation. Nevertheless, I have found CommShop to be a very useful program, since it includes much more than just duplexer isolation calculations. More info is here: www.dcico.com/dcilmr.htm Basic calculations of suggested duplexer isolation require only four factors: TX power in watts, RX sensitivity in microvolts at 12 dB SINAD, TX frequency, and RX frequency. The antenna gain, mounting height, and length of feedline are irrelevant, since they have nothing to do with how the duplexer performs with a 50 ohm dummy load connected. As always, YMMV... 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Tony KT9AC Sent: Saturday, August 22, 2009 10:07 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] isolation Other than ordering the software, is there an old-school formula that can be used for this? I been using the decibel-wheel to convert from microvolts to dbm. NORM KNAPP wrote: H How about a mastr ii pll Vhf 147.225/147.825 with db224a @ 270' with 300' ldf7-50a and 110watts. I am running 45 watts right now. Thanks De N5NPO Norm - Original Message - From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Sat Aug 22 10:22:36 2009 Subject: RE: [Repeater-Builder] isolation My CommShop calculates 99.65 dB is required. I'd definitely be looking at a six-cavity BpBr duplexer for this station. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com ] On Behalf Of kj4si Sent: Saturday, August 22, 2009 6:55 AM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] isolation Hope someone may have a program,commshop? What I need to know is what amount of isolation with duplexers that is required for a GE m2 receiver with .1...@12db and a m2 pll exciter,100 watt PA on vhf,600kc split?1/2in helix,with 4pole db224 antenna at 70 ft. thanks kj4si
Re: [Repeater-Builder] isolation
Eric, Are you sure about your six-cavity recommendation? The MASTR II PLL exciter has 22 dB less side-band noise than a typical multiplier exciter - using 600 kHz TX to RX separation. Assuming his preamp isn't driven into a non-linear region (it shouldn't be), a good 4 cavity duplexer, like a WACOM WP-641, should give plenty of isolation... Kevin Custer My CommShop calculates 99.65 dB is required. I'd definitely be looking at a six-cavity BpBr duplexer for this station. 73, Eric Lemmon WB6FLY --- Hope someone may have a program,commshop? What I need to know is what amount of isolation with duplexers that is required for a GE m2 receiver with .1...@12db and a m2 pll exciter,100 watt PA on vhf,600kc split?1/2in helix,with 4pole db224 antenna at 70 ft. thanks kj4si
[Repeater-Builder] Re: isolation
Tony, Try this one at RB website. http://www.repeater-builder.com/downloads/download-index.html --- In Repeater-Builder@yahoogroups.com, Tony KT9AC kt...@... wrote: Other than ordering the software, is there an old-school formula that can be used for this? I been using the decibel-wheel to convert from microvolts to dbm. NORM KNAPP wrote: H How about a mastr ii pll Vhf 147.225/147.825 with db224a @ 270' with 300' ldf7-50a and 110watts. I am running 45 watts right now. Thanks De N5NPO Norm - Original Message - From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Sat Aug 22 10:22:36 2009 Subject: RE: [Repeater-Builder] isolation My CommShop calculates 99.65 dB is required. I'd definitely be looking at a six-cavity BpBr duplexer for this station. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com ] On Behalf Of kj4si Sent: Saturday, August 22, 2009 6:55 AM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] isolation Hope someone may have a program,commshop? What I need to know is what amount of isolation with duplexers that is required for a GE m2 receiver with .1...@12db and a m2 pll exciter,100 watt PA on vhf,600kc split?1/2in helix,with 4pole db224 antenna at 70 ft. thanks kj4si
RE: [Repeater-Builder] isolation
Kevin, Nothing about duplexers is for certain. While I agree that a PLL exciter is inherently less noisy than its multiplier counterpart, I never assume that it's okay to plan ahead for less than optimum isolation. Some duplexer designs are known to have better performance than physically identical designs from other manufacturers- the silver-plated copper cans from Decibel Products are one example. I feel that it's better to have a duplexer that is perfectly tuned and has absolutely zero desense, than a lower-performance duplexer that has only a little desense. In an ideal world, KJ4SI should be able to buy a four-cavity BpBr duplexer and try it out for 30 days to see if it had zero desense- with the option to purchase two more cans and the appropriate jumpers at a discount for upgrading it to a six-cavity duplexer. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Kevin Custer Sent: Saturday, August 22, 2009 12:52 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] isolation Eric, Are you sure about your six-cavity recommendation? The MASTR II PLL exciter has 22 dB less side-band noise than a typical multiplier exciter - using 600 kHz TX to RX separation. Assuming his preamp isn't driven into a non-linear region (it shouldn't be), a good 4 cavity duplexer, like a WACOM WP-641, should give plenty of isolation... Kevin Custer My CommShop calculates 99.65 dB is required. I'd definitely be looking at a six-cavity BpBr duplexer for this station. 73, Eric Lemmon WB6FLY -- Hope someone may have a program,commshop? What I need to know is what amount of isolation with duplexers that is required for a GE m2 receiver with .1...@12db and a m2 pll exciter,100 watt PA on vhf,600kc split?1/2in helix,with 4pole db224 antenna at 70 ft. thanks kj4si
Re: [Repeater-Builder] isolation
Eric, You may have missed the point. While your program calculated a necessary isolation amount of 99.65 dB, using a GE M2 PLL exciter would dictate 77.65 dB of necessary isolation - which is easily obtainable with a quality 4 cavity (okay, 4 large cavity) duplexer. While I certainly wouldn't recommend a duplexer using four 5 cavities, a four cavity duplexer utilizing 8 inch cavities would provide more than adequate isolation (90+ dB of isolation) for this gentleman's arrangement. If he were using a multiplier exciter (which the 'program' assumed), then one can certainly understand your recommendation - but - he did say PLL exciter and M2 equipment. I'm not sure I understand your statement Nothing about duplexers is for certain. All of the duplexers I have ever tuned came out to factory specifications or better. If not, something was physically wrong - lightning damage - cabling problems - loop problems, etc. I don't believe that if this person were to utilize a quality four cavity duplexer that we'd be setting him up for failure. Engineering is on our side, and he can benefit from not needing to spend extra money for something that isn't really necessary. BTW: It is possible to duplex a PLL exciter (200 mW) and M2 receiver (no preamp) at 600 kHz with nothing more than a tee connector. You do have to skew the helical tuning a bit so the skirt is sharp on the side of the transmitter; which reduces receive sensitivity to less than factory specification. I won't say there will be zero desense, but you won't even get close with a multiplier exciter in the same test. It's fun - tastes great - less filling! Kevin Kevin, Nothing about duplexers is for certain. While I agree that a PLL exciter is inherently less noisy than its multiplier counterpart, I never assume that it's okay to plan ahead for less than optimum isolation. Some duplexer designs are known to have better performance than physically identical designs from other manufacturers- the silver-plated copper cans from Decibel Products are one example. I feel that it's better to have a duplexer that is perfectly tuned and has absolutely zero desense, than a lower-performance duplexer that has only a little desense. In an ideal world, KJ4SI should be able to buy a four-cavity BpBr duplexer and try it out for 30 days to see if it had zero desense- with the option to purchase two more cans and the appropriate jumpers at a discount for upgrading it to a six-cavity duplexer. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Kevin Custer Sent: Saturday, August 22, 2009 12:52 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] isolation Eric, Are you sure about your six-cavity recommendation? The MASTR II PLL exciter has 22 dB less side-band noise than a typical multiplier exciter - using 600 kHz TX to RX separation. Assuming his preamp isn't driven into a non-linear region (it shouldn't be), a good 4 cavity duplexer, like a WACOM WP-641, should give plenty of isolation... Kevin Custer My CommShop calculates 99.65 dB is required. I'd definitely be looking at a six-cavity BpBr duplexer for this station. 73, Eric Lemmon WB6FLY -- Hope someone may have a program,commshop? What I need to know is what amount of isolation with duplexers that is required for a GE m2 receiver with .1...@12db and a m2 pll exciter,100 watt PA on vhf,600kc split?1/2in helix,with 4pole db224 antenna at 70 ft. thanks kj4si
Re: Fw: [Repeater-Builder] Re: Sinclair UHF Receive Antenna Multicoupler Question
At 8/22/2009 07:49, you wrote: Let's never forget that ANY loss between the antenna and the receiver will degrade the rx's noise figure. That means feedline, duplexer, cavities, connectors, Polyphasers, etc. In theory, yes. However, if the noise floor (antenna noise temperature) is much higher than the noise temperature/figure of the receiver, then some loss between the antenna receiver will have a negligible affect on overall system sensitivity. This is often the case at 6 meters, sometimes even on 2 meters depending on location receiver sensitivity. At higher frequencies the antenna noise temperature is usually much lower than 300 K, so in those cases yes you want to minimize all loss between the antenna RX. Bob NO6B
RE: [Repeater-Builder] isolation
Kevin, I agree with your conclusions- provided that the exciter meets your expected performance. I would never assume that I could automatically subtract 22 dB from the proposed isolation, merely because it was a PLL exciter, without knowing for certain that its performance met or surpassed the specifications. It doesn't happen very often, to be sure, but I have found PLL exciters that were considered to be working perfectly by their owners, but were producing less than perfect outputs. Maybe I'm getting too cranky in my old age, but I don't feel like making another trip to the mountain because I did not do my homework thoroughly. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Kevin Custer Sent: Saturday, August 22, 2009 3:38 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] isolation Eric, You may have missed the point. While your program calculated a necessary isolation amount of 99.65 dB, using a GE M2 PLL exciter would dictate 77.65 dB of necessary isolation - which is easily obtainable with a quality 4 cavity (okay, 4 large cavity) duplexer. While I certainly wouldn't recommend a duplexer using four 5 cavities, a four cavity duplexer utilizing 8 inch cavities would provide more than adequate isolation (90+ dB of isolation) for this gentleman's arrangement. If he were using a multiplier exciter (which the 'program' assumed), then one can certainly understand your recommendation - but - he did say PLL exciter and M2 equipment. I'm not sure I understand your statement Nothing about duplexers is for certain. All of the duplexers I have ever tuned came out to factory specifications or better. If not, something was physically wrong - lightning damage - cabling problems - loop problems, etc. I don't believe that if this person were to utilize a quality four cavity duplexer that we'd be setting him up for failure. Engineering is on our side, and he can benefit from not needing to spend extra money for something that isn't really necessary. BTW: It is possible to duplex a PLL exciter (200 mW) and M2 receiver (no preamp) at 600 kHz with nothing more than a tee connector. You do have to skew the helical tuning a bit so the skirt is sharp on the side of the transmitter; which reduces receive sensitivity to less than factory specification. I won't say there will be zero desense, but you won't even get close with a multiplier exciter in the same test. It's fun - tastes great - less filling! Kevin Kevin, Nothing about duplexers is for certain. While I agree that a PLL exciter is inherently less noisy than its multiplier counterpart, I never assume that it's okay to plan ahead for less than optimum isolation. Some duplexer designs are known to have better performance than physically identical designs from other manufacturers- the silver-plated copper cans from Decibel Products are one example. I feel that it's better to have a duplexer that is perfectly tuned and has absolutely zero desense, than a lower-performance duplexer that has only a little desense. In an ideal world, KJ4SI should be able to buy a four-cavity BpBr duplexer and try it out for 30 days to see if it had zero desense- with the option to purchase two more cans and the appropriate jumpers at a discount for upgrading it to a six-cavity duplexer. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder@yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder@yahoogroups.com ] On Behalf Of Kevin Custer Sent: Saturday, August 22, 2009 12:52 PM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] isolation Eric, Are you sure about your six-cavity recommendation? The MASTR II PLL exciter has 22 dB less side-band noise than a typical multiplier exciter - using 600 kHz TX to RX separation. Assuming his preamp isn't driven into a non-linear region (it shouldn't be), a good 4 cavity duplexer, like a WACOM WP-641, should give plenty of isolation... Kevin Custer My CommShop calculates 99.65 dB is required. I'd definitely be looking at a six-cavity BpBr duplexer for this station. 73, Eric Lemmon WB6FLY -- Hope someone may have a program,commshop? What I need to know is what amount
RE: [Repeater-Builder] isolation
Dan Kagabine, the chief engineer at TX-RX systems use to always say that once you have enough isolation to overcome any desense, then any more is a waste of money as it does nothing for you. If you only need 70 db then a 100 db duplexer does nothing more for you than a 70 db duplexer. 73 Gary K4FMX _ From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Kevin Custer Sent: Saturday, August 22, 2009 5:38 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] isolation Eric, You may have missed the point. While your program calculated a necessary isolation amount of 99.65 dB, using a GE M2 PLL exciter would dictate 77.65 dB of necessary isolation - which is easily obtainable with a quality 4 cavity (okay, 4 large cavity) duplexer. While I certainly wouldn't recommend a duplexer using four 5 cavities, a four cavity duplexer utilizing 8 inch cavities would provide more than adequate isolation (90+ dB of isolation) for this gentleman's arrangement. If he were using a multiplier exciter (which the 'program' assumed), then one can certainly understand your recommendation - but - he did say PLL exciter and M2 equipment. I'm not sure I understand your statement Nothing about duplexers is for certain. All of the duplexers I have ever tuned came out to factory specifications or better. If not, something was physically wrong - lightning damage - cabling problems - loop problems, etc. I don't believe that if this person were to utilize a quality four cavity duplexer that we'd be setting him up for failure. Engineering is on our side, and he can benefit from not needing to spend extra money for something that isn't really necessary. BTW: It is possible to duplex a PLL exciter (200 mW) and M2 receiver (no preamp) at 600 kHz with nothing more than a tee connector. You do have to skew the helical tuning a bit so the skirt is sharp on the side of the transmitter; which reduces receive sensitivity to less than factory specification. I won't say there will be zero desense, but you won't even get close with a multiplier exciter in the same test. It's fun - tastes great - less filling! Kevin Kevin, Nothing about duplexers is for certain. While I agree that a PLL exciter is inherently less noisy than its multiplier counterpart, I never assume that it's okay to plan ahead for less than optimum isolation. Some duplexer designs are known to have better performance than physically identical designs from other manufacturers- the silver-plated copper cans from Decibel Products are one example. I feel that it's better to have a duplexer that is perfectly tuned and has absolutely zero desense, than a lower-performance duplexer that has only a little desense. In an ideal world, KJ4SI should be able to buy a four-cavity BpBr duplexer and try it out for 30 days to see if it had zero desense- with the option to purchase two more cans and the appropriate jumpers at a discount for upgrading it to a six-cavity duplexer. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Kevin Custer Sent: Saturday, August 22, 2009 12:52 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] isolation Eric, Are you sure about your six-cavity recommendation? The MASTR II PLL exciter has 22 dB less side-band noise than a typical multiplier exciter - using 600 kHz TX to RX separation. Assuming his preamp isn't driven into a non-linear region (it shouldn't be), a good 4 cavity duplexer, like a WACOM WP-641, should give plenty of isolation... Kevin Custer My CommShop calculates 99.65 dB is required. I'd definitely be looking at a six-cavity BpBr duplexer for this station. 73, Eric Lemmon WB6FLY -- Hope someone may have a program,commshop? What I need to know is what amount of isolation with duplexers that is required for a GE m2 receiver with .1...@12db and a m2 pll exciter,100 watt PA on vhf,600kc split?1/2in helix,with 4pole db224 antenna at 70 ft. thanks kj4si
[Repeater-Builder] Information needed on Aerotron Railroad radio
I acquired an Alpha 1600 and would like to reprogram the home channels (this is RX enabled only BTW.) I was able to locate a PDF manual for the Alpha 1700 which is almost identical externally, but apparently has some more advanced features that appear to make it equivalent to a Moto RR spectra. Do the programming instructions for the 1700 apply to the 1600 as well? Thanks Adam KC8WJG
Fw: [Repeater-Builder] OT:THE MOBILE TELEPHONE
What I recall about these mobile telephones (at least in NJ when I lived there) was that they didn't put quarter-wave VHF whips on roof or trunk but used a genuine coaxial dipole on about a 2 foot long mast installed on a fender. I guess they felt that a better way. --John --- On Fri, 8/21/09, Joe k1ike_m...@snet.net wrote: From: Joe k1ike_m...@snet.net Subject: [Repeater-Builder] OT:THE MOBILE TELEPHONE To: Repeater-Builder@yahoogroups.com Date: Friday, August 21, 2009, 5:37 PM http://www.wb6nvh.. com/Carphone. htm This is from another list. It is an interesting trip down memory lane about the evolution of the mobile telephone. 73, Joe K1ike
Fw: Re: [Repeater-Builder] Diversity FM reception
I turn out that use of CP in urban suburban areas results in somewhat more signal strength on linearly polarized antennas, e.g. vertical whips on cars straight rod aerials on portable FM radios. Due to preferential scattering of vertically polarized sigs from typical urban structures, there tends to be more of that available, esp. good for auto FM reception. The Germans for example are more concerned with signal quality than quantity so don't use CP. However, there is a drawback: there's more multipath. So the tradeoff was made--more signal strength but at lesser quality (due to multipath distortion). Well designed FM radios reduce separation intelligently in the presence of multipath: first they gradually blend the stereo channels into mono, high audio frequencies L-R info first, then all audio (L+R) is gradually lowpass filtered. This happens dynamically, on the fly. Works well IMO when done properly. TV broadcasters tried CP as well but couldn't live the extra multipath: it was easily visible as more ghosting. See for example: http://www.ham-radio.com/k6sti/ for more on this. --John --- On Fri, 8/21/09, larynl2 lar...@hotmail.com wrote: From: larynl2 lar...@hotmail.com Subject: Fw: Re: [Repeater-Builder] Diversity FM reception To: Repeater-Builder@yahoogroups.com Date: Friday, August 21, 2009, 9:08 PM In reference to below, what would be the real advantage to using CP antennas in addition to the V and H you'd have already? Any signal that arrives will excite a V and/or H antenna according to it's arriving polarization, and I don't see where CP would be a help. Most FM broadcasters use CP. Those that don't are licensed for only V or H or choose to use a less-expensive single-polarization antenna. And many of them look like rototillers, and other shapes. Laryn K8TVZ --- In Repeater-Builder@ yahoogroups. com, John Sehring wb...@... wrote: There's more to be done with polarization as well: Circular, both RH LH. It is possibile to make omnidirectional CP antennas. FM broadcasters use a lot of them. They look like a bunch of arrows.
Fw: Re: [Repeater-Builder] Diversity FM reception
Oh, I forgot...circular polarization would be excellent to use on VHF and UHF repeater. We want the extra signal strength the multipath would be way less; less deviation 5 kHz vs. 75 kHz means less susceptability to multipath. Pasternak's Repeater Handbook shows actual results. --- On Fri, 8/21/09, larynl2 lar...@hotmail.com wrote: From: larynl2 lar...@hotmail.com Subject: Fw: Re: [Repeater-Builder] Diversity FM reception To: Repeater-Builder@yahoogroups.com Date: Friday, August 21, 2009, 9:08 PM In reference to below, what would be the real advantage to using CP antennas in addition to the V and H you'd have already? Any signal that arrives will excite a V and/or H antenna according to it's arriving polarization, and I don't see where CP would be a help. Most FM broadcasters use CP. Those that don't are licensed for only V or H or choose to use a less-expensive single-polarization antenna. And many of them look like rototillers, and other shapes. Laryn K8TVZ --- In Repeater-Builder@ yahoogroups. com, John Sehring wb...@... wrote: There's more to be done with polarization as well: Circular, both RH LH. It is possibile to make omnidirectional CP antennas. FM broadcasters use a lot of them. They look like a bunch of arrows.
