[Repeater-Builder] Re: LMR-400 Cable
When You say you're hearing a buzz in the background indicates to me either severe line noise or, more likely, TV video from some high power station TV transmitter. Try a substitute simple home made ground plane antenna to rule out intermod generated from the antenna. If noise is still present, you probably have to add a bandpass cavity between your receiver and the duplexer Rx port to kill out of band strong signals. Most duplexers don't have good out of band rejection curves, usually only down -20 to -30 dB. Next thing to add would be a circulator between your TX output and the duplexer Tx port. I know these will add $$$ to your project, but in today's high noise RF environments, they are almost always a necessity. YMMV. 73's, George --- In Repeater-Builder@yahoogroups.com, [EMAIL PROTECTED] wrote: At 10/3/2008 00:10, you wrote: Here is the latest. I terminated the cable at the antenna with a dummy load and no desense. I hooked back up to the antenna and if listen to the receiver with the squelch open I hear a buzz in the background of the receiver white noise audio in addition to desense which doesn't show up when terminated. Sounds like you probably have a mix that's external to your hardware, but still possible that the mix is occurring within the shielding of the LMR-400. Bob NO6B
[Repeater-Builder] Re: Krylon Spray Paint
Skipp, I was also surprised by your problem with the Krylon clear spray. I have also been using the clear UV-resistant Krylon #1305 spray (NOT the regular stuff)for over 45 years on both my ham commercial installations without any problems. The UV clear spray is usually a special item available only from Art picture frame distributors. It's usually NOT found in your local hardware or craft store. Even the UV stuff will eventually crack/flake off after many years. I believe the only thing that has changed in the formula, over the years, is the propellant used. YMMV. WA2VNV, George --- In Repeater-Builder@yahoogroups.com, skipp025 [EMAIL PROTECTED] wrote: Hi Al, Might have been another brand of paint but I bought mostly Krylon because it was only $.99 cents a big spray can for many decades. But the clear spray paint did something to the antenna to make it unusable and I still have it here. The issue is how a person should first try to investigate the properties of sealers and paints for RF issues before they hit the same brick wall. cheers, s. Al Wolfe k9si@ wrote: Skipp, I'm very surprised at your experience with clear Krylon. I have been using it quite successfully since 1964 in many hundreds of commercial as well as amateur antenna projects. It's been S. O. P. to hose down all connections and hardware with it after antenna structure and electrical connections are assembled. Never had a problem with it effecting antenna performance. It dries thin enough that even small screws and nuts covered with it can be easily undone. An application of clear Krylon has always been the final step in over forty years on antenna work here from 500 kHz. to 12 GHz. But then I haven't bought a new can of clear Krylon in a year or two so maybe it's been changed. 73, Al, K9SI, retired, mostly Re: antenna question - Dip It and Scotch Kote Posted by: skipp025 skipp025@ skipp025 Date: Sun May 4, 2008 6:44 am ((PDT)) I constructed a 6 meter beam some years back, worked like a bomb even at 25ft above ground elevation. To ensure my pride and joy would last a long time I sprayed it with clear Krylon brand spray paint. The antenna was instantly unusable regardless of my efforts to remove the paint, re-tune or otherwise modify the antenna. I later learned that type of paint contained materials with a horible D-Factor. I was never able to use the antenna again, although it remains in my back yard as a reminder. cheers, s.
[Repeater-Builder] Re: Motorola N1254A Power Amp for 2M repeater info
Eric, Tnx for the suggestion - I called Motorola and after navigating - my life history, etc. with the call screener - Parts ID said they no longer support or have any info on anything this old. I also tried to get the 68P manual number so I could search more, but they didn't want to look for anything more. Dead end for them. How long ago did you get the N1275A manual from them? George WA2VNV --- In Repeater-Builder@yahoogroups.com, Eric Lemmon [EMAIL PROTECTED] wrote: George, Call Motorola at 800-422-4210, and navigate to Parts ID. Ask for the manual number that covers the amp. That's how I finally located the manual for my N1275A amplifier. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of George Sintchak Sent: Tuesday, April 01, 2008 7:48 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Motorola N1254A Power Amp for 2M repeater info SNIP
[Repeater-Builder] Re: Motorola N1254A Power Amp for 2M repeater info
Ron, Tnx for your input. I have an older Mocom70 mobile manual that's no help. What I'm specifically looking for is the schematic on the Input attenuator RF sense keying PC board, NLD7141A, so I can enable/disable the amplifier from the repeater controller. This input RF sense keying board would not normally be used in a base station or a mobile, so it's a little different. I'd also like to see the schematic of the power controller section to see if I could utilize the temperature sensor to activate an external heat sink fan. I don't like to run a fan continously as they tend to fail after a few months. Default case is to key a 12 Volt heat sink fan only on transmit - thus I would like to get a schematic of the RF sense keying board without having to reverse engineer it - not easy to remove. George WA2VNV --- In Repeater-Builder@yahoogroups.com, Ron Wright [EMAIL PROTECTED] wrote: George, Is this PA in a unified chassis. Mot built base stations with such a PA that was mounted beside the exciter With heat sink sticking out. It used the same PA as in the mobiles. 73, ron, n9ee/r From: George Sintchak [EMAIL PROTECTED] Date: 2008/04/01 Tue PM 09:48:06 CDT To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Motorola N1254A Power Amp for 2M repeater info Hi All, I've searched the archives website for info on this Amp and can't find anything. It's sort of similar to the N1275A or the N1248A convert-a-com amps but for a Motorcycle (I was told). It looks like the back end of a MoCom 70 heat sink. I need more specific schematic or manual info so I can integrate it into the repeater keying control logic. The Amp is working fine on 147 MHz, keys up on RF input and makes rated output. I want to use it in repeater service at reduced (~40 Watts) output, possibly with a small fan for cooling, as needed. Anyone have any history/info using this Amp? Model N1254A, 150.8 to 162.0 MHz, Mfg Aug 1977. Max input 7 Watts, Output 60 Watts. FCC # CC 3303. Power Amp board TLD8922A uses M9622/23/24 two M9625's for final transistors. Output directional coupler/power monitor board, TLD8922A. Input attenuator (-3 dB) RF sense keying board, NLD7141A. Input/Output bypass relays are 23C84103B01. Any info, links, etc. much appreciated. Tnx, 73's George
[Repeater-Builder] Motorola N1254A Power Amp for 2M repeater info
Hi All, I've searched the archives website for info on this Amp and can't find anything. It's sort of similar to the N1275A or the N1248A convert-a-com amps but for a Motorcycle (I was told). It looks like the back end of a MoCom 70 heat sink. I need more specific schematic or manual info so I can integrate it into the repeater keying control logic. The Amp is working fine on 147 MHz, keys up on RF input and makes rated output. I want to use it in repeater service at reduced (~40 Watts) output, possibly with a small fan for cooling, as needed. Anyone have any history/info using this Amp? Model N1254A, 150.8 to 162.0 MHz, Mfg Aug 1977. Max input 7 Watts, Output 60 Watts. FCC # CC 3303. Power Amp board TLD8922A uses M9622/23/24 two M9625's for final transistors. Output directional coupler/power monitor board, TLD8922A. Input attenuator (-3 dB) RF sense keying board, NLD7141A. Input/Output bypass relays are 23C84103B01. Any info, links, etc. much appreciated. Tnx, 73's George
[Repeater-Builder] Re: Possible interference on 146.160
Some years back, when we installed the repeater (also 146.760/160) in a new building, we noticed a weak buzz...buzz signal ~once a second, very near the input frequrncy. After much searching, it turned out to be the smoke alarm heads within the building, all hard wired into their own AC line. Not all of them emitted a signal. Fortunately the signal was pretty weak and drifted around somewhat. We use PL on the input so it masked the problem so it wasn't a serious problem. Good luck hunting. George --- In Repeater-Builder@yahoogroups.com, lpcoates [EMAIL PROTECTED] wrote: Hi Our radio club has a portable repeater on 146.760 (-). Each time we install it on a commercial building we find what appears to be interference on or very near the input frequncy of 146.160. This repeater was installed at two private homes for several weeks each and worked flawlessley. Tonight it began to act up after just a few minutes. Another repeater was tried at one of these commercial sites and it also appeared to be receiving interference on 146.160. Tonight I tried a simple test of tuning my hand held to 146.160 and found several hot spots in the room where I picked up something as well as picking up something radiating from the electrical conduit. Both of the commercial sites have elevator equipment, one quite old and one very modern. One site hosts several other radio systems from 400 MHz to 10 GHz and the other site has not other radio equipment. Both buildings are 12 story office buildings. My question is, have other people found that this frequency is especially prone to interference from nearby electrical and electronic equipment? I know that the output frequency of 146.760 can be a problem because it's very close to the 41nd harmonic of the colorburst crystal, but I haven't been able to find any mention of problems on the input frequency of 146.160. Thanks Bruce - VE5BNC
[Repeater-Builder] Mirage B1016 / B1016G 2 Meter Amplifier
I have a Mirage B1016 Amp that uses SRF3417 bipolar transistors as the finals dated from 1988. I have schematics dated 5-1-84 and also a newer schematic for the G gasfet version dated 8/7/89 that uses MRF247's. The amp is operating normal and making rated output power of 160 Watts in class C FM mode with ~10 Watts input. I'm not over- driving the amp. Here's the problem. I'm trying to improve the linearity in SSB mode (Class AB1) as the amplifier has 2-tone IMD distortion products only down about -10 dB as measured on my 7L14 spectrum analyzer. They should be down about -30 dB. Adjusting the bias pot for the finals makes no improvement in IMD. The bias network network in my 1988 amplifier doesn't match the schematic and uses some unusual(?)circuit involving a 7808 TO-220 voltage regulator that seems to derive power from rectification of the input drive signal. It also uses two 30 Ohm 5W resistors instead of the 50 Ohm 5W resistors as shown on the schematics. I suspect Mirage used this method as there is no keyed +13.6 Volts to supply the 7808 in the usual case. The regulator is not damaged as it supplies the standard 8 Volts when I power it directly from 13 V with a clip lead. In regular RF operation, I don't see any 8 volts on the 7808 output. The newer G version schematic uses the 50 Ohm resistors and ties the red Xmit LED into the circuit as part of the self bias network. No 7808 shown. Does anyone have a schematic that shows the 7808 bias circuit for my 1988 Amp? I've done the usual internet searching and found nothing about it. Do I have a one of a kind factory experiment? Any ideas? George, WA2VNV
[Repeater-Builder] Milcom/Uniden ARX2125 220MHz Amplifier - Need Parts
Anyone have an extra Amp available for spare parts. It looks like I've lost one of the finals due to self oscillation and destruction. Polyfet has a few in stock (lotsa $$$) but it's no longer reccommended for new designs. I can't seem to find a suitable (newer)substitute using the AT package. Any Ideas out there? George, WA2VNV
[Repeater-Builder] Re: First repeater?
I remember reading an article about a repeater in the late 40's or early 50's that was on a mountain top in Arizona. It was AM mode, repeated from 28 MHz (I think) to 50 or 144 Mhz, or maybe it was split site. To be legal, all was logged on a very slow tape recorder. That's about all I can remember - do a search on that. There might be an article on it in the QST archives. George, WA2VNV --- In Repeater-Builder@yahoogroups.com, mch [EMAIL PROTECTED] wrote: I know this is somewhat controversial, but I'm looking for the date/year the first ham repeater was put on the air. Anyone know of a webpage with repeater history? Would like to have this info tonight for a presentation tomorrow. Joe M.
[Repeater-Builder] Re: Repeater Builder language
I cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the hmuan mnid, aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoatnt tihng is taht the frist and lsat ltteer be in the rghit pclae. The rset can be a taotl mses and you can sitll raed it wouthit a porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Amzanig huh? yaeh and I awlyas thought slpeling was ipmorantt! Jsut ejony a good lugah. QED
[Repeater-Builder] Milcom/Uniden ARX2125 220 MHz Amplifier schematics/info
Hello all. I'm looking for more info, schematics, etc on this nice 220 MHz amp, built around 1992. I have the info that N2CKH has posted on his website (see http://www.n2ckh.com/125m_rptr.htm) but I would like more specific info (schematics) about this amplifier chassis. I've searched the 'net and both Uniden Milcom websites without any other results. This Amp was part of the now defunct ACSB system that UPS was going to use back when we lost part of the 220 band. Any new info would be helpful. ( I already have info on the CA2832C hybrid and the Polyfet F1004 devices) Tnx, George, WA2VNV
[Repeater-Builder] Re: 1953 Motorola BaseRadio for 6meters
Gez! Sorry for your confusion. The It in the sentance referred to the preceeding noun, that being receivers, meaning that the Sensicon A series receivers all had miniature tubes. The receiver I think you have, a 13V(A), has all Loctal tubes (do yo know what they are?). As I asked earlier, What is the model number stamped on the front panel? George --- In Repeater-Builder@yahoogroups.com, Rod Shaner [EMAIL PROTECTED] wrote: That's really weird, because it's all enclosed in a metal box, and the only visible connector is a RCA connector on each end! There doesn't SEEM to be any plethora of tube supply wires, etc..I'll have to look again. R. On Sun, 18 Feb 2007 22:53:30 -0500, George Sintchak [EMAIL PROTECTED] wrote: The K-8436-A Permakay filter (first generation)was the large sized 455 kHz unit that was used in the Sensicon A series receivers. It had all miniature tubes. That filter was superceeded with the TU455 series (smaller size - 2nd generation) 455 kHz filters used in the Unichannel G (and other) series receivers. George --- In Repeater-Builder@yahoogroups.com, Rod Shaner kb8fly@ wrote: How about this: Filter number on I.F. is K-8436-A. Possibly K-6436-A (hard to resolve whether it's an eight or a six.) Another idea: How about using enough preamps that the selectivity is increased and sensitivity (spread) is decreased? As I understand it, the receiver is too broadbanded at present by a factor of 3. SNIP
[Repeater-Builder] Re: 1953 Motorola BaseRadio for 6meters
I remember having a similar 6 Volt Tx/Rx version in the mobile. That vintage Xmtr used 807's in the final for 50 Watts output and an AT cut FT243 xtal running at 1.0943 MHz with 48 times multiplication to get adequate deviation of +/-15 kHz. The xtal would rattle in it's holder. (that was normal) It was a MONSTER TVI generator in it's day because it put out spurs +/- 1.09 MHz either side of the main carrier for about +/- 5 MHz. They were only down about 20 dB due to the large 48x multiplication and not enough selectivity in the stages to eliminate the unwanted emissions. (There's a story here how I ended up on 6M FM back in ~1961 on 52.525 52.640; wow, it's been a long time!) The receivers (13VA) didn't have the (newer research line) Permakay 455 kHz IF filter and the rcvr selectivity was determined by the 1.7 MHz last IF stages. Tubes are mostly Loctal types, hard to find today. Not too practical to narrowband these old clunkers. Sad to say, they belong on a shelf in a Museum somewhere. That being said, I'm still using a high band version (16VA) of the same rcvr on 2 Meters as a repeater monitor receiver. The (then) wide band channel spacing was 120 or 240 KHz on high band. The broadcast people liked to use this family of receivers because it has a 600 Ohm audio output winding along with the 4 Ohms for the spkr. They made nice HiFi audio studio link 150 MHz receivers and could feed dedicated phone lines directly. Good luck with your project. You need to find someone who still has one of the infamous red or yellow Motorola schematic books that Sherman Wolf published in Boston in the late 60's for more info. George, WA2VNV. --- In Repeater-Builder@yahoogroups.com, rod_shaner [EMAIL PROTECTED] wrote: Hi all, I'm seeking schematics, manuals, and advice on peaking a working unit. Its model number is FSTR520BR(FW)1ASP2. Just tearing that model number apart is a workload! It was a commercial base radio, and it's crystalled for 52.525 FM. Right now I'm trying to get as much as possible out of the receiver. It works, but 25 mile away 40W signal radiated through a vertical antenna is just out of the noise on this end. My receive antenna's base is 30 inches off the ground for test purposes. Advice is requested. Thanks.
[Repeater-Builder] Re: 1953 Motorola BaseRadio for 6meters
As I mentioned in my earlier posting, The last IF is probably 1.7 MHz if the receiver model is a FMRU13V(A). A rcvr without the (A) in the model number was a less selective receiver that (I believe) used a higher freq last IF. That may be what you have with the 2.9 MHz last IF for low band receiver. NONE of these receivers had any type of Permakay filter or a 455 kHz last IF! What is the complete model number stamped on the blue front panel of the receiver under the Motorola name? You really need one of those Yellow schematic books I mentioned before. You are really testing my memory on all of this George --- In Repeater-Builder@yahoogroups.com, Rod Shaner [EMAIL PROTECTED] wrote: What is the IF for this 1953 Motorola 520BR rig? 2.9MHz?? R. On Sat, 17 Feb 2007 20:09:50 -0500, Eric Lemmon [EMAIL PROTECTED] wrote: www.com-spec.com/narrow.htm -- Using Opera's revolutionary e-mail client: http://www.opera.com/mail/
[Repeater-Builder] Re: Super Sataionmaster Disassembly
Steve, I will send you an email with description pictures of PD220 antenna dissassenbly I did about a year ago. I want to contribute this as an article for the group, but didn't have the time to finish it up yet, but all the info you need is included. Need ur email address. George / WA2VNV
[Repeater-Builder] Re: Micro Exciter, Low Output?
Don, You don't mention what band/frequency the Micor is on, (I assume UHF) and if you have a station monitor as you stated, it has a wattmeter built in that can measure the power level from the low level exciter board up through the output stage. Of course, you'll need an RF RCA connector to connect to the low level exciter board output. Not sure what you mean by the statement What difference should I see in exciter output from sitting in an no receive, idle state, opposed to transmitting? ??? George --- In Repeater-Builder@yahoogroups.com, donlspivey [EMAIL PROTECTED] wrote: I'm currently in the process of converting a Micor (unified type chassis) base station to repeater duty. I have all factory docs, a service monitor and a Motorola test set, unfortunately I don't have a low wattage slug for my wattmeter. I was fortunate (dumb luck, I guess) to find two Micor Unified chassis with ALL ham band split components, (one is missing the PA and power control boards, but it has the good receiver). I've got it up and running using the original squelch gate card and station control module for now. It receives great, the COR is tripping but it's not yet transmitting. Not having a means of measuring the 400mw output of the exciter, I'm depending on the ball park readings the manual and various articles I've found say the test set should be displaying. I tuned the exciter as per the manual, however, when plugging the test set into the PA and switched to position 1, the manual says there should be a reading of 15uA which is drive from the exciter, I'm only seeing 3 or 4uA. I tuned up the second exciter and see the same reading. I swapped the exciter filter and no change. I even took a TFD6112APR filter, drilled holes to allow retuning and tuned it under operating conditions, same reading. I'm either seeing a false reading from the test set or there's a problem with the PA/power control board (if it's not an issue with the exciter(s), of course). I did not have the luxury of testing the base station first, the crystals were removed from the channel elements. Yes weird, but I believe these base stations were used by the FBI at one time. Also, I currently have the xmit channel element running all the time. I may not leave it this way, but this machine is going to a site of limited accessibility and I want to age the crystal. What difference should I see in exciter output from sitting in an no receive, idle state, opposed to transmitting? I could be missing something simple and obvious here, but I would appreciate a push in the right direction as well as any tips and tricks you guys may have to help me finish this project. Thanks. Don Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Info needed. 450 MHz, 75 Watt Amp Micor TLE1713A-3
Micor series TLE1713A-3. Looking for schematics, metering info, etc. and/or a manual if you have one to spare or can copy part of a manual. For non-commercial use in an amatuer repeater. The amplifier seems to be working fine. 2 Watts in ~90+ max Watts out (un-controlled) at 449 MHz. I will be controlling the output to use at the ~50-60 Watt level. I just need documentation at the rptr site for future reference. This way, if I have the documentation, I'll never need to fix it - Inverse Murphy's Law. :D Tnx. George, WA2VNV Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
