[Repeater-Builder] Re: DB224-JJ Dimensions Wanted
What good would it be to have the folded dipoles (erroneously referred to as loops) constructed if there was no (impedance matching) harness to use with them? For one to use 222-225 dipoles with the harness from a 150-160 DB 224 is just plain stupid. The coax matching lengths and impedance's in the 150-160 harness are no where near being correct to achieve the proper impedance matching and power division for 222-225 dipoles. Has anyone designed, built, and tested a proper harness for use at 222-225? or even measured the coax in the JJ model? Has anyone even measured the impedance of a dipole made for use at 222-225? Or even modeled one? Allan Crites WA9ZZU --- In Repeater-Builder@yahoogroups.com, "skipp025" wrote: > > > > I'm looking for a DB224-JJ. They are becoming hard to > > find, even from manufacturers. I would also consider > > a Hustler HD6-5 or something similar to that. > > If someone has the dimensions for the 224-JJ Loops and maybe > the spacing distance... I think I can get them made. A local > (to me) Ham has made a metal forming jig for loop antenna > materials and is currently cranking out 440 loop antennas like > crazy. I could get him to re-size the jig and crank out some > 224 MHz loops with their mounts. Anyone have the "JJ" info > available? > > > I'm currently using a Hustler G7-220 side mounted, which > > works OK, but looking for something that could be top > > mounted. > > I've got a G7-220 Tower Top Mounted and it works killer (good). > > > Having problems getting coverage in the areas I need > > due to shadowing from the tower. Any help or suggestions > > would be greatly appreciated! > > Changing the spacing of the antenna to the tower would modify > the pattern. > > s. >
[Repeater-Builder] Re: 220 Mhz repeaters
-ED Are these for FM or for ACSSB ? AC -- In Repeater-Builder@yahoogroups.com, "Com/Rad Inc" wrote: > > 6 Sept 2009 > > Hello 220 enthusiasts > > We have a quantity of 220 Mhz T/R modules from R F Technology Pty Ltd., > which can be configured into > functional repeaters. These are demos or new stock. It is possible if you > are interested in a serious build we may be able to > offer some hardware for your project. > > See: > http://www.rftechnology.com.au > Http://www.com-rad.com/transtech.htm > > Best regards > > Ed Folta > Com/Rad Inc >
[Repeater-Builder] Re: DB-224 Matching
-Don't expect anything for another month or so as I just arrived home after an extended vacation. I agree that most hams will have trouble handling even the most simple impedance matching information in the ARRL Antenna Book so when I can get something together on matching on the DB 224 I will submit it. AC -- In Repeater-Builder@yahoogroups.com, "Chuck Kelsey" wrote: > > How about an article with examples to post at the Repeater Builder site? > > Chuck > WB2EDV > > > - Original Message - > From: "wa9zzu" > To: > Sent: Friday, August 21, 2009 3:11 PM > Subject: [Repeater-Builder] Re: DB-224 Matching > > > > -Well guys, > > > > With all due respect to Jim and his tried and true dipole modifications in > > which he changes the load impedance presented to the cable harness which > > is in turn reflected to the 1st junction connected to the antenna pigtail, > > and all the others who do some sort of extensive dipole modification to > > get a resulting VSWR to their liking, I find that the simpliest and most > > rewarding, easiest, least labor intensive, not to mention least possible > > to create mechanical problems, is the addition of just two short lengths > > of 50 ohm coax at the antenna feed point coax, one in series and one in > > shunt, to a tee connector. This matching section has been done to several > > DB 224 antennas by my self with great success. > > > > No strain, no pain, and only a minimum of cost and time, with low VSWR > > over the 144-148 band. > > > > And I challenge any one to tell the difference in the gain of the DB224 > > using the original dipoles with my impedance matching section to the > > modified dipoles with the loss in the mismatch created in the antenna > > harness with the modified dipoles. > > > > All it takes is some effort with a Smith Chart and some simple coax cable > > construction after measuring the feed point impedance / VSWR at the band > > edge and the center frequencies from 144 to 148 MHz. All done at gound > > level. Simple matching stub design can be found and is well described in > > the ARRL Antenna Book, 13th edition on Pp. 122-126. > > > > I have done this same type of coaxial impedance matching on several of the > > DB 420 antennas as well with good results. > > > > 73 Allan Crites WA9ZZU >
[Repeater-Builder] Re: DB-224 Matching
-Well guys, With all due respect to Jim and his tried and true dipole modifications in which he changes the load impedance presented to the cable harness which is in turn reflected to the 1st junction connected to the antenna pigtail, and all the others who do some sort of extensive dipole modification to get a resulting VSWR to their liking, I find that the simpliest and most rewarding, easiest, least labor intensive, not to mention least possible to create mechanical problems, is the addition of just two short lengths of 50 ohm coax at the antenna feed point coax, one in series and one in shunt, to a tee connector. This matching section has been done to several DB 224 antennas by my self with great success. No strain, no pain, and only a minimum of cost and time, with low VSWR over the 144-148 band. And I challenge any one to tell the difference in the gain of the DB224 using the original dipoles with my impedance matching section to the modified dipoles with the loss in the mismatch created in the antenna harness with the modified dipoles. All it takes is some effort with a Smith Chart and some simple coax cable construction after measuring the feed point impedance / VSWR at the band edge and the center frequencies from 144 to 148 MHz. All done at gound level. Simple matching stub design can be found and is well described in the ARRL Antenna Book, 13th edition on Pp. 122-126. I have done this same type of coaxial impedance matching on several of the DB 420 antennas as well with good results. 73 Allan Crites WA9ZZU -- In Repeater-Builder@yahoogroups.com, "tahrens301" wrote: > > Hi Jim, thanks for the words on corrosion, and Laryn... aah, the > voice of experience! No holes will be drilled!! > > Thanks to all. I believe that will be the easiest way to make > it work. > > Tim W5FN > > > > > --- In Repeater-Builder@yahoogroups.com, "larynl2" wrote: > > > > Perhaps > > > drilling a hole through the original element for > > > connection might be better. > > > > > > Uh, I wouldn't drill holes in elements. I did drill small holes in each of > > four elements years ago and within a year all four elements had cracked > > right where I drilled. > > > > Laryn K8TVZ > > >
[Repeater-Builder] Re: 2M Vertical Dipoles
What was the spacing between the tower legs at the mounting location of the dipoles in your model? Allan Crites WA9ZZU -- In Repeater-Builder@yahoogroups.com, n...@... wrote: > > At 8/9/2009 05:47, you wrote: > > > >As frequency decreases, so does the importance of keeping the dipoles > >exactly above one another. This is why you can get away with mounting the > >bays of a LB array around a smaller tower (like Rohn 25) and still have > >very good omni-directional performance. Positioning the bays around a > >central supporting mast of a UHF array creates considerable pattern > >distortion and gain is lost. > > I once modeled this arrangement in NEC-Win: the resulting pattern looked > like a warped pancake. On-horizon gain was all over the place. > > Bob NO6B >
[Repeater-Builder] Re: DB224 Question
Ed-- -Upon further consideration the top half of a db224 would do what you want if you provide a suitable Z matching section, but I could not provide a solution for the appropriate matching section until I get a chance to look at my previous data measurements until I get back to EGV. The bottom half of a db224 needs a Z compensation at the jct where the top half connects to make it work as a separated ant, perhaps also needing some Z stub at the ant pigtail. Maybe not if the top matching Z section is proper. Need to make a measurement. All what you are wanting to do is possible but needs some work measuring the separated sections and constructing the appropriate Z matching sections. I did some work years ago on mounting two db224 dipoles at the same point on the pipe which would save some valuable mounting space and could be added to an existing pipe, and I constructed the necessary Z matching section which would do the same thing you want with the db222 but unknown if the resulting radiation pattern may be something you would be happy with. If you want to make your own matching section for the two dipoles located at the same point on the pipe it, if I remember correctly (and I am reliaing on my memory here now ) requires a 1/2 WL in 50 ohm coax to the jct of the 50 ohm feed line from each dipole. Each dipole has a Z=120+jxx and two in parallel would get close to 50 ohms. AC -- In Repeater-Builder@yahoogroups.com, "Com/Rad Inc" wrote: > > Hello Al > > Thanks for reply - I figured that to be the case > Do you have anything in your collection resembling a DB222 > that would do 152-158 range ? > Ed > Com-Rad Inc > > ED > ----- Original Message - > From: wa9zzu > To: Repeater-Builder@yahoogroups.com > Sent: Saturday, August 01, 2009 9:11 AM > Subject: [Repeater-Builder] Re: DB224 Question > > > -I apologize for not giving a complete answer. > The short answer to the first question is yes. > The short answer to the second is no. > > Al Crites > > -- In Repeater-Builder@yahoogroups.com, "wa9zzu" wrote: > > > > -No > > > > Al Crites > > > > -- In Repeater-Builder@yahoogroups.com, "Com/Rad Inc" wrote: > > > > > > Turning to the experiences of the group as all vendor info sources are > > > off for the weekend - ( probably could research this on line ) > > > > > > Do any of you have knowledge of the chatachteristics of 1/2 of the DB > 224 antenna? > > > > > > With harness' intact does either section of this array resemble the DB > 222 ( 2 element ) antenna stack? > > > Concerned with feed impedance etc. I recall doing thihs with a UHF > version once and had reasonable results in a pinch... > > > > > > Any comments would be appreciated. > > > > > > Ed K9QPJ > > > > > >
[Repeater-Builder] Re: DB224 Question
-I'm not sure I may have, but I cannot give you a good answer for another 3 weeks until I return from my vacation in Mexico. AC -- In Repeater-Builder@yahoogroups.com, "Com/Rad Inc" wrote: > > Hello Al > > Thanks for reply - I figured that to be the case > Do you have anything in your collection resembling a DB222 > that would do 152-158 range ? > Ed > Com-Rad Inc > > ED > - Original Message - > From: wa9zzu > To: Repeater-Builder@yahoogroups.com > Sent: Saturday, August 01, 2009 9:11 AM > Subject: [Repeater-Builder] Re: DB224 Question > > > -I apologize for not giving a complete answer. > The short answer to the first question is yes. > The short answer to the second is no. > > Al Crites > > -- In Repeater-Builder@yahoogroups.com, "wa9zzu" wrote: > > > > -No > > > > Al Crites > > > > -- In Repeater-Builder@yahoogroups.com, "Com/Rad Inc" wrote: > > > > > > Turning to the experiences of the group as all vendor info sources are > > > off for the weekend - ( probably could research this on line ) > > > > > > Do any of you have knowledge of the chatachteristics of 1/2 of the DB > 224 antenna? > > > > > > With harness' intact does either section of this array resemble the DB > 222 ( 2 element ) antenna stack? > > > Concerned with feed impedance etc. I recall doing thihs with a UHF > version once and had reasonable results in a pinch... > > > > > > Any comments would be appreciated. > > > > > > Ed K9QPJ > > > > > >
[Repeater-Builder] Re: DB224 Question
-I apologize for not giving a complete answer. The short answer to the first question is yes. The short answer to the second is no. Al Crites -- In Repeater-Builder@yahoogroups.com, "wa9zzu" wrote: > > -No > > Al Crites > > -- In Repeater-Builder@yahoogroups.com, "Com/Rad Inc" wrote: > > > > Turning to the experiences of the group as all vendor info sources are > > off for the weekend - ( probably could research this on line ) > > > > Do any of you have knowledge of the chatachteristics of 1/2 of the DB 224 > > antenna? > > > > With harness' intact does either section of this array resemble the DB 222 > > ( 2 element ) antenna stack? > > Concerned with feed impedance etc. I recall doing thihs with a UHF version > > once and had reasonable results in a pinch... > > > > Any comments would be appreciated. > > > > Ed K9QPJ > > >
[Repeater-Builder] Re: DB224 Question
-No Al Crites -- In Repeater-Builder@yahoogroups.com, "Com/Rad Inc" wrote: > > Turning to the experiences of the group as all vendor info sources are > off for the weekend - ( probably could research this on line ) > > Do any of you have knowledge of the chatachteristics of 1/2 of the DB 224 > antenna? > > With harness' intact does either section of this array resemble the DB 222 ( > 2 element ) antenna stack? > Concerned with feed impedance etc. I recall doing thihs with a UHF version > once and had reasonable results in a pinch... > > Any comments would be appreciated. > > Ed K9QPJ >
[Repeater-Builder] Re: Closed Repeaters
The same analogy could be made for AM-FM-TV stations as well as Cellular, Nextel, and other such similar private owners of the public radio spectrum who get exclusive use granted. Allan Crites WA9ZZU --- In Repeater-Builder@yahoogroups.com, "Dennis Zabawa" wrote: > > The point has been made that a closed repeater (actually any repeater) is > private property and others have no right to utilize it. I would agree to > that premise except for the fact that the repeater utilizes PUBLIC spectrum. > > The analogy would be: I have a large tent that I like to set up on my > property. If I take that same tent and permanently set it up in a public > park and, I keep others from entering my tent, I am using PUBLIC property for > my own, exclusive use. Would that set well with most of you? > > I have a closed repeater that has PUBLIC spectrum coordinated for it. That > has the effect of allocating that PUBLIC asset for my exclusive use. > > Why should a repeater be different than the tent? >
RE: [Repeater-Builder] Re: Help with Duplexer
Eric: I wonder if you are aware that any BP two loop cavity can be made into a BP/BR cavity by using only one of the 2 loops, having a coaxial "T" connector on the loop, with a tuning capacitor (in the form of a O.C. transmission line) connected to one side of the "T" and on the other side a 1/4 W.L. transmission line connecting to a "T" connector on the main line. The tuning capacitance parallel resonates the loop inductance for the notch freq. and the cavity is tuned for the pass freq. This was an original Sinclair design. I view having a tuning cap in series internally with the loop as a cost reduced version and probably better performing. Several years ago DB made a BP/BR duplexer for Motorola on HB by using a BP 2 loop cavity with a coaxial "T" connector on both loops, one side of the input "T" was connected with a 1/4 W.L. coax to a jct box containing a variable air cap series connected to the cc of the one coax and to the cc of another 1/4 W.L. coax which connected to the output "T". The cavity tuned the BP freq., and the air variable tuned the notch. 73 WA9ZZU --- On Sun, 6/28/09, Eric Lemmon wrote: From: Eric Lemmon Subject: RE: [Repeater-Builder] Re: Help with Duplexer To: Repeater-Builder@yahoogroups.com Date: Sunday, June 28, 2009, 10:44 PM Ron, Your Q202G must be an earlier version, with a different method of adjusting the notch. A Sinclair bandpass cavity uses two loops, so the cavities you have are not bandpass. A photo would be helpful. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@ yahoogroups. com [mailto:Repeater-Builder@ yahoogroups. com] On Behalf Of n4sfu Sent: Sunday, June 28, 2009 6:39 PM To: Repeater-Builder@ yahoogroups. com Subject: [Repeater-Builder] Re: Help with Duplexer Eric, Thanks for the reply. The Sinclair Q202G duplexers that I have do not have the tiny threaded cap next to the loop connector. 1 set of cans are labeled as High pass while the other set is marked as Low pass. I did notice a plate on top of all 4 cans that has noting going to it but cannot fing anything else that shows it can be changed other than the tuning rod. I do currently have these tuned at 146.715/146. 115. 73 Ron Hill N4SFU --- In Repeater-Builder@ yahoogroups. com <mailto:Repeater- Builder%40yahoog roups.com> , "Eric Lemmon" wrote: > > Ron, > > If you really have a Q202G (I'm guessing that "Q020G" was a typo) cavity > set, they are not bandpass. What suggests that they are bandpass? The > standard Q202G BpBr duplexer has only one loop per can, and a blank plate is > installed where a second loop would be. A tiny threaded cap next to each > loop connector covers the notch adjustment. Be aware that a Q202G duplexer > that was in commercial service will probably have the high-split harness > that measures about 12" between the centers of each tee, and will not tune > down to the 2m band. The harness drawing is found here: > > > 73, Eric Lemmon WB6FLY > > > -Original Message- > From: Repeater-Builder@ yahoogroups. com <mailto:Repeater- Builder%40yahoog roups.com> > [mailto:Repeater-Builder@ yahoogroups. com <mailto:Repeater- Builder%40yahoog roups.com> ] On Behalf Of n4sfu > Sent: Saturday, June 27, 2009 7:13 PM > To: Repeater-Builder@ yahoogroups. com <mailto:Repeater- Builder%40yahoog roups.com> > Subject: [Repeater-Builder] Help with Duplexer > > > > I dont usually post on the forum but rcv the emails everyday and follow all > posts. I recently purchased a 4 can set of Sinclair Q020G cavities not > knowing until I had them tuned and connected to the MSR2000 that they are > Bandpass only. Needless to say that desense will not permit the rcv of weak > signals at all say 5 miles away. Does anyone know of a good place to acquire > a couple of the notch cavities with the cables to go with this set or of a > good set of BP/BR cavities at a reasonable price to complete this repeater > installation. We are located in South GA and are locating this repeaer on > 146.715 mhz. All help is appreciated. > Ron/N4SFU >
[Repeater-Builder] Re: Motorola tansistor
--- In Repeater-Builder@yahoogroups.com, "jim80362000" <[EMAIL PROTECTED]> wrote: > > I have a high voltage power supply/tpn1131A. Need Q51/48-869349/M9349 > transistor, for power control board,Can I use a substitute? And who may > carry them. Tried a few local supply places with no luck.Any help would > be appreciated. Thank you. > The EIA 274 marking on the TO66 package indicates the item was mfg'd by RCA. The device is an SCR. I suggest you try a 2n3525 which is now mfg'd by GE and is cross referenced on their data sheet as 5A & 500V. 73 Allan Crites WA9ZZU
[Repeater-Builder] Re: Reverse Burst Comments (Com Spec RB-1)
--- In Repeater-Builder@yahoogroups.com, "skipp025" <[EMAIL PROTECTED]> wrote: > > Re: Reverse Burst Comments (Com Spec RB-1) > > If you add a circuit like the Com Spec RB-1 board to the typical > repeater system using a ts-32/ts-54 board... the tx ctcss is not > disabled or removed before the RB-1 delayed ptt line drops. > > So you have the phase inverted ctcss present for at most up to > 200 ms typical before the tx drop. If you don't remove the ctcss > source the inverted ctcss remains up until the tx off/drop... > > Any of you actually running the RB-1 board with a true reverse > burst type ctcss decoder (built into your radio)? Is a true > reverse burst decoder in your commercial radio completely "fooled" > by the phase inverted ctcss before carrier drop function. > > Or do you actually still hear some minor difference from the > rb-1 type operation vs an original true Motorhead (Motorola) > encoder - decoder operation? > > Thinking out-loud about having to possibly mute the ctcss at some > time after invert and before the delayed ptt drop as a requirement > to get the full/true reverse burst quiet squelch close. > > Any of you been down that road already? > > skipp > Skipp, I find your comments interesting in that the purpose that Motorola had in using "reverse burst" of the PL tone was to quickly damp the mechanical reed in the PL decoder to close the squelch and eliminate the user from hearing the noise burst. But of course you knew that. However, in later model radios there is no mechanical vibrating reed to abruptly dampen and stop the vibrating from being detected. So where is the need for a inverted burst if there are no receivers using mechanical reeds as PL tone decoders? Incidently Motorola did not use an inverted reverse burst of 180 degrees. Their designs used 270 degrees since the PL reed then stopped vibrating faster and the amplitude of the burst was also increased to hasten the reed to stop. Don't modern day receivers use electronic circuitry to detect PL tones, and aren't the detectors not using a ringing decoder? If so isn't the purpose of having a "reverse burst" unnecessary? I can remember many years ago that some hams used a circuit which they refered to as "polish PL" which turned off the PL tone before the xmtr dropped and had no "reverse burst". It seems like I'm hearing more of the same. Where am I going wrong here? Allan Crites
[Repeater-Builder] Re: Mot. IC cross reference
--- In Repeater-Builder@yahoogroups.com, "sgreact47" <[EMAIL PROTECTED]> wrote: > > What are the other numbers and letters on these IC's? > That mite help narrow it down to an age range. Then we can check > our older parts books.--- > The info on the top is "61L23 RCA 8715 (which I assume 8715 is the date code) and on the bottom are "4ZLRC on one line and below that is P6502" in the standard 8 pin DIP. wa9zzu
[Repeater-Builder] Re: Mot. IC cross reference
--- In Repeater-Builder@yahoogroups.com, "Tedd Doda" <[EMAIL PROTECTED]> wrote: > > On Thu, 18 Jan 2007 05:52:15 -, wa9zzu wrote: > > >The IC's came from K9MDM's wharehouse liquidation sale last November > >and I have no idea where they were used. The parts are 8 pin DIP with > >the no. 61L23 marked and mfg'd by RCA. I've tried connections using > >the generic 741 & dual op amp and was unable to get any voltage or > >signal out. I'm stumped. > > HI Allan: > > Maybe you can tell us what you are trying to do? > You have an UNKNOWN IC on an UNKNOWN board...right? > > Are trying to salvage parts or what? > > Tedd Doda, VE3TJD > Lazer Audio and Electronics > Baden, Ontario, Canada > > www.ve3tjd.com (personal) > www.eraradio.ca (Linked repeater system) > Tedd: I have a bag of unknown ID's I'm trying to ID before I decide to throw them in the trash. wa9zzu
[Repeater-Builder] Re: Mot. IC cross reference
--- In Repeater-Builder@yahoogroups.com, "Eric Lemmon" <[EMAIL PROTECTED]> wrote: > > I searched MOL to see if "61L23" appeared anywhere within a current part > number, but found nothing. If you can describe the board it came out of, or > post a picture of the board, that may help. > > 73, Eric Lemmon WB6FLY > > > -Original Message- > From: Repeater-Builder@yahoogroups.com > [mailto:[EMAIL PROTECTED] On Behalf Of wa9zzu > Sent: Wednesday, January 17, 2007 10:04 AM > To: Repeater-Builder@yahoogroups.com > Subject: [Repeater-Builder] Mot. IC cross reference > > I need a commercial cross reference to a Mot. IC #61L23. Can anyone > help? Unknown the board number. Got no help from IC suppliers. > Thanks, wa9zzu. > The IC's came from K9MDM's wharehouse liquidation sale last November and I have no idea where they were used. The parts are 8 pin DIP with the no. 61L23 marked and mfg'd by RCA. I've tried connections using the generic 741 & dual op amp and was unable to get any voltage or signal out. I'm stumped. wa9zzu
[Repeater-Builder] Mot. IC cross reference
I need a commercial cross reference to a Mot. IC #61L23. Can anyone help? Unknown the board number. Got no help from IC suppliers. Thanks, wa9zzu.
[Repeater-Builder] Re: LOOKING for Micor t-Band 470-494 rcvr board (or is it bored)
--- In Repeater-Builder@yahoogroups.com, Ted Bleiman K9MDM - MDM Radio <[EMAIL PROTECTED]> wrote: > > need 1 working for repair job. > > mdm ted > > happy holidaze to all > > Ted Bleiman K9MDM > MDM Radio > P O Box 31353 > Chicago, IL 60631-0353 > 773.631.5130 fax 773.775.8096 > > web http://www.mdmradio.com - > alt email [EMAIL PROTECTED] > or [EMAIL PROTECTED] > I have several. What do you have to trade ? Allan Crites wa9zzu > > > > > > > > > > > > __ __ > Cheap talk? > Check out Yahoo! Messenger's low PC-to-Phone call rates. > http://voice.yahoo.com >
[Repeater-Builder] Re: LOOKING for Micor t-Band 470-494 rcvr board (or is it bored)
--- In Repeater-Builder@yahoogroups.com, Ted Bleiman K9MDM - MDM Radio <[EMAIL PROTECTED]> wrote: > > need 1 working for repair job. > > mdm ted > > happy holidaze to all > > Ted Bleiman K9MDM > MDM Radio > P O Box 31353 > Chicago, IL 60631-0353 > 773.631.5130 fax 773.775.8096 > > web http://www.mdmradio.com - > alt email [EMAIL PROTECTED] > or [EMAIL PROTECTED] > I have several. What do you have to trade ? Allan Crites wa9zzu > > > > > > > > > > > > __ __ > Cheap talk? > Check out Yahoo! Messenger's low PC-to-Phone call rates. > http://voice.yahoo.com >
