[Repeater-Builder] Decibel dipole array sweeps
I'm in the process of putting up a remote receiver for a 440 ham repeater using a Decibel DB413 dipole array cut for 450-470 MHz. Since Decibel/Andrew stopped making the 440-450 MHz custom models, I've used the usual 450-470 split antennas for receive sites, and they've performed well. I swept the DB413, and it measured as I expected. While I had the Sitemaster out, I grabbed a few other Decibel dipole arrays out of the warehouse and swept them and prepared a little document. Since the topic of using commercial-band antennas on amateur frequencies comes up fairly often, I figured these measurements might be of some interest to list members. I tested these antennas with them mounted above ground level, and away from nearby objects, with the Sitemaster connected right to the pigtail so what you're seeing is the true return loss at the feedpoint. I'll continue to test more antennas (not just DB dipole arrays) over time and continue to add them to this document. I have gobs of sweeps of antennas, but unfortunately many of them were swept at the bottom end of heliax runs rather than right at the feedpoint. From now on I'll make it a point to sweep them on the ground this way. The antennas I tested in this first batch are: DB413, 450-470 MHz DB408D, 450-470 MHz DB411, 450-470 MHz DB411, 406-420 MHz Note that the DB408D is actually two DB404's on a common mast, each with its own pigtail/feedpoint, so there are separate plots for the upper antenna and lower antenna. Its performance wasn't what I expected. I have more of the same model of antenna, I'll try to test one of the others the next time. The document can be found here: http://www.broadsci.com/Antenna Sweeps r1.pdf If anyone finds this useful please let me know, so I know whether or not it's worth the time/effort to continue to test antennas and add them to the doc. --- Jeff WN3A
Re: [Repeater-Builder] Re: 2 GM300 UHF Mobile Radios for Repeater
hi, we have been using surplus GM300 Radios as repeater about one year and have no problem with it.. very good radios. Either using back to back interface from ebay or HLNB controller both work great. We are planning to link our repeaters and need help for interfacing it. I appreciate if anybody can help us. What we have in the workshop left are one more HLMB and 2 unit back to back interface cable that we bought from ebay. regards azam On Fri, Mar 20, 2009 at 8:14 PM, aisendwight aisendwi...@yahoo.com wrote: --- In Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com, Romy ve7...@... wrote: Sorry if this question might have been asked before already. I am planning to use 2 GM300 Radios (M44GMC20D3AA) to build a simple repeater in a back to back configuration . For those who used this configuration can you please share any tips and ideas. How is the performance and reliability of this configuration? I am also planning to use the repeater on Echolink. Hello Romy, one of my repeaters is made out of two Motorola M120's (the two channel version of the GM300). And it works great. As long as you place it on a place with good ventilation and place a fan on the back of the transmitting radio you should have no problems. You should also set the power of the transmitting radio to about 25 to 30 watts. All M44's can do 40 watts, but it's better to limit the power to reduce the risk of a TX transistor burnout do to excesive use. Remember that these radios are not 100% duty cycle. I use mine to provide comm service to a private ambulance company and it's worked well until now. A 15 amp power supply will be enough, (that's what I use) but you can use more power if you have it. About the interface, I assume you will be using the simple cable being sold in ebay. I use one of those also. Although I'm planning to use a more sophisticated controller later. One thing...are your radios 8 channel or 16 channel? if they are 8 channel models, I believe that you wont have to reassign functions to the 16 pin logic. But if 16 channels...you will have to change the function of pin 8 to enable it to send the COR signal nesessary for operation. That's the good thing about the 8 channel GM300, the two channel M120 and the single channel M10, you don't have to change anything, just plug and play. Finally, if you need programming software for the radios, let me know, I've got several versions, including the v.5 Version. Aisen
Re: [Repeater-Builder] Decibel dipole array sweeps
At 3/22/2009 11:32, you wrote: The document can be found here: http://www.broadsci.com/Antenna Sweeps r1.pdf I get a The file is damaged could not be repaired error. Bob NO6B
RE: [Repeater-Builder] SCR-200(A)
Perhaps the last update on the SCT1000/SCR200 rebuild: We took the duplexer that we had been using for testing back to the guy who tuned it. It turns out that it was tuned for another repeater frequency so we were ok with the setup of the repeater itself. Thanks to Larry and Joe specifically and to the list in general for all your good assistance and appropriate questions. The repeater should soon be back on task. 73 de Morris KI4IUA -Original Message- From: Morris Dillingham [mailto:mdi...@nnwifi.com] Sent: Tuesday, March 17, 2009 6:54 PM To: 'k1ike_m...@snet.net' Cc: 'Repeater-Builder@yahoogroups.com' Subject: RE: [Repeater-Builder] SCR-200(A) Continuing saga of the SCR-1000 which received signals that keyed COR but with no received audio: We tested again today with the transmitter inhibited but using the duplexer. Receiver performed fine up to 5 or more miles away. Apparently the duplexer is questionably aligned and is causing desense. We go on Saturday to the original tuner who is expressing doubts about how he originally tuned the duplexer. He has spectrum analyzer and other equipment which will allow checking for spurs, etc. so it's not all that bad that this happened, especially since I learned so much about the importance of separation of signals. 73 de Morris KI4IUA -Original Message- From: Morris Dillingham [mailto:mdi...@nnwifi.com] Sent: Friday, March 13, 2009 10:34 PM To: 'k1ike_m...@snet.net' Cc: 'Repeater-Builder@yahoogroups.com' Subject: RE: [Repeater-Builder] SCR-200(A) Joe, the duplexer had been tuned by someone else. It did appear to work ok in another lashup with other equipment. I haven't been back to the test site to try it without the transmitter but it could have been desense as the COR worked. I'll have to get my cohort to try it as he is close to the equipment in fact it's at his QTH. You may have guessed by now that I'm new to this facet of radio. I'm beginning to realize how important this desense topic is. Thanks for the great question you pose. We plan another test tomorrow with the transmitter off. 73 de Morris KI4IUA -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- buil...@yahoogroups.com] On Behalf Of Joe Sent: Friday, March 13, 2009 9:39 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] SCR-200(A) Hello Morris, I'm glad to heard the that you got the receiver working! Just one question, was the test duplexer tuned to the proper frequencies? Was it desense or just loss of sensitivity when using the duplexer? In other words, were you able to hear distant signals with the transmitter turned off? 73, Joe, K1ike Morris Dillingham wrote: Well, guys, I promised to follow up with the results of my attempt to repair the old Spectrum 1000 with the later model receiver. Thanks to Larry and Joe, I have determined that my receiver is not an SCR200A but probably a later model of the SCR-200. I obtained at least three versions of the schematic from this series receiver thanks to these two gentlemen. Of utmost importance was finding out the transistor part number since my schematic was the wrong version. I was able to replace the front RF amp and get the receiver working again. Before doing that, however, I noted the inadequate wiring, IMHO, in the power supply. The SCR-1000 upgraded PS has plenty of safety factor designed in as far as series pass transistors, etc. but the size of the wires was amazingly small. I completely rewired the high current circuits to match the rest of the design. I am wondering if during the period of this antique repeater there was a shortage of copper and the price was high. After rewiring, the power output of the transmitter was noticeably increased to about 78 watts while it's specified as a 70 watt PA. I took the repeater to a staging area where we had another duplexer to test it on the air. (The actual installation is in the county jail in a jail cell) Distant signals would develop a COR but there was no audio when using the duplexer. When the antenna is directly attached to the receiver with the transmitter on dummy load, it works fine. At this point we were too tired to go further so will get back on it again soon. I suppose the front end may need touching up with that duplexer which has been checked out on another setup. Thanks again to Joe, Larry and the list for their excellent help. 73 de Morris KI4IUA Yahoo! Groups Links Yahoo! Groups Links
[Repeater-Builder] Master II station 66 split conversion to 56 split
Now that you have helped me close out the old Spectrum issues, can anyone point me to the list of caps and their new values to convert the exciter board of a Master II station? On the NHRC site I see mention of the need to change out a dozen or so caps but no other references. 73 de Morris KI4IUA attachment: winmail.dat
Re: [Repeater-Builder] Decibel dipole array sweeps
n...@no6b.com wrote: At 3/22/2009 11:32, you wrote: The document can be found here: http://www.broadsci.com/Antenna Sweeps r1.pdf I get a The file is damaged could not be repaired error. And I get a 404 Page not found error. Paul
Re: [Repeater-Builder] Decibel dipole array sweeps
The link is broken if you try to use it as it came through.. the space in the file name is the killer... http://www.broadsci.com/Antenna%20Sweeps%20r1.pdf is the correct link Doug At 03:31 PM 3/22/2009, you wrote: mailto:no6b%40no6b.comn...@no6b.com wrote: At 3/22/2009 11:32, you wrote: The document can be found here: http://www.broadsci.com/Antennahttp://www.broadsci.com/Antenna Sweeps r1.pdf I get a The file is damaged could not be repaired error. And I get a 404 Page not found error. Paul
[Repeater-Builder] RE: AF2140 filter
I have come across this filter in my junk box and am unable to find much information on it. I think it is a Sinclair unit, but does not appear to be listed in the Sinclair Catalog. I am sure it is a vhf unit but am not sure of the tuning procedures. It follows a Isolator. Is it a LP filter or a 2nd harmonic filter?? It only has one tuning control which is offset from the centre of the small block and appears to be a capacitor similar to those used in Sinclair's notch cavities. Lots of listings on ebay for them, but no tuning instructions or descriptions otherwise. Since I have it, I thought I might as well use it... How do I tune it?? Thanks Doug
[Repeater-Builder] Re: Decibel dipole array sweeps
No luck accessing the website. Have you tested the DB420. I know they are pretty broad banded. I have a damaged one and only the top half is useable. What type of impedence mismatch am I looking at if I feed the top half at the mid point connector. And it if is way off, how would I correct it to bring it back to 50 Ohms +/- ?? Doug N3DAB
RE: [Repeater-Builder] Decibel dipole array sweeps
Boy, Yahoo really mangled the URL, even though I put it in angle brackets. Let's try re-naming the file without spaces, maybe that will work... http://www.broadsci.com/AntennaSweepsR1.pdf Bob - the file opened fine for me, both locally and from the web site. I'm using Acrobat 9.0. The document info shows it's PDF version 1.5 for Acrobat version 6.x or later. I've had a few other cases where I couldn't open recently-produced PDF's sent to me by others using Acrobat 9; upgrading to the current version of Reader fixed it, even though the files should be compatible with Acrobat 6 or later. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Paul N1BUG Sent: Sunday, March 22, 2009 3:32 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Decibel dipole array sweeps n...@no6b.com mailto:no6b%40no6b.com wrote: At 3/22/2009 11:32, you wrote: The document can be found here: http://www.broadsci.com/Antenna http://www.broadsci.com/Antenna Sweeps r1.pdf I get a The file is damaged could not be repaired error. And I get a 404 Page not found error. Paul No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: 270.11.3/1970 - Release Date: 03/21/09 17:58:00
Re: [Repeater-Builder] Decibel dipole array sweeps
Jeff; This is very interesting findings especially in that using an antenna longer than your freq tends to exhibit down tilt... that 440 use of a 450 antenna seems to be working in the correct direction. I for one found it very interesting to read It may be real interesting to see some of the amateur antennas tested too as multiband ones seem to rarely work very well on the upper bands compared to the lower bands of those I have seen Doug At 02:32 PM 3/22/2009, you wrote: I'm in the process of putting up a remote receiver for a 440 ham repeater using a Decibel DB413 dipole array cut for 450-470 MHz. Since Decibel/Andrew stopped making the 440-450 MHz custom models, I've used the usual 450-470 split antennas for receive sites, and they've performed well. I swept the DB413, and it measured as I expected. While I had the Sitemaster out, I grabbed a few other Decibel dipole arrays out of the warehouse and swept them and prepared a little document. Since the topic of using commercial-band antennas on amateur frequencies comes up fairly often, I figured these measurements might be of some interest to list members. I tested these antennas with them mounted above ground level, and away from nearby objects, with the Sitemaster connected right to the pigtail so what you're seeing is the true return loss at the feedpoint. I'll continue to test more antennas (not just DB dipole arrays) over time and continue to add them to this document. I have gobs of sweeps of antennas, but unfortunately many of them were swept at the bottom end of heliax runs rather than right at the feedpoint. From now on I'll make it a point to sweep them on the ground this way. The antennas I tested in this first batch are: DB413, 450-470 MHz DB408D, 450-470 MHz DB411, 450-470 MHz DB411, 406-420 MHz Note that the DB408D is actually two DB404's on a common mast, each with its own pigtail/feedpoint, so there are separate plots for the upper antenna and lower antenna. Its performance wasn't what I expected. I have more of the same model of antenna, I'll try to test one of the others the next time. The document can be found here: http://www.broadsci.com/Antennahttp://www.broadsci.com/Antenna Sweeps r1.pdf If anyone finds this useful please let me know, so I know whether or not it's worth the time/effort to continue to test antennas and add them to the doc. --- Jeff WN3A
[Repeater-Builder] Re: Decibel dipole array sweeps
Jeff , I'm interested, however, I can't pull up the website you posted below for some reason. Also I'm curious about your findings with regard to using the upper half of atennas like the DB420 and impedance you are seeing at the mid point connector. I'm assuming the entire antenna presents a 50 +/-ohm load at the original feed point but what impedance do you actually see if you using the top half (of a damage antenna)and feed it at the mid-point connector ? Thanks Doug N3DAB --- In Repeater-Builder@yahoogroups.com, Jeff DePolo j...@... wrote: I'm in the process of putting up a remote receiver for a 440 ham repeater. . The document can be found here: http://www.broadsci.com/Antenna Sweeps r1.pdf doc. --- Jeff WN3A
Re: [Repeater-Builder] Re: Decibel dipole array sweeps
It should work fine. It is at 50-ohms there. Chuck WB2EDV - Original Message - From: n3dab rb_n3...@tds.net To: Repeater-Builder@yahoogroups.com Sent: Sunday, March 22, 2009 3:46 PM Subject: [Repeater-Builder] Re: Decibel dipole array sweeps No luck accessing the website. Have you tested the DB420. I know they are pretty broad banded. I have a damaged one and only the top half is useable. What type of impedence mismatch am I looking at if I feed the top half at the mid point connector. And it if is way off, how would I correct it to bring it back to 50 Ohms +/- ?? Doug N3DAB Yahoo! Groups Links
Re: [Repeater-Builder] Decibel dipole array sweeps
Page cannot be found using your fixed link. Chuck WB2EDV - Original Message - From: Doug Bade k...@thebades.net To: Repeater-Builder@yahoogroups.com Sent: Sunday, March 22, 2009 3:54 PM Subject: Re: [Repeater-Builder] Decibel dipole array sweeps The link is broken due to the space in the name... The actual url is http://www.broadsci.com/Antenna%20Sweeps%20r1.pdf Doug this may be a dup.. my outbound mail seems to be randomly getting delayed..
RE: [Repeater-Builder] RE: AF2140 filter
I'm almost positive that it's a Celwave, not a Sinclair, but I don't recognize that exact part number. Their tunable low-pass filters (actually second harmonic notch filters) had part numbers like AF150-T which was for highband VHF (the 150 being the nominal center of the passbasnd frequency, i.e. 150 MHz, with the reject notch being 2X that frequency). If you sweep it, it will be obvious how it works/tunes. You'll basically see a notch that is tunable with the trimmer cap. It's normally tuned to notch the transmitter's second harmonic. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Doug Sent: Sunday, March 22, 2009 3:54 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] RE: AF2140 filter I have come across this filter in my junk box and am unable to find much information on it. I think it is a Sinclair unit, but does not appear to be listed in the Sinclair Catalog. I am sure it is a vhf unit but am not sure of the tuning procedures. It follows a Isolator. Is it a LP filter or a 2nd harmonic filter?? It only has one tuning control which is offset from the centre of the small block and appears to be a capacitor similar to those used in Sinclair's notch cavities. Lots of listings on ebay for them, but no tuning instructions or descriptions otherwise. Since I have it, I thought I might as well use it... How do I tune it?? Thanks Doug No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: 270.11.3/1970 - Release Date: 03/21/09 17:58:00
Re: [Repeater-Builder] Decibel dipole array sweeps
That's strange. I'm using Foxfire 3.0.7 and the original link was OK. Joe Doug Bade wrote: The link is broken if you try to use it as it came through.. the space in the file name is the killer... http://www.broadsci.com/Antenna%20Sweeps%20r1.pdf
RE: [Repeater-Builder] Decibel dipole array sweeps
For a parallel-fed (aka binary-fed, corporate-fed, etc.) antenna, if all of the elements are fed in-phase (i.e. the branches in the phasing harness are all the same length), as it typical with most dipole arrays, there won't be any uptilt/downtilt as you vary the transmitter frequency outside of the design range a bit. No matter what the frequency of the carrier is, it's always going to hit the elements in-phase, so there won't be any beamtilt. This is constrast to an end-fed (series-fed) collinear, where you will get UPTILT if transmitting at a frequency ABOVE the antenna's design range, and DOWNTILT if transmitting at a frequency BELOW the antenna's design range. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Doug Bade Sent: Sunday, March 22, 2009 4:10 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Decibel dipole array sweeps Jeff; This is very interesting findings especially in that using an antenna longer than your freq tends to exhibit down tilt... that 440 use of a 450 antenna seems to be working in the correct direction. I for one found it very interesting to read It may be real interesting to see some of the amateur antennas tested too as multiband ones seem to rarely work very well on the upper bands compared to the lower bands of those I have seen Doug At 02:32 PM 3/22/2009, you wrote: I'm in the process of putting up a remote receiver for a 440 ham repeater using a Decibel DB413 dipole array cut for 450-470 MHz. Since Decibel/Andrew stopped making the 440-450 MHz custom models, I've used the usual 450-470 split antennas for receive sites, and they've performed well. I swept the DB413, and it measured as I expected. While I had the Sitemaster out, I grabbed a few other Decibel dipole arrays out of the warehouse and swept them and prepared a little document. Since the topic of using commercial-band antennas on amateur frequencies comes up fairly often, I figured these measurements might be of some interest to list members. I tested these antennas with them mounted above ground level, and away from nearby objects, with the Sitemaster connected right to the pigtail so what you're seeing is the true return loss at the feedpoint. I'll continue to test more antennas (not just DB dipole arrays) over time and continue to add them to this document. I have gobs of sweeps of antennas, but unfortunately many of them were swept at the bottom end of heliax runs rather than right at the feedpoint. From now on I'll make it a point to sweep them on the ground this way. The antennas I tested in this first batch are: DB413, 450-470 MHz DB408D, 450-470 MHz DB411, 450-470 MHz DB411, 406-420 MHz Note that the DB408D is actually two DB404's on a common mast, each with its own pigtail/feedpoint, so there are separate plots for the upper antenna and lower antenna. Its performance wasn't what I expected. I have more of the same model of antenna, I'll try to test one of the others the next time. The document can be found here: http://www.broadsci.com/Antenna http://www.broadsci.com/Antenna http://www.broadsci.com/Antenna http://www.broadsci.com/Antenna Sweeps r1.pdf If anyone finds this useful please let me know, so I know whether or not it's worth the time/effort to continue to test antennas and add them to the doc. --- Jeff WN3A No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: 270.11.3/1970 - Release Date: 03/21/09 17:58:00
RE: [Repeater-Builder] Decibel dipole array sweeps
I got the same result. The link was parsed incorrectly. Try this: www.broadsci.com/Antennasweepsr1.pdf 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of n...@no6b.com Sent: Sunday, March 22, 2009 12:10 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Decibel dipole array sweeps At 3/22/2009 11:32, you wrote: The document can be found here: http://www.broadsci.com/Antenna http://www.broadsci.com/Antenna Sweeps r1.pdf I get a The file is damaged could not be repaired error. Bob NO6B
RE: [Repeater-Builder] Re: 2 GM300 UHF Mobile Radios for Repeater
I use a few M-10 with a controller on ebay from MRE and it works just fine. Peter Summerhawk -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Azam Sent: Sunday, March 22, 2009 9:53 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: 2 GM300 UHF Mobile Radios for Repeater hi, we have been using surplus GM300 Radios as repeater about one year and have no problem with it.. very good radios. Either using back to back interface from ebay or HLNB controller both work great. We are planning to link our repeaters and need help for interfacing it. I appreciate if anybody can help us. What we have in the workshop left are one more HLMB and 2 unit back to back interface cable that we bought from ebay. regards azam On Fri, Mar 20, 2009 at 8:14 PM, aisendwight aisendwight@ mailto:aisendwi...@yahoo.com yahoo.com wrote: --- In Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com, Romy ve7...@... wrote: Sorry if this question might have been asked before already. I am planning to use 2 GM300 Radios (M44GMC20D3AA) to build a simple repeater in a back to back configuration . For those who used this configuration can you please share any tips and ideas. How is the performance and reliability of this configuration? I am also planning to use the repeater on Echolink. Hello Romy, one of my repeaters is made out of two Motorola M120's (the two channel version of the GM300). And it works great. As long as you place it on a place with good ventilation and place a fan on the back of the transmitting radio you should have no problems. You should also set the power of the transmitting radio to about 25 to 30 watts. All M44's can do 40 watts, but it's better to limit the power to reduce the risk of a TX transistor burnout do to excesive use. Remember that these radios are not 100% duty cycle. I use mine to provide comm service to a private ambulance company and it's worked well until now. A 15 amp power supply will be enough, (that's what I use) but you can use more power if you have it. About the interface, I assume you will be using the simple cable being sold in ebay. I use one of those also. Although I'm planning to use a more sophisticated controller later. One thing...are your radios 8 channel or 16 channel? if they are 8 channel models, I believe that you wont have to reassign functions to the 16 pin logic. But if 16 channels...you will have to change the function of pin 8 to enable it to send the COR signal nesessary for operation. That's the good thing about the 8 channel GM300, the two channel M120 and the single channel M10, you don't have to change anything, just plug and play. Finally, if you need programming software for the radios, let me know, I've got several versions, including the v.5 Version. Aisen
Re: [Repeater-Builder] Decibel dipole array sweeps
Joe; The original posted file name had spaces in between Antenna, Sweeps, and r1 ...and some or all windows client email programs likley displayed as he sent it... Mine did but I spotted it as it showed as fractured hyperlink... Foxfire my have corrected it in your case. When I COPIED ( as in copy and paste) it into IE it inserted the %20's.. but if you launched it as a hyperlink directly it dropped everything after the first space... as being not part of the file name.. hence the broken links some found Doug At 04:16 PM 3/22/2009, you wrote: That's strange. I'm using Foxfire 3.0.7 and the original link was OK. Joe Doug Bade wrote: The link is broken if you try to use it as it came through.. the space in the file name is the killer... http://www.broadsci.com/Antenna%20Sweeps%20r1.pdfhttp://www.broadsci.com/Antenna%20Sweeps%20r1.pdf
RE: [Repeater-Builder] Decibel dipole array sweeps
Jeff; What is your thoughts on the radiation launch angle in this case if beam tilt does not suffer/gain ??? I have a case in point of a wideband 406-470 uhf sinclair dipole 310C4.. on VHF as the elements are larger than vhf needs ??? in other words using it on both vhf and uhf assuming reasonable vswr Doug At 04:17 PM 3/22/2009, you wrote: For a parallel-fed (aka binary-fed, corporate-fed, etc.) antenna, if all of the elements are fed in-phase (i.e. the branches in the phasing harness are all the same length), as it typical with most dipole arrays, there won't be any uptilt/downtilt as you vary the transmitter frequency outside of the design range a bit. No matter what the frequency of the carrier is, it's always going to hit the elements in-phase, so there won't be any beamtilt. This is constrast to an end-fed (series-fed) collinear, where you will get UPTILT if transmitting at a frequency ABOVE the antenna's design range, and DOWNTILT if transmitting at a frequency BELOW the antenna's design range. --- Jeff WN3A -Original Message- From: mailto:Repeater-Builder%40yahoogroups.comRepeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Doug Bade Sent: Sunday, March 22, 2009 4:10 PM To: mailto:Repeater-Builder%40yahoogroups.comRepeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Decibel dipole array sweeps Jeff; This is very interesting findings especially in that using an antenna longer than your freq tends to exhibit down tilt... that 440 use of a 450 antenna seems to be working in the correct direction. I for one found it very interesting to read It may be real interesting to see some of the amateur antennas tested too as multiband ones seem to rarely work very well on the upper bands compared to the lower bands of those I have seen Doug At 02:32 PM 3/22/2009, you wrote: I'm in the process of putting up a remote receiver for a 440 ham repeater using a Decibel DB413 dipole array cut for 450-470 MHz. Since Decibel/Andrew stopped making the 440-450 MHz custom models, I've used the usual 450-470 split antennas for receive sites, and they've performed well. I swept the DB413, and it measured as I expected. While I had the Sitemaster out, I grabbed a few other Decibel dipole arrays out of the warehouse and swept them and prepared a little document. Since the topic of using commercial-band antennas on amateur frequencies comes up fairly often, I figured these measurements might be of some interest to list members. I tested these antennas with them mounted above ground level, and away from nearby objects, with the Sitemaster connected right to the pigtail so what you're seeing is the true return loss at the feedpoint. I'll continue to test more antennas (not just DB dipole arrays) over time and continue to add them to this document. I have gobs of sweeps of antennas, but unfortunately many of them were swept at the bottom end of heliax runs rather than right at the feedpoint. From now on I'll make it a point to sweep them on the ground this way. The antennas I tested in this first batch are: DB413, 450-470 MHz DB408D, 450-470 MHz DB411, 450-470 MHz DB411, 406-420 MHz Note that the DB408D is actually two DB404's on a common mast, each with its own pigtail/feedpoint, so there are separate plots for the upper antenna and lower antenna. Its performance wasn't what I expected. I have more of the same model of antenna, I'll try to test one of the others the next time. The document can be found here: http://www.broadsci.com/Antennahttp://www.broadsci.com/Antenna http://www.broadsci.com/Antenna http://www.broadsci.com/Antennahttp://www.broadsci.com/Antenna http://www.broadsci.com/Antenna Sweeps r1.pdf If anyone finds this useful please let me know, so I know whether or not it's worth the time/effort to continue to test antennas and add them to the doc. --- Jeff WN3A No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: 270.11.3/1970 - Release Date: 03/21/09 17:58:00
Re: [Repeater-Builder] Decibel dipole array sweeps
The link is broken due to the space in the name... The actual url is http://www.broadsci.com/Antenna%20Sweeps%20r1.pdf Doug this may be a dup.. my outbound mail seems to be randomly getting delayed.. At 03:31 PM 3/22/2009, you wrote: mailto:no6b%40no6b.comn...@no6b.com wrote: At 3/22/2009 11:32, you wrote: The document can be found here: http://www.broadsci.com/Antennahttp://www.broadsci.com/Antenna Sweeps r1.pdf I get a The file is damaged could not be repaired error. And I get a 404 Page not found error. Paul
RE: [Repeater-Builder] RE: AF2140 filter
Doug, The Sinclair AF-2140 is a VHF harmonic filter that is intended to follow a ferrite isolator. According to my Sinclair catalog, it comes in two versions: 132-150 MHz, and 150-174 MHz. It has a 0.1 dB insertion loss and can attenuate the second harmonic a minimum of 40 dB. It can be tuned easily with a TG-equipped spectrum analyzer; just tune for maximum notch at the second harmonic. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Doug Sent: Sunday, March 22, 2009 12:54 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] RE: AF2140 filter I have come across this filter in my junk box and am unable to find much information on it. I think it is a Sinclair unit, but does not appear to be listed in the Sinclair Catalog. I am sure it is a vhf unit but am not sure of the tuning procedures. It follows an Isolator. Is it a LP filter or a 2nd harmonic filter?? It only has one tuning control which is offset from the centre of the small block and appears to be a capacitor similar to those used in Sinclair's notch cavities. Lots of listings on ebay for them, but no tuning instructions or descriptions otherwise. Since I have it, I thought I might as well use it... How do I tune it?? Thanks Doug
RE: [Repeater-Builder] Decibel dipole array sweeps
As I mentioned a few minutes ago, there won't be any change in the take-off angle (beamtilt) for these parallel-fed dipole arrays. However, as you go lower in frequency, as we typically do when using a 450-470 antenna down in the 440's, the elements are effectively spaced closer together (in terms of wavelength) than they would be if we were operating at, say, 460 MHz. Because of the reduction in the intra-bay spacing, there will be slightly less peak gain on the horizon, and some variation in the minor lobes, but the major lobe will still be centered on the horizon. On-horizon gain tends to peak at a little under 1 wavelength for the intra-bay spacing. As you go above 1 wavelength, the elevation pattern quickly starts to fall apart. As you go under 1 wavelength, the peak gain gradually starts to decrease as the major lobe gets fatter. At half-wavelength spacing (i.e. element tips almost touching each other), the gain is on the order of roughly 2 dB below what it would be as compared to the full-wavelength spacing case. A spacing of around 0.9 wavelengths at the highest-rated frequency is used for many VHF/UHF dipole arrays as a good compromise. Some dipole arrays with 4 or more bays have a little variation between the element spacing too, which has the affect of altering the sidelobes to help fill some of the nulls below the horizon, but that alone won't create appreciable beamtilt of the major lobe. Dipole arrays that ARE designed for beamtilt have a phasing harness with unequal-length branches that puts more progressively more delay in the branches to the lower elements. A long time ago I modeled a 4-bay VHF dipole array in NEC using the lengths and spacings from a DB224 dipole array that was cut for 155 MHz. Down at 146 MHz, the peak gain was only degraded about half a dB as compared to the 155 MHz case, and the main lobe got just a little fatter. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Joe Sent: Sunday, March 22, 2009 4:22 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Decibel dipole array sweeps Although, in some cases, the return loss (or VSWR) looks to be acceptable I wonder what the take-off angle of radiation and radiation pattern looks like at frequencies out of it's design range. 73, Joe, K1ike Jeff DePolo wrote: I tested these antennas with them mounted above ground level, and away from nearby objects, with the Sitemaster connected right to the pigtail so what you're seeing is the true return loss at the feedpoint. No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: 270.11.3/1970 - Release Date: 03/21/09 17:58:00
Re: [Repeater-Builder] Decibel dipole array sweeps
Jeff is correct. A corporate fed antenna will only start to loose a bit of gain when you go outside of the band. Obviously you go too far and the return loss goes sour. Chuck WB2EDV - Original Message - From: Jeff DePolo j...@broadsci.com To: Repeater-Builder@yahoogroups.com Sent: Sunday, March 22, 2009 4:17 PM Subject: RE: [Repeater-Builder] Decibel dipole array sweeps For a parallel-fed (aka binary-fed, corporate-fed, etc.) antenna, if all of the elements are fed in-phase (i.e. the branches in the phasing harness are all the same length), as it typical with most dipole arrays, there won't be any uptilt/downtilt as you vary the transmitter frequency outside of the design range a bit. No matter what the frequency of the carrier is, it's always going to hit the elements in-phase, so there won't be any beamtilt. This is constrast to an end-fed (series-fed) collinear, where you will get UPTILT if transmitting at a frequency ABOVE the antenna's design range, and DOWNTILT if transmitting at a frequency BELOW the antenna's design range. --- Jeff WN3A
Re: [Repeater-Builder] Decibel dipole array sweeps
The group hereby accepts Joe's offer to construct an antenna test range to conduct pattern testing. What a nice guy! LOL!! Chuck WB2EDV - Original Message - From: Joe k1ike_m...@snet.net To: Repeater-Builder@yahoogroups.com Sent: Sunday, March 22, 2009 4:22 PM Subject: Re: [Repeater-Builder] Decibel dipole array sweeps Although, in some cases, the return loss (or VSWR) looks to be acceptable I wonder what the take-off angle of radiation and radiation pattern looks like at frequencies out of it's design range. 73, Joe, K1ike
Re: [Repeater-Builder] Decibel dipole array sweeps
Jeff - When you are testing next time, it might be interesting to see results of a sweep using some feedline attached to the antenna. I have to wonder what impact it may (or may not) have. When you test with your instrument connected to the pigtail, are you standing right there, or is the antenna completely in the clear? Chuck WB2EDV
RE: [Repeater-Builder] Decibel dipole array sweeps
An interesting project, I look forward to reading your report however your link was incorrectly typed. Here is a corrected link; http://www.broadsci.com/AntennaSweepsr1.pdf Gary -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Jeff DePolo Sent: Sunday, March 22, 2009 11:33 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Decibel dipole array sweeps I'm in the process of putting up a remote receiver for a 440 ham repeater using a Decibel DB413 dipole array cut for 450-470 MHz. Since Decibel/Andrew stopped making the 440-450 MHz custom models, I've used the usual 450-470 split antennas for receive sites, and they've performed well. I swept the DB413, and it measured as I expected. While I had the Sitemaster out, I grabbed a few other Decibel dipole arrays out of the warehouse and swept them and prepared a little document. Since the topic of using commercial-band antennas on amateur frequencies comes up fairly often, I figured these measurements might be of some interest to list members. I tested these antennas with them mounted above ground level, and away from nearby objects, with the Sitemaster connected right to the pigtail so what you're seeing is the true return loss at the feedpoint. I'll continue to test more antennas (not just DB dipole arrays) over time and continue to add them to this document. I have gobs of sweeps of antennas, but unfortunately many of them were swept at the bottom end of heliax runs rather than right at the feedpoint. From now on I'll make it a point to sweep them on the ground this way. The antennas I tested in this first batch are: DB413, 450-470 MHz DB408D, 450-470 MHz DB411, 450-470 MHz DB411, 406-420 MHz Note that the DB408D is actually two DB404's on a common mast, each with its own pigtail/feedpoint, so there are separate plots for the upper antenna and lower antenna. Its performance wasn't what I expected. I have more of the same model of antenna, I'll try to test one of the others the next time. The document can be found here: http://www.broadsci.com/Antenna Sweeps r1.pdf If anyone finds this useful please let me know, so I know whether or not it's worth the time/effort to continue to test antennas and add them to the doc. --- Jeff WN3A Yahoo! Groups Links http://groups.yahoo.com/group/Repeater-Builder/ Individual Email | Traditional http://groups.yahoo.com/group/Repeater-Builder/join (Yahoo! ID required) mailto:repeater-builder-dig...@yahoogroups.com mailto:repeater-builder-fullfeatu...@yahoogroups.com repeater-builder-unsubscr...@yahoogroups.com http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Decibel dipole array sweeps
The link in Doug's email below still has spaces in it (%20 hex ASCII for space character). Use the revised name I sent out that doesn't have spaces in it: http://www.broadsci.com/AntennaSweepsR1.pdf --- Jeff -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey Sent: Sunday, March 22, 2009 4:08 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Decibel dipole array sweeps Page cannot be found using your fixed link. Chuck WB2EDV - Original Message - From: Doug Bade k...@thebades.net mailto:kd8b%40thebades.net To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Sunday, March 22, 2009 3:54 PM Subject: Re: [Repeater-Builder] Decibel dipole array sweeps The link is broken due to the space in the name... The actual url is http://www.broadsci.com/Antenna%20Sweeps%20r1.pdf http://www.broadsci.com/Antenna%20Sweeps%20r1.pdf Doug this may be a dup.. my outbound mail seems to be randomly getting delayed.. No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: 270.11.3/1970 - Release Date: 03/21/09 17:58:00
RE: [Repeater-Builder] Decibel dipole array sweeps
It wouldn't suprise me if the VSWR wasn't terrible since you'd be operating the antenna at an odd multiple of its original design frequency. However, the elevation pattern will likely be a mess. In other words, it may look just dandy on the Sitemaster, but under-perform by a whole lot out in the far field. A 1/2 wavelength dipole has a free space pattern which has one major lobe at 90 degrees perpendicular to the element, so, with the dipole oriented vertically, the major lobe sits right on the horizon. A 3/2 wavelength dipole, which is what you'd have if you took a dipole cut for VHF but used it on UHF at 3X its design frequency, has two equal major lobes, one about 42 degrees above the horizon and one about 42 degrees below the horizon if memory serves. There is also a third, minor lobe at the horizon. So, unless you want to talk to worms or martians, the 3/2 wave dipole probably isn't going to give you the elevation pattern you're looking for. Of course, when you stack multiple elements, the fields from each element interact, so it's hard to say what it will really look like for a multi-bay antenna without modeling it, but I wouldn't expect it to be pretty... --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Doug Bade Sent: Sunday, March 22, 2009 4:37 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Decibel dipole array sweeps Jeff; What is your thoughts on the radiation launch angle in this case if beam tilt does not suffer/gain ??? I have a case in point of a wideband 406-470 uhf sinclair dipole 310C4.. on VHF as the elements are larger than vhf needs ??? in other words using it on both vhf and uhf assuming reasonable vswr Doug At 04:17 PM 3/22/2009, you wrote: For a parallel-fed (aka binary-fed, corporate-fed, etc.) antenna, if all of the elements are fed in-phase (i.e. the branches in the phasing harness are all the same length), as it typical with most dipole arrays, there won't be any uptilt/downtilt as you vary the transmitter frequency outside of the design range a bit. No matter what the frequency of the carrier is, it's always going to hit the elements in-phase, so there won't be any beamtilt. This is constrast to an end-fed (series-fed) collinear, where you will get UPTILT if transmitting at a frequency ABOVE the antenna's design range, and DOWNTILT if transmitting at a frequency BELOW the antenna's design range. --- Jeff WN3A -Original Message- From: mailto:Repeater-Builder%40yahoogroups.comrepeater-buil...@ya hoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com ] On Behalf Of Doug Bade Sent: Sunday, March 22, 2009 4:10 PM To: mailto:Repeater-Builder%40yahoogroups.comrepeater-buil...@ya hoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: Re: [Repeater-Builder] Decibel dipole array sweeps Jeff; This is very interesting findings especially in that using an antenna longer than your freq tends to exhibit down tilt... that 440 use of a 450 antenna seems to be working in the correct direction. I for one found it very interesting to read It may be real interesting to see some of the amateur antennas tested too as multiband ones seem to rarely work very well on the upper bands compared to the lower bands of those I have seen Doug At 02:32 PM 3/22/2009, you wrote: I'm in the process of putting up a remote receiver for a 440 ham repeater using a Decibel DB413 dipole array cut for 450-470 MHz. Since Decibel/Andrew stopped making the 440-450 MHz custom models, I've used the usual 450-470 split antennas for receive sites, and they've performed well. I swept the DB413, and it measured as I expected. While I had the Sitemaster out, I grabbed a few other Decibel dipole arrays out of the warehouse and swept them and prepared a little document. Since the topic of using commercial-band antennas on amateur frequencies comes up fairly often, I figured these measurements might be of some interest to list members. I tested these antennas with them mounted above ground level, and away from nearby objects, with the Sitemaster connected right to the pigtail so what you're seeing is the true return loss at the feedpoint. I'll continue to test more antennas (not just DB dipole arrays) over time and continue to add them to this document. I have gobs of sweeps of antennas, but unfortunately many of them were swept at the bottom end of heliax runs rather than right at the feedpoint. From now on I'll make it a point to sweep them on the ground this way. The antennas I tested in this first batch are:
[Repeater-Builder] Re: Decibel dipole array sweeps
On a somewhat related notes...I had to do some research on the rare (and not currently made) down tilt models from db products. I have some paperwork with measurements and notes on them from their archives. Not complete or easy to read (originally faxed) but it helps to determine if you might have a 4 or 9 degree downtilt harness and other related parts measurements. If someone is in need of them I can either e-mail or perhaps post on this site. Also, I have seen some of the dipoles get modified with short stainless machine screws+nuts drilled through the top bottom of the dipole elements, to help get the Return Loss even better at lower freqs. Not sure what, if any, skewed pattern is introduced by doing the machine screw mod or not. Quite often it's hard to tell any changes in the field unless it is very drastic. Tom
RE: [Repeater-Builder] Decibel dipole array sweeps
In general, the loss in the feedline will only make the return loss look better. If you have an antenna with a 14 dB return loss at the frequency of interest at the feedpoint, and connect it to a feedline that has 2 dB of loss, the return loss will be 14dB + 2 x 2dB = 18 dB looking into the transmitter end of the coax. Why do you add 2X the feedline loss? Because you have feedline loss in the forward direction, heading toward the antenna, where at the feedpoint there is a reflection, and the reflected power likewise is attenuated due to feedline loss on the way back down the line, hence twice the loss in decibels (or the square root of the power loss in linear terms). I connected the Sitemaster to the pigtail and stepped away a few feet, reaching up from below to hit the Save Display button. Moving the Sitemaster around, even closer to the lowest element, had no measurable effect until it, or the pigtail, got within a couple of inches of the lowest element, and even then the change was only slight (remember, there are 4 or 8 or however many elements, so even de-tuning one element slightly isn't as significant as compared to if you just had one element). --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey Sent: Sunday, March 22, 2009 4:44 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Decibel dipole array sweeps Jeff - When you are testing next time, it might be interesting to see results of a sweep using some feedline attached to the antenna. I have to wonder what impact it may (or may not) have. When you test with your instrument connected to the pigtail, are you standing right there, or is the antenna completely in the clear? Chuck WB2EDV No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: 270.11.3/1970 - Release Date: 03/21/09 17:58:00
Re: [Repeater-Builder] Master II station 66 split conversion to 56 split
I have retuned 10+ GE Mastr II exciters - base/moble and have never had to change a component. Put the ICOM in for the new frequency and tune per the manual. I use a Bird milliWatt meter that has a 250 mW full scale and an internal 50 Ohm load to finish the tuning, after going through the test points with a Simpson 260. Peaking the previous stage and dipping for the input to the next stage as per the tuning instructions will give you a working exciter as long as there is no component issue in the exciter. 73 - Jim W5ZIT --- On Sun, 3/22/09, Morris Dillingham mdi...@nnwifi.com wrote: From: Morris Dillingham mdi...@nnwifi.com Subject: [Repeater-Builder] Master II station 66 split conversion to 56 split To: Repeater-Builder@yahoogroups.com Date: Sunday, March 22, 2009, 2:20 PM Now that you have helped me close out the old Spectrum issues, can anyone point me to the list of caps and their new values to convert the exciter board of a Master II station? On the NHRC site I see mention of the need to change out a dozen or so caps but no other references. 73 de Morris KI4IUA
Re: [Repeater-Builder] Re: Decibel dipole array sweeps
I have done the mod mentioned on several DB-224 antennas by taking some six inch lengths of an old TV antenna and flattening about three inches on one end and wrapping the flattened end around the end of the dipole and putting a machine screw through the flats to hold the extension to the dipole. I then cut the extension back to two inches. This has resulted in a lower SWR in the ham band after moving the 155 mHz antennas down. I have made no changes to the harness to move the antenna. Something like a change from 1.8:1 down to 1.2:1 is what I have measured at the antenna. 73 - Jim W5ZIT --- On Sun, 3/22/09, Tom, N6MVT n6...@comcast.net wrote: From: Tom, N6MVT n6...@comcast.net Subject: [Repeater-Builder] Re: Decibel dipole array sweeps To: Repeater-Builder@yahoogroups.com Date: Sunday, March 22, 2009, 4:09 PM Also, I have seen some of the dipoles get modified with short stainless machine screws+nuts drilled through the top bottom of the dipole elements, to help get the Return Loss even better at lower freqs. Not sure what, if any, skewed pattern is introduced by doing the machine screw mod or not. Quite often it's hard to tell any changes in the field unless it is very drastic. Tom
RE: [Repeater-Builder] Decibel dipole array sweeps
Using the link Eric posted below, I got the same error message that Bob NO6B got - file damaged and could not be repaired... Mark - N9WYS -Original Message- From: Repeater-Builder@yahoogroups.com On Behalf Of Eric Lemmon I got the same result. The link was parsed incorrectly. Try this: www.broadsci.com/Antennasweepsr1.pdf 73, Eric Lemmon WB6FLY
RE: [Repeater-Builder] Re: Decibel dipole array sweeps
I'd be interested in seeing what you have. Back in the old days of Decibel, they would send you good info if you were able to get to the right person. I haven't had that kind of success since Andrew bought them out. Just this week I came across a non-catalog Decibel antenna on a tower (the one where this DB413 is going). It was a Decibel DB478E-JJ fiberglass omni. I can't find it any of my catalogs, nor on the web. I'm fairly certain it's a 220 MHz antenna based on the -JJ suffix. I also have a DB420 that has a factory label on it that says 450-482 MHz. There's a lot of custom stuff out there from the old Decibel, too bad Andrew has drastically cut back on the special-order products... --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Tom, N6MVT Sent: Sunday, March 22, 2009 5:10 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Decibel dipole array sweeps On a somewhat related notes...I had to do some research on the rare (and not currently made) down tilt models from db products. I have some paperwork with measurements and notes on them from their archives. Not complete or easy to read (originally faxed) but it helps to determine if you might have a 4 or 9 degree downtilt harness and other related parts measurements. If someone is in need of them I can either e-mail or perhaps post on this site. Also, I have seen some of the dipoles get modified with short stainless machine screws+nuts drilled through the top bottom of the dipole elements, to help get the Return Loss even better at lower freqs. Not sure what, if any, skewed pattern is introduced by doing the machine screw mod or not. Quite often it's hard to tell any changes in the field unless it is very drastic. Tom No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: 270.11.3/1970 - Release Date: 03/21/09 17:58:00
[Repeater-Builder] off topic
Any one know what or how a kenwood tk-710 is programmed? I have cables for kenwoods but can't find any software. Thisis an older radio maybe it is still got crystals? Google is not my friend this time! Thanks, Mike Ka2NDW
RE: [Repeater-Builder] Decibel dipole array sweeps
Mark, It may be a browser issue. I clicked on the link below, and the correct page opened. It works fine with XP Pro and IE7. Go figure... 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Mark Sent: Sunday, March 22, 2009 3:08 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Decibel dipole array sweeps Using the link Eric posted below, I got the same error message that Bob NO6B got - file damaged and could not be repaired... Mark - N9WYS -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com On Behalf Of Eric Lemmon I got the same result. The link was parsed incorrectly. Try this: www.broadsci.com/Antennasweepsr1.pdf 73, Eric Lemmon WB6FLY
RE: [Repeater-Builder] Re: Decibel dipole array sweeps
Re-reading your message about downtilt antennas brought back a distant memory. I was putting up a new 440 ham repeater, and grabbed a used DB408 out of the stash, checked the tag, and it said 450-470 MHz. A quick sweep on the Sitemaster looked fine, so off I went. A few hours later I get to the top of the tower with the 408 hanging from my belt. I mount the pipe-to-pipe clamps on the leg, grab the 408, swing it right-side up, and just as I'm dropping it into the clamp set I look closer at the label and it says DB408B-T9. The -T9 suffix indicates it was a 9 degree downtilt model! ARGH! Should have looked closer at the label while I was still on terra firma. Being freezing cold and already tired, I mounted it anyway. The primary coverage target area was a close-in valley at an elevation about 1500 feet below the repeater antenna, so it worked OK where it mattered. Distant coverage out on the horizon was probably sub-par, but there weren't many users outside the valley. Never did get back up there to change it out...still on the to-do list 10+ years later... --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Tom, N6MVT Sent: Sunday, March 22, 2009 5:10 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Decibel dipole array sweeps On a somewhat related notes...I had to do some research on the rare (and not currently made) down tilt models from db products. I have some paperwork with measurements and notes on them from their archives. Not complete or easy to read (originally faxed) but it helps to determine if you might have a 4 or 9 degree downtilt harness and other related parts measurements. If someone is in need of them I can either e-mail or perhaps post on this site. Also, I have seen some of the dipoles get modified with short stainless machine screws+nuts drilled through the top bottom of the dipole elements, to help get the Return Loss even better at lower freqs. Not sure what, if any, skewed pattern is introduced by doing the machine screw mod or not. Quite often it's hard to tell any changes in the field unless it is very drastic. Tom No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: 270.11.3/1970 - Release Date: 03/21/09 17:58:00
RE: [Repeater-Builder] Decibel dipole array sweeps
At 3/22/2009 13:01, you wrote: Boy, Yahoo really mangled the URL, even though I put it in angle brackets. Let's try re-naming the file without spaces, maybe that will work... http://www.broadsci.com/AntennaSweepsR1.pdf Bob - the file opened fine for me, both locally and from the web site. I'm using Acrobat 9.0. The document info shows it's PDF version 1.5 for Acrobat version 6.x or later. I've had a few other cases where I couldn't open recently-produced PDF's sent to me by others using Acrobat 9; upgrading to the current version of Reader fixed it, even though the files should be compatible with Acrobat 6 or later. Well, without a long explanation, I can't view files made for Acrobat 6 later. No way around it unless I want to lose PDF authoring capability. Bob NO6B
Re: [Repeater-Builder] Re: Decibel dipole array sweeps
A better method might be to actually cut each half of the element at about the mid-point (not at the bend - at the straight section), then slide some smaller tubing inside. Slide the element ends in and out while testing and then use some stainless screws to attach things back together at your new length. I suppose you could also measure the length of the extension and cut that length from a piece of tubing that is the same size as the original element. This would effectively hide your repair and keep the element the same diameter for the entire length. Chuck WB2EDV - Original Message - From: Jim Brown To: Repeater-Builder@yahoogroups.com Sent: Sunday, March 22, 2009 6:13 PM Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps I have done the mod mentioned on several DB-224 antennas by taking some six inch lengths of an old TV antenna and flattening about three inches on one end and wrapping the flattened end around the end of the dipole and putting a machine screw through the flats to hold the extension to the dipole. I then cut the extension back to two inches. This has resulted in a lower SWR in the ham band after moving the 155 mHz antennas down. I have made no changes to the harness to move the antenna. Something like a change from 1.8:1 down to 1.2:1 is what I have measured at the antenna. 73 - Jim W5ZIT --- On Sun, 3/22/09, Tom, N6MVT n6...@comcast.net wrote: From: Tom, N6MVT n6...@comcast.net Subject: [Repeater-Builder] Re: Decibel dipole array sweeps To: Repeater-Builder@yahoogroups.com Date: Sunday, March 22, 2009, 4:09 PM Also, I have seen some of the dipoles get modified with short stainless machine screws+nuts drilled through the top bottom of the dipole elements, to help get the Return Loss even better at lower freqs. Not sure what, if any, skewed pattern is introduced by doing the machine screw mod or not. Quite often it's hard to tell any changes in the field unless it is very drastic. Tom
RE: [Repeater-Builder] Decibel dipole array sweeps
On Sun, 22 Mar 2009 n...@no6b.com wrote: Well, without a long explanation, I can't view files made for Acrobat 6 later. No way around it unless I want to lose PDF authoring capability. Buy a Mac and image the Windows box and use it in a virtual machine. Then you can author in PDFs and the Mac has a built-in PDF viewer and Postscript conversion engine. Totally not the solution you were looking for. =) -- Kris Kirby, KE4AHR Disinformation Analyst
Re: [Repeater-Builder] Decibel dipole array sweeps
OK, that makes sense. It would still be interesting to see if the loss theory holds true using a known quantity of feedline. Chuck WB2EDV - Original Message - From: Jeff DePolo j...@broadsci.com To: Repeater-Builder@yahoogroups.com Sent: Sunday, March 22, 2009 5:29 PM Subject: RE: [Repeater-Builder] Decibel dipole array sweeps In general, the loss in the feedline will only make the return loss look better. If you have an antenna with a 14 dB return loss at the frequency of interest at the feedpoint, and connect it to a feedline that has 2 dB of loss, the return loss will be 14dB + 2 x 2dB = 18 dB looking into the transmitter end of the coax. Why do you add 2X the feedline loss? Because you have feedline loss in the forward direction, heading toward the antenna, where at the feedpoint there is a reflection, and the reflected power likewise is attenuated due to feedline loss on the way back down the line, hence twice the loss in decibels (or the square root of the power loss in linear terms). I connected the Sitemaster to the pigtail and stepped away a few feet, reaching up from below to hit the Save Display button. Moving the Sitemaster around, even closer to the lowest element, had no measurable effect until it, or the pigtail, got within a couple of inches of the lowest element, and even then the change was only slight (remember, there are 4 or 8 or however many elements, so even de-tuning one element slightly isn't as significant as compared to if you just had one element). --- Jeff WN3A
Re: [Repeater-Builder] Master II station 66 split conversion to 56 split
At 3/22/2009 15:03, you wrote: I have retuned 10+ GE Mastr II exciters - base/moble and have never had to change a component. Put the ICOM in for the new frequency and tune per the manual. Same experience here, except that if you want to put one on the 144.390 APRS frequency you may find that some exciters don't quite make it down that far. Bob NO6B
Re: [Repeater-Builder] Re: Decibel dipole array sweeps
On Sun, 22 Mar 2009, Chuck Kelsey wrote: A better method might be to actually cut each half of the element at about the mid-point (not at the bend - at the straight section), then slide some smaller tubing inside. Slide the element ends in and out while testing and then use some stainless screws to attach things back together at your new length. I suppose you could also measure the length of the extension and cut that length from a piece of tubing that is the same size as the original element. This would effectively hide your repair and keep the element the same diameter for the entire length. If you're adding pieces of metal to the ends of the antenna, you're effectively decreasing the spacing of the elements from each other. Give me some parameters and I'll run an analysis of it in the modeling program. -- Kris Kirby, KE4AHR Disinformation Analyst
RE: [Repeater-Builder] Decibel dipole array sweeps
On Sun, 22 Mar 2009, Jeff DePolo wrote: the elements are fed in-phase (i.e. the branches in the phasing harness are all the same length), as it typical with most dipole arrays, there won't be any uptilt/downtilt as you vary the transmitter frequency outside of the design range a bit. No matter what the frequency of the carrier is, it's always going to hit the elements in-phase, so there won't be any beamtilt. This is constrast to an end-fed (series-fed) collinear, where you will get UPTILT if transmitting at a frequency ABOVE the antenna's design range, and DOWNTILT if transmitting at a frequency BELOW the antenna's design range. I'm modeling a half-wave dipole with the bottom .25 wavelength (at 145MHz) above zero, with five meters added from the bottom. This antenna, five plus meters above ground, shows that when transmitting at 165MHz, the highest point of gain is a lower degree of elevation than when transmitting at 120MHz. When you remove the sense of ground and use a free-space model, nothing changes, except SWR and impedance. I just ran a stacked dipole configuration, essentially a DB-224 without phasing harnesses or the losses associated thereof. This antenna, with a design resonance of 145MHz, exhibits a maximum gain (again, mounted five meters above ground at the bottom of the antenna [not the center of radiation]) at 2.8 degrees above zero, with a gain of 12.44 dBi. Frequency: 174MHz Gain: 12.53 dBi Center of lobe: +2.4 degrees Frequency: 165MHz Gain: 12.5 dBi Center of lobe: +2.5 degrees Frequency: 145MHz Gain: 12.44 dBi Center of lobe: +2.8 degrees Frequency: 137MHz Gain: 12.29 dBi Center of lobe: +3.0 degrees Frequency: 120MHz Gain: 11.69 dBi Center of lobe: +3.4 degrees This antenna has a *design* frequency of 145MHz. This analysis doesn't factor for SWR at a 50-ohm feedpoint as the SWR wildly varies. In this case, the antenna exhibits downtilt of the resulting lobe as a result of lowering the transmit frequency, and uptilt as a result of increasing the transmit frequency. So I've proven the original poster's point. But moreover that it affects both collinear and dipole array antennas. Here's a comparison for the more likely scenario: Design resonance: 165MHz Gain: 12.59dBi Center of lobe: +2.7 degrees Frequency: 147MHz Gain: 12.24dBi Center of lobe: +3.0 degrees Frequency: 145MHz Gain: 12.15dBi Center of lobe: +3.0 degrees The results, I would say in practical terms, is that a DB-224 cut for 165MHz isn't a bad thing. You'll experience some uptilt. But matching the antenna to a 50-ohm transmitter is another issue altogether. I am researching antenna inversion (mounting the antenna upside-down) at the moment. -- Kris Kirby, KE4AHR Disinformation Analyst
Re: [Repeater-Builder] Decibel dipole array sweeps
On Mar 22, 2009, at 3:29 PM, Jeff DePolo wrote: In general, the loss in the feedline will only make the return loss look better. This leads to situations on poorly built systems where an antenna has gone bad but the feedline is such poor quality, that the transmitter is still quite happy with what it is seeing at the other end of the lossy cable... but of course, with the antenna broken, it doesn't really radiate. Measuring VSWR at the repeater end of things, sometimes just doesn't tell the whole story. One of those things one can learn the hard way if you're not paying attention and measuring each portion of your antenna system as a baseline at installation... -- Nate Duehr, WY0X n...@natetech.com
Re: [Repeater-Builder] Re: Decibel dipole array sweeps
On Mar 22, 2009, at 4:13 PM, Jim Brown wrote: I have done the mod mentioned on several DB-224 antennas by taking some six inch lengths of an old TV antenna and flattening about three inches on one end and wrapping the flattened end around the end of the dipole and putting a machine screw through the flats to hold the extension to the dipole. I then cut the extension back to two inches. I like the ingenuity Jim, but isn't that just begging for dissimilar metal contact noise down the road after a few years of grime, corrosion, and weathering? I'd want to see how those antennas performed after 3-5 years and whether or not site noise was seeming to wander up, or others on-site were complaining of new mixes hitting receivers, etc. One of those things coming loose and scraping back and forth as the add-on extension swung in high winds, would probably make a hell of a crackling noise on the machine connected to it, too -- wouldn't it? Joints that can move, even only after some kind of damage, to me anyway = lots of trouble down the road. -- Nate Duehr, WY0X n...@natetech.com
Re: [Repeater-Builder] Master II station 66 split conversion to 56 split
On Sun, 22 Mar 2009 n...@no6b.com wrote: I have retuned 10+ GE Mastr II exciters - base/moble and have never had to change a component. Put the ICOM in for the new frequency and tune per the manual. Same experience here, except that if you want to put one on the 144.390 APRS frequency you may find that some exciters don't quite make it down that far. What sort of temperature coeffiecent does the exciter have? If I want to find the limits of lock, do I need to freeze it or heat it up to 140 degrees? -- Kris Kirby, KE4AHR Disinformation Analyst
[Repeater-Builder] Re: Decibel dipole array sweeps
--- In Repeater-Builder@yahoogroups.com, Kris Kirby k...@... wrote: The results, I would say in practical terms, is that a DB-224 cut for 165MHz isn't a bad thing. You'll experience some uptilt. But matching the antenna to a 50-ohm transmitter is another issue altogether. So the question is, does anyone have an out-of-service DB-224 (hopefully on the ground) that was custom built for amateur service that dimensions can be lifted from from? I have access to 316 stainless tube am willing to take a shot at fabricating replacement elements. Martin
[Repeater-Builder] OT: Making PDFs
At 15:37 3/22/2009, Kris Kirby wrote: No way around it unless I want to lose PDF authoring capability. Buy a Mac Actually WordPerfect makes beautiful PDF files and has for years... -- Dave Gomberg, San Francisco NE5EE gomberg1 at wcf dot com All addresses, phones, etc. at http://www.wcf.com/ham/info.html -
Re: [Repeater-Builder] Decibel dipole array sweeps
On Mar 22, 2009, at 12:32 PM, Jeff DePolo wrote: The antennas I tested in this first batch are: DB413, 450-470 MHz DB408D, 450-470 MHz DB411, 450-470 MHz DB411, 406-420 MHz By the way, I like it, Jeff! Got any Sinclairs handy for a comparison between common brands? -- Nate Duehr, WY0X n...@natetech.com
RE: [Repeater-Builder] Decibel dipole array sweeps
At 3/22/2009 15:37, you wrote: On Sun, 22 Mar 2009 n...@no6b.com wrote: Well, without a long explanation, I can't view files made for Acrobat 6 later. No way around it unless I want to lose PDF authoring capability. Buy a Mac Of all the possible solutions, that is probably the most expensive least practical. Bob NO6B
Re: [Repeater-Builder] Master II station 66 split conversion to 56 split
On Mar 22, 2009, at 4:40 PM, Kris Kirby wrote: On Sun, 22 Mar 2009 n...@no6b.com wrote: I have retuned 10+ GE Mastr II exciters - base/moble and have never had to change a component. Put the ICOM in for the new frequency and tune per the manual. Same experience here, except that if you want to put one on the 144.390 APRS frequency you may find that some exciters don't quite make it down that far. What sort of temperature coeffiecent does the exciter have? If I want to find the limits of lock, do I need to freeze it or heat it up to 140 degrees? I'll say this: Many people put their repeaters in temperature controlled environments and then hunt needlessly for 2C ICOM's. There's a chart in the LBIs for where/when the temperature compensation kicks in. More folks should read it. (GRIN!) -- Nate Duehr, WY0X n...@natetech.com
RE: [Repeater-Builder] Decibel dipole array sweeps
I'm modeling a half-wave dipole with the bottom .25 wavelength (at 145MHz) above zero, with five meters added from the bottom. This antenna, five plus meters above ground, shows that when transmitting at 165MHz, the highest point of gain is a lower degree of elevation than when transmitting at 120MHz. Wait. You're saying that a center-fed dipole has a major lobe that's not exactly perpendicular to the element? Something's amiss. I just ran a stacked dipole configuration, essentially a DB-224 without phasing harnesses or the losses associated thereof. This antenna, with a design resonance of 145MHz, exhibits a maximum gain (again, mounted five meters above ground at the bottom of the antenna [not the center of radiation]) at 2.8 degrees above zero, with a gain of 12.44 dBi. Something has to be wrong here. 12.44 dBi of net gain for a 4-bay? What is the element spacing? Or does that include azimuth gain due to the mount pipe? Center of lobe: +2.7 degrees When you're saying the center of lobe, do you mean the midpoint between the -3 dB points, or the point of maximum gain? By the way, what are you using to model it? --- Jeff WN3A
Re: [Repeater-Builder] Re: Decibel dipole array sweeps
On Sun, 22 Mar 2009, rahwayflynn wrote: I have access to 316 stainless tube am willing to take a shot at fabricating replacement elements. Sounds like fun. I think the DB antennas are made from aluminum, however. If you're going to be making a DB antenna clone, it makes more sense to either punch them out of plate or cut them from rod. Any mechanical engineers on the list? :-) -- Kris Kirby, KE4AHR Disinformation Analyst
RE: [Repeater-Builder] Decibel dipole array sweeps
I have a Sinclair 8-bay with half-wave element to mast spacing stored in the Sitemaster, but it was swept from the far end of 600' of 1-5/8 with a topside TX-RX crossband coupler. It's spec'ed for 406-512 MHz. I can't keep track of Sinclair's model numbers, it's probably a SD318-HF2P2SNM, previously known as a SRL310C8NM*2-2. I can send you the sweep anyway if you want it. It talks extremely well. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Nate Duehr Sent: Sunday, March 22, 2009 6:52 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Decibel dipole array sweeps On Mar 22, 2009, at 12:32 PM, Jeff DePolo wrote: The antennas I tested in this first batch are: DB413, 450-470 MHz DB408D, 450-470 MHz DB411, 450-470 MHz DB411, 406-420 MHz By the way, I like it, Jeff! Got any Sinclairs handy for a comparison between common brands? -- Nate Duehr, WY0X n...@natetech.com mailto:nate%40natetech.com No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: 270.11.3/1970 - Release Date: 03/21/09 17:58:00
Re: [Repeater-Builder] Re: Decibel dipole array sweeps
I don't have any parameters. I was just suggesting this method (lengthening the entire element) as opposed to adding stubs to the ends of the elements. Yes, the elements will be closer to each other either way, but that may be a constraint of the phasing harness. If there was some slack, the spacing could be increased as well. Chuck WB2EDV - Original Message - From: Kris Kirby k...@catonic.us To: Repeater-Builder@yahoogroups.com Sent: Sunday, March 22, 2009 6:39 PM Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps On Sun, 22 Mar 2009, Chuck Kelsey wrote: A better method might be to actually cut each half of the element at about the mid-point (not at the bend - at the straight section), then slide some smaller tubing inside. Slide the element ends in and out while testing and then use some stainless screws to attach things back together at your new length. I suppose you could also measure the length of the extension and cut that length from a piece of tubing that is the same size as the original element. This would effectively hide your repair and keep the element the same diameter for the entire length. If you're adding pieces of metal to the ends of the antenna, you're effectively decreasing the spacing of the elements from each other. Give me some parameters and I'll run an analysis of it in the modeling program. -- Kris Kirby, KE4AHR Disinformation Analyst
Re: [Repeater-Builder] Decibel dipole array sweeps
Actually, years ago I did some really crude antenna test range tests on an antenna. I brought it up on the roof on a 10 foot mast and monitored a repeater. Then I tilted the pole back and forth towards the repeater to see if I could find the major lobe while watching the S meter on my HT. It gave me an idea of the take-off angle of the antenna. 73, Joe, K1ike Chuck Kelsey wrote: The group hereby accepts Joe's offer to construct an antenna test range to conduct pattern testing. What a nice guy! LOL!! Chuck WB2EDV - Original Message - From: Joe k1ike_m...@snet.net To: Repeater-Builder@yahoogroups.com Sent: Sunday, March 22, 2009 4:22 PM Subject: Re: [Repeater-Builder] Decibel dipole array sweeps Although, in some cases, the return loss (or VSWR) looks to be acceptable I wonder what the take-off angle of radiation and radiation pattern looks like at frequencies out of it's design range. 73, Joe, K1ike
Re: [Repeater-Builder] Decibel dipole array sweeps
Why not just include it with your article already posted? Just add the notes along with it. Chuck WB2EDV - Original Message - From: Jeff DePolo j...@broadsci.com To: Repeater-Builder@yahoogroups.com Sent: Sunday, March 22, 2009 7:11 PM Subject: RE: [Repeater-Builder] Decibel dipole array sweeps I have a Sinclair 8-bay with half-wave element to mast spacing stored in the Sitemaster, but it was swept from the far end of 600' of 1-5/8 with a topside TX-RX crossband coupler. It's spec'ed for 406-512 MHz. I can't keep track of Sinclair's model numbers, it's probably a SD318-HF2P2SNM, previously known as a SRL310C8NM*2-2. I can send you the sweep anyway if you want it. It talks extremely well. --- Jeff WN3A
Re: [Repeater-Builder] Decibel dipole array sweeps
I've had arguments with tower crews about antennas that are too good when doing a system sweep. They would proudly state that the install was really good because the Return Loss was 28 dB on a wide band 800Mhz antenna that was only suppose to be about 14-18dB RL at the antenna. Turned out to be a bad (lossy) connector many times. Reinstalling the connector would fix it. This is where the Distance to Fault sweep comes in handy. 73, Joe, K1ike Jeff DePolo wrote: In general, the loss in the feedline will only make the return loss look better. If you have an antenna with a 14 dB return loss at the frequency of interest at the feedpoint, and connect it to a feedline that has 2 dB of loss, the return loss will be 14dB + 2 x 2dB = 18 dB looking into the transmitter end of the coax.
RE: [Repeater-Builder] Decibel dipole array sweeps
I got to the page, but the file wouldn't open... Mark - N9WYS -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Eric Lemmon Sent: Sunday, March 22, 2009 5:25 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Decibel dipole array sweeps Mark, It may be a browser issue. I clicked on the link below, and the correct page opened. It works fine with XP Pro and IE7. Go figure... 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Mark Sent: Sunday, March 22, 2009 3:08 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Decibel dipole array sweeps Using the link Eric posted below, I got the same error message that Bob NO6B got - file damaged and could not be repaired... Mark - N9WYS -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com On Behalf Of Eric Lemmon I got the same result. The link was parsed incorrectly. Try this: www.broadsci.com/Antennasweepsr1.pdf 73, Eric Lemmon WB6FLY Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: 270.11.23/2016 - Release Date: 03/21/09 17:58:00
[Repeater-Builder] Re: Decibel dipole array sweeps
--- In Repeater-Builder@yahoogroups.com, Kris Kirby k...@... wrote: On Sun, 22 Mar 2009, rahwayflynn wrote: I have access to 316 stainless tube am willing to take a shot at fabricating replacement elements. Sounds like fun. I think the DB antennas are made from aluminum, however. If you're going to be making a DB antenna clone, it makes more sense to either punch them out of plate or cut them from rod. Any mechanical engineers on the list? :-) -- Kris Kirby, KE4AHR Disinformation Analyst Good point. Aluminum is way easier to work with. The request for dimensions still stands. Martin / W2RWJ
[Repeater-Builder] moducom manual.
Looking for a manual for a Moducom ultra-page 96 pager encoder. Does any one have one? I contacted Moducom, no luck. They seem to be like Zetron. Thanks -Jason
RE: [Repeater-Builder] Decibel dipole array sweeps
On Sun, 22 Mar 2009, Jeff DePolo wrote: Wait. You're saying that a center-fed dipole has a major lobe that's not exactly perpendicular to the element? Something's amiss. It's a theoretical antenna over a real ground. In free space, the lobes are closer to zero, but even over a perfect ground, there will be interaction effects due to the waves bouncing off of the ground. Something has to be wrong here. 12.44 dBi of net gain for a 4-bay? What is the element spacing? Or does that include azimuth gain due to the mount pipe? No losses. Element spacing is one wavelength at 145MHz. Center of lobe: +2.7 degrees When you're saying the center of lobe, do you mean the midpoint between the -3 dB points, or the point of maximum gain? Point of maximum gain. According to the graph, it's inbetween the -3 dB points. By the way, what are you using to model it? MMANA-GAL (it's free, runs on Windows). I'd be happy to post the file if anyone wants to compare it. Also, I did build the antenna out of copper pipe, not aluminum. -- Kris Kirby, KE4AHR Disinformation Analyst
RE: [Repeater-Builder] Decibel dipole array sweeps
Bob, Paste the link into your location bar then remove the '%20' groups of characters from the link. The result should look like this- http://www.broadsci.com/AntennSweepsR1.pdf Gary N6LRV -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of n...@no6b.com Sent: Sunday, March 22, 2009 3:29 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Decibel dipole array sweeps At 3/22/2009 13:01, you wrote: Boy, Yahoo really mangled the URL, even though I put it in angle brackets. Let's try re-naming the file without spaces, maybe that will work... http://www.broadsci.com/AntennaSweepsR1.pdf Bob - the file opened fine for me, both locally and from the web site. I'm using Acrobat 9.0. The document info shows it's PDF version 1.5 for Acrobat version 6.x or later. I've had a few other cases where I couldn't open recently-produced PDF's sent to me by others using Acrobat 9; upgrading to the current version of Reader fixed it, even though the files should be compatible with Acrobat 6 or later. Well, without a long explanation, I can't view files made for Acrobat 6 later. No way around it unless I want to lose PDF authoring capability. Bob NO6B Yahoo! Groups Links
RE: [Repeater-Builder] Decibel dipole array sweeps
I guess I could, but you'd also see the effect of the crossband coupler, jumpers, and everything else in-line. I figured I'd start afresh with all new antennas tested at ground level. -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey Sent: Sunday, March 22, 2009 7:18 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Decibel dipole array sweeps Why not just include it with your article already posted? Just add the notes along with it. Chuck WB2EDV - Original Message - From: Jeff DePolo j...@broadsci.com mailto:jd0%40broadsci.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Sunday, March 22, 2009 7:11 PM Subject: RE: [Repeater-Builder] Decibel dipole array sweeps I have a Sinclair 8-bay with half-wave element to mast spacing stored in the Sitemaster, but it was swept from the far end of 600' of 1-5/8 with a topside TX-RX crossband coupler. It's spec'ed for 406-512 MHz. I can't keep track of Sinclair's model numbers, it's probably a SD318-HF2P2SNM, previously known as a SRL310C8NM*2-2. I can send you the sweep anyway if you want it. It talks extremely well. --- Jeff WN3A No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: 270.11.3/1970 - Release Date: 03/21/09 17:58:00
RE: [Repeater-Builder] Decibel dipole array sweeps
On Sun, 22 Mar 2009, Gary wrote: Bob, Paste the link into your location bar then remove the '%20' groups of characters from the link. The result should look like this- http://www.broadsci.com/AntennSweepsR1.pdf This works: http://www.broadsci.com/AntennaSweepsR1.pdf -- Kris Kirby, KE4AHR Disinformation Analyst
RE: [Repeater-Builder] Decibel dipole array sweeps
On Sun, 22 Mar 2009, Jeff DePolo wrote: Wait. You're saying that a center-fed dipole has a major lobe that's not exactly perpendicular to the element? Something's amiss. It's a theoretical antenna over a real ground. In free space, the lobes are closer to zero, but even over a perfect ground, there will be interaction effects due to the waves bouncing off of the ground. Free space doesn't have a ground. Can you disable ground altogether and see what the gain and pattern is? Something has to be wrong here. 12.44 dBi of net gain for a 4-bay? What is the element spacing? Or does that include azimuth gain due to the mount pipe? No losses. Element spacing is one wavelength at 145MHz. What does it give you for the gain of a single half-wave dipole with no ground or support structure? MMANA-GAL (it's free, runs on Windows). I'd be happy to post the file if anyone wants to compare it. Not familiar with it. What code base is it based on? --- Jeff
Re: [Repeater-Builder] Re: Decibel dipole array sweeps
I tried adding length to the tubes on a DB-224A. I sacrificed some DB-420 elements to do it. They fit perfectly. Inside the DB-224A. This was quite a bit of work. The end results was not favorable. The SWR did not improve by adding lenght. In fact it got worse. I don't know why. I have not tried adding stubs to the ends yet. I also have not tried the adding a 50ohm jumper between the top half and bottom half of the harness. I had thought about putting spacers between the mast and the elements, but haven't tried that yet. Any comments? Norm N5NPO - Original Message - From: Repeater-Builder@yahoogroups.com Repeater-Builder@yahoogroups.com To: Repeater-Builder@yahoogroups.com Repeater-Builder@yahoogroups.com Sent: Sun Mar 22 18:10:31 2009 Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps I don't have any parameters. I was just suggesting this method (lengthening the entire element) as opposed to adding stubs to the ends of the elements. Yes, the elements will be closer to each other either way, but that may be a constraint of the phasing harness. If there was some slack, the spacing could be increased as well. Chuck WB2EDV - Original Message - From: Kris Kirby k...@catonic.us mailto:kris%40catonic.us To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Sunday, March 22, 2009 6:39 PM Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps On Sun, 22 Mar 2009, Chuck Kelsey wrote: A better method might be to actually cut each half of the element at about the mid-point (not at the bend - at the straight section), then slide some smaller tubing inside. Slide the element ends in and out while testing and then use some stainless screws to attach things back together at your new length. I suppose you could also measure the length of the extension and cut that length from a piece of tubing that is the same size as the original element. This would effectively hide your repair and keep the element the same diameter for the entire length. If you're adding pieces of metal to the ends of the antenna, you're effectively decreasing the spacing of the elements from each other. Give me some parameters and I'll run an analysis of it in the modeling program. -- Kris Kirby, KE4AHR Disinformation Analyst
RE: [Repeater-Builder] Decibel dipole array sweeps
On Sun, 22 Mar 2009, Jeff DePolo wrote: Free space doesn't have a ground. Can you disable ground altogether and see what the gain and pattern is? Yes. It looks like what you'd expect a perfect antenna to look like. What does it give you for the gain of a single half-wave dipole with no ground or support structure? 2.16 dBi, as expected. -3dB comes at around 38.5 degrees, so the total -3dB beamwidth would be 77 degrees, vertical. With no ground (free space), the antenna (four stacked dipoles), simulates at 8.6dBi, lobe at zero degrees, -3dB at 6.5 degrees, total -3dB beamwidth is 13 degrees. None of my computations so far have factored for antenna mounting structures; just one or four dipoles in space, over some ground. MMANA-GAL (it's free, runs on Windows). I'd be happy to post the file if anyone wants to compare it. Not familiar with it. What code base is it based on? MININEC-3. -- Kris Kirby, KE4AHR Disinformation Analyst
Re: [Repeater-Builder] OT: Making PDFs
Dave, try down loading a small program called Cute PDF writer...it's free and will make PDF's for you. It is set up as a printer but saves them to a file on your computer. 73 John VE3AMZ - Original Message - From: Dave Gomberg da...@wcf.com To: Repeater-Builder@yahoogroups.com Sent: Sunday, March 22, 2009 6:55 PM Subject: [Repeater-Builder] OT: Making PDFs At 15:37 3/22/2009, Kris Kirby wrote: No way around it unless I want to lose PDF authoring capability. Buy a Mac Actually WordPerfect makes beautiful PDF files and has for years... -- Dave Gomberg, San Francisco NE5EE gomberg1 at wcf dot com All addresses, phones, etc. at http://www.wcf.com/ham/info.html - Yahoo! Groups Links
RE: [Repeater-Builder] Decibel dipole array sweeps
At 3/22/2009 16:23, you wrote: Bob, Paste the link into your location bar then remove the '%20' groups of characters from the link. The result should look like this- Not the problem. Acrobat 5 is as far as my home system goes. Unfortunately the full version of Acrobat overrides any Reader installation. Not Windows' fault, but Adobe's. I do have a 1 GHz PIII backup system I could put the new reader on if I was desperate, but not worth the trouble right now. Bob NO6B
[Repeater-Builder] Re: Decibel dipole array sweeps
--- In Repeater-Builder@yahoogroups.com, Chuck Kelsey wb2...@... wrote: ... it might be interesting to see results of a sweep using some feedline attached to the antenna. I have to wonder what impact it may (or may not) have. ... --- Eagle has some application notes that explain return loss and how to interpret return loss sweeps. You can learn quite a bit from a sweep done at the bottom of the feedline. http://www.eagle-1st.com/notes/aandf/af.htm
RE: [Repeater-Builder] Decibel dipole array sweeps
Free space doesn't have a ground. Can you disable ground altogether and see what the gain and pattern is? Yes. It looks like what you'd expect a perfect antenna to look like. What does it give you for the gain of a single half-wave dipole with no ground or support structure? 2.16 dBi, as expected. -3dB comes at around 38.5 degrees, so the total -3dB beamwidth would be 77 degrees, vertical. With no ground (free space), the antenna (four stacked dipoles), simulates at 8.6dBi, lobe at zero degrees, -3dB at 6.5 degrees, total -3dB beamwidth is 13 degrees. OK, that's more like it. At a realistic antenna height (100 feet+, or around 30 wavelengths at 2m), I would expect ground reflection effects to be negligible, and that the major lobe would be on the horizon where it belongs. And, yes, with ground reflections, the elevation pattern WILL change as you vary frequency, because the distance as measured in *wavelengths* between the ground and antenna elements will obviously vary as you shift frequency around. Try running your previous models again with ground disabled, or at a high height above ground, and see what you come up with. Or, try offsetting your antenna 1/4 wavelength (about 1.7 feet) vertically with respect to ground and re-run your original models and you should see the beamtilt change accordingly. --- Jeff WN3A
RE: [Repeater-Builder] OT: Making PDFs
Or Microsoft office has a free plug-in that gives pdf export capability to office apps. Chris Kb0wlf 3185 Btw, my wife is a graphics designer for the local newspaper and has MAC stuff all over the place but I'm still die hard wintel -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of John J. Riddell Sent: Sunday, March 22, 2009 7:28 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] OT: Making PDFs Dave, try down loading a small program called Cute PDF writer...it's free and will make PDF's for you. It is set up as a printer but saves them to a file on your computer. 73 John VE3AMZ - Original Message - From: Dave Gomberg da...@wcf.com To: Repeater-Builder@yahoogroups.com Sent: Sunday, March 22, 2009 6:55 PM Subject: [Repeater-Builder] OT: Making PDFs At 15:37 3/22/2009, Kris Kirby wrote: No way around it unless I want to lose PDF authoring capability. Buy a Mac Actually WordPerfect makes beautiful PDF files and has for years... -- Dave Gomberg, San Francisco NE5EE gomberg1 at wcf dot com All addresses, phones, etc. at http://www.wcf.com/ham/info.html - Yahoo! Groups Links Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: 270.11.19/2011 - Release Date: 03/21/09 17:58:00
Re: [Repeater-Builder] Re: Decibel dipole array sweeps
First, I have never played with a DB224. However, I have changed the length of a DB-212 to get it on 6-meters and it worked fine. I have heard that people have improved VSWR on the DB-224 by adding bolts through the ends of the loops to lengthen them. If that did indeed work, I would assume that cutting and extending the elements themselves would also work. The real problem may be with the harness - it may be causing the bottleneck. However, only being four elements, it shouldn't be too bad making up a new harness for that particular antenna. Chuck WB2EDV - Original Message - From: NORM KNAPP nkn...@twowayradio.net To: Repeater-Builder@yahoogroups.com Sent: Sunday, March 22, 2009 8:26 PM Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps I tried adding length to the tubes on a DB-224A. I sacrificed some DB-420 elements to do it. They fit perfectly. Inside the DB-224A. This was quite a bit of work. The end results was not favorable. The SWR did not improve by adding lenght. In fact it got worse. I don't know why. I have not tried adding stubs to the ends yet. I also have not tried the adding a 50ohm jumper between the top half and bottom half of the harness. I had thought about putting spacers between the mast and the elements, but haven't tried that yet. Any comments? Norm N5NPO - Original Message - From: Repeater-Builder@yahoogroups.com Repeater-Builder@yahoogroups.com To: Repeater-Builder@yahoogroups.com Repeater-Builder@yahoogroups.com Sent: Sun Mar 22 18:10:31 2009 Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps I don't have any parameters. I was just suggesting this method (lengthening the entire element) as opposed to adding stubs to the ends of the elements. Yes, the elements will be closer to each other either way, but that may be a constraint of the phasing harness. If there was some slack, the spacing could be increased as well. Chuck WB2EDV - Original Message - From: Kris Kirby k...@catonic.us mailto:kris%40catonic.us To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Sunday, March 22, 2009 6:39 PM Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps On Sun, 22 Mar 2009, Chuck Kelsey wrote: A better method might be to actually cut each half of the element at about the mid-point (not at the bend - at the straight section), then slide some smaller tubing inside. Slide the element ends in and out while testing and then use some stainless screws to attach things back together at your new length. I suppose you could also measure the length of the extension and cut that length from a piece of tubing that is the same size as the original element. This would effectively hide your repair and keep the element the same diameter for the entire length. If you're adding pieces of metal to the ends of the antenna, you're effectively decreasing the spacing of the elements from each other. Give me some parameters and I'll run an analysis of it in the modeling program. -- Kris Kirby, KE4AHR Disinformation Analyst Yahoo! Groups Links
Re: [Repeater-Builder] OT: Making PDFs
I also have used the freeware Cute PDF Writer for a number of years. We used it in the 1000's at work. Have it on my home computer now that I am retired. http://www.cutepdf.com/Products/CutePDF/writer.asp Roger W5RDW - Original Message - From: John J. Riddell To: Repeater-Builder@yahoogroups.com Sent: Sunday, March 22, 2009 6:27 PM Subject: Re: [Repeater-Builder] OT: Making PDFs Dave, try down loading a small program called Cute PDF writer...it's free and will make PDF's for you. It is set up as a printer but saves them to a file on your computer. 73 John VE3AMZ - Original Message - From: Dave Gomberg da...@wcf.com To: Repeater-Builder@yahoogroups.com Sent: Sunday, March 22, 2009 6:55 PM Subject: [Repeater-Builder] OT: Making PDFs At 15:37 3/22/2009, Kris Kirby wrote: No way around it unless I want to lose PDF authoring capability. Buy a Mac Actually WordPerfect makes beautiful PDF files and has for years... -- Dave Gomberg, San Francisco NE5EE gomberg1 at wcf dot com All addresses, phones, etc. at http://www.wcf.com/ham/info.html -- Yahoo! Groups Links
Re: [Repeater-Builder] Decibel dipole array sweeps
n...@no6b.com wrote: Not the problem. Acrobat 5 is as far as my home system goes. Unfortunately the full version of Acrobat overrides any Reader installation. Not Windows' fault, but Adobe's. I do have a 1 GHz PIII backup system I could put the new reader on if I was desperate, but not worth the trouble right now. Or -- you could install Foxit reader. Kevin
RE: [Repeater-Builder] Decibel dipole array sweeps
Bob. Always the trouble maker. Try this HTML version. It was produced by Microsoft Word which has the most god-awful HTML generator on the planet IMHO. I make no guarantees as to its readability. http://www.broadsci.com/AntennaSweepsR1.htm --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of n...@no6b.com Sent: Sunday, March 22, 2009 8:30 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Decibel dipole array sweeps At 3/22/2009 16:23, you wrote: Bob, Paste the link into your location bar then remove the '%20' groups of characters from the link. The result should look like this- Not the problem. Acrobat 5 is as far as my home system goes. Unfortunately the full version of Acrobat overrides any Reader installation. Not Windows' fault, but Adobe's. I do have a 1 GHz PIII backup system I could put the new reader on if I was desperate, but not worth the trouble right now. Bob NO6B
RE: [Repeater-Builder] RE: AF2140 filter
Well since I don't have access to sweep gear, I will leave it and just use a BP filter on the transmit side after the isolator. Thanks for the help. Doug
RE: [Repeater-Builder] Decibel dipole array sweeps
At 3/22/2009 17:44, you wrote: Bob. Always the trouble maker. Try this HTML version. It was produced by Microsoft Word which has the most god-awful HTML generator on the planet IMHO. I make no guarantees as to its readability. http://www.broadsci.com/AntennaSweepsR1.htm --- Jeff WN3A Thanks Jeff; it actually looks quite good. By now I've already managed to get the original PDF downconverted to something everyone should be able to read. Then again, unless you're going to print it HTML is the most universal format. Re: other PDF generators/readers: unfortunately they probably aren't options for me. I need the ability to generate PDFs with tightly controlled parameters for work applications. It's not likely the low-end PDF generators can handle those requirements. And as I stated previously, Acrobat 5 doesn't play nice with other PDF readers. Bob NO6B
Re: [Repeater-Builder] Re: Decibel dipole array sweeps
Cutting and extending the loops did not work in my case. The SWR went up. I am useing a DB-224A on 147.225/147.825. The swr on TX is around 2.0:1. Despite this little problem, the repeater has great coverage. - Original Message - From: Repeater-Builder@yahoogroups.com Repeater-Builder@yahoogroups.com To: Repeater-Builder@yahoogroups.com Repeater-Builder@yahoogroups.com Sent: Sun Mar 22 19:35:39 2009 Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps First, I have never played with a DB224. However, I have changed the length of a DB-212 to get it on 6-meters and it worked fine. I have heard that people have improved VSWR on the DB-224 by adding bolts through the ends of the loops to lengthen them. If that did indeed work, I would assume that cutting and extending the elements themselves would also work. The real problem may be with the harness - it may be causing the bottleneck. However, only being four elements, it shouldn't be too bad making up a new harness for that particular antenna. Chuck WB2EDV - Original Message - From: NORM KNAPP nkn...@twowayradio.net mailto:nknapp%40twowayradio.net To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Sunday, March 22, 2009 8:26 PM Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps I tried adding length to the tubes on a DB-224A. I sacrificed some DB-420 elements to do it. They fit perfectly. Inside the DB-224A. This was quite a bit of work. The end results was not favorable. The SWR did not improve by adding lenght. In fact it got worse. I don't know why. I have not tried adding stubs to the ends yet. I also have not tried the adding a 50ohm jumper between the top half and bottom half of the harness. I had thought about putting spacers between the mast and the elements, but haven't tried that yet. Any comments? Norm N5NPO - 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: Sun Mar 22 18:10:31 2009 Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps I don't have any parameters. I was just suggesting this method (lengthening the entire element) as opposed to adding stubs to the ends of the elements. Yes, the elements will be closer to each other either way, but that may be a constraint of the phasing harness. If there was some slack, the spacing could be increased as well. Chuck WB2EDV - Original Message - From: Kris Kirby k...@catonic.us mailto:kris%40catonic.us mailto:kris%40catonic.us To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Sunday, March 22, 2009 6:39 PM Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps On Sun, 22 Mar 2009, Chuck Kelsey wrote: A better method might be to actually cut each half of the element at about the mid-point (not at the bend - at the straight section), then slide some smaller tubing inside. Slide the element ends in and out while testing and then use some stainless screws to attach things back together at your new length. I suppose you could also measure the length of the extension and cut that length from a piece of tubing that is the same size as the original element. This would effectively hide your repair and keep the element the same diameter for the entire length. If you're adding pieces of metal to the ends of the antenna, you're effectively decreasing the spacing of the elements from each other. Give me some parameters and I'll run an analysis of it in the modeling program. -- Kris Kirby, KE4AHR Disinformation Analyst Yahoo! Groups Links
Re: [Repeater-Builder] Re: Decibel dipole array sweeps
I had a buddy who did physically lengthen the two ends of each dipole by cutting them and inserting aluminum tubing and welding the assembly back together. His brother in law was good at aluminum welding. Again, he did not change anything in the harness and the antennas work fine now in the ham band. 73 - Jim W5ZIT --- On Sun, 3/22/09, Chuck Kelsey wb2...@roadrunner.com wrote: From: Chuck Kelsey wb2...@roadrunner.com Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps To: Repeater-Builder@yahoogroups.com Date: Sunday, March 22, 2009, 5:30 PM A better method might be to actually cut each half of the element at about the mid-point (not at the bend - at the straight section), then slide some smaller tubing inside. Slide the element ends in and out while testing and then use some stainless screws to attach things back together at your new length. I suppose you could also measure the length of the extension and cut that length from a piece of tubing that is the same size as the original element. This would effectively hide your repair and keep the element the same diameter for the entire length. Chuck WB2EDV - Original Message - From: Jim Brown To: Repeater-Builder@ yahoogroups. com Sent: Sunday, March 22, 2009 6:13 PM Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps I have done the mod mentioned on several DB-224 antennas by taking some six inch lengths of an old TV antenna and flattening about three inches on one end and wrapping the flattened end around the end of the dipole and putting a machine screw through the flats to hold the extension to the dipole. I then cut the extension back to two inches. This has resulted in a lower SWR in the ham band after moving the 155 mHz antennas down. I have made no changes to the harness to move the antenna. Something like a change from 1.8:1 down to 1.2:1 is what I have measured at the antenna. 73 - Jim W5ZIT --- On Sun, 3/22/09, Tom, N6MVT n6...@comcast. net wrote: From: Tom, N6MVT n6...@comcast. net Subject: [Repeater-Builder] Re: Decibel dipole array sweeps To: Repeater-Builder@ yahoogroups. com Date: Sunday, March 22, 2009, 4:09 PM Also, I have seen some of the dipoles get modified with short stainless machine screws+nuts drilled through the top bottom of the dipole elements, to help get the Return Loss even better at lower freqs. Not sure what, if any, skewed pattern is introduced by doing the machine screw mod or not. Quite often it's hard to tell any changes in the field unless it is very drastic. Tom
Re: [Repeater-Builder] Maratrac CTCSS injection point
Since the Maratrac radio is basically a Maxtrac with a larger PA, I would take a look at the 16 pin accessory connector on the exciter/receiver portion of the Maratrac radio and compare it to a Maxtrac. Without specific documentation I'm going from memory but there is a Maxtrac configuration that operates as a community repeater. HOWEVER, if there is no need for multiple tone codes, use the radio to generate the tones rather than trying to mess around with controller based tones. Milt N3LTQ - Original Message - From: jstechnicalservice jska...@in-touch.net To: Repeater-Builder@yahoogroups.com Sent: Friday, March 20, 2009 9:53 PM Subject: [Repeater-Builder] Maratrac CTCSS injection point Can someone tell me where I would need to inject the subtone from a tone panel to the modulator of a maratrac. I'm attempting to build a backup repeater for our dept and have all the connections figured out except that one. I'm not planning to use a control head just the radio itself for transmit only. Thanks. Jeff Skaggs Concord-Greene FD Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.278 / Virus Database: 270.11.21/2014 - Release Date: 03/20/09 06:59:00
Re: [Repeater-Builder] Master II station 66 split conversion to 56 split
Hey - I thought we were talking about the standard osc/multiplier exciters for VHF. The only thing I have ever had to do to move a PLL exciter down into the ham band is replace the aluminum slug in the PLL coil with a ferrite slug. My installs are non temperature controlled and the temps range from -10 to about 100 deg F. No problems with maintaining a lock over that range, but the exciter was optimized at room temp for the correct lock voltage on only one frequency. The applications have all been repeaters with no frequency switching. I understand that some component values are changed for a factory change in frequency from commercial frequencies down into the ham band, but I have not had to make any changes other than the slug change when converting a 66 range PLL exciter. 73 - Jim W5ZIT --- On Sun, 3/22/09, Kris Kirby k...@catonic.us wrote: From: Kris Kirby k...@catonic.us Subject: Re: [Repeater-Builder] Master II station 66 split conversion to 56 split To: Repeater-Builder@yahoogroups.com Date: Sunday, March 22, 2009, 5:40 PM On Sun, 22 Mar 2009 n...@no6b.com wrote: I have retuned 10+ GE Mastr II exciters - base/moble and have never had to change a component. Put the ICOM in for the new frequency and tune per the manual. Same experience here, except that if you want to put one on the 144.390 APRS frequency you may find that some exciters don't quite make it down that far. What sort of temperature coeffiecent does the exciter have? If I want to find the limits of lock, do I need to freeze it or heat it up to 140 degrees? -- Kris Kirby, KE4AHR Disinformation Analyst
Re: [Repeater-Builder] Re: Decibel dipole array sweeps
I manage to clamp the addition to the element pretty tight with the machine screw and nut through a hole drilled through both sides of the flattened part of the addition wrapped around the element. And since only aluminum touches the aluminum element, I don't see any dissimilar metal problems in the conduction part of the element. Sure enough, the stainless screws that clamp the extensions are not aluminum, but they do not conduct any current to speak of at the hot ends of the dipoles. The oldest one that I have modified was just taken down in favor of a new DB-224E. The old dipoles and harness were 30 plus years old, and the wood phone pole the antenna was on broke off and fell five years ago. That is when the extensions were added, along with a new aluminum mast. We did see some improvement in coverage when the antenna was replaced, but we never had any noise or desense that I could attribute to the old antenna. I have modified several antennas this way, and have been pleased with the way they work after the mod. A buddy in Florida modified one and it is in operation on their repeater in a much more humid environment and he has not reported any antenna problems to me. So I can recommend this simple mod to get a better SWR for the duplexer to look into, for what that is worth. I used unmodified antennas for lots of years and just used what they showed for SWR and tuned the duplexer to give a good SWR to the transmitter. But I like being able to tune up the duplexer on the bench using 50 ohm loads and pads and not having to do any field tuning because of a mis-matched antenna. This mod may not be suitable for some sites I am sure, but has worked well for me so far. 73 - Jim W5ZIT --- On Sun, 3/22/09, Nate Duehr n...@natetech.com wrote: From: Nate Duehr n...@natetech.com Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps To: Repeater-Builder@yahoogroups.com Date: Sunday, March 22, 2009, 5:47 PM On Mar 22, 2009, at 4:13 PM, Jim Brown wrote: I have done the mod mentioned on several DB-224 antennas by taking some six inch lengths of an old TV antenna and flattening about three inches on one end and wrapping the flattened end around the end of the dipole and putting a machine screw through the flats to hold the extension to the dipole. I then cut the extension back to two inches. I like the ingenuity Jim, but isn't that just begging for dissimilar metal contact noise down the road after a few years of grime, corrosion, and weathering? I'd want to see how those antennas performed after 3-5 years and whether or not site noise was seeming to wander up, or others on-site were complaining of new mixes hitting receivers, etc. One of those things coming loose and scraping back and forth as the add-on extension swung in high winds, would probably make a hell of a crackling noise on the machine connected to it, too -- wouldn't it? Joints that can move, even only after some kind of damage, to me anyway = lots of trouble down the road. -- Nate Duehr, WY0X n...@natetech. com
Re: [Repeater-Builder] Re: Decibel dipole array sweeps
We made one back in the '70s from 3/4 inch aluminum angle. We sawed a vee at each bend point and welded the bent angle back together and made a very stable element. The dimensions we used were from an old VHF handbook and the elements were spaced quite a bit farther from the mast than a DB-224. Our matching harness never did work out right for that antenna and it was never put in service, but mechanically it seemed to be pretty sturdy. 73 - Jim W5ZIT --- On Sun, 3/22/09, Kris Kirby k...@catonic.us wrote: From: Kris Kirby k...@catonic.us Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps To: Repeater-Builder@yahoogroups.com Date: Sunday, March 22, 2009, 6:01 PM On Sun, 22 Mar 2009, rahwayflynn wrote: I have access to 316 stainless tube am willing to take a shot at fabricating replacement elements. Sounds like fun. I think the DB antennas are made from aluminum, however. If you're going to be making a DB antenna clone, it makes more sense to either punch them out of plate or cut them from rod. Any mechanical engineers on the list? :-) -- Kris Kirby, KE4AHR Disinformation Analyst
RE: [Repeater-Builder] Re: Decibel dipole array sweeps
Great information. I was at Ace Hardware today and picked up some aluminum tape to seal an HVAC duct. I surprised how sticky the stuff was and you can cut it to fit the joint. I wonder if this would be any good for modifying a dipole? I am not sure how it would stand up in the elements though. Not very thick, but really sticky, I was really impressed, plus it forms well around the HVAC ducts. Has anyone tried to use stainless steel hose clamps to clamp the extensions in place? I hope everyone has a wonderful week. 73's Butch, KE7FEL/r To: Repeater-Builder@yahoogroups.com From: w5...@yahoo.com Date: Sun, 22 Mar 2009 20:19:55 -0700 Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps I manage to clamp the addition to the element pretty tight with the machine screw and nut through a hole drilled through both sides of the flattened part of the addition wrapped around the element. And since only aluminum touches the aluminum element, I don't see any dissimilar metal problems in the conduction part of the element. Sure enough, the stainless screws that clamp the extensions are not aluminum, but they do not conduct any current to speak of at the hot ends of the dipoles. The oldest one that I have modified was just taken down in favor of a new DB-224E. The old dipoles and harness were 30 plus years old, and the wood phone pole the antenna was on broke off and fell five years ago. That is when the extensions were added, along with a new aluminum mast. We did see some improvement in coverage when the antenna was replaced, but we never had any noise or desense that I could attribute to the old antenna. I have modified several antennas this way, and have been pleased with the way they work after the mod. A buddy in Florida modified one and it is in operation on their repeater in a much more humid environment and he has not reported any antenna problems to me. So I can recommend this simple mod to get a better SWR for the duplexer to look into, for what that is worth. I used unmodified antennas for lots of years and just used what they showed for SWR and tuned the duplexer to give a good SWR to the transmitter. But I like being able to tune up the duplexer on the bench using 50 ohm loads and pads and not having to do any field tuning because of a mis-matched antenna. This mod may not be suitable for some sites I am sure, but has worked well for me so far. 73 - Jim W5ZIT --- On Sun, 3/22/09, Nate Duehr n...@natetech.com wrote: From: Nate Duehr n...@natetech.com Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps To: Repeater-Builder@yahoogroups.com Date: Sunday, March 22, 2009, 5:47 PM On Mar 22, 2009, at 4:13 PM, Jim Brown wrote: I have done the mod mentioned on several DB-224 antennas by taking some six inch lengths of an old TV antenna and flattening about three inches on one end and wrapping the flattened end around the end of the dipole and putting a machine screw through the flats to hold the extension to the dipole. I then cut the extension back to two inches. I like the ingenuity Jim, but isn't that just begging for dissimilar metal contact noise down the road after a few years of grime, corrosion, and weathering? I'd want to see how those antennas performed after 3-5 years and whether or not site noise was seeming to wander up, or others on-site were complaining of new mixes hitting receivers, etc. One of those things coming loose and scraping back and forth as the add-on extension swung in high winds, would probably make a hell of a crackling noise on the machine connected to it, too -- wouldn't it? Joints that can move, even only after some kind of damage, to me anyway = lots of trouble down the road. -- Nate Duehr, WY0X n...@natetech. com
Re: [Repeater-Builder] Re: Decibel dipole array sweeps
Since there's been quite a bit of talk about extending the elements on DB224s, I'll throw my experience in. I tried to extend the elements on a DB420, using the method of adding screws at the bends to lengthen the elements -- this was a TEST, so I didn't get too worried about them being steel screws. It only had to work or not work for about 10 minutes. Anyway, on the DB420, my experiment failed miserably. The only conclusion I have been able to speculate wildly at is that the extra amount of coax harness for 16 dipoles instead of 4 has something to do with it. The one thing I noticed was that, while I could not drag it down far enough in frequency, I was able to drag it a little and significantly narrow the useable bandwidth. 73 DE N0MJS On Mar 22, 2009, at 10:26 PM, Jim Brown wrote: We made one back in the '70s from 3/4 inch aluminum angle. We sawed a vee at each bend point and welded the bent angle back together and made a very stable element. The dimensions we used were from an old VHF handbook and the elements were spaced quite a bit farther from the mast than a DB-224. Our matching harness never did work out right for that antenna and it was never put in service, but mechanically it seemed to be pretty sturdy. 73 - Jim W5ZIT --- On Sun, 3/22/09, Kris Kirby k...@catonic.us wrote: From: Kris Kirby k...@catonic.us Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps To: Repeater-Builder@yahoogroups.com Date: Sunday, March 22, 2009, 6:01 PM On Sun, 22 Mar 2009, rahwayflynn wrote: I have access to 316 stainless tube am willing to take a shot at fabricating replacement elements. Sounds like fun. I think the DB antennas are made from aluminum, however. If you're going to be making a DB antenna clone, it makes more sense to either punch them out of plate or cut them from rod. Any mechanical engineers on the list? :-) -- Kris Kirby, KE4AHR Disinformation Analyst -- Cort Buffington H: +1-785-838-3034 M: +1-785-865-7206
Re: [Repeater-Builder] Re: Decibel dipole array sweeps
Oh yeah, I forgot. In the end my solution was to just use the DB420 as it is. It's worked ok. This spring we're replacing it with a Telewave ANT450D6-9. Yeah, a lot less antenna than the DB420, but it is designed to cover the amateur band, so we'll give it a go. On Mar 22, 2009, at 10:26 PM, Jim Brown wrote: We made one back in the '70s from 3/4 inch aluminum angle. We sawed a vee at each bend point and welded the bent angle back together and made a very stable element. The dimensions we used were from an old VHF handbook and the elements were spaced quite a bit farther from the mast than a DB-224. Our matching harness never did work out right for that antenna and it was never put in service, but mechanically it seemed to be pretty sturdy. 73 - Jim W5ZIT --- On Sun, 3/22/09, Kris Kirby k...@catonic.us wrote: From: Kris Kirby k...@catonic.us Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps To: Repeater-Builder@yahoogroups.com Date: Sunday, March 22, 2009, 6:01 PM On Sun, 22 Mar 2009, rahwayflynn wrote: I have access to 316 stainless tube am willing to take a shot at fabricating replacement elements. Sounds like fun. I think the DB antennas are made from aluminum, however. If you're going to be making a DB antenna clone, it makes more sense to either punch them out of plate or cut them from rod. Any mechanical engineers on the list? :-) -- Kris Kirby, KE4AHR Disinformation Analyst -- Cort Buffington H: +1-785-838-3034 M: +1-785-865-7206
Re: [Repeater-Builder] Re: Decibel dipole array sweeps
The dimensions are in the FILES here on the Repeater-Builder list. http://f1.grp.yahoofs.com/v1/MPvGSaXwn7VidapqNO9aJxssOWkx7N4yimg7VCgz9rDCxTSilYgmOPHi-yTakY_HTGB5tEDhwoOUFpePfhgiw9oi/db-224e-diagram-dz.pdf With the luck everyone had with Jeff's link, this one will probably not work. But look in the FILES section of the site at Yahoo to find the docs. 73 - Jim W5ZIT --- On Sun, 3/22/09, rahwayflynn mafl...@att.net wrote: From: rahwayflynn mafl...@att.net Subject: [Repeater-Builder] Re: Decibel dipole array sweeps To: Repeater-Builder@yahoogroups.com Date: Sunday, March 22, 2009, 5:53 PM --- In Repeater-Builder@ yahoogroups. com, Kris Kirby k...@... wrote: The results, I would say in practical terms, is that a DB-224 cut for 165MHz isn't a bad thing. You'll experience some uptilt. But matching the antenna to a 50-ohm transmitter is another issue altogether. So the question is, does anyone have an out-of-service DB-224 (hopefully on the ground) that was custom built for amateur service that dimensions can be lifted from from? I have access to 316 stainless tube am willing to take a shot at fabricating replacement elements. Martin
Re: [Repeater-Builder] Re: Decibel dipole array sweeps
I had to copy the link and paste it into the browser and then go back through and take out all the spaces that Yahoo added, but with that done I got back to the doc OK. 73 - Jim W5ZIT --- On Sun, 3/22/09, Jim Brown w5...@yahoo.com wrote: From: Jim Brown w5...@yahoo.com Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps To: Repeater-Builder@yahoogroups.com Date: Sunday, March 22, 2009, 10:48 PM The dimensions are in the FILES here on the Repeater-Builder list. http://f1.grp. yahoofs.com/ v1/MPvGSaXwn7Vid apqNO9aJxssOWkx7 N4yimg7VCgz9rDCx TSilYgmOPHi- yTakY_HTGB5tEDhw oOUFpePfhgiw9oi/ db-224e-diagram- dz.pdf With the luck everyone had with Jeff's link, this one will probably not work. But look in the FILES section of the site at Yahoo to find the docs. 73 - Jim W5ZIT --- On Sun, 3/22/09, rahwayflynn mafl...@att. net wrote: From: rahwayflynn mafl...@att. net Subject: [Repeater-Builder] Re: Decibel dipole array sweeps To: Repeater-Builder@ yahoogroups. com Date: Sunday, March 22, 2009, 5:53 PM --- In Repeater-Builder@ yahoogroups. com, Kris Kirby k...@... wrote: The results, I would say in practical terms, is that a DB-224 cut for 165MHz isn't a bad thing. You'll experience some uptilt. But matching the antenna to a 50-ohm transmitter is another issue altogether. So the question is, does anyone have an out-of-service DB-224 (hopefully on the ground) that was custom built for amateur service that dimensions can be lifted from from? I have access to 316 stainless tube am willing to take a shot at fabricating replacement elements. Martin
RE: [Repeater-Builder] Re: Decibel dipole array sweeps
At 3/22/2009 20:27, you wrote: Great information. I was at Ace Hardware today and picked up some aluminum tape to seal an HVAC duct. I surprised how sticky the stuff was and you can cut it to fit the joint. I wonder if this would be any good for modifying a dipole? The problem is that the adhesive used on that tape is not conductive (if it's the same stuff I have on my shelf), so you'd have to rely on capacitance between the tape the element in order for it to work. Then there is the issue of the unknown loss tangent of the adhesive. You may end up with low reflected power because some of it may get dissipated as heat in that adhesive. You may get lucky make a few point contacts from the antenna through the adhesive to the tape, but then you've just made diodes at those contacts. Bob NO6B
[Repeater-Builder] Misc. For Sale
Cleaning out the fire station storage room, and we have a bunch of stuff for sale: (1) Regency H256B field-programmable VHF mobile. Includes short power cord, mounting bracket, and hand mic. (1) Midland 70-340B VHF 32 ch 40W mobile. Includes mounting bracket and hand mic but no power cord. (1) Uniden FMH 350D VHF mobile. Includes hand mic and mounting bracket but no power cord. (2) Uniden SMH 1525DT VHF 10 ch 40W mobiles. Include hand mics and mounting brackets (one is mismatched). No power cords. (1) Uniden SMU 4525KT VHF 10 ch 4W mobile. Includes desk mic. No power cord. (2) CES SM-10 RepeaterMaker repeater controllers. These are currently wired together to fit the Uniden SMU/SMH radios for bidirectional repeat, but can be separated. I know one of them works, and assume the other does as well, but have not fully tested them. Documentation available at CES website. (1) RCA MFAO2-AC21B 2 ch VHF mobile. Includes power cord and hand mic. All of these were working when removed from service. I've tested some of them and can fully test any of the radios you might be interested in if you want me to. I can also provide pictures. I'm not very up to speed on what all of this stuff is worth, so please make a reasonable offer. Email me off-list andykn...@gmail.com if interested. Andy
Re: [Repeater-Builder] Decibel dipole array sweeps
Kris Kirby, This is directed to you: If I have a DB413 and I am going to use it on 441.950 you are saying there will be some down tilt in the pattern? This doesn't bother me. I am more curious than anything about this antenna that is due to go up 140ft on a tower in a couple of months. Brian, k5in - Original Message - From: Kris Kirby To: Repeater-Builder@yahoogroups.com Sent: Sunday, March 22, 2009 3:37 PM Subject: RE: [Repeater-Builder] Decibel dipole array sweeps On Sun, 22 Mar 2009 n...@no6b.com wrote: Well, without a long explanation, I can't view files made for Acrobat 6 later. No way around it unless I want to lose PDF authoring capability. Buy a Mac and image the Windows box and use it in a virtual machine. Then you can author in PDFs and the Mac has a built-in PDF viewer and Postscript conversion engine. Totally not the solution you were looking for. =) -- Kris Kirby, KE4AHR Disinformation Analyst
[Repeater-Builder] Re: OT: Making PDFs
--- In Repeater-Builder@yahoogroups.com, John J. Riddell ve3...@... wrote: Dave, try down loading a small program called Cute PDF writer...it's free and will make PDF's for you. It is set up as a printer but saves them to a file on your computer. 73 John VE3AMZ - Original Message - From: Dave Gomberg da...@... To: Repeater-Builder@yahoogroups.com Sent: Sunday, March 22, 2009 6:55 PM Subject: [Repeater-Builder] OT: Making PDFs At 15:37 3/22/2009, Kris Kirby wrote: No way around it unless I want to lose PDF authoring capability. Buy a Mac Actually WordPerfect makes beautiful PDF files and has for years... -- Dave Gomberg, San Francisco NE5EE gomberg1 at wcf dot com All addresses, phones, etc. at http://www.wcf.com/ham/info.html - Another option is to use OpenOffice, it will allow to to expert most formats to pdf documents. Allan WB5QNG
Re: [Repeater-Builder] OT: Making PDFs
Gee, look at all the solutions to a problem I said I don't have. At 21:59 3/22/2009, Larry wrote: Dave, The OpenOffice Suite also exports to PDF. Free .. just download and install. Comes in Windows and Linux versions. http://download.openoffice.org/other.htmlhttp://download.openoffice.org/other.html Choose what you like. You get the whole Office Suite and it does everything Windows Office does. Larry - N7FM Dave Gomberg wrote: At 15:37 3/22/2009, Kris Kirby wrote: No way around it unless I want to lose PDF authoring capability. Buy a Mac Actually WordPerfect makes beautiful PDF files and has for years... -- Dave Gomberg, San Francisco NE5EE gomberg1 at wcf dot com All addresses, phones, etc. at http://www.wcf.com/ham/info.htmlhttp://www.wcf.com/ham/info.html -- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: 270.11.24/2017 - Release Date: 03/22/09 17:51:00 -- Dave Gomberg, San Francisco NE5EE gomberg1 at wcf dot com All addresses, phones, etc. at http://www.wcf.com/ham/info.html -
Re: [Repeater-Builder] OT: Making PDFs
Gee, look at all the solutions to a problem I said I don't have. At 21:59 3/22/2009, Larry wrote: Dave, The OpenOffice Suite also exports to PDF. Free .. just download and install. Comes in Windows and Linux versions. http://download.openoffice.org/other.htmlhttp://download.openoffice.org/other.html Choose what you like. You get the whole Office Suite and it does everything Windows Office does. Larry - N7FM Dave Gomberg wrote: At 15:37 3/22/2009, Kris Kirby wrote: No way around it unless I want to lose PDF authoring capability. Buy a Mac Actually WordPerfect makes beautiful PDF files and has for years... -- Dave Gomberg, San Francisco NE5EE gomberg1 at wcf dot com All addresses, phones, etc. at http://www.wcf.com/ham/info.htmlhttp://www.wcf.com/ham/info.html -- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: 270.11.24/2017 - Release Date: 03/22/09 17:51:00 -- Dave Gomberg, San Francisco NE5EE gomberg1 at wcf dot com All addresses, phones, etc. at http://www.wcf.com/ham/info.html -
Re: [Repeater-Builder] PL Reeds
try er...@aol.com for the reeds. Ted Bleiman K9MDM MDM Radio If its in stock...we've got it! P O Box 31353 Chicago, IL 60631-0353 773.631.5130 fax 773.775.8096 web http://www.mdmradio.com email - mdmra...@yahoo.com DIRECT ALL EMAIL --- On Sat, 3/21/09, ke8hr1 ke8...@yahoo.com wrote: From: ke8hr1 ke8...@yahoo.com Subject: [Repeater-Builder] PL Reeds To: Repeater-Builder@yahoogroups.com Date: Saturday, March 21, 2009, 5:07 PM I am looking for several 100 Hz, 1Z pl reeds TLN8381A or equivalent. Will pay cash, trade for other frequencies. Will be used in the 146.760 repeater in Detroit. Adding satellite receivers. Also looking for Spectra Tac Satellite Receiver PL boards. TRN 6083A Also, anyone added a CommSpec PL decoder to a Spectra Tac Receiver, best model to buy, where to mount, etc. Thanks for the help. KE8HR Wallace
