[Repeater-Builder] Re: Measure return loss and cable fault with HP 8924C
Hi all, I just discovered an Australian company Measurement Innovation Pty Ltd has made a Windows PC based software for HP 892x series radio service monitor for measuring cable fault location and much more. http://www.measurement.ashop.com.au/c/25306/1/rf-tools.html Demo on YouTube http://www.youtube.com/watch?v=MUJaFbR8JK4 I guess they made the PC software that communicates with the HP 892x via the GPIB command. The screen looks better and presents more sophisticated features. Looks like it is more expensive than the 11807 Opt 100 software that only runs on the machine, but I wonder I can develop my own application using LabView framework becase the HP 892x series GPIB is available on the web. Thanks and Regards, Dickson Fu VR2WHF --- In Repeater-Builder@yahoogroups.com, ve7fet yahoogro...@... wrote: See page five for an explanation of the process... http://206.209.106.106/datasheets/Miscellaneous/54100a-4.pdf Again, doable, but messy. Lee --- In Repeater-Builder@yahoogroups.com, Dickson dicksonfuhk@ wrote: Hi, Thanks for your info. Though a bit complicated, it is still doable. By the way, how to measure the cable fault location without the 11807 software? Thanks and Regards, Dickson Fu VR2WHF --- In Repeater-Builder@yahoogroups.com, ve7fet yahoogroups@ wrote: First you'll need a return loss bridge. No replacing that. The 11807 software can make things a little prettier, but you can still do return loss quite easily. Distance to fault is going to be a bit more challenge, but it can be done too. Return loss is the easiest to set up. You'll need to set up the tracking generator/spectrum analyzer for the range you want to measure. Use the Duplex Output and connect it to the Source port on the RLB. Use the Antenna Input and connect it to the Reflected port on the RLB. You optionally may want to put a 6dB pad in between the Duplex Out and RLB Source port. With the DUT port open on the RLB, you should have a trace on the spectrum analyzer over the range you are sweeping. Now, you can turn up the output power of the Duplex Port until the trace gets close to the reference level at the top, or go into the menus on the spectrum analyzer and do a Save A and then a A-B to null out the sweep. Now, when you put a good load on the DUT port, you should get a return loss down ~40dB or so. Hook up the DUT you want to sweep and go. Yes, this is quick and dirty, but it gets the job done when you are not looking for fractions of a dB... Lee --- In Repeater-Builder@yahoogroups.com, Dickson dicksonfuhk@ wrote: Hi all, Without the RF Tools provided by 11807E opt 100 on HP 8924C, how to measure return loss and cable fault? The 11807E opt 100 provides the IBASIC program that can show the return loss profile over the range of frequency and indicates the max/min return loss and the corresponding frequency. Thanks and Regards, Dickson Fu VR2WHF
Re: [Repeater-Builder] Fw: TKR750 -Preamp
Hi Ed, Understood, was just coincidental that you message popped up as was looking at potentially adding a pre-amp to my repeater which is not at a great height nor ever likely to be - long story. Have tried a few from very good kit form to general purpose broad banded variable types with little improvement and as you say managed to overload the front end. There was a fellow ham over here who was making pre-amps to order but he seems to have suffered the fate of many small businesses in the financial downturn. Although not expensive in themselves, if I bring something in from the US, postage, insurance and value added tax soon bumps the cost up. I'll probably just stick with what I have without adding extra problems. Thank you for your input and advice, always appreciated. Best regards, Doug - GM7SVK - Glasgow - Scotland On 30/07/2010 2:26 AM, Com/Rad Inc wrote: Hello Doug Pre amplifiers are nifty gadgets. In my email I am seeking some personal references about this particular radio and a pre-amp which may have been tried wioth some level of success. When you start inserting GAIN ahead of a front end you have to be careful of overloading the system and introducing harful side effects. In very densly congested sites ( lots o f transmitters ) you may havdet ocomprimise the sensitivity of the reciever for selectivity. Crystal filter may help - I have found using a receiver with a tight front end and / or sufficient preselection will triumph over trying to make a lesser piece of equipment work. Example a GE Mastr III is a super reciever - In my case I am trying to set up a clients 2 recievers with a little additional sensitivity - we are using this equipment in a remote site away form other forms of interference ( boondock tower site ). Some manufacturers are ARR and EMR - EMR makes a bi-polar amp with variable gain. ARR also has a fixed gain version - ARR was very popular with GaS fet low noise stuff for 800 Mhz - used a lot of them - exccellent results. Costs $100 thru $350 Best r egards Ed Folta Com/Rad INc - Original Message - *From:* Doug Hutchison mailto:specialq@ntlworld.com *To:* repeater-builder@yahoogroups.com mailto:repeater-builder@yahoogroups.com *Sent:* Thursday, July 29, 2010 12:30 PM *Subject:* Re: [Repeater-Builder] Fw: TKR750 -Preamp Where does one obtain these and at what cost? Doug On 29/07/2010 15:58:54, Ken Arck (ah...@ah6le.net mailto:ah...@ah6le.net) wrote: At 04:30 AM 7/29/2010, Com/Rad Inc wrote: ubject: TKR750 -Preamp Greetings Group Have any of you experimented with a RX pre-amp for the TKR 750 repeater? I am seeking results of actual trials of a product - Anyone care to comment on their experience(s) ? We use AngleLinear PHEMT preamps all the time on TKR- 750's that we sell. They work very well without overloading the front end as many of the higher gain ones on the market do (generally, 12 to 15 dB is all that is needed in a receiver system, not the 20 to 24 dB some preamps deliver. Ken -- President and CTO - Arcom Communications Makers of repeater controllers and accessories. http://www.arcomcontrollers.com/ Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp.net We don't just make 'em. We use 'em! Yahoo! Groups Links
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Tim, I have a two meter repeater that outputs 250 watts (approximately +54 dBm) into the duplexer. After the 93 dB of rejection that the duplexer provides for shear power reduction toward the receiver port, -39 dBm of transmitter power leaves the duplexer receiver port - headed toward the receiver. The repeater is a Motorola MICOR VHF equipped with a MICOR preamp. Bench sensitivity is -125 dBm for 12 dB SINAD. The duplexer is a stock Wacom WP-641. This repeater normally uses a tube type power amplifier to achieve the 250 watt level. Using the tube power amp, no desense occurs on the repeater. I also have a the stock 110 watt MICOR power amplifier (solid state) that can be switched in. The repeater has a slight amount of desense when running the solid state PA. Why? It's obviously not the shear amount of power, as it has been reduced over 3 dB. The culprit is /transmitter side-band noise/. The solid-state power amplifier provides no additional protection of the amount of transmitter side-band noise being produced by the exciter, in fact, being wide-band in nature, the solid-state unit amplifies the noise. The tube power amplifier, however, is a High Q (very narrow band - tuned to the exact transmit frequency) device only providing power gain on the 'desired' repeater output frequency, and reducing (or at least not amplifying) the transmitter side-band noise appearing on the receiver frequency. From your explanation below, I don't believe shear power is ruining your ability to duplex, but rater the amount of transmitter side-band noise reaching the receiver. To prove this, install a notch cavity in the transmit leg tuned to the receiver frequency. If your duplexer isn't capable of allowing the present radio equipment to properly duplex, either the duplexer needs replaced, or you can change the type of transmitter to something else - no, I'm not suggesting tube-type. General Electric built a VHF exciter that has 22 dB less transmitter side band noise (600 kHz from its primary carrier) than most multiplier counterparts (like your Motorola MICOR). Using it is like installing a 22 dB notch filter between the exciter (transmitter) and receiver where side-band noise is concerned. This exciter is the MASTR II PLL. To comment on the folks privately emailing you telling you a MICOR receiver cannot handle an off frequency carrier of -53 - they are full of it - period. The answer is HOW CLEAN the adjacent frequency signal is. If the adjacent carrier is full of noise, and that noise falls on the frequency the receiver is listening to - then no the receiver can't handle it, but that's a totally different thing ruining your lunch - comparing apples to oranges. Hope this helps... Kevin Custer Hi guys, Took some time away from the project... loosing too many hairs. Ok, I've gotten another receiver strip, and it has the specified sensitivity per Mot. Guess I want to bounce some ideas around with those of you who are more learned in the arts! With 250mW (+24dBm) into the transmit port... antenna port is a quality 50 ohm load, I see -72dBM at the receiver port. (pretty much what I expect.. 1.8dB loss through the xmit side, 100dB notch through the RX side. With it all hooked up receiving an input signal of about 0.7uV, application of the 250mw to the transmitter side will cause noise in the receiver, although not much. So, it appears that if I add an additional 30dB notch (another 'can'), the problem at high power may go away. If I compare what 50 watts with an additional can would be (-130dB) to what I get with 250mW current notch (100dB), then it looks like I just need to add an additional can. 50 w = +47dBm - 130dB future notch = -83dBm at receiver. 250mw = +24 - 100dB current notch = -76dBm With the current notch @ 50 watts, I see a receive signal of -53dBm. Some have said that the Micor can handle that, while others (off-line) have said no way. This setup appears to support the opinion that -53 is still way too much. Any comments and thoughts would be most appreciated! Thanks, Tim
Re: [Repeater-Builder] Adjusting low power on an R1225 repeater
Here is the duty spec on the R1225 radio. I used to maintain LOTS of these in different flavors. You can have the GR 1225 desktop, a RKR 1225 rack mount housing or a GR400 wall mount housing. All of the GR1225 repeaters that I inherited failed eventually because they were set at high power. Easy to fix by changing out the complete PA unit. When fixed and the PA aligned and set to 25 watts MAX out of the radio, only had 1 failure after that. However, I set the fan to run continuously. In the RKR1225 chassis, fan runs on high blowing right on the PA. Radio might last longer at high power but it's still outside the duty cycle and will most likely fail at sometime. I would not try to reduce the transmit power to less than 25 watts on the high power radio because of the spurious problems others have mentioned. If you need to drive an external amp or run less power, either find the 1-10 watt radio or get a in-line attenuator, 25 watt rated at 3 or 6 db attenuation. You'd then have about 6.25 or 12.5 watts available at the output of the attenuator. Dave NN4TT Duty Cycle: Continuous @ 25W and 1-10W 50% @ 45 / 50 W ( 5 min. on / 5 min. standby) From: Robert McNeill rob...@ncbfi.org To: Repeater-Builder@yahoogroups.com Sent: Thu, July 29, 2010 11:11:43 PM Subject: RE: [Repeater-Builder] Adjusting low power on an R1225 repeater Is there an issue running one of those at 25 watts continuous? It is a repeater. What was it’s intent if not to be used in a heavy duty cycle? 73, Robert K5ILS From:Repeater-Builder@ yahoogroups. com [mailto:Repeater- buil...@yahoogro ups.com] On Behalf Of Joe Sent: Thursday, July 29, 2010 9:06 PM To: Repeater-Builder@ yahoogroups. com Subject: Re: [Repeater-Builder] Adjusting low power on an R1225 repeater Thanks Eric, I though there was a caveat to turning it down, but couldn't remember why. I want to experiment with an EchoLink repeater, but I'm not sure that the R1225 UHF hi power could hold up at 25 watts continuous duty. I think I'll do some shopping as you suggest. 73 and Thanks, Joe On 7/29/2010 10:01 PM, Eric Lemmon wrote: Joe, Yes, indeed! The UHF high-power version will likely either go spurious or burn up if set that low. The only way to go with the radio you have is to add a 6 or 10 dB power attenuator rated at no less than 25 watts, and set your TX power at the low end. Admittedly, this is a kluge of the first degree, but hey- you asked! Otherwise, try to get your hands on one of the 1-to-10 watt R1225 units, and you can have a ball. I suppose you could modify your high-power R1225 into the low-power version, but that is a lot of work, and the opportunities for permanently damaging the mainboard are legion. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@ yahoogroups. com [mailto:Repeater-Builder@ yahoogroups. com] On Behalf Of Joe Sent: Thursday, July 29, 2010 6:45 PM To: Repeater-Builder@ yahoogroups. com Subject: [Repeater-Builder] Adjusting low power on an R1225 repeater Hello to All, I want to turn the power down on my Motorola R1225 repeater to about 5 watts. It is the high power UHF version (25-45 watts). The reason for the low power is to drive a power amp at the output I want to achieve. Any drawbacks to running the R1225 this low? 73, Joe, K1ike
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Hi Kevin, Thanks for the info. I've used the PLL MastrII exciter on a couple of systems also. Now, since this duplexer is of the 'notch' variety, I already have about 100db of notch (on the TX side) that is tuned to the RX freq. Shouldn't this be enough? Tim
RE: [Repeater-Builder] Repeater transmit levels at the receiver?
With 250mW (+24dBm) into the transmit port... antenna port is a quality 50 ohm load, I see -72dBM at the receiver port. (pretty much what I expect.. 1.8dB loss through the xmit side, 100dB notch through the RX side. Those numbers are fine. With it all hooked up receiving an input signal of about 0.7uV, application of the 250mw to the transmitter side will cause noise in the receiver, although not much. That's bad. With the amount of isolation you have (assuming you have the same amount of noise supression - did you confirm that?), you shouldn't need any more isolation. Whatever problem you have that's manifesting as desense is NOT due to insufficient carrier supression or noise supression (assuming they're symmetrical - again, you should measure the latter). How are you injecting the signal into the receiver while transmitting, by the way? Lossy tee or some other method? So, it appears that if I add an additional 30dB notch (another 'can'), the problem at high power may go away. Probably not. If I compare what 50 watts with an additional can would be (-130dB) to what I get with 250mW current notch (100dB), then it looks like I just need to add an additional can. Probably not. With the current notch @ 50 watts, I see a receive signal of -53dBm. Some have said that the Micor can handle that, while others (off-line) have said no way. The others are wrong, and if they they want to defend their position, I invite them to do it here on the list. -53 dBm 1 MHz away is not a problematic signal by any stretch of the imagination. Here's a simple sanity check for those that feel otherwise. I like using real-world examples as sanity checks. How many thousands of 2m repeaters are out there running 100 watts at 600 kHz offset without desense? Let's be generous and say they have 100 dB of isolation in the duplexer. +50 dBm TPO - 100 dB = -50 dBm transmit carrier hitting the receiver. No big deal. And that's on 2m. The offset on 2m is only 0.4% (0.6 MHz / 146 MHz), whereas on 6m, it's 1.9% (1 / 53 MHz), making isolation requirements that much more stringent on 2m. Now let's look at a 6m example. You have a 6m repeater on a 1 MHz split? Let's say it's on 53.99-, highest channel in the band, putting your receiver on 52.99. Some other ham is working simplex on 52.525, using 100 watts into a unity-gain antenna, and he's 40 miles away. His signal into your receiver, assuming unity gain on your end too, and line-of-sight, is -53 dBm (that's what the free-space path loss works out to: 103 dB for 40 miles on 6m, check my math). Would you expect this guy 40 miles away talking on 525 to desense your repeater? If so, then you should expect *every* ham who transmits on 525 (or potentially any other frequency within 1 MHz of your receiver) within a 40 mile radius of your repeater to cause you desense; those that are closer than 40 miles are just going to desense it even worse. Silly. Just plain silly. This setup appears to support the opinion that -53 is still way too much. No, it doesn't. You're drawing a conclusion from incomplete data. The only thing you know at this point is that what you have DOESN'T work, but what you DON'T KNOW is WHY it doesn't work. And I'm telling you, with the utmost certainty, that based on the numbers you've given, lack of carrier supression and/or noise supression in your duplexer at your operating frequencies is NOT the problem, you should be looking elsewhere. There are many potential causes of desense beyond just carrier supression and transmitter noise supression afforded by the duplexer at the Tx and Rx frequencies proper. To say that all of your problems will be solved by increasing either/both is not a valid conclusion to draw. Just a few of many possible issues that could be causing your desense problem: - lack of mid-band isolation - noisy components/connections in your duplexer, cabling, etc. - spurious transmitter - spurious LO - component breaking down/arcing when excited by RF - insufficient shielding (cabling, radio chassis/subassemblies, etc.) - bad test load or antenna - bad channel element or crystal - corroded/oxidized connector, contact, pin, etc. - cracked/broken/microscopically-intermittent connection, trace, conductor, etc. - bad/cold solder joint - other problem in exciter or receiver - loose, mis-installed, or otherwise faulty RF connector - bad RF cables (LMR, bare copper braid, etc.) - bad luck, bad karma, bad mojo, phase of the moon, alignment of the planets, etc. When you're duplexing, everything has to be damn near perfect otherwise you end up with desense. On 6m, you have a few things going for you, including a wide frequency split (percentage-wise), a high ambient noise floor (hides some sins/duplex noise), but otherwise, all of the same issues/caveats apply as they do on any other band when duplexing, noise is noise, dynamic range is dynamic range, whether you're on 50 MHz or 50 GHz.
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Kevin - how did you get the MICOR 250 Watt VHF Amplifier to go down to 2-Meters? Or was it a factory 140-150 MHz range unit originally? I see plenty of the 100-watt (I think they're a TLD-1692) amps that are factory 2-Meter range PA decks (I have a few spares, in case I ever need them) but haven't ever seen a factory 140-150 range 1/4 KW PA. I know they do exist, and a few people have them. I just haven't found one, or found anyone who can move the 150-170 MHz range units down to 2-Meters. Thanks and 73, LJ -Original Message- From: Kevin Custer Sent: Jul 30, 2010 6:25 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Repeater transmit levels at the receiver? Tim, I have a two meter repeater that outputs 250 watts (approximately +54 dBm) into the duplexer. After the 93 dB of rejection that the duplexer provides for shear power reduction toward the receiver port, -39 dBm of transmitter power leaves the duplexer receiver port - headed toward the receiver. The repeater is a Motorola MICOR VHF equipped with a MICOR preamp. Bench sensitivity is -125 dBm for 12 dB SINAD. The duplexer is a stock Wacom WP-641. This repeater normally uses a tube type power amplifier to achieve the 250 watt level. Using the tube power amp, no desense occurs on the repeater. I also have a the stock 110 watt MICOR power amplifier (solid state) that can be switched in. The repeater has a slight amount of desense when running the solid state PA. Why? It's obviously not the shear amount of power, as it has been reduced over 3 dB. The culprit is transmitter side-band noise. The solid-state power amplifier provides no additional protection of the amount of transmitter side-band noise being produced by the exciter, in fact, being wide-band in nature, the solid-state unit amplifies the noise. The tube power amplifier, however, is a High Q (very narrow band - tuned to the exact transmit frequency) device only providing power gain on the 'desired' repeater output frequency, and reducing (or at least not amplifying) the transmitter side-band noise appearing on the receiver frequency. From your explanation below, I don't believe shear power is ruining your ability to duplex, but rater the amount of transmitter side-band noise reaching the receiver. To prove this, install a notch cavity in the transmit leg tuned to the receiver frequency. If your duplexer isn't capable of allowing the present radio equipment to properly duplex, either the duplexer needs replaced, or you can change the type of transmitter to something else - no, I'm not suggesting tube-type. General Electric built a VHF exciter that has 22 dB less transmitter side band noise (600 kHz from its primary carrier) than most multiplier counterparts (like your Motorola MICOR). Using it is like installing a 22 dB notch filter between the exciter (transmitter) and receiver where side-band noise is concerned. This exciter is the MASTR II PLL. To comment on the folks privately emailing you telling you a MICOR receiver cannot handle an off frequency carrier of -53 - they are full of it - period. The answer is HOW CLEAN the adjacent frequency signal is. If the adjacent carrier is full of noise, and that noise falls on the frequency the receiver is listening to - then no the receiver can't handle it, but that's a totally different thing ruining your lunch - comparing apples to oranges. Hope this helps... Kevin Custer Hi guys, Took some time away from the project... loosing too many hairs. Ok, I've gotten another receiver strip, and it has the specified sensitivity per Mot. Guess I want to bounce some ideas around with those of you who are more learned in the arts! With 250mW (+24dBm) into the transmit port... antenna port is a quality 50 ohm load, I see -72dBM at the receiver port. (pretty much what I expect.. 1.8dB loss through the xmit side, 100dB notch through the RX side. With it all hooked up receiving an input signal of about 0.7uV, application of the 250mw to the transmitter side will cause noise in the receiver, although not much. So, it appears that if I add an additional 30dB notch (another 'can'), the problem at high power may go away. If I compare what 50 watts with an additional can would be (-130dB) to what I get with 250mW current notch (100dB), then it looks like I just need to add an additional can. 50 w = +47dBm - 130dB future notch = -83dBm at receiver. 250mw = +24 - 100dB current notch = -76dBm With the current notch @ 50 watts, I see a receive signal of -53dBm. Some have said that the Micor can handle that, while others (off-line) have said no way. This setup appears to support the opinion that -53 is still way too much. Any comments and thoughts would be most appreciated! Thanks, Tim
RE: [Repeater-Builder] Repeater transmit levels at the receiver?
Hi Jeff, Thanks for the reality check... loved the real-world example of the mobile unit. At this point, I'm leaning towards the bad mojo/karma phase of the moon! Got a 'spare' set of low-band cans that need to be stored somewhere it's warm? :-) Thanks, Tim
RE: [Repeater-Builder] Repeater transmit levels at the receiver?
Jeff, You did an excellent job of explaining the complex interrelationships among 2m repeaters. However, not all 6m repeaters have a 1 MHz split; my 6m repeater on Tranquillon Peak follows the California band plan and has a 500 kHz split. The duplexer has four cans about 12 in diameter and five feet tall. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Jeff DePolo Sent: Friday, July 30, 2010 7:30 AM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Repeater transmit levels at the receiver? snip How many thousands of 2m repeaters are out there running 100 watts at 600 kHz offset without desense? Let's be generous and say they have 100 dB of isolation in the duplexer. +50 dBm TPO - 100 dB = -50 dBm transmit carrier hitting the receiver. No big deal. And that's on 2m. The offset on 2m is only 0.4% (0.6 MHz / 146 MHz), whereas on 6m, it's 1.9% (1 / 53 MHz), making isolation requirements that much more stringent on 2m. Now let's look at a 6m example. You have a 6m repeater on a 1 MHz split? Let's say it's on 53.99-, highest channel in the band, putting your receiver on 52.99. Some other ham is working simplex on 52.525, using 100 watts into a unity-gain antenna, and he's 40 miles away. His signal into your receiver, assuming unity gain on your end too, and line-of-sight, is -53 dBm (that's what the free-space path loss works out to: 103 dB for 40 miles on 6m, check my math). Would you expect this guy 40 miles away talking on 525 to desense your repeater? If so, then you should expect *every* ham who transmits on 525 (or potentially any other frequency within 1 MHz of your receiver) within a 40 mile radius of your repeater to cause you desense; those that are closer than 40 miles are just going to desense it even worse. snip --- Jeff WN3A
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Tim wrote: Hi Kevin, Thanks for the info. I've used the PLL MastrII exciter on a couple of systems also. Now, since this duplexer is of the 'notch' variety, I already have about 100db of notch (on the TX side) that is tuned to the RX freq. Shouldn't this be enough? Yes, 100 dB of duplexer isolation should be plenty - something is obviously a amiss. How dirty is the transmitter (spectral purity)?
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
On 7/30/2010 10:15 AM, Kevin Custer wrote: Tim wrote: Hi Kevin, Thanks for the info. I've used the PLL MastrII exciter on a couple of systems also. Now, since this duplexer is of the 'notch' variety, I already have about 100db of notch (on the TX side) that is tuned to the RX freq. Shouldn't this be enough? Yes, 100 dB of duplexer isolation should be plenty - something is obviously a amiss. How dirty is the transmitter (spectral purity)? I'd also look for other signal paths, leaky jumpers, ground loops, poor shielding... -- mailto:o...@ozindfw.net Oz POB 93167 Southlake, TX 76092 (Near DFW Airport)
[Repeater-Builder] Re: Simrex - GLB Pre-Selector Pre-Amplifier
Re: Simrex - GLB Pre-Selector Pre-Amplifier Yes, but the NF is unpublished unknown. I therefore assume it's poor, maybe 3 dB? Once again, the NF depends on what device arrives in your specific Simrex (aka GLB) Pre-Selector. It wouldn't hurt or be impossible to ask. A Chip Angle GaAsFET @ UHF has 0.5 dB NF. Put a 1/4 wave pass cavity with 0.5 dB loops in front of it you have a narrow 1 dB NF front-end. I'll take 1 dB NF over 3 dB NF any day. You're actually comparing two different boxes. The Angle, ARR, Telewave, Hamtronics, yadda-yadda brand Pre-amplifiers are just Pre-amplifiers. The Simrex / GLB box is an RF Amplifier with both Pre and Post filters. The lower realized gain of the Simrex / GLB unit is directly related to the additional filtering included inside the box. The Simrex unit makes a nice solution if you don't have the physical space for a 1/4 wave bottle. But it's not the primary reason why I like them. Then again, I know someone who just ordered an even smaller MtronPTI front-end crystal filter to solve a front-end overload problem from a TX over 1 MHz away from his RX. Crystal filters can be very helpful but people tend to depend on them to cure a Symptom. Not the best solution (higher loss, can't be re-tuned if he ever has to change freq.), but I guess it works for him. Sometimes you need a large brick wall with only a small doorway so they obviously have their usefulness. If you picked the UHF Simrex unit with less gain, more selectivity than the standard model, then the noise factor should be better? The less gain is related to the internal filtering stages, not the device. I would expect the version with the GasFet to have the typical expected NF for that device. Any other available active devices to have Noise Figures commensurate with their typical expected values (for those devices). I doubt it. But without any real NF numbers, it's all guesswork. I have measured all the original GLB Pre-selectors and their performance values are very realistic (no surprises). I wouldn't expect a surprise/difference if I ordered the GasFet equipped Simrex Pre-selector. I guess it comes back to price too, a 1/4 wave can plus pre-amp will cost more money... No, your selection should be based on your needs. Do you need a bare RF-Pre-amplifier or do you need an integrated, amplified RF Pre-selector box? GaAsFET preamp is ~$130. I don't think I've ever paid more than $50 for a pass cavity, so the total is ~$100 less than the GLB unit. Reads like you're comparing a new Preamp with a used cavity against the price of a new Simrex (GLB) Pre-selector. That's not really fair... One of the really nice (and mostly overlooked) items about the Simrex (GLB) unit construction (and operation) is the Post (active) Amplifier Filtering (tuned circuits). For more than one real reason they can be one of the most under reported bacon saver in your fry pan. s.
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Larry - I didn't. The 250 watts is produced by a GE MASTR Pro/II 4EF5A1 capable of 330 watts continuous. The MICOR high-band tube amplifier, IMHO, is junk compared to the GE 4CX250R based VHF power amplifier. The 4EF5A1 is designed to operate from 144 to 174 MHz. without modification. Obtaining proper drive for it was the fun part. Read all about it here: http://www.kuggie.com/ahra/hmft.html Pictures of it here: http://www.kuggie.com/ahra/hmft.html Kevin Kevin - how did you get the MICOR 250 Watt VHF Amplifier to go down to 2-Meters? Or was it a factory 140-150 MHz range unit originally? I see plenty of the 100-watt (I think they're a TLD-1692) amps that are factory 2-Meter range PA decks (I have a few spares, in case I ever need them) but haven't ever seen a factory 140-150 range 1/4 KW PA. I know they do exist, and a few people have them. I just haven't found one, or found anyone who can move the 150-170 MHz range units down to 2-Meters. Thanks and 73, LJ
Re: [Repeater-Builder] Re: Simrex - GLB Pre-Selector Pre-Amplifier
skipp025 wrote: The less gain is related to the internal filtering stages, not the device. I would expect the version with the GasFet to have the typical expected NF for that device. Any other available active devices to have Noise Figures commensurate with their typical expected values (for those devices). I doubt it. But without any real NF numbers, it's all guesswork. I have measured all the original GLB Pre-selectors and their performance values are very realistic (no surprises). I wouldn't expect a surprise/difference if I ordered the GasFet equipped Simrex Pre-selector. What you are missing is that ANY losses ahead of the first active stage add to the noise figure of the system - directly. So, while filtering exists in the GLB device, so does loss, and this loss is more than what is experienced when using a quality large diameter cavity. Many times Skipp you tell us there is no free lunch, and the same applies to the comparison of selectivity and loss between the GLB and a quality cavity followed by a good active stage. Real world test. Take a Hamtronics receiver (no preamp) and do a basic bench sensitivity test to obtain a baseline. If you find something around -123 dBm your in the right ballpark. Now install a bi-polar GLB preselector/preamp in front and measure the sensitivity again - you'll find you have lost several dB of bench sensitivity - at least 3 or 4 dB. Take the same receiver and add a quality 1/4 bottle with a good preamp (your choice - something with 1.5 dB NF or less) and do the test again. Now, the receiver hears at -123 to -127 dBm (dependent mainly upon the quality of the preamp that follows) because the filter hasn't severely ruined the system NF ahead of the first active stage. Even though the GLB has gain, the noise figure of the design has already determined the sensitivity that will be realized by the receiver that follows. The GLB preselector/preamp should not be considered for adding basic sensitivity, because it's possible (depending on how good the receiver is to begin with) the opposite will happen - however, it will protect a receiver that lacks good front-end filtering, like the Hamtronics. Like everything, the situation helps to dictate what equipment will give the best results. Kevin
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Hi as do most european 6mtr repeaters, 500Kc split 73 Steve - Original Message - From: Eric Lemmon wb6...@verizon.net To: Repeater-Builder@yahoogroups.com Sent: Friday, July 30, 2010 3:57 PM Subject: RE: [Repeater-Builder] Repeater transmit levels at the receiver? Jeff, You did an excellent job of explaining the complex interrelationships among 2m repeaters. However, not all 6m repeaters have a 1 MHz split; my 6m repeater on Tranquillon Peak follows the California band plan and has a 500 kHz split. The duplexer has four cans about 12 in diameter and five feet tall. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Jeff DePolo Sent: Friday, July 30, 2010 7:30 AM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Repeater transmit levels at the receiver? snip How many thousands of 2m repeaters are out there running 100 watts at 600 kHz offset without desense? Let's be generous and say they have 100 dB of isolation in the duplexer. +50 dBm TPO - 100 dB = -50 dBm transmit carrier hitting the receiver. No big deal. And that's on 2m. The offset on 2m is only 0.4% (0.6 MHz / 146 MHz), whereas on 6m, it's 1.9% (1 / 53 MHz), making isolation requirements that much more stringent on 2m. Now let's look at a 6m example. You have a 6m repeater on a 1 MHz split? Let's say it's on 53.99-, highest channel in the band, putting your receiver on 52.99. Some other ham is working simplex on 52.525, using 100 watts into a unity-gain antenna, and he's 40 miles away. His signal into your receiver, assuming unity gain on your end too, and line-of-sight, is -53 dBm (that's what the free-space path loss works out to: 103 dB for 40 miles on 6m, check my math). Would you expect this guy 40 miles away talking on 525 to desense your repeater? If so, then you should expect *every* ham who transmits on 525 (or potentially any other frequency within 1 MHz of your receiver) within a 40 mile radius of your repeater to cause you desense; those that are closer than 40 miles are just going to desense it even worse. snip --- Jeff WN3A Yahoo! Groups Links
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Hi Tim it should be plenty, what about the notch on,the rx side, which I assume is tuned to reject the tx freq. Steve - Original Message - From: Tim tahr...@swtexas.net To: Repeater-Builder@yahoogroups.com Sent: Friday, July 30, 2010 4:42 PM Subject: Re: [Repeater-Builder] Repeater transmit levels at the receiver? Hi Kevin, Thanks for the info. I've used the PLL MastrII exciter on a couple of systems also. Now, since this duplexer is of the 'notch' variety, I already have about 100db of notch (on the TX side) that is tuned to the RX freq. Shouldn't this be enough? Tim Yahoo! Groups Links
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Hi Steve, Both sides are exhibiting pretty much the same specs - about a 100dB notch (each side tuned to the opposite freq), and about 1.5dB attenuation at the desired freq. All cables are new RG142. Something's gotta be bad wrong if a 250mW input on the TX side will make noise. Using the Micor's exciter - about 270mW. Cannot see any spurs/noise within 80dB of the main carrier. Tim
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Kevin - Thanks for the clarification. I have one of those 1/4 KW VHF MICOR Repeaters in my garage, and wish I could get it to move down to 2-Meters. We have a local government agency that has one on 151 MHz, the sticker (the Motorola sticker that says ___ ua = ___ watts) on the inside of the cabinet says that it's doing 430 watts output! We always thought that one would be fun to move to 2-Meters on a simplex channel, but moving it there would be nearly impossible. LJ -Original Message- From: Kevin Custer Sent: Jul 30, 2010 8:38 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Repeater transmit levels at the receiver? Larry - I didn't. The 250 watts is produced by a GE MASTR Pro/II 4EF5A1 capable of 330 watts continuous. The MICOR high-band tube amplifier, IMHO, is junk compared to the GE 4CX250R based VHF power amplifier. The 4EF5A1 is designed to operate from 144 to 174 MHz. without modification. Obtaining proper drive for it was the fun part. Read all about it here: http://www.kuggie.com/ahra/hmft.html Pictures of it here: http://www.kuggie.com/ahra/hmft.html Kevin Kevin - how did you get the MICOR 250 Watt VHF Amplifier to go down to 2-Meters? Or was it a factory 140-150 MHz range unit originally? I see plenty of the 100-watt (I think they're a TLD-1692) amps that are factory 2-Meter range PA decks (I have a few spares, in case I ever need them) but haven't ever seen a factory 140-150 range 1/4 KW PA. I know they do exist, and a few people have them. I just haven't found one, or found anyone who can move the 150-170 MHz range units down to 2-Meters. Thanks and 73, LJ
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Hi Tim that should work fine, very strange. As a matter of interest how far apart are the tx and rx units and I take it all the covers and screening cans are fitted.. Steve
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Tim wrote: Using the Micor's exciter - about 270mW. Cannot see any spurs/noise within 80dB of the main carrier. I wonder Most of the MICOR exciters I have converted to 6M result in more than 270 mW of power - in fact, 400 to 600 mW is common. I wonder if something is amiss at the exciter, like a bad crystal or stage not peaked correctly generating noise. If you have a 6M hand-held or mobile rig capable of transmitting on your repeater output frequency, try substituting it for the MICOR and see what happens to your receiver with one of these transmitting instead. Kevin
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Actually, the output is about +26dBm, so it's closer to 400mW. I've also tried a VX-5 on low power, and got the same result. Tim On 7/30/2010 9:52 AM, Kevin Custer wrote: Tim wrote: Using the Micor's exciter - about 270mW. Cannot see any spurs/noise within 80dB of the main carrier. I wonder Most of the MICOR exciters I have converted to 6M result in more than 270 mW of power - in fact, 400 to 600 mW is common. I wonder if something is amiss at the exciter, like a bad crystal or stage not peaked correctly generating noise. If you have a 6M hand-held or mobile rig capable of transmitting on your repeater output frequency, try substituting it for the MICOR and see what happens to your receiver with one of these transmitting instead. Kevin
RE: [Repeater-Builder] GE Mobile Radio
Hi thanks for the reply here is what the radio looks like. The 0 could be an 8, the data plate has a gouge on that digit making it hard to tell, I was guessing as the lower right quarter of the digit is missing. --- On Fri, 7/30/10, Eric Lemmon wb6...@verizon.net wrote: From: Eric Lemmon wb6...@verizon.net Subject: RE: [Repeater-Builder] GE Mobile Radio To: Repeater-Builder@yahoogroups.com Date: Friday, July 30, 2010, 3:49 AM Charlie, This is a tough one. The Y prefix indicates an RCC duplex radio, and the ER42M and ET59L indicate a Mastr Progress Line 35 watt radio for the 450-470 MHz band. I wonder if the 80 you quoted might actually be 88? Better double-check the Combination Number to make sure you're reading it correctly. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of glad3933 Sent: Thursday, July 29, 2010 7:44 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] GE Mobile Radio Hi I have an old GE mobile trunk mounting type radio with a control head and can't find any info on the radio. The only numbers are on the front of the radio as follows: YT55TPU80 serial number 2120935 er-42-m FCC DATA ET 59 L. On the front of the radio is a large chrome handle the width of the radio and folds out of the way to allow access to the front of the radio and the cable connectors. I suppose the handle is for carring the radio when it would be removed for service or repair. I think the radio might be a UHF unit. Any help would be appreciated. Thanks Charlie.
[Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
Our Amateur radio club's Motorola MSR 2000 continuous duty amp needs repair. I cant figure out how to remove the amp board from the heat sink. I removed all screws from corners as well as the transistors. It seems to be held by the center, just below the tall air variable cap. I tried heating the solder in the area but, no joy. I don't want to crack the board. The drawings in the manual I found here do not show even the screw holes. Thanks in advance, 73, Marty (WB2BEW)
[Repeater-Builder] Re: GMRS Radio
Most lmr radios will program gmrs frequencies. Be mindful of output power programmed as most will do over the limit. Many ameuter radios with transmitter mods will also do this. My radio vendor of choice is Icom. They are very tough with mil specs and all. --- In Repeater-Builder@yahoogroups.com, Joel joellan...@... wrote: Anybody have any reviews or maybe a used GMRS radio? I would like a 4 watt radio. Is the FCC doing in with GMRS repeaters? Does anybody have them for sale? Do they make a portable repeater?
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Hi Kev would it be feasable to use a sig gen cranked right up ? Steve - Original Message - From: Kevin Custer kug...@kuggie.com To: Repeater-Builder@yahoogroups.com Sent: Friday, July 30, 2010 5:52 PM Subject: Re: [Repeater-Builder] Repeater transmit levels at the receiver? Tim wrote: Using the Micor's exciter - about 270mW. Cannot see any spurs/noise within 80dB of the main carrier. I wonder Most of the MICOR exciters I have converted to 6M result in more than 270 mW of power - in fact, 400 to 600 mW is common. I wonder if something is amiss at the exciter, like a bad crystal or stage not peaked correctly generating noise. If you have a 6M hand-held or mobile rig capable of transmitting on your repeater output frequency, try substituting it for the MICOR and see what happens to your receiver with one of these transmitting instead. Kevin Yahoo! Groups Links
Re: Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Agree on the MSTR PRO 4EF5A1. Had one in service on the amateur band (VHF HI) and it ran withoout a burp for 8 years. Would like to find another one to use with the MASTR II. David Jul 30, 2010 03:39:08 PM, Repeater-Builder@yahoogroups.com wrote: Larry - I didn't. The 250 watts is produced by a GE MASTR Pro/II 4EF5A1 capable of 330 watts continuous. The MICOR high-band tube amplifier, IMHO, is junk compared to the GE 4CX250R based VHF power amplifier. The 4EF5A1 is designed to operate from 144 to 174 MHz. without modification. Obtaining proper drive for it was the fun part. Read all about it here: http://www.kuggie.com/ahra/hmft.html Pictures of it here: http://www.kuggie.com/ahra/hmft.html Kevin Kevin - how did you get the MICOR 250 Watt VHF Amplifier to go down to 2-Meters? Or was it a factory 140-150 MHz range unit originally? I see plenty of the 100-watt (I think they're a TLD-1692) amps that are factory 2-Meter range PA decks (I have a few spares, in case I ever need them) but haven't ever seen a factory 140-150 range 1/4 KW PA. I know they do exist, and a few people have them. I just haven't found one, or found anyone who can move the 150-170 MHz range units down to 2-Meters. Thanks and 73, LJ
RE: [Repeater-Builder] Repeater transmit levels at the receiver?
You did an excellent job of explaining the complex interrelationships among 2m repeaters. However, not all 6m repeaters have a 1 MHz split; my 6m repeater on Tranquillon Peak follows the California band plan and has a 500 kHz split. The duplexer has four cans about 12 in diameter and five feet tall. 73, Eric Lemmon WB6FLY Even at 500 kHz split, 100+ dB is more than enough isolation on channel center on 6m. Using simple frequency scaling (not to say that's truly the way to compare, but it gives a rough approximation), that would be like 1.4 MHz split on 2m with the same (100 dB) isolation. 500 kHz on 6m is about 0.9%, still more than twice as much as 0.4% on 2m with 600 kHz split. --- Jeff WN3A
RE: [Repeater-Builder] Repeater transmit levels at the receiver?
At this point, I'm leaning towards the bad mojo/karma phase of the moon! Let's start out with the basics: 1. How much desense do you have? 2. How are you injecting the Rx signal, and what are you using for the signal source? 3. What are you using for a dummy load when doing the desense test? 4. Have you look at both the Tx and the Rx LO to confirm neither are spurious? 5. For the heck of it, have you tried using a totally different Tx and Rx (even just using ham mobile rigs, you have 100 dB of isolation which should make even ham rigs play without desense on the bench, though I'd never use them in production). 6. If do #5, and you still have desense, try flipping Tx and Rx frequencies and see if you still have desense, it might help point to a problem on one side of the duplexer versus the other (e.g. something on the Tx leg generating noise which ceases to be a problem when you're not passing high-level RF through that leg when you have the frequencies flipped). --- Jeff WN3A
Re: [Repeater-Builder] Re: question for commercial radio shops
Didn't Lloyd Bridges work that one to death in Airplane ? At 07:43 PM 07/13/10, you wrote: Nothing if you're name is roger. Smile emoticon From: mailto:llhorl...@gmail.comLarry Horlick Sent: Tuesday, July 13, 2010 10:02 PM To: mailto:Repeater-Builder@yahoogroups.comRepeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: question for commercial radio shops Hey, what's wrong with a roger beep?'beep' On Tue, Jul 13, 2010 at 9:56 PM, skipp025 mailto:skipp...@yahoo.comskipp...@yahoo.com wrote: If a person whom you knew and is involved in a number of church youth camps activities asked you to program FRS frequencies into a 4w UHF HT type accepted for LMR would you do so ? It would only be for extended range at camp. If the radio power can be reduced, turn it down and program the FRS frequencies in. If the power can't be reduced, put the radios on GMRS Frequencies. Many of the Kenwood Portables I sell allow power level programming per channel so the FRS gets low and the other stuff gets the nominal rated power. FRS Radios are sold cheap at the big box stores... try to find the ones that allow you to turn off the $...@%@*% stupid roger beeps s. inline: 1130f514.gif
Re: [Repeater-Builder] Re: question for commercial radio shops
We have clearance Clarence. Roger, Roger, whats our vector, Victor? John Hymes La Rue Communications 10 S. Aurora Street Stockton, CA 95202 http://tinyurl.com/2dtngmn - Original Message - From: Mike Morris To: Repeater-Builder@yahoogroups.com Sent: Friday, July 30, 2010 11:07 AM Subject: Re: [Repeater-Builder] Re: question for commercial radio shops Didn't Lloyd Bridges work that one to death in Airplane ? At 07:43 PM 07/13/10, you wrote: Nothing if you're name is roger. From: Larry Horlick Sent: Tuesday, July 13, 2010 10:02 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: question for commercial radio shops Hey, what's wrong with a roger beep?'beep' On Tue, Jul 13, 2010 at 9:56 PM, skipp025 skipp...@yahoo.com wrote: If a person whom you knew and is involved in a number of church youth camps activities asked you to program FRS frequencies into a 4w UHF HT type accepted for LMR would you do so ? It would only be for extended range at camp. If the radio power can be reduced, turn it down and program the FRS frequencies in. If the power can't be reduced, put the radios on GMRS Frequencies. Many of the Kenwood Portables I sell allow power level programming per channel so the FRS gets low and the other stuff gets the nominal rated power. FRS Radios are sold cheap at the big box stores... try to find the ones that allow you to turn off the $...@%@*% stupid roger beeps s. 1130f514.gif
RE: [Repeater-Builder] Re: question for commercial radio shops
No it doesn't. and don't call me Shirley! Kb0wlf -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- buil...@yahoogroups.com] On Behalf Of MCH Sent: Friday, July 30, 2010 3:19 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: question for commercial radio shops We have clearance. Over. That's Clarence Over Just doesn't work as well in print, does it? :-) Joe M. La Rue Communications wrote: We have clearance Clarence. Roger, Roger, whats our vector, Victor? John Hymes La Rue Communications 10 S. Aurora Street Stockton, CA 95202 http://tinyurl.com/2dtngmn - Original Message - *From:* Mike Morris mailto:wa6i...@verizon.net *To:* Repeater-Builder@yahoogroups.com mailto:Repeater-Builder@yahoogroups.com *Sent:* Friday, July 30, 2010 11:07 AM *Subject:* Re: [Repeater-Builder] Re: question for commercial radio shops Didn't Lloyd Bridges work that one to death in Airplane ? At 07:43 PM 07/13/10, you wrote: Nothing if you're name is roger. Smile emoticon *From:* Larry Horlick mailto:llhorl...@gmail.com *Sent:* Tuesday, July 13, 2010 10:02 PM *To:* Repeater-Builder@yahoogroups.com mailto:Repeater-Builder@yahoogroups.com *Subject:* Re: [Repeater-Builder] Re: question for commercial radio shops Hey, what's wrong with a roger beep?'beep' On Tue, Jul 13, 2010 at 9:56 PM, skipp025 skipp...@yahoo.com mailto:skipp...@yahoo.com wrote: If a person whom you knew and is involved in a number of church youth camps activities asked you to program FRS frequencies into a 4w UHF HT type accepted for LMR would you do so ? It would only be for extended range at camp. If the radio power can be reduced, turn it down and program the FRS frequencies in. If the power can't be reduced, put the radios on GMRS Frequencies. Many of the Kenwood Portables I sell allow power level programming per channel so the FRS gets low and the other stuff gets the nominal rated power. FRS Radios are sold cheap at the big box stores... try to find the ones that allow you to turn off the $...@%@*% stupid roger beeps s. Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.441 / Virus Database: 271.1.1/2962 - Release Date: 07/30/10 06:34:00
RE: [Repeater-Builder] Re: question for commercial radio shops
Both. There was a transmitter on beep (that almost nobody heard), and there was a transmitter off beep that everyone heard - with about 100Hz difference in the two tone frequencies. Read this: http://en.wikipedia.org/wiki/Quindar_tones What it doesn't mention is that there was an audio notch filter that took out the beep from the audio fed to the actual transmitter. Mike WA6ILQ (who worked at NASA -JPL in the 1970s, plus two additional contract gigs, one in the 80s and one in the 90s) At 08:02 PM 07/13/10, you wrote: Meant a lot to the First Astronauts with Communications that is how it got started I think , I forget if it was a Pre or after Transmission Don KA9QJG Nothing if you're name is roger. Smile emoticon From: mailto:llhorl...@gmail.comLarry Horlick Sent: Tuesday, July 13, 2010 10:02 PM To: mailto:Repeater-Builder@yahoogroups.comRepeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: question for commercial radio shops Hey, what's wrong with a roger beep?'beep' On Tue, Jul 13, 2010 at 9:56 PM, skipp025 mailto:skipp...@yahoo.comskipp...@yahoo.com wrote: inline: 113874e1.gif
RE: [Repeater-Builder] Re: question for commercial radio shops
Alright Everyone get it out of your system http://www.imdb.com/title/tt0080339/quotes -- President and CTO - Arcom Communications Makers of repeater controllers and accessories. http://www.arcomcontrollers.com/ Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp.net We don't just make 'em. We use 'em!
Re: [Repeater-Builder] Re: GMRS Radio
Please note that we are not allowed (i.e. it's illegal) to modify our Part 97 Amateur radios to transmit in any other service. We can bring Part 90 and 95 radios into Part 97, but not the other way around. -Brian On Fri, Jul 30, 2010 at 8:29 AM, cmr359 cmr...@yahoo.com wrote: Most lmr radios will program gmrs frequencies. Be mindful of output power programmed as most will do over the limit. Many ameuter radios with transmitter mods will also do this. My radio vendor of choice is Icom. They are very tough with mil specs and all. --- In Repeater-Builder@yahoogroups.com, Joel joellan...@... wrote: Anybody have any reviews or maybe a used GMRS radio? I would like a 4 watt radio. Is the FCC doing in with GMRS repeaters? Does anybody have them for sale? Do they make a portable repeater? Yahoo! Groups Links
Re: [Repeater-Builder] Re: GMRS Radio
I would disagree with that. It is legal to 'open up' our radios. What is illegal is actually transmitting on other services (genuine emergencies exempted for the sake of argument). Joe M. Brian Raker wrote: Please note that we are not allowed (i.e. it's illegal) to modify our Part 97 Amateur radios to transmit in any other service. We can bring Part 90 and 95 radios into Part 97, but not the other way around. -Brian On Fri, Jul 30, 2010 at 8:29 AM, cmr359 cmr...@yahoo.com mailto:cmr...@yahoo.com wrote: Most lmr radios will program gmrs frequencies. Be mindful of output power programmed as most will do over the limit. Many ameuter radios with transmitter mods will also do this. My radio vendor of choice is Icom. They are very tough with mil specs and all. --- In Repeater-Builder@yahoogroups.com mailto:Repeater-Builder@yahoogroups.com, Joel joellan...@... wrote: Anybody have any reviews or maybe a used GMRS radio? I would like a 4 watt radio. Is the FCC doing in with GMRS repeaters? Does anybody have them for sale? Do they make a portable repeater? Yahoo! Groups Links repeater-builder-fullfeatu...@yahoogroups.com mailto:repeater-builder-fullfeatu...@yahoogroups.com Internal Virus Database is out of date. Checked by AVG - www.avg.com Version: 9.0.783 / Virus Database: 271.1.1/2746 - Release Date: 03/14/10 03:33:00
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Steve wrote: Hi Kev would it be feasable to use a sig gen cranked right up ? Depends on how clean the signal generator is. I'd think it doesn't have enough smoke (output capability) to really be beneficial Many generators have a strong carrier (here we go again) adjacent from the desired carrier by few, several, many kHz/MHz. Also, depending on make/model, it may not be as clean (spurious emissions) as a tuned circuit (read MICOR exciter). I wonder how many of the -53 naysayers have or have used a Cushman CE-3? LOL! The folks that have looked at the output of one of these on a spectrum analyzer will get it. K
[Repeater-Builder] Re: Interesting RSS occurence
I just ran into this again last night. This time I was working with a high band HT600 that I was going to put on 2m. It is a 146-152 unit. The bandsplit screen shows the radio as a 146-152 unit, but when programing each channel, at the top right of the screen, the software displays 143-152. I didn't need to do any hex editing to enter frequencies below 146. Again I forgot to notate what version of the software I actually have. But none the less, this is kind of weird. So anyone ever encounter this before? --- In Repeater-Builder@yahoogroups.com, hitekgearhead hitekgearh...@... wrote: I had an interesting occurrence the other night while programing one of my UHF P200's It is a radio I use for 70cm and is a 438-470 unit. Usually at the top right of the display when running the software, the bandsplit is displayed. Well, I noticed last night that it did not display 438-470, but it displayed 430-470. I could easily enter frequencies down to 430 without the need to do the hex editing tricks. I just thought this was interesting and never noticed it before. I am going to check my other UHF P200 and see if they display the same bandsplit. I wonder if it is the radio or the software that was modified or otherwise hacked somewhere along the way. Anyone else ever run into anything like this? Albert
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Tim wrote: Actually, the output is about +26dBm, so it's closer to 400mW. Good - that's more like it. I've also tried a VX-5 on low power, and got the same result. Obviously, something is wrong with the operation of your duplexer or interconnecting cabling. I really don't think it's providing the isolation you believe it is... Can you explain in detail how you are determining the notch depth of the duplexer. Also, what exactly are you using for the components of the duplexer? If it's the coax stub type, which article have you followed? Thanks, Kevin
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Hi was just a thought, I use a Marconi 2015 with the synth unit and that is pretty clean, be interesting to see what Tim,s problem is Steve - Original Message - From: Kevin Custer kug...@kuggie.com To: Repeater-Builder@yahoogroups.com Sent: Friday, July 30, 2010 9:50 PM Subject: Re: [Repeater-Builder] Repeater transmit levels at the receiver? Steve wrote: Hi Kev would it be feasable to use a sig gen cranked right up ? Depends on how clean the signal generator is. I'd think it doesn't have enough smoke (output capability) to really be beneficial Many generators have a strong carrier (here we go again) adjacent from the desired carrier by few, several, many kHz/MHz. Also, depending on make/model, it may not be as clean (spurious emissions) as a tuned circuit (read MICOR exciter). I wonder how many of the -53 naysayers have or have used a Cushman CE-3? LOL! The folks that have looked at the output of one of these on a spectrum analyzer will get it. K Yahoo! Groups Links
RE: [Repeater-Builder] Repeater transmit levels at the receiver?
I think they use that spec trace on the opening of the tv show Fraser _ From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Kevin Custer Sent: Friday, July 30, 2010 4:51 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Repeater transmit levels at the receiver? Steve wrote: Hi Kev would it be feasable to use a sig gen cranked right up ? Depends on how clean the signal generator is. I'd think it doesn't have enough smoke (output capability) to really be beneficial Many generators have a strong carrier (here we go again) adjacent from the desired carrier by few, several, many kHz/MHz. Also, depending on make/model, it may not be as clean (spurious emissions) as a tuned circuit (read MICOR exciter). I wonder how many of the -53 naysayers have or have used a Cushman CE-3? LOL! The folks that have looked at the output of one of these on a spectrum analyzer will get it. K
[Repeater-Builder] Re: 420Mhz Radio for Voter?
Are the CDM's similar to the Radius M1225? --- In Repeater-Builder@yahoogroups.com, James Adkins adkins.ja...@... wrote: I disagree on the price of the CDM's. You can get the CDM-750 (4-channel) for as low as $75 to $125 if you watch for them on e-bay. The CDM-1250 and CDM-1550 are more expensive used, but still you should be able to get them for $250 or less if you just have to have the 128 channels and alpha display. On our setup, I program the RX CDM for PL on receive, but leave it in monitor mode. I then feed the PL detect from the RX radio to the PL encode of the TX CDM. When it gets back to the site, if the radio receives a PL, then it sends the logic out the PL detect pin. If it doesn't, then no logic is sent. This way you can turn the PL tone at all your remote sites locally with your controller. On Thu, Jul 29, 2010 at 3:35 PM, Glenn (Butch) Kanvick hotl...@...wrote: Hello Tim. I just looked in my storage site and I found a Micor Base/Repeater which is on the band split of 402-430 MHz. I do not have channel elements for it. I know it was working when it came out of service a few years ago, and the PA can be used as a digital station, as it takes the four pin channel elements. It is the complete base repeater which is designed for continious duty as it has the large pa heatsinks. Let me know if you would like pictures of it. I have $200.00 into it and it weighs alot so I am sure shipping via ground would be around $50.00. If you need the cabinet and power supply it would be $400.00 plus actual shipping. Butch, KE7FEL/r On Thu, Jul 29, 2010 at 1:33 PM, Tim - WD6AWP tisaw...@... wrote: Those CDM radios are a bit pricy at $550 each. But I appreciate the suggestion. And you've given me some ideas. I still like the idea of building an out of band repeater for the remote receive site from a Micor chassis. I would need a 406-420 exciter, bandpass filter and trippler. If anybody on the list has those or can help me find them I'd really appreciate it. --- In Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com, James Adkins adkins.james@ wrote: I am using the Motorola CDM series of radios for 420-425 MHz links from voting sites. They make a low-split UHF split that covers 403-470 MHz out of the box, no mods needed. On the transmit sites, you will want to use a fan for cooling. We mount the RX radio and a UHF TX radio on a 1U rack shelf, use a 4 hole saw and drill a hole under the UHF TX radio, and purchase a nice Dayton 24vdc fan that is actually a ball bearing fan that you can count on for years of use, and let it go. Have not had any problems to date with these rigs over a 4 year span. at W6KGBs article on moving 450-470 Mastr IIs to 420-450. It's on the GE Mastr II page at repeater-builder. You could use a Mastr II UHF mobile with the receiver, exciter and IPA converted to 420, then use the receiver in an aux receiver chassis at the voter site. You wouldn't need to convert the PA, the IPA (driver) and a beam would be enough for a point-to-point link. Bob Meister WA1MIK did an article on converting the multiplier chains so that the UHF Micor receivers could hear down as low as 435 MHz (where the front ends run out of tuning range). Mike WA6ILQ At 05:10 PM 07/27/10, you wrote: Thanks Jeff, I'll keep looking around for those low split UHF Micor receivers. What about the transmit side? Maybe I should look for a unified chassis low split UHF repeater. Swap out the UHF receiver for a VHF high band receiver and use that for my remote receiver site. Then use the low split UHF receiver on the other end of the link. That make sense? --- In Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com Repeater-Builder%40yahoogroups.com, Jeff DePolo jd0@ wrote: When you say low split, are you talking about the Motorola TRE1201/TRE8031 406-420 Mhz receivers? I don't have a manual in front of me, but yes, 406-420 receivers, they'll work fine well into the mid 430's without mods. What Canadian sources might have these? Well, Spantek comes to mind as a dealer. CW Wolfe used to get a lot of stuff out of Canada, but I haven't talked to Bud in quite a few years, not sure if he's still in business. This list is probably the best resource. eBay as an alternative. If you get desperate I still have a few dozen low-split Micors in the warehouse, but really don't have the time (or patience) to deal with packing and shipping radios for what few dollars I'd get out of them (i.e. value of my time $value of radio). But if you just wanted a receiver, you can consider me a last resort if you strike out
[Repeater-Builder] EP39-A Receiver power Supply
Found three in the garage. Anyone want them for the price of the shipping. Jim K7OET
RE: [Repeater-Builder] Repeater transmit levels at the receiver?
I wonder how many of the -53 naysayers have or have used a Cushman CE-3? LOL! The folks that have looked at the output of one of these on a spectrum analyzer will get it. K Where I come from, we call that a comb generator, not a signal generator... Ya gotta know the limitations of your test equipment. I recently went several rounds via telephone with a friend of mine who was trying to troubleshoot an apparent desense problem on the bench involving a Mastr II and a 6-cavity DB Products duplexer that I had tuned up for him on the VNA. Long story short, it turned out that when he was doing the desense test using his service monitor (R2600?) as the dummy load and signal source simultaneously that the sig gen would go spurious and result in apparent desense. When he finally did a lossy tee test using an external dummy load, no desense, and likewise when hooked up to the antenna at the site, no desense. --- Jeff WN3A
RE: [Repeater-Builder] Repeater transmit levels at the receiver?
Sounds like someone has been watching The EnforcerMr Eastwood.every man has got to know his limitations? Soory could not resist!! D On 30/07/2010 22:35:35, Jeff DePolo (j...@broadsci.com) wrote: I wonder how many of the -53 naysayers have or have used a Cushman CE-3? LOL! The folks that have looked at the output of one of these on a spectrum analyzer will get it. K Where I come from, we call that a comb generator, not a signal generator... Ya gotta know the limitations of your test equipment. I recently went several rounds via telephone with a friend of mine who was trying to troubleshoot an apparent desense problem on the bench involving a Mastr II and a 6-cavity DB Products duplexer that I had tuned up for him on the VNA. Long story short, it turned out that when he was doing the desense test using his service monitor (R2600?) as the dummy load and signal source simultaneously that the sig gen would go spurious and result in apparent desense. When he finally did a lossy tee test using an external dummy load, no desense, and likewise when hooked up to the antenna at the site, no desense. --- Jeff WN3A Yahoo! Groups Links
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Hi Kevin, Yes, the original used RG-58.. couldn't see using it. Figured it would give me desense! As far as the amount of notch, I was surprised that the total was more than each one added, but with 50 watts coming out of the antenna port, I see -55dBm at the RX port. - kinda made me think the original measurements were ok. I cut them to 35 each. (visible coax showing between each end of the PL-259). Not exactly to length. Might affect performance a bit. Tim
[Repeater-Builder] Re: 420Mhz Radio for Voter?
Butch, I replied to you off list but maybe your spam filter got me. I'm interested so please check your email. -- Tim --- In Repeater-Builder@yahoogroups.com, Glenn (Butch) Kanvick hotl...@... wrote: Hello Tim. I just looked in my storage site and I found a Micor Base/Repeater which is on the band split of 402-430 MHz. I do not have channel elements for it. I know it was working when it came out of service a few years ago, and the PA can be used as a digital station, as it takes the four pin channel elements. It is the complete base repeater which is designed for continious duty as it has the large pa heatsinks. Let me know if you would like pictures of it. I have $200.00 into it and it weighs alot so I am sure shipping via ground would be around $50.00. If you need the cabinet and power supply it would be $400.00 plus actual shipping. Butch, KE7FEL/r On Thu, Jul 29, 2010 at 1:33 PM, Tim - WD6AWP tisaw...@... wrote: Those CDM radios are a bit pricy at $550 each. But I appreciate the suggestion. And you've given me some ideas. I still like the idea of building an out of band repeater for the remote receive site from a Micor chassis. I would need a 406-420 exciter, bandpass filter and trippler. If anybody on the list has those or can help me find them I'd really appreciate it. --- In Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com, James Adkins adkins.james@ wrote: I am using the Motorola CDM series of radios for 420-425 MHz links from voting sites. They make a low-split UHF split that covers 403-470 MHz out of the box, no mods needed. On the transmit sites, you will want to use a fan for cooling. We mount the RX radio and a UHF TX radio on a 1U rack shelf, use a 4 hole saw and drill a hole under the UHF TX radio, and purchase a nice Dayton 24vdc fan that is actually a ball bearing fan that you can count on for years of use, and let it go. Have not had any problems to date with these rigs over a 4 year span. at W6KGBs article on moving 450-470 Mastr IIs to 420-450. It's on the GE Mastr II page at repeater-builder. You could use a Mastr II UHF mobile with the receiver, exciter and IPA converted to 420, then use the receiver in an aux receiver chassis at the voter site. You wouldn't need to convert the PA, the IPA (driver) and a beam would be enough for a point-to-point link. Bob Meister WA1MIK did an article on converting the multiplier chains so that the UHF Micor receivers could hear down as low as 435 MHz (where the front ends run out of tuning range). Mike WA6ILQ At 05:10 PM 07/27/10, you wrote: Thanks Jeff, I'll keep looking around for those low split UHF Micor receivers. What about the transmit side? Maybe I should look for a unified chassis low split UHF repeater. Swap out the UHF receiver for a VHF high band receiver and use that for my remote receiver site. Then use the low split UHF receiver on the other end of the link. That make sense? --- In Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com Repeater-Builder%40yahoogroups.com, Jeff DePolo jd0@ wrote: When you say low split, are you talking about the Motorola TRE1201/TRE8031 406-420 Mhz receivers? I don't have a manual in front of me, but yes, 406-420 receivers, they'll work fine well into the mid 430's without mods. What Canadian sources might have these? Well, Spantek comes to mind as a dealer. CW Wolfe used to get a lot of stuff out of Canada, but I haven't talked to Bud in quite a few years, not sure if he's still in business. This list is probably the best resource. eBay as an alternative. If you get desperate I still have a few dozen low-split Micors in the warehouse, but really don't have the time (or patience) to deal with packing and shipping radios for what few dollars I'd get out of them (i.e. value of my time $value of radio). But if you just wanted a receiver, you can consider me a last resort if you strike out everywhere else... --- Jeff WN3A --- In Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.comRepeater-Builder%2540yahoogroups.com Repeater-Builder%2540yahoogroups.com , Jeff DePolo jd0@ wrote: What is a good radio for building a one way 420 link? The link will be for a remote receiver and will not need to be duplex... RX at the voter and TX at the remote receiver. The link RX has to live on a noisy hill. Thanks for your advice. My preferences, in no particular order, would be Micor/SpectraTAC (low
Re: [Repeater-Builder] Re: 420Mhz Radio for Voter?
Not even close. Joe M. Tim - WD6AWP wrote: Are the CDM's similar to the Radius M1225?
[Repeater-Builder] Re: 420Mhz Radio for Voter?
I guess you don't care to elaborate. --- In Repeater-Builder@yahoogroups.com, MCH m...@... wrote: Not even close. Joe M. Tim - WD6AWP wrote: Are the CDM's similar to the Radius M1225?
Re: [Repeater-Builder] Re: 420Mhz Radio for Voter?
Hello Tim. The entire radio, with the transmitter, receiver, card cage, power supply and cabinet is $400.00 If you need just the receiver, transmitter and card cage is $200.00. Some people do not want to pay the shipping for the power supply or cabinet, that is why I break it up into a smaller package. I will goto the storage placeand get pictures foryou. Thanks, Butch, KE7FEL/r On Fri, Jul 30, 2010 at 5:13 PM, Tim - WD6AWP tisaw...@gmail.com wrote: I guess you don't care to elaborate. --- In Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com, MCH m...@... wrote: Not even close. Joe M. Tim - WD6AWP wrote: Are the CDM's similar to the Radius M1225?
[Repeater-Builder] Re: 420Mhz Radio for Voter?
I just need the rx, tx and pa. I can use the DC cables too. I don't need the ps or cabinet. Pictures would be nice if you can send them. And you're sure it's UHF low split 406-420? --- In Repeater-Builder@yahoogroups.com, Glenn (Butch) Kanvick hotl...@... wrote: Hello Tim. This message made it through. Do you need just the transmitter, receiver and the card cage or do you want the complete radio with power supply and cabinet? Do you need pictures of the repeater? Thanks, Butch, KE7FEL/r On Fri, Jul 30, 2010 at 5:03 PM, Tim - WD6AWP tisaw...@... wrote: Butch, I replied to you off list but maybe your spam filter got me. I'm interested so please check your email. -- Tim --- In Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com, Glenn (Butch) Kanvick hotlrv1@ wrote: Hello Tim. I just looked in my storage site and I found a Micor Base/Repeater which is on the band split of 402-430 MHz. I do not have channel elements for it. I know it was working when it came out of service a few years ago, and the PA can be used as a digital station, as it takes the four pin channel elements. It is the complete base repeater which is designed for continious duty as it has the large pa heatsinks. Let me know if you would like pictures of it. I have $200.00 into it and it weighs alot so I am sure shipping via ground would be around $50.00. If you need the cabinet and power supply it would be $400.00 plus actual shipping. Butch, KE7FEL/r On Thu, Jul 29, 2010 at 1:33 PM, Tim - WD6AWP tisawyer@ wrote: Those CDM radios are a bit pricy at $550 each. But I appreciate the suggestion. And you've given me some ideas. I still like the idea of building an out of band repeater for the remote receive site from a Micor chassis. I would need a 406-420 exciter, bandpass filter and trippler. If anybody on the list has those or can help me find them I'd really appreciate it. --- In Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com Repeater-Builder%40yahoogroups.com, James Adkins adkins.james@ wrote: I am using the Motorola CDM series of radios for 420-425 MHz links from voting sites. They make a low-split UHF split that covers 403-470 MHz out of the box, no mods needed. On the transmit sites, you will want to use a fan for cooling. We mount the RX radio and a UHF TX radio on a 1U rack shelf, use a 4 hole saw and drill a hole under the UHF TX radio, and purchase a nice Dayton 24vdc fan that is actually a ball bearing fan that you can count on for years of use, and let it go. Have not had any problems to date with these rigs over a 4 year span. at W6KGBs article on moving 450-470 Mastr IIs to 420-450. It's on the GE Mastr II page at repeater-builder. You could use a Mastr II UHF mobile with the receiver, exciter and IPA converted to 420, then use the receiver in an aux receiver chassis at the voter site. You wouldn't need to convert the PA, the IPA (driver) and a beam would be enough for a point-to-point link. Bob Meister WA1MIK did an article on converting the multiplier chains so that the UHF Micor receivers could hear down as low as 435 MHz (where the front ends run out of tuning range). Mike WA6ILQ At 05:10 PM 07/27/10, you wrote: Thanks Jeff, I'll keep looking around for those low split UHF Micor receivers. What about the transmit side? Maybe I should look for a unified chassis low split UHF repeater. Swap out the UHF receiver for a VHF high band receiver and use that for my remote receiver site. Then use the low split UHF receiver on the other end of the link. That make sense? --- In Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com Repeater-Builder%40yahoogroups.com Repeater-Builder%40yahoogroups.com, Jeff DePolo jd0@ wrote: When you say low split, are you talking about the Motorola TRE1201/TRE8031 406-420 Mhz receivers? I don't have a manual in front of me, but yes, 406-420 receivers, they'll work fine well into the mid 430's without mods. What Canadian sources might have these? Well, Spantek comes to mind as a dealer. CW Wolfe used to get a lot of stuff out of Canada, but I haven't talked to Bud in quite a few years, not sure if he's still in business. This list is probably the best resource. eBay as an alternative. If you get desperate I still have a few dozen low-split Micors in the warehouse, but really don't have the time (or patience) to deal with packing and shipping radios for what
Re: [Repeater-Builder] Re: Simrex - GLB Pre-Selector Pre-Amplifier
Well, I have decided to buy and try a Simrex Pre-Selector,experiment with it, test it...whatever. At the very least I will learn something from my experiences and it may end up being useful to me, anyway. I certainly appreciate the different points of view here and have learn't of alternative methods and the reasoning behind them. For me, all of it is good information :-) 73, Jack. VK4JRC Sent from my Apple iPad Tablet PC On Jul 31, 2010, at 8:53 AM, skipp025 skipp...@yahoo.com wrote: Re: Simrex - GLB Pre-Selector Pre-Amplifier Kevin Custer kug...@... wrote: What you are missing is that ANY losses ahead of the first active stage add to the noise figure of the system - directly. What we have here is... failure to communicate... (a line from a famous movie). Actually I was trying to high-lite the active device Noise Figure comparison and the lower spec'd gain value of (at least) the GasFET GLB was mostly from the insertion loss of the Pre and Post Filtering. So, while filtering exists in the GLB device, so does loss, and this loss is more than what is experienced when using a quality large diameter cavity. Sure... but again we are comparing a box to another box and they are not the same device. Please allow me to paste some of the text from a recent post (by me). [pasted text] The Simrex (aka GLB) units are actually amplified pre-selector assemblies, not just plain wide-band Receive Pre-Amplifiers. [end of pasted text] Many times Skipp you tell us there is no free lunch, and the same applies to the comparison of selectivity and loss between the GLB and a quality cavity followed by a good active stage. Correct... and a Simrex GLB Pre-Selector should really not really be directly compared to a cavity followed by a good active stage. The Simrex GLB box is more of a true Pre-Selector layout and contains post amplifier filtering. To better equate a similar layout would have you add at least one or more cavities after the active device. And yes we should clearly acknowledge the hopefully obvious lower loss through a higher Q Quality Cavity. Real world test. Take a Hamtronics receiver (no preamp) and do a basic bench sensitivity test to obtain a baseline. If you find something around -123 dBm your in the right ballpark. Now install a bi-polar GLB preselector/preamp in front and measure the sensitivity again - you'll find you have lost several dB of bench sensitivity - at least 3 or 4 dB. Take the same receiver and add a quality 1/4 bottle with a good preamp (your choice - something with 1.5 dB NF or less) and do the test again. Now, the receiver hears at -123 to -127 dBm (dependent mainly upon the quality of the preamp that follows) because the filter hasn't severely ruined the system NF ahead of the first active stage. Even though the GLB has gain, the noise figure of the design has already determined the sensitivity that will be realized by the receiver that follows. The primary land mine in the above comparison is the Now install a bi-polar GLB preselector/preamp. Remember Simrex and GLB offer or did offer a GasFet version of their Pre- selector box. Separate the above in the proper context and the focus should be on the filtering in front of the same type of active device. No one here should discount the higher Q cavity will be the better spec. But again even a high Q cavity with a same or similar active trailing device is still not the same box as the Simrex GLB Pre-selector. You should account for the Simrex GLB integrated post active device filtering. The GLB preselector/preamp should not be considered for adding basic sensitivity, Did anyone make that claim? because it's possible (depending on how good the receiver is to begin with) the opposite will happen - You are correct. however, it will protect a receiver that lacks good front-end filtering, like the Hamtronics. Like everything, the situation helps to dictate what equipment will give the best results. We agree and it's a Friday... Mark today on your calendar. What more could anyone ask for? Kevin cheers, skipp
Re: [Repeater-Builder] Re: Simrex - GLB Pre-Selector Pre-Amplifier
Friday, July 30th 2010 - Duly noted on my calendar! LOL - Original Message - From: skipp025 To: Repeater-Builder@yahoogroups.com Sent: Friday, July 30, 2010 6:53 PM Subject: [Repeater-Builder] Re: Simrex - GLB Pre-Selector Pre-Amplifier Re: Simrex - GLB Pre-Selector Pre-Amplifier Kevin Custer kug...@... wrote: What you are missing is that ANY losses ahead of the first active stage add to the noise figure of the system - directly. What we have here is... failure to communicate... (a line from a famous movie). Actually I was trying to high-lite the active device Noise Figure comparison and the lower spec'd gain value of (at least) the GasFET GLB was mostly from the insertion loss of the Pre and Post Filtering. So, while filtering exists in the GLB device, so does loss, and this loss is more than what is experienced when using a quality large diameter cavity. Sure... but again we are comparing a box to another box and they are not the same device. Please allow me to paste some of the text from a recent post (by me). [pasted text] The Simrex (aka GLB) units are actually amplified pre-selector assemblies, not just plain wide-band Receive Pre-Amplifiers. [end of pasted text] Many times Skipp you tell us there is no free lunch, and the same applies to the comparison of selectivity and loss between the GLB and a quality cavity followed by a good active stage. Correct... and a Simrex GLB Pre-Selector should really not really be directly compared to a cavity followed by a good active stage. The Simrex GLB box is more of a true Pre-Selector layout and contains post amplifier filtering. To better equate a similar layout would have you add at least one or more cavities after the active device. And yes we should clearly acknowledge the hopefully obvious lower loss through a higher Q Quality Cavity. Real world test. Take a Hamtronics receiver (no preamp) and do a basic bench sensitivity test to obtain a baseline. If you find something around -123 dBm your in the right ballpark. Now install a bi-polar GLB preselector/preamp in front and measure the sensitivity again - you'll find you have lost several dB of bench sensitivity - at least 3 or 4 dB. Take the same receiver and add a quality 1/4 bottle with a good preamp (your choice - something with 1.5 dB NF or less) and do the test again. Now, the receiver hears at -123 to -127 dBm (dependent mainly upon the quality of the preamp that follows) because the filter hasn't severely ruined the system NF ahead of the first active stage. Even though the GLB has gain, the noise figure of the design has already determined the sensitivity that will be realized by the receiver that follows. The primary land mine in the above comparison is the Now install a bi-polar GLB preselector/preamp. Remember Simrex and GLB offer or did offer a GasFet version of their Pre- selector box. Separate the above in the proper context and the focus should be on the filtering in front of the same type of active device. No one here should discount the higher Q cavity will be the better spec. But again even a high Q cavity with a same or similar active trailing device is still not the same box as the Simrex GLB Pre-selector. You should account for the Simrex GLB integrated post active device filtering. The GLB preselector/preamp should not be considered for adding basic sensitivity, Did anyone make that claim? because it's possible (depending on how good the receiver is to begin with) the opposite will happen - You are correct. however, it will protect a receiver that lacks good front-end filtering, like the Hamtronics. Like everything, the situation helps to dictate what equipment will give the best results. We agree and it's a Friday... Mark today on your calendar. What more could anyone ask for? Kevin cheers, skipp
Re: [Repeater-Builder] Repeater transmit levels at the receiver?
Tim wrote: Hi Kevin, Yes, the original used RG-58.. couldn't see using it. Figured it would give me desense! As far as the amount of notch, I was surprised that the total was more than each one added, Don't be - it's common for the apparent notch to be deeper than the measured addition of individual cavities - added together. Don't be fooled, the depth was there the whole time (no black magic here), it just wasn't all being realized in the test set-up. Proper interconnect cable lengths can do a bunch for notch depths. but with 50 watts coming out of the antenna port, I see -55dBm at the RX port. - kinda made me think the original measurements were ok. What you see coming out the RX port depends on several factors: How good the match of the attached equipment is - at the frequency being tested, and the phase angle of the connecting cable. Other factors play a part too, but these two play the bigger part. I cut them to 35 each. (visible coax showing between each end of the PL-259). Not exactly to length. Might affect performance a bit. I wouldn't have chosen UHF connectors for building the duplexer. IMHO, their construction leaves a lot to be desired when trying to optimize a duplexer for maximum performance, unless you take their inherent flaws into consideration when using them. Wacom built a good duplexer which uses UHF connectors, but they actually used those properties to their advantage. 35 inches, plus the amount inside the connector results in approximately 37-1/2 inches of interconnecting cable. From my calculations, I have extrapolated your optimum notch depth to appear on 54.44 MHz. I believe, with RG-142 coax, that a length longer than 38 inches will be needed, depending on your exact frequency. From your photo, I believe some of your problem to be the UHF connector and how you have it mounted. A solid ground all around the connector is important to achieve a low impedance (low inductive reactance) connection. I have always preferred the Utah Cap approach for building the Heliax duplexer. It allows you to realize most/all of the potential of the stub. The thicker the copper (within reason) the better. Also - it looks like you might be using only one connector per stub. If this is true, and you are using a UHF tee connector with the stub - it won't work as expected. The electrical length of the tee will throw the whole thing off - this might be your biggest problem with your design/construction. Kevin
Re: [Repeater-Builder] Re: 420Mhz Radio for Voter?
It was asked if they were similar. I replied that they are not. I figured there were too many things that were different to elaborate further. They are both made by Motorola in Malaysia. They are both programmed using a PC computer (albeit by different SW packages). They share the same programming cable, although most Motorola mobiles do. Hence, the same microphones. The 16-pin accessory connector can be used in the CDM as long as you don't need pins 17-20 - just remember to align it in the center of the connector. They take the same power cord. They both use the mini UHF RF connector. That's about all that is the same. So, if you want to know how they are different, well, anything other than the above. Joe M. Tim - WD6AWP wrote: I guess you don't care to elaborate. --- In Repeater-Builder@yahoogroups.com, MCH m...@... wrote: Not even close. Joe M. Tim - WD6AWP wrote: Are the CDM's similar to the Radius M1225? Yahoo! Groups Links
Re: [Repeater-Builder] Re: 420Mhz Radio for Voter?
Hello Tim. Yes, it is the 402-430 Mhz. split radio. I have a coupleoftheMicorsandafew GEMastr II's. The TX is on 419.3750 and the RX is on 414.4750 I will get you pictures probably tommorrow afternoon. Butch, KE7FEL/r On Fri, Jul 30, 2010 at 6:02 PM, Tim - WD6AWP tisaw...@gmail.com wrote: I just need the rx, tx and pa. I can use the DC cables too. I don't need the ps or cabinet. Pictures would be nice if you can send them. And you're sure it's UHF low split 406-420? --- In Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com, Glenn (Butch) Kanvick hotl...@... wrote: Hello Tim. This message made it through. Do you need just the transmitter, receiver and the card cage or do you want the complete radio with power supply and cabinet? Do you need pictures of the repeater? Thanks, Butch, KE7FEL/r On Fri, Jul 30, 2010 at 5:03 PM, Tim - WD6AWP tisaw...@... wrote: Butch, I replied to you off list but maybe your spam filter got me. I'm interested so please check your email. -- Tim --- In Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com Repeater-Builder%40yahoogroups.com, Glenn (Butch) Kanvick hotlrv1@ wrote: Hello Tim. I just looked in my storage site and I found a Micor Base/Repeater which is on the band split of 402-430 MHz. I do not have channel elements for it. I know it was working when it came out of service a few years ago, and the PA can be used as a digital station, as it takes the four pin channel elements. It is the complete base repeater which is designed for continious duty as it has the large pa heatsinks. Let me know if you would like pictures of it. I have $200.00 into it and it weighs alot so I am sure shipping via ground would be around $50.00. If you need the cabinet and power supply it would be $400.00 plus actual shipping. Butch, KE7FEL/r On Thu, Jul 29, 2010 at 1:33 PM, Tim - WD6AWP tisawyer@ wrote: Those CDM radios are a bit pricy at $550 each. But I appreciate the suggestion. And you've given me some ideas. I still like the idea of building an out of band repeater for the remote receive site from a Micor chassis. I would need a 406-420 exciter, bandpass filter and trippler. If anybody on the list has those or can help me find them I'd really appreciate it. --- In Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com Repeater-Builder%40yahoogroups.com Repeater-Builder%40yahoogroups.com, James Adkins adkins.james@ wrote: I am using the Motorola CDM series of radios for 420-425 MHz links from voting sites. They make a low-split UHF split that covers 403-470 MHz out of the box, no mods needed. On the transmit sites, you will want to use a fan for cooling. We mount the RX radio and a UHF TX radio on a 1U rack shelf, use a 4 hole saw and drill a hole under the UHF TX radio, and purchase a nice Dayton 24vdc fan that is actually a ball bearing fan that you can count on for years of use, and let it go. Have not had any problems to date with these rigs over a 4 year span. at W6KGBs article on moving 450-470 Mastr IIs to 420-450. It's on the GE Mastr II page at repeater-builder. You could use a Mastr II UHF mobile with the receiver, exciter and IPA converted to 420, then use the receiver in an aux receiver chassis at the voter site. You wouldn't need to convert the PA, the IPA (driver) and a beam would be enough for a point-to-point link. Bob Meister WA1MIK did an article on converting the multiplier chains so that the UHF Micor receivers could hear down as low as 435 MHz (where the front ends run out of tuning range). Mike WA6ILQ At 05:10 PM 07/27/10, you wrote: Thanks Jeff, I'll keep looking around for those low split UHF Micor receivers. What about the transmit side? Maybe I should look for a unified chassis low split UHF repeater. Swap out the UHF receiver for a VHF high band receiver and use that for my remote receiver site. Then use the low split UHF receiver on the other end of the link. That make sense? --- In Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com Repeater-Builder%40yahoogroups.com Repeater-Builder%40yahoogroups.com Repeater-Builder%40yahoogroups.com, Jeff DePolo jd0@ wrote: When you say low split, are you talking about the Motorola TRE1201/TRE8031 406-420 Mhz receivers? I don't have a manual in front of me, but yes, 406-420 receivers, they'll work fine well into the mid
