Re: [Repeater-Builder] Adjusting low power on an R1225 repeater
The R100 likes to run at its rated power turning down will make it run hotter then if you leave it at the higher power they are not a good choice for a repeater tx. --- On Thu, 7/29/10, Joe k1ike_m...@snet.net wrote: From: Joe k1ike_m...@snet.net Subject: [Repeater-Builder] Adjusting low power on an R1225 repeater To: Repeater-Builder@yahoogroups.com Received: Thursday, July 29, 2010, 9:44 PM 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] 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] Adjusting low power on an R1225 repeater
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-buil...@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] 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-buil...@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] Adjusting low power on an R1225 repeater
If you have a spectrum analyzer, be sure and check it for spectral purity. *Most* radios don't like to have their power cut back that far. Scott Scott Zimmerman Amateur Radio Call N3XCC 474 Barnett Road Boswell, PA 15531 Joe wrote: 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 Yahoo! Groups Links
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...@yahoogroups.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%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com ] On Behalf Of Joe Sent: Thursday, July 29, 2010 6:45 PM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.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] Adjusting low power on an R1225 repeater
Robert, The R1225 was never intended to be used in a heavy duty application. When marketed in its GR1225 desktop configuration, it was presented as a light-duty, local-area repeater for construction sites and similar low duty-cycle applications. Since the GR1225 included a temperature-controlled fan, Motorola suggested that the power be set to 25 watts when heavy use was expected. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Robert McNeill Sent: Thursday, July 29, 2010 8:12 PM To: Repeater-Builder@yahoogroups.com 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 its intent if not to be used in a heavy duty cycle? 73, Robert K5ILS From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.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%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com ] On Behalf Of Joe Sent: Thursday, July 29, 2010 6:45 PM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.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
