UHF Repeater Input Frequency Issues
Hello from Michigan!
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I'm wondering if some folks have an idea of what might be going on here.
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Equipment:
Yaesu DR-2X
Glenayre 97 series 250W UHF amp
Glenayre 2728 PSU
Sinclair preamp with a PA8075 chip.? Output split to 8 ports.? ASSY 363750, Board 261022
4 can UHF duplexer.? Unclear make/model.
1/2" Heliax, N Connectors
Polyphaser
Diamond 11dBi fiberglass vert
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I have an amateur band UHF repeater I've been working with exhibiting the following symptoms:
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Input desense when output amp is turned on, set to 100W.? ? It's being driven at 100W due to power supply current limitations of a single Glenayre 2728.? We've turned this off for now and are running the repeater barefoot at medium power (~20W).? This resolved this issue.? We'd obviously like our 100W back.
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Now what we have, again with the amp off and disconnected from RF, is that the input is nearly completely gone after significant rain or snow.? After the roof of the building dries up from evaporation, the input comes back.? There is no water in the antenna, feedline, or connectors after double checking all of this with 24 hours of rainfall.? SWR seems to be the same whether the input is functioning or not.? I'll attach photos of a NanoVNA sweep taken while the input was not working yesterday.
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I have someone running down to the site today to attach a regular HT to the antenna directly, bypassing the repeater, duplexer, and preamp.? With the input currently down, we'll see whether the HT fares better.
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Any suggestions would be appreciated.
Pic 1: Base of tower, connection to polyphaser.
Pic 2: After duplexer
Pic 3: After Polyphaser, 60ft of Heliax, but before preamp and duplexer.
Input frequency is 442.900.
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Thanks I will take a look. ?
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From: [email protected] <[email protected]> On Behalf Of M M via groups.io
Sent: Wednesday, April 2, 2025 10:38 PM
To: [email protected]
Subject: Re: [repeater-builder] TPL PA6-1AE UHF amp? An attenuator something like this one may be easier....?? use your
existing 5w input amp... I have no idea who this guy is, I'm just using his auction as an example.?? But $27 and free shipping? Decades ago I saw an attenuator between an exciter and an amplifier... it was a (roughly) 100 foot coil of RG58....? Please don't do that.
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An attenuator something like this one may be easier....?? use your
existing 5w input amp...
I have no idea who this guy is, I'm just using his auction as an
example.?? But $27 and free shipping?
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Decades ago I saw an attenuator between an exciter and an amplifier...
it was a (roughly) 100 foot coil of RG58....? Please don't do that.
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Mike WA6ILQ
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Re: THREAT TO 222-225MHz Spectrum
I am not just a ham, but I am a master falconer, and help?with tracking Wildlife collars. For??USF&W ?And the collars and bird tracking transmitters?operate on the 219mhz ?spectrum.
On Wednesday, April 2, 2025, 12:43 PM, MICHAEL MAY via groups.io <may2142@...> wrote: Remember guys that it's not just us hams that may be interfered with either.
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Up here in Oregon the 217 to 219 MHz range is heavily used by the Electric power company for Their Tier II capacty plus DMR system.
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If we also make other non ham users of the band aware that they will also suffer then this could help us out.
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Chad,
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The easiest solution by far is an external power attenuator between the TPL amplifier and your transmitter to reduce power. This is a bolt on, or rather thread-on option that works easiest.
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Power attenuators are easy to order from Pasternack, ebay or Amazon and can be ordered with appropriate "N" connectors attached. Calculate the power you need to dissipate and the dB level of attenuation for the correct "drive", order appropriate model, then attach..... That simple!
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The above is the "solderless" solution to your problem........
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? ?You can't 100% rely on what the manuals say for TPL over at RB because if you own a later FET designed amplifier, they have no manuals for them, (RD60/RD70 FET) designs from the early 2000's onward till their demise.
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Rick w6re
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Re: THREAT TO 222-225MHz Spectrum
Remember guys that it's not just us hams that may be interfered with either.
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Up here in Oregon the 217 to 219 MHz range is heavily used by the Electric power company for Their Tier II capacty plus DMR system.
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If we also make other non ham users of the band aware that they will also suffer then this could help us out.
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Re: DR-2X Failure to Switch to DC
Yes Mike pulled me head out of my rear end with his answer.
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The 120VAC coil would go between battery output and the repeater (either plug or hard wire config on your repeater), all it is doing is not letting the charging current to enter the repeater. If you lose AC Mains, he relay drops out about as fast as the system tries to swap to backup and you never notice anything. It has no effect on normal use, plugged into a wall outlet.
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Kory
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Re: DR-2X Failure to Switch to DC
Does the repeater still work on AC supply?
I ask because there's another failure condition which requires power cycling the RX and TX chassis's with a external FTM-400 control head. I had one on the shelf for months that wouldn't power up and that was the simple fix. Unfortunately no power button populated on the internal pair of FTM-400 control head boards used to drive the repeater's front panel.
Jeremy. K1LFK
See post 211955, if you break the DC lines with a high current 120VAC relay then you don’t have to remove any fuse or worry about the charger inducing noise. The battery will charge when AC is present and will be isolated from the repeater then will connect the battery when AC fails.?
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Re: DR-2X Failure to Switch to DC
See post 211955, if you break the DC lines with a high current 120VAC relay then you don’t have to remove any fuse or worry about the charger inducing noise. The battery will charge when AC is present and will be isolated from the repeater then will connect the battery when AC fails.?
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Re: DR-2X Failure to Switch to DC
Jim,
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You might know off the top of your head, in reference to the F6001 (1 amp ) fuse. If you were to pull this fuse from the circuit, #1 it should "disconnect" the internal battery charger circuit output and #2 will it have any effect operational wise on the repeater??
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As many of us know don't let the repeater charge LifePo4 batteries, my thought was and I can not find anything anywhere really on this, use an external charger on a 120VAC coil for on/off states, with this fuse removed, it should eliminate the internal charger and I do not see any reason it would have any negative performance results to the repeater itself.?
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Next Question on this line, has anyone heard of anyone complaining about RFI/EMI noise issues (transmitted over the air like a hum or whine) charging the battery with an external charger, during repeater normal VAC operations? I know HF world some power supplies can cause a whine/squeal/hum to be transmitted.
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This will be our first (two of them) Yaesu repeaters, and just trying to get some facts to get them ready to go on the air soon.
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Thanks
Kory
W4RZ
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Hey joe thanks for that, I'll have my radio shop guy maybe take a look at it and see what wecan do. I don't dare go in there because I'm blind and I don't know what I'm looking for. Chad Nelson WI9HF/WRPL979 Janesville Wisconsin 608-754-8671 Send from my spectrum iPhone 16.
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On Apr 1, 2025, at 9:12?PM, Joe Burkleo via groups.io <jburkleo@...> wrote:
? Chad,
From what I see in the manual, it says 1-6 watts input for 70-100 watts output.
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My experience with various TPL amps is that a little less drive is better than over driving them.
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It looks like the label on yours doesn't quite match this copy of the manual. That is not all that uncommon.
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I would start at 3 watts and work your way up. If you get to full output, that's where I would stop at with drive level.
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As was mentioned in a earlier post if you delete the pre-driver board your amplifier becomes a PA6-1BE and requires 10-15 watts drive for the 70-100 watts output.
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Joe - WA7JAW
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Chad,
From what I see in the manual, it says 1-6 watts input for 70-100 watts output.
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My experience with various TPL amps is that a little less drive is better than over driving them.
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It looks like the label on yours doesn't quite match this copy of the manual. That is not all that uncommon.
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I would start at 3 watts and work your way up. If you get to full output, that's where I would stop at with drive level.
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As was mentioned in a earlier post if you delete the pre-driver board your amplifier becomes a PA6-1BE and requires 10-15 watts drive for the 70-100 watts output.
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Joe - WA7JAW
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Re: Tektronix Y400 vs Anritsu Cell Master
Thanks for the insight on this and the detailed comparison. I ended up buying an HP8921A but will consider the Tektronix or Anritsu down the road as a more portable option. Thanks again.?
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Re: Quantar running on batter
Thank you.? I will have check that.? Not familiar with Motorola or most repeaters in general and have never had to program one to use a battery, but that explains why.? ?Just need to get my old laptop working again so I can.
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Hey joe, curious if I can drive that amp using a 5 W minimum from the repeater? Don't know how that tolerance is if it's one watt above the minimum of your level of the drive for the amp. My amp is rated for one to 4 W input, so don't want to burn it out Chad Nelson WI9HF/WRPL979 Janesville Wisconsin 608-754-8671 Send from my spectrum iPhone 16.
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On Apr 1, 2025, at 6:10?PM, Joe Burkleo via groups.io <jburkleo@...> wrote:
? Chad,
The 851's were originally designed for the overseas market where 25 watts was the max allowed in some countries. Kenwood later on started selling them here in the US. They are roughly? based on the 850 Version 2 firmware and use the same software.
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They are rated for 1-25 watts continuous duty, where as the TKR-850 are 45 watt radios that are rated for continuous duty at 25 watts.
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If you have a TKR-851, that is the ideal radio to use with your amp.
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Joe - WA7JAW
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Chad,
The 851's were originally designed for the overseas market where 25 watts was the max allowed in some countries. Kenwood later on started selling them here in the US. They are roughly? based on the 850 Version 2 firmware and use the same software.
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They are rated for 1-25 watts continuous duty, where as the TKR-850 are 45 watt radios that are rated for continuous duty at 25 watts.
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If you have a TKR-851, that is the ideal radio to use with your amp.
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Joe - WA7JAW
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Re: Tektronix Y400 vs Anritsu Cell Master
I have had a Y400 with both modules for a few years now, and also have a Cellmaster MT8212B.
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For starters, the Y400 has Windows CE as its operating system. It is a touchscreen.
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I compared the Y400 to a Sitemaster S331L that was a few months old and still in calibration. We swept several antennas from low band to 470 MHz. The Y400 and the 331L were within 1-2 db of each other on all the measurements we made. In my opinion other than the portability, the Y400 will produce very accurate results for return loss measurements for antenna testing. ?
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As far as the Spectrum Analyzer goes, I actually think the Y400 might be just a touch nicer to use. The Cellmaster S/A goes down to 9 KHz so it looks pretty low in frequency. You can adjust the span from zero to several MHz depending on the frequency you are looking at. The Cellmaster also has built-in attenuation and preamp to choose from.
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For tuning duplexers, isolators, filters...etc...the edge goes to the Cellmaster but it has to have the Transmission option.? With either one you have to change modes when going from looking at gain to return loss. Both will do the job quite well but you can not display both screens at once like you can with a real VNA. Both have a range of 20-25 MHz to 1000 MHz. There is an option for the Cellmaster that allows it o go lower in frequency in the transmission mode.
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They both need to have good quality test cables and calibration loads. For the Anritsu the Instacal module is OK, but individual loads or an OSL device will give you a bit more precise calibration.
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I recently had the need to add a new window to a master receive antenna system and 2 new channels to a transmit combiner. I used the Cellmaster to do pretty much everything involved in that onsite, including tuning the EMR dual port isolators, the transmit combiner cavities, and the receive window filter.? Since I have the CW generator option, I was able to use that option to speed up the scan refresh rate so there was less delay in the screen updates when tuning everything.
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The CW generator option is not something that I see as real useful as there are no audio generators and it requires the use of a external variable attenuation kit to vary the output level.
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I think the Y400 and the Cellmaster are about the same for battery run time.? The Y400 may actually last a bit longer but mine has 2 batteries in it also making it a bit heavier.
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Whichever route you go try and find something that has as many cables, loads and other accessories with it as possible as those can sometimes cost as much or more than what you pay for the unit.
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Joe - WA7JAW
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I bought a couple of new TKR-851's from Kenwood when they were closing them out. That was 12 years ago. Hope that helps with the time line.
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Re: THREAT TO 222-225MHz Spectrum
Check this group out:
Just heard about it I don’t know if they’re any better than the ARRL but maybe they will give them a run for their money.?
Martin L. Grillo EMT-P, CIC, EMC
COM L Inst. / ITSL(t) / COM?T / INTD / INCM / RADO / AUXC Inst
W1EMR / Amateur Extra?
PGGB063396 / GROL/ R
8 EMS - 37 PAPD - 23 NYPD - 343 FDNY
Never forget our Brother & Sister Heroes 9/11/01.?
It was not how they died that made them heroes.....
It was how they lived!
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Emergency Medical Rescue of New York City's?30th Anniversary 1995 - 2025
Website?
Telephone?718 474 0680
Email:?info@...
On Tue, Apr 1, 2025 at 17:39 Chris Boone WB5ITT via <setxtelecom= [email protected]> wrote: Nothing new..in the early 80s we had offshore radio location under an experimental license in the UHF...10KW Pulsed wideband and center carrier of 439.200...wiped out the input of our local ATV rptr, which I was half owner...we tracked one down to a tower on the Gulf of Mexico and the license was posted there ..the company, based out of the UK , offered to buy us "amateur hams" linear amplifiers!! NNNOOOOO that wasn't going to fix anything...finally got them off the band since they were secondary to part 97 users under the license...
Chris WB5ITT?
Geniuses. Give them an STA to operate IN THE BAND and expect them to not cause interference. Sounds like the federal government alright. Milair has their own band to operate in, why not do it there?
It's okay.. give it time, PTC-220 will be coming after 1.25m next anyways, since every railroad in the US is converting to the 220MHz band for all essential wayside functions.. it'll get jammed fast, and they'll need more bandwith, if they don't already.. they're already getting the boot out of the 800/900 segment by Anterix anyways, because 3MHz x 3MHz isn't enough spectrum for private broadband deployment, allegedly.
Mike
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Re: THREAT TO 222-225MHz Spectrum
Nothing new..in the early 80s we had offshore radio location under an experimental license in the UHF...10KW Pulsed wideband and center carrier of 439.200...wiped out the input of our local ATV rptr, which I was half owner...we tracked one down to a tower on the Gulf of Mexico and the license was posted there ..the company, based out of the UK , offered to buy us "amateur hams" linear amplifiers!! NNNOOOOO that wasn't going to fix anything...finally got them off the band since they were secondary to part 97 users under the license...
Chris WB5ITT?
Geniuses. Give them an STA to operate IN THE BAND and expect them to not cause interference. Sounds like the federal government alright. Milair has their own band to operate in, why not do it there?
It's okay.. give it time, PTC-220 will be coming after 1.25m next anyways, since every railroad in the US is converting to the 220MHz band for all essential wayside functions.. it'll get jammed fast, and they'll need more bandwith, if they don't already.. they're already getting the boot out of the 800/900 segment by Anterix anyways, because 3MHz x 3MHz isn't enough spectrum for private broadband deployment, allegedly.
Mike
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Chris Boone WB5ITT