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DB-420 bottom half 470-490 MHz cut antenna project.
14
Hello RB members, I have a potential project that I thought I would list for those of you who like things like this. I have the bottom half of a Decibel DB-420 16-bay antenna array here that is cut for the 470-490MHz band according to the dipole loop sizes. They are a good 1.5-2" shorter than the 450-470MHz cut versions I have used in the past. The harness is in great shape and there is no damage to the hardware. Basically it is laid out like a DB-408 with the connector at the top of the harness to feed another DB-408 making up the full DB-420 16-bay array. I will ship it less the bottom half of the mast to anyone needing it or interested in a project for $150 + actual shipping to you. Maybe it can work on GMRS frequencies since they are quite broad banded, maybe the harness can be terminated at the mid-point connector and used as is, maybe someone can modify the harness and use it as is. Basically it is a project or for someone with a damaged bottom half of your DB-420 higher cut that needs the parts. I don't see many parts for these come up anywhere so I figured list for the RB group. Thanks for looking, Rick w6re
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Getting sites for amateur repeaters.
2
Hi George, Here in Australia we have a "Men's Shed" movement supported by our government as a "Men's Health Initiative". This gives an opportunity for antennas on the building. And, with sufficient members interested in radio, a community. Then there's HF repeaters! Our Ambulance service has invested in HF digital radios in 100+ vehicles and stations and thus a mesh network. All we hams need is to convince the software developer of such as FreeDV to think along the lines of, data in the transmission such that an intelligent receiver can decide to repeat (do something) a signal or not. We have CTCSS tones in VHF/UHF repeaters and here we use just three of the 50+ tones, so three bits/sec would be enough. Keep smiling Alan VK2ZIW (making use of my Men's Shed) On Fri, 30 May 2025 07:06:44 -0700, George Csahanin wrote > Before I retired I was Director of Engineering for a large group of TV stations. Towers were my responsibility. I can tell you that as much as I wanted to get hams on our towers my hands were tied by two of the worst parts of the biz world, insurance companies and lawyers. The couple of times we were able to accommodate hams was where the capacity for antennas were included in tower design. And I'd give the group a zero dollar lease that I could terminate with 30 day notice if I had a paying customer. Heck, even for my own repeater back in the 80's in Austin the only way I was able to get on our tower (I was chief engineer at this station at the time) was when a paging company abandoned their antenna/line on our tower. During a lamp changing session I had the guy doing the work to swap their antenna for my Stationmaster. But more and more as insurance was dictating and our own lawyers looking over our shoulder the deal was this: anything going on the tower needed a structural analysis. If changes were needed to accommodate the antenna the "customer" was responsible for paying for the mods. Climbers needed big insurance and the tenant needed insurance. That's just the way things went. > > And if you look at the tower and figure the antenna and line won't hurt you can be very wrong. > > What didn't help me was my experience in 1996 when I was in DFW and having work done on one of our 1500' towers in Cedar Hill that a tower crew made an error hoisting their "gin pole" and with three guys on the tower collapsed the tower, three dead. I had engineering done on it but the crew made a mistake and the tower came down. THAT one error cost a huge amount of money, insurance didn't quite cover all since our tenants sued us, the deceased's families sued us. And we sued the tower company. Who won? The lawyers. I met many lawyers I could have lived better not knowing (except ours-he was a shark). Met OSHA people. It was ugly. And then we needed to build a new tower. Not cheap > > Add into this the fact that it was a "thing" back 15 years ago for stations to sell their towers to companied like American Tower, then lease it back (never made any sense to me) so many towers that were locally controlled were now corporately managed. More damned lawyers. Companied like this now control towers, rooftops, water tanks, etc. I've been wanting a site for one of my 900 mhz repeaters here in Ft. Worth area. Just not happening. My other one is on a tower that had an abandoned paging antenna and not managed by the corporate world. > > GeorgeC W2DB > > --------------------------------------------------- Alan VK2ZIW Before the Big Bang, God, Sela. OpenWebMail 2.53, nothing in the cloud.
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ASL Allstar node
14
I found my RIM RLC USB FOB.....but I cant remember what the ip address is on the Pi....I dont have a monitor handy (Im at the tower site now),,is there a way to determine it from the ETH connection? Ive been running ZENMAP to try to find it via scans but no joy...If I can figure it out, I can SSH in and set it up and have my allstar node on my new site today (its an hour drive from the house)... Any ideas?? Thanks Chris WB5ITT
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Getting tower sites for amateur repeaters.
16
I've been debating on trying to aquire a site to put a repeater vs here on my vertically challenged tower. In the past I've found contact information & asked tower owners for space. But this was probably 18yrs or more ago. One spot almost worked out, but in the end engineers said the tower was already too loaded. So that was a no go. Then at one other site I was actually offered space, but I decided not too. Just because of location wasn't desirable to me. Then I've also heard horror stories of tower owners changing hands & Hams getting locked out & stuff turned off. ? Now here recently I decided to kick the idea around about acquiring a site again. In particular one of the sites I was almost in the door on years back but engineers said it was too loaded. I've noticed the tower has had most everything removed now. So I wonder if that might be a possibility. What I am curious about is what all is to be expected. So I figured I'd ask here..since there might be a high probability of Hams with repeaters on towers owned by others or government organizations. Do you have to carry insurance with having space on them? Was is difficult to get the equipment on the tower with red tape? Do you have free access to go there whenever needed with keys? Do you pay anything for the space? Do you pay anything for electricity? What do you feel helped you aquire the space? Little background about myself. I started off rock climbing in my youth. I was already into radio. Later that led to working for a tower company doing installation & tear downs of towers/equipment. This also helped fellow Hams around me. I'd donate used long runs of heliax to local clubs. Plus help put up repeaters & equipment on commercial towers for other repeater owners. Im older now & I don't do tower stuff for others anymore. Having kids & wanting to be around for them changed a few things for me. Im still willing to do tower stuff for my own projects though, just because of necessity. I have land here. I've always wanted to just put up 120ft or more of tower of my own. Life always seems to say nope. You can't afford that now. Its a shame though. I actually live on a good size hill with nice HAAT. Radio communications do really well here. Its just having a repeater with antenna at tree levels still produces shadow areas plus foliage antennuations when leaves & greenery come back in season. Ideally having one here would be less worry I feel. If you don't want to reply publicly here you're welcome to email me. N4fox.r@...
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I listed this yesterday but I have pictures today of the unit. This repeater works great and will come with a power cord with Anderson power poles on it. It is a TKR 850 UHF repeater with about 29.5 W and a receive sensitivity 0.25 mill volts at 463.975. Unit was bench test tested for receive and transmit by a local radio shop and works 100%. I listed it for 600+ shipping, but I will sell it for 600 including shipping.Chad Nelson WI9HF/WRPL979 Janesville Wisconsin 608-754-8671 Send from my spectrum iPhone 16. ? image.png image.png image.png image.png image.png image.png image.png image.png -- K Jones He/Him/His Visual Interpreter 1
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DMR & GMRS Repeater use of same antenna?
3
I had a question posed to me so thought I would pose it here. The local club has a 7cm DMR repeater antenna is at 500 ft.. They are interested in adding a GMRS repeater use cavities to combine the two to use the same antenna. Has anyone seen that style of arrangement? I know major radio markets you see FMs use combiners, but this arrangement is not involving only transmit. Any thoughts appreciated. -- Mikeal R. Hughes, BA., MA., D.Min., Th.D. Amateur Extra - N9GI EchoLink - 810004, Allstar link node - 58465 GROL, MOS, CompTia A+, Network+, Security+, CEH
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Motorola GR1225 Hanging Open after random transmissions
2
An organization I work with has an old Motorola GR1225 (business freq) with an odd issue that we're trying to diagnose. None of us are radio technicians...just audio/visual & IT guys (a couple of us with basic ham radio background). After some transmissions (seemingly at random...maybe 2-3 times per hour), the repeater hangs open and transmits loud static for around 30-60 seconds. In the last 10 (or so) seconds, the static begins getting quieter and cuts in and out until the repeater finally drops. We were able to get our hands on the software and will be attempting to connect to the repeater for troubleshooting tomorrow.... in the meantime, does anyone recognize this behavior? What should we be looking at to fix this? Thank you!
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Crescend Technologies P25-2AC1-C1-002 amplifier info?
Does anyone know anything about the Crescend Technologies P25-2AC1-C1-002 amplifier? I found one that is for sale and its label says it operates 42 to 50Mhz and 2.5 watts input for 250 watts out. But I'm trying to figure out if it will for sure work okay on 6 meters, or if it can easily be modified to work there. I need it to operate on 53.19Mhz. Has anyone successfully used one of these amps on 6 meters? I have looked on the internet and have found no information on this amp. Even contacted Crescend directly and they told me they no longer have any documentation on it. Thanks, Dan
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TKR-850 not being used. F.S.
Hello to all. I have a real nice Kenwood TKR-850 repeater that I have no location for. It is currently on 444.700. I will program it for you and ship it for 575.00. I also have several zetron 38A cntrollers (all have new memory and battery backup) with access code if you need a nice controller. Email me at jrbluz2@... or call 813-473-0831. Visit wb9zpy.com and thank you. Wayne
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CDM1250 rx audio from mic jack
4
I'm trying to get rx audio from the mic jack on my CDM1250. The pinout says it is the same as the maxtrac and I should have rx audio on pin 8, however it isn't there. I'm using a signalink USB and trying to setup echolink on the CDM rather then the maxtrac. Everything works fine on the maxtrac, but if I plug it into the the CDM there is no audio. I was going to use the accessory connector (pin 11) but that is unsquelched. Not like on the maxtrac where you changed the jumper on the inside for PL to unmute the audio. Not seeing anything in the RSS to set pin 11 for muted or PL audio. Thanks for any help.
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whelen siren
50
i am looking for a dtmf decoder to connect to a receiver to decode our local ema whelen siren to give a message on the repeater that the sirens have been activated i monitor the frequency that they activate the sirens on and the dtmf is very fast i am sure different tone sequence has different meanings i just want an announcement that the sirens were set off ,any thoughts ? Thanks
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Looking for a connector
5
I¡¯m looking for the connector to go on the back or the whole cable kit for a dc backup on a quantar. Does anyone here have anything they would be willing to part with? I can¡¯t find anything online. Thanks!
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F/S Kenwood TKR 850 repeater
I have a good condition works fine Kenwood TKR 850 Peter with about 30 W output and the receive sensitivity is about .25 mill volts. It will come with a power cord with Anderson power poles on one end. This Peter was just tested by a local radio shop and was determined to be working with good performance. $600 plusshipping. Chad Nelson WI9HF/WRPL979 Janesville Wisconsin 608-754-8671 Send from my spectrum iPhone 16.
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ISO service manual
2
Does anyone know where to get the service manual for the DR-2X? I have tried OEM's site, manuals dk, etc but nothing yet. -- - Regards, Karl Shoemaker Please remember not to reply (email) from this group as I won't get it. Please visit SRG's web site at https://www.srgclub.org under "contacts" for the current email address.
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Scom 7330 repeater controller software
8
hi , does anyone have any of the following ? a cable from a Kenwood T K R eight fifty to the S com seven three three zero controller ? and , I'm looking for a copy of the programming software for that controller . weird question , is there any blind hams on this list who may have used the programming software with a screen reader? And is that accessible? A screen reader is a piece of software that reads text on the screen out loud so someone who can't see the screen can hear it and interact with programs and a computer. Chad Nelson WI9HF/WRPL979 Janesville Wisconsin 608-754-8671 Send from my spectrum iPhone 16.
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TKR720 for sale
3
Asking $300 obo + shipping...programmed in 462 range Chris WB5ITT
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Selling the last Kenwood TKR-850-1 UHF repeater I have in the system. We are going to simulcasting so all repeaters needed a 10MHz reference input for the time base stability required to simulcast. As a result I have pulled non 10MHz reference input repeaters we had in service. This is the very last TKR-850 we were using and was used with an external controller however it does have internal control if desired. Not much more to say as it has worked well and been on the air over a decade. It is a version 1 that is tuned to the 447/442MHz band area right now. It is fully functional with power turned down to around 5 or 6 Watts at the present time. Rated at 25 Watts continuous duty, it has always driven an amplifier. $550 + actual shipping costs to your door CONUS 48. PayPal or Zelle preferred. Thanks for looking.
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Desense is driving me crazy. Might be a short ride there. ? Warning: This will be long & descriptive. In hopes I cover everything for getting good advice in return. Last year I bought a new Yaesu DR-2X & a new Hustler G7-144. I'm using some older Andrew's 1/2 heliax. The duplexer was purchased from a wholesaler as new old stock. It's a Sinclair Q201GC 6 cavity (7" diameter) set in it's own cabinet. The data sheet says it left Sinclair in 2015. Originally tuned to 170Mhz. This makes the 4th repeater I've messed with in the 26+ yrs of being a ham. I've done lots of tower & antenna work over the years. I even used to work for a tower company many years ago climbing. One thing I never messed with was tuning duplexers. So this time I wanted to do everything myself. One reason was I didn't want to haul this large duplexer many miles away to get it tuned. I didn't have a safe way to haul it sitting upright (vertical). So I decided it was time to invest in some test equipment. For tuning & other ham radio projects. Originally I already had a Lite VNA 64. I used it to check the duplexer cavities individually to see if they will tune down from 170MHz to 145MHz. They looked like they would. So I decided to move forward with this set. Now, as I mentioned, I was told these were "new old stock". They look great! Still shiny. They had a cardboard box cover over the cabinet for shipping. Plus as stated the data sheet from Sinclair inside. One thing that strikes me as odd, was all 6 of the brass dust covers for the trim capacitors were missing. I'm to understand those are important to keep the caps clean. I've gotten some great help from people here on repeater builder to get started. I may have even gotten on some nerves asking so many questions lol. It was mentioned I will need to make a new harness for the duplexer to get it down to 145.330. I was able to get information on the correct lengths for the cables. Using RG214U & silver N hex crimp-on connectors. I made each cable 13.5 inches long. I used silver plated amphenol tees. I had to buy the tees used. As they were impossible to find new at a reasonable price. With the cable, connectors & tools I had nearly $300 dollars tied up in just materials to make the harness. I needed some more test equipment to begin alignment of the duplexer. Keep in mind this is my first time tuning a duplexer & getting equipment for it. I was originally going to invest in a used VNA like HP, Keysight etc. But the turn off there was age of equipment vs cost. Then being worried about buying old equipment that might be a problem later with failing parts due to age of components. Then finding parts to repair them. Plus most everything that was suggested still only had about 100db of dynamic range. Which wasn't going to be enough for this duplexer. I started looking around at other equipment that's newer. Plus more in my budget. I decided to buy a LibreVNA. It's advised as 90 to 100db of dynamic range & seemed to be better than my Lite VNA 64. It still wasn't going to get me past 100db for final tuning. But it was great for all the individual cavity tuning. To final tune I decided to buy a Siglent SSA3021X + spectrum analyzer with tracking generator. I used this stuff to tune the duplexer. It appeared to have about 120db of rejection. When I hooked everything up & started testing out the repeater it all worked OK. But I'm not one to just stop there. So I decided to start testing for desense. I also have a TinySA ultra. This has a spectrum analyzer plus a signal generator. I'd generate a low power signal with that & listen to the DR-2X receiver speaker by ear. Get the signal down low & listen. Then engage the transmitter & listen for any changes to how the receiver sounds via the speaker. Sure enough I was hearing changes aka desense. I tried this with the repeater hooked to the coax & antenna. Then I'd try it into a 250 watt TX/RX dummy load. It was worse with the coax & antenna hooked up. But it was also still slightly present into the dummy load that bypassed the hardline & antenna. Now for the coax & anten
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I am in need of one PMLN5644BS rear connector board for an XPR8400. This is the board in the rear of the repeater that has the accessory connector and Ethernet connector on it. Please message me at my email or my email listed on qrz if you have one you want to sell/part with. Thank you, Jacob AD0JA Picture of what I need:
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I have for sale this Micro Magic 6 cavity flat pack duplexer in very good shape. Currently tuned for 462.65TX 467.65 RX with N female connectors. model: MICRO-4201-C6-3 S/N: 011422010 micromagic2way.com This is lightly used but has a couple of minor scratches, but otherwise works great. I believe this is able to be tuned into the 70cm ham band if desired. I will ship for $75.00, brand new over $160.00 I have jumpers for TX and RX if needed, will throw those in. 73 Chad WI9HF
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Sat 8:39am
Sat 8:39am