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Folks, I have an MFJ VHF/UHF SWR/Watt Meter (MFJ-842). Lately the forward and reflect needle has not been at zero when its unplugged. Haven't dropped it or anything. Is this a known issue? Any way to correct? Thanks, -J

Hello All, Just thought I'd post this since I've seen many posts in the past, sometimes with incorrect information. Generally for light duty repeaters, I use some Motorola mobiles that have been modified for better cooling. But for the link radio (linking to a hub repeater), the LPI Motorola's...

Probably the best reference is this presentation: http://www.repeater-builder.com/antenna/pdf/ve2azx-duplexerinfo.pdf slide 4 covers 2 loop design. Easy to understand as the loops are magnetically coupled with the resonantor. I can wrap my head around this. Slide 26, single loop. I can't wrap...

Hello all, I know several threads have discussed issues with using mobile radios (such as the Maxtrac/Radius) for repeater usage because of their designed duty cycle. Besides adding forced air cooling with fans, has anyone tired extending the cooling fins with aluminum using a thermal adhesive...

Over the past few months I've been reading various duplexer designs and one that I can't wrap my head around is the single loop bandpass/reject cavity. I get the dual loop where the cavity is tuned to be resonant at the bandpass and the Capacitor is tuned to the reject. But the single loop I...

well, it looks like it was just a loose connection on J8. After cleaning, and punching down pin 4 on JP8, my audio is good. Even bench tested it with a 1Khz tone and I get the same output on pin 1 & 4 on JP8. Looking at the schematic, there isn't much to the audio out circuitry....

Folks, I have a Motorola Maxtrac with very low audio on MIC pin 8. I'm going to review the schematic to see if I can figure it out, but thought I'd reach out to you all and see if there is a common (or well known) issue I should be aware of. The audio to the internal speaker is just...

I think KG6ABF was hijacking the thread a little bit. What I was originally asking was, what is a lower cost method to tune a notch filter (like the mobile duplexers for home use) without a service monitor? With SDR dongles being significantly cheaper, has one tried using these to tune and...

So I take it, based on no responses, that this is not possible?

Hello folks, I've read through the Repeater Builder Dot Com site on duplexers both bandpass and notch filter designs. And even though there is the poor man's way of tuning listed, I was wondering about a different approach. Most of us don't have a service monitor or a scope that can go up to...

So, I started building a repeater and set a PL tone (the same) on the RX and TX side and interestingly, I got a weird loop where the RX side would stay squelched for 10's of seconds.... (like 30 seconds). It sounded like the buzzing/hum sound that you mentioned earlier. At first I thought...

hmm...I guess you could look at it that way...but I want to filter to hear what I ACTUALLY want to hear. That meaning, if you are not TX'ing on the PL code that I'm expecting...I want to filter the audio. Heck, if you are in a metro area, then generally you should only be getting the repeater...

OK. so maybe I'm a little clueless here :-) or not connecting the dots.... which has occurred more than once :-O But, there are times when you are traveling through the city where there is a lot of UHF noise...I mean a lot of noise. And if we had a PL tone set on the transmit side of the...

Hello all, Just a curiosity question here. Why do most repeaters only use an RX PL code and not BOTH an RX and TX PL code? The reason I ask, it seems like it would clean things up with some of us using multi-band radios which can be more prone to intermod...and our RX wouldn't come...

Well, I went ahead and bit the bullet and bought a programming cable off of Amazon ( Programming Cable for Motorola Maxtrac GP88 GM300) for $21.36. It worked just fine for my Maxtrac and Maxtrac 100 radios. Somethings to keep in mind if you're interested in programming this yourself...

Hello, I got a couple of Motorola Maxtrac's and want to program them for GMRS use - potentially building a repeater. Do you have any recommendations in the Portland, Oregon Metro area of someone (shop or personal hobbyist) that programs them and has the RIB & software to program them...

Via the front panel there is a wide,mid, and narrow option. That is documented in the manual. Its the darn software tool that has no documentation....So its processs of elimination to figure it out. If I set the channel spacing to 12.5khz in the software then narr shows up on front display for...

ok. So set my channel memory with Chirp software to FM instead of NFM for 2m/70cm repeaters then. And for the Anytone software, I guess I set the channel spacing to 25K as there is no other option to specify Narrow or wide? -J

Hello everyone. I've googled and googled to try to find clarity on the title and it seems to be very unclear to me how to interpret the programming software for a lot of radios. Perhaps someone can clear things up for me. So I understand the 5K deviation and the 12.5K channel spacing. But...

Hello all. Been a lurker for a while and finally got registered :-) At any rate, I upgraded my home made dipole to a Diamond X50A and wanted to share my experience. With the gain increase over the vertical dipole, I've taken repeaters that were weak at 1 S unit and now they are full quieting...