Now what's wrong???

[W3MPS]

Ok,

We've established that long runs of LMR-400 for UHF/VHF is not
a good thing.

Here's my problem now:

For a lack of anything better to do, I hooked up some mystery flavor RG-8X cable.
The run was just barely enough to make it to the ground. In my attempt to join a group conference in North East, MD (Some 25 miles away) it was announced "Hmmm we got a carrier, but no modulation." immediately after I had just got done giving my call.

After much wondering, I tuned my HT to an open freq and did likewise on the 857. I heard myself clear as day on the HT.

What's going on here??? Have I offended the Ham gods???? Could I have wonky SWR from a factory antenna? It's a Comet GP-3.

On a side note, I'm still running off the deep cycle battery. RX is great, TX just isn't there.


I get roughly half a volt drop when I key the mic. I'm going to buy a new power supply and screw around with the Astron in my spare time.

[kc7jty]

The mobile radio is designed to operate on 13.8 volts. If your battery isn't able to supply 12 under load that will lower your output capabilities.

[W3MPS]

So basically it's what's been screwing me the whole time.

I suspected as much. Hell, the manual even said "Do not operate at below 13.8 volts, sucky operational characteristics will result."

Oh well, hamfest on Saturday. Power supply is on the shopping list.

I'll just have to be content with listening for right now.

[ad4mg]

Ok,

We've established that long runs of LMR-400 for UHF/VHF is not
a good thing.

Here's my problem now:

For a lack of anything better to do, I hooked up some mystery flavor RG-8X cable.
The run was just barely enough to make it to the ground. In my attempt to join a group conference in North East, MD (Some 25 miles away) it was announced "Hmmm we got a carrier, but no modulation." immediately after I had just got done giving my call.

After much wondering, I tuned my HT to an open freq and did likewise on the 857. I heard myself clear as day on the HT.

What's going on here??? Have I offended the Ham gods???? Could I have wonky SWR from a factory antenna? It's a Comet GP-3.

On a side note, I'm still running off the deep cycle battery. RX is great, TX just isn't there.


I get roughly half a volt drop when I key the mic. I'm going to buy a new power supply and screw around with the Astron in my spare time.

The 1/2 volt drop shouldn't be significant enough to cause problems. I use my rigs on batteries all the time when power is out, and I can operate until the voltage gets down around 10 volts. So ... you keyed the repeater, but the stations on frequency didn't hear any audio. I understand you heard yourself ... listening with another rig?

If the radio is used, you might have an intermittent problem in the mic cord or connector, or even possibly the PTT switch.

It would be easier if you can locate another ham close by, and have him/her work with you on simplex. I wished one of us was close to your location so we could help. At this point, it's a guessing game. I'm confident that the problem isn't SWR or voltage related, nor a problem with your antenna.

If they still have them, the Radio Shack (ugh!) switching power supply (15 amp model is plenty for a 50 watt rig) is affordable, and works well. I have one, but I'll admit that it's a little noisy in the HF spectrum. Astron also makes switching power supplies that are lighter and cheaper than the linear supplies.

I hope you find some local help with this, so you don't get frustrated with the whole process!

Good Luck!

73 - Luke

[W3MPS]

I bought my radios from an SK's estate.


I had the HT on and and heard myself when I TXed on the other radio I've been trying to get to work.

With a run of only 16 feet, the line loss should not have been enough to cut down my output power.

I ran a continuity check on the mic cable and the cable from the head unit to the radio.
That's all fine.

Could something have gone stupid in my radio? I'm re reading the manual to see if I missed something.

I have reset it to factory defaults, and still no change

After reading the manual, the mic gain may need to be adjusted. I'll look into that tomorrow.

If the previous owner never registered for the warranty, can I?

[W3MPS]

Ok,

As per the manual, I adjusted the FM mic gain. I'll get on the air and see what happens after work tomorrow.

[N9FE]

Did you check your coax after putting on connectors with an ohm meter ???

[W3MPS]

I stuck an ohm meter on it, but was unsure of what to look for.

I got identical readings for the new store bought cable and the one I got with the radio which were assembled but the previous owner.

I'll stick the meter on them again and post the results when I get home tonight.

Where do I check, just on the center pin and the outer connector? My reading wasn't 50 ohms. Did I not test correctly?

Well it should never read 50 ohms unless you have it hooked up to a dummy load.

http://i104.photobucket.com/albums/m165/n9xr/coax.jpg

Between the center conductor and the center conductor, you should show something very close to zero ohms. Between the shield of one side and the shield of the other side, you should also read zero ohms. Between the shield and center conductor, you should read infinite resistance.

If you have it hooked up to an antenna that is like a loop, you should read near zero ohms in the shack due to the shorted loop from the center conductor to the shield.

The 50 ohms of the coax is the characteristic impedance of the coax at RF. It is not to be construed as a DC measurement as with your DC ohmmeter.

[W3MPS]

That's exactly what the readings came out to be.

So now that I have time to actually do something, I'll give it a try and see if I can hit some repeaters.

When I went into the mic gain menu and checked it, I had no modulation.
After adjusting the gain I'm seeing the modulation.

If all else fails, I'll take it down to the radio club I'm now a member of and get them to point out what will more than likely be some stupid oversight on my part. :doh:

Kind of like when you spend all morning looking for something in a store and when you finally ask the clerk, it's right behind you on the shelf.