Batboard

I would like to test the antenna from my MT1000 low band to see what the forward/reflected power looks like. I have the proper program cable to hook the radio to the watt meter but I do not have an adapter that will allow me to connect to the portable antenna to the output of the watt meter. Anyone know what I need and where I can find it.

Thanks

Mark

P.S. You can also add the adapter for the Waris series as well.

The RF adapter is NTN5368A. It provides a 3.5mm jack. The NKN6408A cable will adapt the 3.5mm jack to a UHF connector. Both are still available from Motorola.

Thanks for the reply but it sounds like you are referring to the connction betweent he radio and the input to the watt meter. What I need is from the output of my watt meter into the antenna that is for the radio. I need something that takes the threads on the antenna and converts it to BNC lets say. If what you are describing will do this then my apologies.

Thanks,

Mark

Thanks for the reply but it sounds like you are referring to the connction betweent he radio and the input to the watt meter. What I need is from the output of my watt meter into the antenna that is for the radio. I need something that takes the threads on the antenna and converts it to BNC lets say. If what you are describing will do this then my apologies.

Thanks,

Mark

this is what he's talking about:

http://cgi.ebay.com/MOTOROLA-MT1000-RF- ... 0026069234

Yes I understand what he is talking about. This just gets me from the radio to the watt meter. I have the capabilty to do this with my OEM Program/Test Cable which has a male BNC adapter. I connect this to the input of my watt meter and then connect a low band base loaded whip to the output and I can see what the radio is putting out for power.

Here is my problem. I think that my helical low band antenna is not cut to the right length for my frequency range. What I would like to do is be able to connect the antenna to the output of my watt meter. I need to go from the output of my watt meter PL-259 UHF connector to the actual threaded connector on the antenna. I am not talking about the RF adapter on the radio.

Mark

No such thing that i know of..

The antennas were tuned originally by using a cutting chart and measuring them. I don't know if shops had any other way of checking them, if they did i doubt it was an adapter like you want.

You might be able to make something if you had some dead radios laying about. Take a chassis and connect a length of cable to it, shield to the chassis and center to the antenna connector pin that would normally go into the rf board. If you tested the antenna by itself chances are your going to be off anyway since without the chassis you don't have a ground plane for it.

That's the problem with radios that use screw in antennas of this type, they don't have a ground reference at the antenna.

The Ht600/MT1000 series radios have a 1/4 x 32 female threaded bushing
antenna "jack".

Testing the radio thru the external antenna connection/adapter and a wattmeter into a 50 ohm dummy load is the correct way to test the radio.

To test the antenna requires a 'dummy radio housing' as kb0nly refered to.
I made up an adapter to test 1/4 32 male thread, MX, style antennas on the MFJ antenna analizer. The MFJ analizer finds bad antennas easaly, and somewhat simulates the radio housing.

What you realy need is the cutting chart for the lowband helflex antenna.

Not having the cutting chart and an "unknown antenna", you could use a PL259 male center pin (without the connector housing) with a 1/4 x 32 small pattern nut soldered to it pluged into the wattmeter. Not sure how that would work, but might be a go/no go test.

Can you take a picture of that adapter you made? I should make one myself, i have a MFJ Analyzer, would be nice to check em quick with that.

If only using the BNC adaptor, you will be missing the ground connection, that's goign to be needed to accurately test SWR.

The programming/test cable has the required BNC connector and the test adaptors for the Genesis radios and is the surest method of getting proper readings.

The test cable takes RF from the accessory connector and routes it through the BNC conn. that is on a short length of cable, so it has RF and ground as well.

Circle-M charges big $$ for it if you can get it though.

The whole thing is a moot point. The swr of the thing is at the feed point.
If you try to measure it any other way it will be false. The frame of the
radio is the counterpoise of the antenna system. if the feed point is
changed in any way you will not get a proper reading. The only correct
way to get an antenna tuned properly like this is to mount the radio and
a field strength meter so that position is not a variable and take readings
as you cut the antenna. Then go to the manual and do the procedure
that gets the proper final current using the antenna matching and loading
devices in the radio. The only reading you can do is with a proper
2 conductor (shield and center) connection to a short jumper and to a
watt meter terminated in a proper load to set the power output level.
Then leave those settings alone and do the field strength measurement
for maximum radiation eficiency. Phrawg

See FS/FT, just listed a new 'M' Genesis RF tap setup.

The SWR of the rubber helical antennas is very dependent on how you're holding the radio, that in practice it doesn't MATTER what you might be able to measure on the workbench.


They also are very lossy, at best, so a mismatch if probably the least of your problems. That said, you can determine whether you've got the antenna that approximates the part of the band you are operating in.

Just ask as a parts house, like Tessco in Baltimore or some other place that has them in stock, to drop a ruler on the one for the band where you are operating.

Compare it to what you can measure on the one you've got in your hand, from the bottom of the threads to the top of the rubber cap.

If there's a difference, just order the correct one For $15 or whatever, and you will be doing the best you can to achieve a good "match."

Paul/VJB
Annapolis