RT524 & MX-6707 Antenna setting?

[decodeme2]

Hi,
Looked all over here and cant find the Antenna setting for my rt524 radio in my hmmwv.
I hooked it up, powers up great. Antenna makes a clicking sound when i change channels. A FAN comes on when i transmit. I have a buddie who is 25 miles away id like to call to see if it works, i also will try and get a tv channel in useing the channels i found on this site..
Question is: what setting do i turn the switch on my Antenna to as in the picture?..Or does it matter..?
THANKS AGAIN!..
Kevin..

 

[Boatcarpenter]

It seems as though your antenna is working properly. The clicking is it changing the frequency setting to correspond to the frequency you are setting on the radio to transmit and/or receive on. Look at the pointer and remember where it is set and then change frequency on the radio until it clicks and then look to see if the pointer has moved. If it has, then I think all is good.
I'm no expert on this subject, but I think I am correct on this.
BC

 

[wsucougarx]

The clicking is normal Your antenna is a "matching antenna". The Antenna unit automatically adjusts according to your freq on the 524

 

[Irv]

The MX6707 antenna is actually a vertical dipole, fed in the middle, where it screws together. The base unit is a matching network with several positions. Depending on where you set your frequency in the 30 to 80 MHz band, it will click in one of several tuning networks designed to translate the odd, complex impedance to standard 50 ohms, or close to it. Caution: Never ever try to turn that rotary switch backwards. It has a direction arrow and must always be obeyed. It is a rotary stepping switch inside that acts as a ratchet. You will break the knob or damage the switch if you go backwards. Seen many like that. The only reason they even put it there is so that if your control cable breaks, you can manually select the proper network for your intended frequency. Otherwise, leave it alone. The frequency is printed on the 6707 next to the switch.
The reason that they went to the vertical dipole instead of a simple vertical is that this antenna needs no ground plane to operate properly. A simple vertical antenna uses either a vehicle body or a few ground radials to work against to get the electric fields arranged right for effective radiation. Since these antennas are generic to a multitude of vehicles, they cannot know in advance how to configure the tuning networks. By going to a vertical dipole where the fields from the top end on the bottom section, the behavior is far more predictable and that means they can just grab this antenna system and install it anywhere on any vehicle, tied down or not, and it will work reasonably well. Not so with a simple vertical antenna.
As for receiving TV, you're a few months too late. Analog TV on channel 2 used to be able to be received. Not anymore. Irv

 

[Irv]

I should elaborate on the feed point. The radio coax cable goes to the base unit, where it uses various coils and capacitors to match the antenna. The output of the matching network feeds into a very small coax cable that then goes up through the middle of that big spring to the fat threaded base of the lower section. Look inside and see the center pin and a ring. That carries the coax signal, center and braid, up inside the lower section to the top of the lower section. There, the braid connects to the lower section and the center connects to the upper section. The bottom end of the section is actually insulated from the big fat connector or the spring. Some people gut the MX6707 and install new parts to use it as a CB antenna. Irv

 

[jwaller]

all normal all good. you can buy a little later model of the same antenna that automatically tunes itself. if you don't hear the clicking then don't transmit after channel swapping. lots of times in the cold the motor will snap it's drive shaft and won't properly tune the antenna and burn up your radio.
make sure after you swap stations you hear it retune.

 

[jatonka]

Hello J waller, Can you PM me sometime to say Hi, I have a question. JT

 

[jwaller]

Hello J waller, Can you PM me sometime to say Hi, I have a question. JT

sure thing.

 

[decodeme2]

Thanks guys,
I understand it now!..All i need now is a "heater" to double my distance!..
Kevin..

 

[86humv]

The sincgars AS-3900, or AS-3916 antennas can be used also , they don't need to be tuned...its automatic.

 

[popacom]

As/3900-as/3916 swr

I work for a Gov't contractor ,and I had occassion to observe the differences in reflected power between the as/3900,as/3916 and the
as/1729 the as/1729 was used in the vrc-12 series radios (RT-524/rt-246 etc) and what we found is the singars ants reflected a lot of power back at the radio
our conclusion was if used with vrc-12 set ups swr checks should be done to avoid radio self destructs on high pwr .not to say don't use them just assure that the particular base you choose isn't gonna zap yer radio.


Thanks for listening to my opinion
popacom

 

[Westex]

My question is somewhat related to this thread; I purchased an unused set of MX-6707/VRC antenna bases (same as in first post) and did so after researching some earlier posts that one could tune the bases to transmit C.B. radio by dialing to the 30-33 Mhz setting and then removing the bottom base and dialing in the associated tuning capacitor. My question is, I assume you just connect your antenna lead to the connector, ground the antenna base and that's it? No power to the antenna base required? There is a 12 pin connector at the 8:00 o'clock position on the antenna base which I hope I don't have to fool with.

 

[Westex]

Previous post referenced above is Military Antenna Conversion for CB

 

[popacom]

The big connector you are refering to is the conn. that links the RT-524 or RT-246 which when connected will make the ant base automatically tune to the frq. that your radio is set to,so to answer the question of does it Have to be hooked up to give pwr to ant for what you are intending to do with it(I.E.---hook up to CB radio) then the answer is "NO" however I have never retuned an MX-6707 to use this way so I can't answer that part from experience,but my gut feeling is that if the tuning coil for lowest setting will dip that far theoretically it should work.

Hope I have helped!popacom BILL KAGIN III

 

[CARNAC]

Bill,

How did the AS3916 perform during the test?

Is there any concern of reflected energy from it that will blow my 12 series?

When finished, my truck will have the 3916 just outside the window of my 12 series on my 1009.

Thanks

CARNAC

 

[popacom]

RE:CARNAC question

Well what we were consistantly seeing was about 6 to 8 watts reflected back at the radio with the AS-3916 we were using (Which is more than I would like to see myself) however we did'nt have another AS-3916 to run to see if this was just a fluke with this particular base. As I stated I would check the base you are gonna use with SWR meter and verify whether or not there was reason for concern. When I get my shop set up when the weather breaks I intend to run a few of these and do some comparisons . Keep in touch CARNAC and I will try to fill you in as I can.

popacom.........BILL KAGIN III KI4QQB

 

[papakb]

Unfortunately your question about TV channels to listen to came in a little too late. When the FCC mandated broadcasters going digital last year it killed any TV listening you would have been able to do.

Normally when I fired up a radio the first thing I did was to tune 59.75, 61.75, or 71.75 which were channel 2, 3, and 4 audio frequencies to check the receiver.

In some areas you might still hear Police, taxis, or wrecker services and the occasional older baby monitor in the 49Mhz region.

Kurt
KG6KMJ

 

[papakb]

A note when using the MX-6707 for CBs. The matching units will work and the best way to find the sweet spot for tuning is with a simple forward/reflected power meter available at Rat Shack or most CB shops. Put it inline with the coax to the antenna and key up the radio. Rotate the tuning knob by hand and watch the meter. When you have the maximum forward power showing with minimum reflected power, that's where you want to leave the 6707's frequency knob.

Kurt
KG6KMJ

 

[Wile E. Coyote]

I think the AS-3900(*) had a VSWR of something like 2.3 or worse across the band. The RT-246/524s will supposedly handle a continuous VSWR of 4.0, though I wouldn't like to put it to the test. Probably the best match on the AS-3900s is the center of the bandspread which would be around amateur 6m freqs anyway (50-54 Mhz), but that's just a logical guess.

(maybe it was a cunning plan to have your RT-524 double as an auxiliary heater )

 

[wsucougarx]

Where can a guy get a NEW Mx-6707 for a decent price? As well as the As-1729 antenna etc to go with it? I've looked into ebay and they look a bit spendy