Ham antenna and other questions

[3.0ranger1227]

I'd get one or two trucks with HAM setups and operators who know where a local repeater is. a lot of base station repeaters have an autopatch function, which allows cell calls to be made from a Ham radio. However it does require a radio set up with a key pad to make the tones over the radio.

 

[--weezl--]

the radios i'm looking at right now, are the FT-1900r and the FT-2900, both have keypads on the mic, not sure if they have autopatch compatability... nor if the repeaters have them...

we have a deal getting setup for our ham licenses up here, where we are going to be getting a 1 day course then the test and license for a really low fee, not sure what it's going to be yet

 

[3.0ranger1227]

the radios i'm looking at right now, are the FT-1900r and the FT-2900, both have keypads on the mic, not sure if they have autopatch compatability... nor if the repeaters have them...

we have a deal getting setup for our ham licenses up here, where we are going to be getting a 1 day course then the test and license for a really low fee, not sure what it's going to be yet

That's good. You should be able to hit a pretty far away repeater with a truck mounted ham setup. Just use google to see if there are any autopatch repeaters nearby. I'm licensed and the local(houston) repeater has both backup power and autopatch, so it is a huge help during the hurricanes when we lose cell phone reception.

Having an autopatch nearby is huge cause it means that you don't need someone at home to be monitoring all the time.

 

[--weezl--]

that would be nice... i assume it just hooks the entire repeater up to your phone call, so if i had a keypad, i could dial up someone's house, then they could use their non keypad radio to talk to who ever answers?

that is a nice feature for sure!

 

[3.0ranger1227]

that would be nice... i assume it just hooks the entire repeater up to your phone call, so if i had a keypad, i could dial up someone's house, then they could use their non keypad radio to talk to who ever answers?

that is a nice feature for sure!

I believe that works. I haven't used our autopatch recently, but I believe it would work that way. anyone who could reach the repeater would be able to talk to whoever is dialed.

I think that's right because everyone else normally has to be quiet so they don't go over your patch. Definitely right actually, the only way that it would not do that is if the ham radios had DSC like the newer marine VHFs.

 

[Spott]

The biggest problem with a VHF-VHF repeater, is that you will effectively have one radio receiving (on 146.040 MHz, for example) and one transmitting (on 146.640 MHz), at the same time. Although they're different frequencies, and even if you're using two separate antennas, the transmitting radio is gonna interfere with the receiving radio. It can make for a poor received signal, or it can even generate enough interference to make a "feedback loop", and the repeater will never shut off. It can kill a battery very quickly that way.

You have to have some massive filtering to keep the two from interfering with each other. Most stationary repeaters use large cavity filters. Dunno about a good solution for a mobile repeater.

The simplex-recording repeaters don't have that problem; they record while the radio is receiving, then after it's finished, re-transmit the same voice recording again. They also only need one transceiver, instead of two radios. The trade-off is that they tie up the frequency for twice as long.

Cross-band repeaters (or radios acting like one) don't have to worry about interference, because the input and output frequencies are so far apart.

Finally, any device that will drive a PA speaker is an audio amplifier. There is a small amplifier built into CB radios that is used to drive the PA system. What I'm saying is that ham radios don't have that built-in amplifier, nor do most of them have a way to add an external amplifier.

Lemme know if you have more questions,
Spott

 

[--weezl--]

ahhhh, ok i got you! yeah, IF i were to put a repeater into my truck, i would hook it up to engine running power only, so if i shut the truck off, it's not draining my battery, thanks again for all the tips and pointers, it's greatly appreciated!

 

[--weezl--]

i realized a problem with cross band repeating... so say you have your base unit set to relay your uhf to vhf, say rx 433.030 and tx 135.030, how would you receive transmission back from whoever is receiving the 135.030 signal? they would have to be transmitting on 433 at what ever ridiculous power, wouldn't they? then even after that, you wouldn't get it to your uhf handheld... unless you were to do a sub repeater to a main repeater, and use a quad band base unit in the truck, essentially working as 2 different repeaters alltogether... one transmitting on the rx frequency of a main tower repeater, and the other receiving on the tx frequency on the same tower repeater...

 

[3.0ranger1227]

i realized a problem with cross band repeating... so say you have your base unit set to relay your uhf to vhf, say rx 433.030 and tx 135.030, how would you receive transmission back from whoever is receiving the 135.030 signal? they would have to be transmitting on 433 at what ever ridiculous power, wouldn't they? then even after that, you wouldn't get it to your uhf handheld... unless you were to do a sub repeater to a main repeater, and use a quad band base unit in the truck, essentially working as 2 different repeaters alltogether... one transmitting on the rx frequency of a main tower repeater, and the other receiving on the tx frequency on the same tower repeater...

No, they would be able to transmit back on 135.030. In Houston we have a repeater downtown that is UHF/VHF(can't remember) to HF. Whoever happens to recieve on HF(usually someone in australia lol) transmits back on HF, and the repeater converts it to UHF/VHF and we recieve it.

 

[--weezl--]

oh... so it receives and transmits on both frequencies?

so say if it is set to 135.040 and 423.040 it will receive signal on both, and re transmit it on the other?

 

[Spott]

Yes, the one's built into a handheld or a mobile rig are a two-way crossband repeater. It would be quite a bit less useful if it were only one-way.

Spott

 

[3.0ranger1227]

oh... so it receives and transmits on both frequencies?

so say if it is set to 135.040 and 423.040 it will receive signal on both, and re transmit it on the other?

Yes that's how cross band recievers are set up.

Our main VHF only repeater at home uses the radio's tone function so that you don't interfere with yourself.

 

[--weezl--]

Yes, the one's built into a handheld or a mobile rig are a two-way crossband repeater. It would be quite a bit less useful if it were only one-way.

Spott

ohhhhh ok, because your standard vhf repeaters are setup so that say, your handhelds transmit on 135.040 and receive on 136.012 and your repeater station receives on 135.040 and transmits on 136.012

which is why i was confused...

 

[AllanD]

the one major flaw with a dual-band 2m/70cm mobile radio in "repeater mode"

Is that they can
A) only do it CROSSBAND because there is really only ONE transmitter for each band
it's the computer control that creates an illusion otherwise.
B)when In "crossband repeat" mode there is a functional issue that other radio operators MUST be aware of and even then normal operating habits will cause you to want to stick their mic up their back passage.....

that is that when in crossband repeat mode if the mobile radio is tuned to a remote repeater the carrier on a remote repeater MUST be allowed to drop. or the mobile radio will simply never hear your controlling handheld, because it'll keep tranmitting to YOU

AND no matter how many times you tell everyone on frequency LET THE CARRIER DROP there is a resistance to letting that happen, people tend to key up immediatly after the "courtesy beep" so the repeater isn't constantly cycling on and off.

Basically because of that factor a mobile radio in crossband repeat isn't actually all that useful in most circumstances.

Now for a true "Repeater" on 2meters you need something called a "cavity duplexer"
there are narrow bandpass filters and to work for 2meters they are typically the size
of a 5gallon soda syrup keg (on 440mhz they are usually the size of a coffee can)

you need three of these filters in series carefully tuned for the the intended frequency
three on the input AND three on the output)to prevent the output from screwing with the input

And even then you often mount seperate xmit and receiver antennae
at different heights on the tower so each antenna is placed in a null lobe
of the other.

even without a repeater 45watts on 2meters will go suprising distances.

I've personally conducted a two-way contact from Northern New Jersey
(Along the Pallisades Parkway) to another operator in Gettysburg PA.

a line of sight distance of just over 200miles, FM simplex (146..55MHz)

Across lots of hilly terrain.

On another occasion I managed to call someone on the Repeater in Liberty NY (Central Sullivan County, North of Port Jervis) Where was I at the time? Just getting on the Garden State parkway off of the Atlantic City Expressway.

I've also conducted a conversation on the Asbury park (NJ) repeater while in the extreme north western corner of susquehana county PA

So a 2meter radio is a rather powerful tool...

And I have a 100watt HF mobile radio.

How about driving across central nebraska and talking to someone you've talked to before in the US Virgin Islands? in the Ukraine? or Sud Afrika?

Amateur radio has some interesting capability and all that is required to do it is a tranciever
an antenna operating knowldge.. Oh and a source of 12vdc...
And lastly someone else with the same things at their disposal...

MY HF radio is the same size as a typical SSB CB radio and it does all the bands from 160meters (just above AM broadcast) to 2meters and nearly everything in between.

 

[4x4junkie]

Now for a true "Repeater" on 2meters you need something called a "cavity duplexer"
there are narrow bandpass filters and to work for 2meters they are typically the size
of a 5gallon soda syrup keg (on 440mhz they are usually the size of a coffee can)

you need three of these filters in series carefully tuned for the the intended frequency
three on the input AND three on the output)to prevent the output from screwing with the input

And even then you often mount seperate xmit and receiver antennae
at different heights on the tower so each antenna is placed in a null lobe
of the other.

I suspect the vast majority of that went completely right over the OP's head lol

But yes, that cavity duplexer is the component that would be difficult to keep aligned with the constant vibration of a mobile environment.

FWIW, radios used in crossband repeat mode typically have an extremely short carrier hang with no courtesy beep (if they have a carrier hang at all, many de-key the xmtr immediately upon the squelch closing, creating the illusion it's not a repeater at all). It's not the same thing as with a typical full-duplex repeater. Where you still can get locked out however is if someone starts jamming the frequency with a continuous signal.