Building a HAM Repeater with HT's

[zz0468]

The amount of amplification that this person is talking about would probably require 1 mile of separation and a microwave or telephone link 0r internet link to link the two halves of the repeater together.

The Duplexer would not be able to handle that level of power and keep the transmit out of the receive.

There are duplexers that are rated for that sort of power level that provide in excess of 120 db of TX/RX isolation, but you really missed the point of the problem with this idea.

It's not so much the actual power levels involved, it's amplifying an HT transmitter and preamplifying an HT receiver, THEN running at this power level that is likely to be a problem.

Several critical parameters critical to high power duplex operation is low transmitter noise, and high off-channel receive rejection, neither of which is likely to be sufficient in a pair of HT's. It's not so much of an issue at low power, and there are plenty of low power commercially built repeaters using HT's that work just fine.

You might be better off to find a old Desktrac or other low profile radio repeater system and adapt it to what you wish it to do.

This is the only piece of sound advice I've ever seen you give out.

 

[Daniel_Boone]

Your are a real funny man, thats probably why everyone laughs at you!
Did you ever consider a career being a comedian?

 

[ramal121]

've read zz's post a couple of times and fail to see any humor. He is exactly right! When I first read this post I thought cool, screw a couple of mt1000s together and make a intermittent duty portable repeater for say a public service event or something. Now it sounds like he wants to make it full blown high power rag chew type of thing and I think he's setting himself up for failure.

ZZ is correct in that the portable transmitter is not ideal for repeater service because of the sideband noise that is generated by it, not to mention the heat it will create when used at full power and close to 100% duty cycle. The same with the receiver, it needs to be higher spec in the selectivity department otherwise it will just buckle under with the transmitter noise, site noise or whatever is out there. A duplexer is only part of the story.

If I was going to spend the bux for a permanent repeater ( considering the cost of antenna, duplexer etc) I would spend a little more and get a real repeater that I know is going to work the way it is intended.

I guess I get a little peeved at someone who throws up a jerry-rigged repeater, ties up a pair, and it runs so crappy that no one will use it. Not that this is toward the OP, I wish him the best, just do it right for the benefit of the amateur community and not your ego....

 

[gewecke]

I have never liked voice ID. I just like the CW myself.

Me too, but we have customers who seem to want all the beeps and bleeps and need it to tell them it's time for dinner. :roll:


73,
n9zas

 

[rfguygg]

Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_2_1 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8C148 Safari/6533.18.5)

Try it and learn. The hobby is about experimentation after all. You will likely be looking for a more selective receiver and/or some good filters. BTDT with mobiles.

 

[zz0468]

I'm not quite sure what to make of this post...

Your are a real funny man, thats probably why everyone laughs at you!

I don't think anyone here really laughs at me except, maybe, the right wing lunatics in the politics forum. Everyone else just finds me annoying. Lucky for me, being annoying here can be a blast. :twisted:

Did you ever consider a career being a comedian?

No, but my wife did. She did quite well at it, maybe you saw her when she showcased at the Icehouse in Pasadena. Probably not... I doubt you travel very far.

Can we get back on topic now?

 

[AK4GA]

Your are a real funny man, thats probably why everyone laughs at you!
Did you ever consider a career being a comedian?

I don't know about funny, but even though zz and I might not see eye to eye on some topics he comes off as someone who knows what the hell he is talking about. You, not so much.

 

[centuryvrproductions]

Well repeater in my town puts out 200 watts... if they can then i think its possible...
anyway my repeater is up and running perfict an 5 watts using the Ht's. once i get a duplexer and an amp ill be all set.

444.5

449.5 input pl100

 

[KG4INW]

Well repeater in my town puts out 200 watts... if they can then i think its possible...

Sure, but they're probably not doing it with a couple HT's as many have already pointed out.

 

[zz0468]

Well repeater in my town puts out 200 watts... if they can then i think its possible...
anyway my repeater is up and running perfict an 5 watts using the Ht's. once i get a duplexer and an amp ill be all set.

What's driving this urgent need to run 200 watts?

The answer to that question would have a great deal of impact on how you should go about hings.

444.5

449.5 input pl100

Is it your intention to interfere with a listed repeater on that frequency only 35 miles away. Yep, 200 watts would do it.

This whole thing comes off as a shady, half-baked, half-wit operation. :roll:

 

[centuryvrproductions]

Kb1vsp

The repeater is working great and has great coverage running 4 watts. once i get a pre amp a duplexer and a power amp it will have better coverage... Visit The KB1VSP Repeater to see it work.

 

[centuryvrproductions]

I will then get the frequencys coordinated if i use a large ammpunt of power*

 

[AK4GA]

I will then get the frequencys coordinated if i use a large ammpunt of power*

I am willing to bet that the repeater you keep talking about is not transmitting 200w. It is entirely more likely that that repeater is transmitting 200w ERP, which is effective radiated power.

Chances are slim to none that you will get coordinated for 200w into the duplexer. Also 200w will also most likely get you a visit from the FCC. I am dealing currently with an issue involving an uncoordinated high power repeater causing interference to our club repeater. The FCC is now involved.

 

[zz0468]

I will then get the frequencys coordinated if i use a large ammpunt of power*

You really should get it coordinated regardless of the power level.

 

[KC4RAF]

"The Repeater Goes On The Air ", June 7, 2011 at 11:29 PM

" Repeater was put on the air June 6. The repeater is not yet fully functional and still needs a Preamp, RF Poweramp, Duplexer, and antennas." How did you get on the air with out an antenna? Dummy load...
What kind of radiation pattern are you trying for with what type of antenna?

 

[mjthomas59]

I read the KB1VSP website and it appears that the handhelds were dumped and he went to 25 watt mobiles.

Is anyone else near this guy's area to try this repeater out? I'm dying to know if this thing actually works or not. If it went on the air without amps, filters, duplexers, and antennas then there is no telling how/if it works at all.

 

[AK4GA]

Glad to hear he decided to ditch the HTs and now appears to be using a pair of Maxtracs. That should give him a solid setup and hopefully he also is using a duplexer.

Part of me wanted to see this thread die, but i can now say I'm glad he has taken the advice of this threads contributors and wish him luck.

 

[gewecke]

Your are a real funny man, thats probably why everyone laughs at you!
Did you ever consider a career being a comedian?

You're even funnier! So it's quite possible that you make us laugh even harder, heh....heh. :twisted: At any rate,the 5 watt repeater idea is not really that efficient nor is any repeater configuration without a true set of cans (duplexer).

n9zas

 

[centuryvrproductions]

this i a side project so i am sorry if it is not perfect.. but yes i finally spent some money on a pair of maxtracs.... only 25 Watts but im still experimenting... I am just interested in making a fully functional repeater.

I am thinking about making my own duplexer out of coffie cans but for the work it will be i have no way of tuning it properly... as for the antenna i have a homemade Dipole from Coax cable, it is also not tuned. lots more work to be done and more money to be spent.

 

[K8TEK]

I am thinking about making my own duplexer out of coffie cans but for the work it will be i have no way of tuning it properly...

This has got to be a joke.