100 Watt UHF Search

[WRVG593]

Hi there! I am on a search for a theoretical radio. This is a very similar question I had in another thread but a more clear and concise thing I'm trying to find. Before I was looking for a unicorn that I realize does not exist. At all. (Was looking for a 100 watt dual band). I've come to a different question (a theoretical one). 

If anyone can reccomend a UHF radio, specifically around 462.xxx. (I realize what I'm about to ask for may be more 450-470). I'm looking for a 100 Watt UHF analog specific radio, not expensive that will just burn money. I can't get an APX8500 and drop 5000. Thanks all, and yes I'm aware I'm looking more for a LMR radio or retired public safety. 

[tweiss3]

TK890H. Just be careful if you want to also use it on ham frequencies. It's designed for 450-480, and needs additional heat dissipation on the final if you intend to use it below 450.

[Sshannon]

I searched eBay for Motorola 100 watt uhf.  Here’s a starting point.  Consult with the commercial radio guys on this forum if you want more info:

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=motorola+100+watt+uhf&_sacat=0&LH_TitleDesc=0&loc=9021317&mktype=&sitelnk=&poi=&cmpgn=18791967966&rlsatarget=dsa-1680301660446&geo_id=&network=g&mkscid=102&gclid=CjwKCAjwrJ-hBhB7EiwAuyBVXdBClxBs9xhu2a0-AnkHKV1O60k8uu8lsJSQRr5QaZZcKQ3D-0GmOBoCUWcQAvD_BwE&mkcid=2&_odkw=motorola+xpr+5550+e+uhf+403+470+mhz&norover=1&MT_ID=&adpos=&adgroupid=141477363565&matchtype=&abcId=&keyword=&mkrid=711-153677-346401-4&crlp=632513917133_&device=t

[marcspaz]

My opinion, if you don't want to run the risk of finding trash or a gem on any given purchase, try Kemp Wireless.  I got luck with friends in the industry, so I haven't purchased anything directly from them. However, I have several people in my life who have done a lot of business with Kemp Wireless who are very, very happy. 

 

Me personally, I got two XTL5000 radios, one UHF and one VHF. Both radios are rock stars, making over 110w and great audio. I have been using them at home for a couple of months, and I'm about to install them in my Jeep, today. 

[WRKC935]

Lets see.

1. Motorola Astro Spectra High power

2. Motorola XTL5000 High power

3. Motorola MaraTrac high power  (have a New in box model with the siren module in storage)

4. Motorola Mitrek High power (Crystal controlled)

5. Motorola Micor high power (crystal)

6. Motorola MoTrac High power (crystal, tube final)

7. Kenwood 890H

8. Kenwood 830H

FORGOT ONE: Syntor X

 

That's just the ones that immediately come to mind.  I would do some research and get the correct part numbers for these radios and then head off to Hamvention in May to find one.  These are all monoband radios, but most if not all have VHF high power counterparts that would also be available.    All these radios are going to be remote mount with a control head separate of the radio body with a cable in between.

As mentioned, I have a MaraTrac UHF 100 watt model sitting in storage that has never been out of the box.  Should be a 99 channel control head and the module and extension head for the 100 watt siren unit. 

I also have a couple Astro Spectra's in my collection and actually going to pickup a high power XTL today to install in my personal vehicle.

Stay away from the crystal controlled radios.  They are also good radios but getting crystals for them would be expensive and they are not programmable, changing or adding frequencies requires new / additional crystals.  ANd finding final tubes for MoTrac radios would also be difficult.

If you are looking to setup a personal vehicle, I would look at the Astro Spectra's.  I ran three in my durango with all the control heads in between the seats in a home build console setup with the radios mounted in the back of the truck.  There are several different styles of control heads available for the Astro Spectra family of radios.  These would be the W series heads and the System9000 head.  So you have options if space is limited.  Those also have 20 watt audio outputs so running one in a loud or open top vehicle like a jeep wouldn't be an issue.

 

Edited April 1, 2023 by WRKC935

[WRUU653]

8 minutes ago, WRKC935 said:

Lets see.

1. Motorola Astro Spectra High power

2. Motorola XTL5000 High power

3. Motorola MaraTrac high power  (have a New in box model with the siren module in storage)

4. Motorola Mitrek High power (Crystal controlled)

5. Motorola Micor high power (crystal)

6. Motorola MoTrac High power (crystal, tube final)

7. Kenwood 890H

8. Kenwood 830H

FORGOT ONE: Syntor X

Yes yes but are they theoretical?

[Radioguy7268]

I will assume you're aware that you can't legally transmit with more than 50 watts on any GMRS frequency. Yes, you can get a higher ERP with a gain antenna, but the rules are pretty clear.  I'd also question the benefit of a 100 watt mobile transmitter in anything other than a Simplex mode.

If you're talking into a decently configured repeater, all you need is enough to get into the machine with a full quieting signal, and the rest is just wasted energy. Getting in at 50 watts when 15 would have done the job does not improve the signal out of the repeater.

The difference between 100 watts and 50 watts is 3dB.  Search up the inverse square law if you want to know what that means when it comes to actual RF coverage. Spoiler: 100 watts isn't giving you as much as you might be thinking.

Theoretically

[WRVG593]

4 hours ago, Radioguy7268 said:

I will assume you're aware that you can't legally transmit with more than 50 watts on any GMRS frequency. Yes, you can get a higher ERP with a gain antenna, but the rules are pretty clear.  I'd also question the benefit of a 100 watt mobile transmitter in anything other than a Simplex mode.

If you're talking into a decently configured repeater, all you need is enough to get into the machine with a full quieting signal, and the rest is just wasted energy. Getting in at 50 watts when 15 would have done the job does not improve the signal out of the repeater.

The difference between 100 watts and 50 watts is 3dB.  Search up the inverse square law if you want to know what that means when it comes to actual RF coverage. Spoiler: 100 watts isn't giving you as much as you might be thinking.

Theoretically

I appreciate the feedback. It actually would be for simplex. I hit repeaters for all 8 repeater channels/frequencies. I have family where we can barely hear each other when using a 25 watt mobile as a base. We both have roof antennas and both like the idea of simplexing, as repeaters could not work at any moment. There are some days where I can pick him up for a few seconds at a time, and his power generally reads 15W. My 50W mobile can make it to where he hears me for almost the entire tike with sporadic intererference. I feel woth the additional 50W it would almost never have drops in signal. My other idea is to get a 460-470 amplifier. The reason I choose gmrs is any people have cheap frs walkie talkies and could hear or talk back. I am aware of the 50 watt limit, but in a situation where I need to get ahold of my family I would like the additional power for guaranteed communication. 

[KAF6045]

6 minutes ago, WRVG593 said:

I appreciate the feedback. It actually would be for simplex. I hit repeaters for all 8 repeater channels/frequencies. I have family where we can barely hear each other when using a 25 watt mobile as a base. We both have roof antennas and both like the idea of simplexing, as repeaters could not work at any moment. There are some days where I can pick him up for a few seconds at a time, and his power generally reads 15W. My 50W mobile can make it to where he hears me for almost the entire tike with sporadic intererference. I feel woth the additional 50W it would almost never have drops in signal. My other idea is to get a 460-470 amplifier. The reason I choose gmrs is any people have cheap frs walkie talkies and could hear or talk back. I am aware of the 50 watt limit, but in a situation where I need to get ahold of my family I would like the additional power for guaranteed communication. 

Getting high-gain antennas would likely be cheaper and remain legal. {the typos make it a bit difficult to figure out your meaning: is "tike" supposed to be "hike" or "time"?).

You mention using a radio as a "base station" and "roof antennas" -- to me this means fixed locations and non-mobile usage. Either install high-gain YAGI antennas (which will have to be pointed at each other as they are directional -- but easier to achieve the gain needed) or a (more costly) omni-directional vertical.

A 10dB gain would make those 25W units transmit as 250W ERP. {note: a dipole measures 2.15dBi/0.0dBd, so if the antenna lists 10dBi gain, that would be 7.85dBd}

 

[BoxCar]

As people keep saying, it isn't the power that's key, it's the antennas. All increased power means is you have a stronger signal in the areas you already cover. UHF is line-of-sight so the "fix" is to get the antennas where they can "see" each other. Raising an antenna 6 feet gives you about a 2 mile increase in coverage area and that is much more important than pushing power into the same smaller area you currently have. This isn't CB (or low band VHF) that will somewhat follow the terrain, this is radio waves that reach the horizon and continue on into the ether.

[Radioguy7268]

You could (legally) gain 3dB just by using a higher gain antenna. If you're already making it there with a 50 watt mobile & negligible gain, you'll spend (a bunch) less money by improving your antenna system.

Yagi antennas are directional - but you can easily get 10 dB (or more) without breaking the bank.

You mention already being able to hit 8 repeaters - do none of them give you enough coverage? It would cost even less to donate a battery backup system for one of those repeaters if you want to get closer to a guarantee of coverage.

Also, if you go with a 100 watt high power GMRS mobile as a base, there's a bunch of FRS radios that might be able to hear you at 15, 20 or even 30 miles away - but you will be further away than they could ever hope to transmit back. At that point you're just a fancy one-way paging system.

 

[wayoverthere]

Started typing A post, but it looks like a few people beat me to mentioning looking at the antenna situation ahead of power increases. Sometimes just a little shift side to side or a little extra height can get you past an obstruction more effectively.

Not only can that help the range to reach out, it also helps receiving as well, which more power does nothing for.

[WRVG593]

10 hours ago, BoxCar said:

As people keep saying, it isn't the power that's key, it's the antennas. All increased power means is you have a stronger signal in the areas you already cover. UHF is line-of-sight so the "fix" is to get the antennas where they can "see" each other. Raising an antenna 6 feet gives you about a 2 mile increase in coverage area and that is much more important than pushing power into the same smaller area you currently have. This isn't CB (or low band VHF) that will somewhat follow the terrain, this is radio waves that reach the horizon and continue on into the ether.

Well the issue is there's foliage in the way of LOS. My 5 watt sometimes can't push through trees when my 50 watt can. I imagined it was the same idea but from 25 to 100.

[WRVG593]

11 hours ago, Radioguy7268 said:

You could (legally) gain 3dB just by using a higher gain antenna. If you're already making it there with a 50 watt mobile & negligible gain, you'll spend (a bunch) less money by improving your antenna system.

Yagi antennas are directional - but you can easily get 10 dB (or more) without breaking the bank.

You mention already being able to hit 8 repeaters - do none of them give you enough coverage? It would cost even less to donate a battery backup system for one of those repeaters if you want to get closer to a guarantee of coverage.

Also, if you go with a 100 watt high power GMRS mobile as a base, there's a bunch of FRS radios that might be able to hear you at 15, 20 or even 30 miles away - but you will be further away than they could ever hope to transmit back. At that point you're just a fancy one-way paging system.

 

With the 50 Watt Mobile, the idea is not for general use. It is for back up comms when SHTF and I can contact my family. The extra 50 watts would be extremely helpful.

My antenna system is NOT the best. But I do have it 30ish feet in the air. The repeaters give more than enough coverage, but I am interested in SIMPLEX use. Something I could do even if I packed up and left the state.

I have 2 areas I live in, and they are no where close to each other. So relying on only repeaters is not what we want. And as for the one way paging system, I see your point. But that would only be so if the other end does not also get a high powered radio. I'm not worried about talking to every Joe Schmoe with an ozark trail or blackfin walkie talkie. In theory, this radio would be moved from a neighborhood area with obstructions, hence the need for the extra wattage, to a mountain top full of trees around it.

The idea with that being IF I needed to hear others I should hear most of the transmissions from the bottom of the mountain. (the second home is in the mountains of Appalachia). 

[KAF6045]

11 hours ago, WRVG593 said:

The idea with that being IF I needed to hear others I should hear most of the transmissions from the bottom of the mountain. (the second home is in the mountains of Appalachia). 

The ONLY THING you can control that affects how well you can hear others is your ANTENNA system.

[marcspaz]

1 hour ago, KAF6045 said:

The ONLY THING you can control that affects how well you can hear others is your ANTENNA system.

 

Not really.  I would be more prone to put money into an antenna first. However, there are some radios that just hear better than others, so you could buy a radio with a better receiver. Some receivers can have their sensitivity increased/tuned. There are also receive pre-amps. And then, of course assuming the antenna and radio are at least working as designed, there is no replacement for elevation. A cheap vertical dipole at 10,000 feet will work better at receiving weak and distant signals, more so than the finest high gain directional antenna only 20 or 30 feet off the ground.

[WRVG593]

2 hours ago, KAF6045 said:

The ONLY THING you can control that affects how well you can hear others is your ANTENNA system.

Yes I understand that. The extra power would be for the neighborhood portion. 

[gortex2]

14 hours ago, WRVG593 said:

Yes I understand that. The extra power would be for the neighborhood portion. 

All 50 watts vs 5 watts will do is help you talk out. You wont receive them any better. AS others said spend money on antenna before radio. Unless all of you are getting better radios its not worth it

[WRVG593]

18 hours ago, gortex2 said:

All 50 watts vs 5 watts will do is help you talk out. You wont receive them any better. AS others said spend money on antenna before radio. Unless all of you are getting better radios its not worth it

Well the issue is is that I am hearing everyone else but they aren't hearing me except in spurts. That's realistically with 5-10 watts. I assume the extra would be the boost I need. I just raised my antenna up by 4 feet and picked up 2 new repeaters. So now I'm about 34 feet off tbe ground. I have about 10 more feet of coax to use. I plan on getting a comet 460-470 antenna. About 10 feet tall. It would add another 7 feet or so to my system. So that coupled with the max watts I can get (50 of course) would be perfect. 

[WRKC935]

Well, here's some food for thought on antenna height.  Amateur radio satellites orbit the earth at about 62 miles up.  And can be higher.  Their transmit power is typically 1 or 2 watts.  The coverage footprint on the earth is also over 1000 miles wide in some instances.  Yes, this is the extreme, but it's also over 60 miles of talk distance with 2 watts of power.

 

[Sshannon]

Ham radio operators often get thousands of miles using only a few watts at lower frequencies.  Radio is funny.  Sometimes more power isn’t the solution, but the smart bet always goes to a good antenna system.

I got on a 2 meter simplex net last night and I used my 20 watt mobile instead of my 5 watt handheld.  I was able to very reliably talk with the net control who was maybe 16 miles away parked on an overpass, but a very strong signal coming from six miles away and above me on a hill came in very broken blasts, signal strength meter pegging “spurts” that were uncopyable until I turned off the mobile radio and picked up my handheld with its rubber duck antenna.  Then I could hear the nearby station very clearly. Sometimes a signal needs attenuation.

The best thing is to try different things to see what works.  

[tweiss3]

I think you are over thinking how to get to your designated simplex. Look into a pair yagi antennas pointed at each other to use just for the hard to reach family. You will also hear the other much better as well.

Look at the numbers:

Your 25W into an assumed 6db gain omni antenna = 99W EIRP

Take the same antenna, boost the power to 100W and you get 398W radiated, but in all directions, and no improved receive from your intended family member.

Take your same 25W radio into a 10.2db gain yagi = 261W EIRP, with better ears and less likely to cause interference to anyone else. There will also be more benefit if you don't have 6db gain on your current antenna. This is taking zero line losses into account.

 

Edit, if you get one of the Yagis that has 12.2db gain, you end up with 414W EIRP with your existing 25W radio.

[SpeedSpeak2Me]

Don't forget to take in coax loss before calculating the ERP though.  I thought the coax type was mentioned but not seeing it  If using something like RG-8X then there will be substantial loss at 460-470 MHz, about 8.6 - 9.0db per 100'.  So need to figure that loss in before the gain of the antenna.

Knowing which coax is being used, plus total length would help with calculating the ERP.

Just some information, but I have Browning BR-6155 (5/8 stacked, 5 dBd gain) mounted where the base of the antenna is about 15' AGL (antenna is 76" tall), and can key repeaters at 30 miles using just 0.4w, with enough audio to carry on a conversation.  For the repeaters at 40+ miles I only need 2.5w.  The antenna is pre-tuned for 450-470 MHz, and as being fed with 50' of LMR400.  Mostly flat around here, and can have simplex communications with ground (car) units out to about 8-10 miles.  Base to base about 10-15 miles.  Previously the antenna base was at 40', and my simplex comms were 20-25 miles for base-to-base, and around 15 miles for mobile.

Before finding a rig that will push 100w+, I'd make sure the coax I was using was as low-loss as I could afford, and then get a very efficient antenna.  Something else to consider is the terrain.  If it's flat, the something like a 1/2 wave antenna would be better, as its azimuth lobes are low down and cover greater distance.  5/8 wave would be the next best for some hilly terrain.

[KAF6045]

18 hours ago, WRVG593 said:

So now I'm about 34 feet off tbe ground. I have about 10 more feet of coax to use.

Better check the zoning regulations for your area. For my area, antennas are limited to 35ft height (I suspect based on 60s-70s horizontally polarized log-periodic TV antennas) -- EXCEPT for LICENSED AMATEUR who are permitted 70ft height.

[WRVG593]

On 4/4/2023 at 6:56 AM, WRKC935 said:

Well, here's some food for thought on antenna height.  Amateur radio satellites orbit the earth at about 62 miles up.  And can be higher.  Their transmit power is typically 1 or 2 watts.  The coverage footprint on the earth is also over 1000 miles wide in some instances.  Yes, this is the extreme, but it's also over 60 miles of talk distance with 2 watts of power.

 

Yes but I live near a lot of hills and valleys. I literally live in a region called the valley. So I understand height is might. But I can only get so high eventually.