coryb27
-
Posts
424 -
Joined
-
Last visited
-
Days Won
66
Content Type
Profiles
Forums
Events
Gallery
Classifieds
Posts posted by coryb27
-
-
Point of curiosity....
In the amateur radio world I noticed repeaters with negative offsets -5 mhz.... in 70cm band
do you need a different duplexer, factory set for negative offset?
I can't imagine that your standard cavity and notch duplexers would be able to be tuned in reverse....
for example instead of 440/445 a negative 445/440 offset....
can't find any info on this, or even experiment (do not have skills or equipment for tuning)
Anyone have some knowledge in this area?
thanks
301
As long as the duplexer covers that frequency range you can tune it any way you like. I have tuned a duplexer to work like a combiner for 2 transmitters. Works great as long as you include isolators in your design.
-
As for measurements, if it ain't a Bird wattmeter, I don't trust it!
I prefer the Telewave 44A, just as accurate and no slugs to change or buy at 75 to 100 each.
-
Maybe referring to the pre selector having a 4 MHz pass? I dunno, a bit confusing to me too. I have 20+ Quantars in service and they are work horses.
I agree, great repeaters but still pricey. I have been building GMRS repeaters out of MTR 2000's, they are bullet proof. I was not sure what he was trying to say with separation of 30 MHz vs 4MHz, GMRS uses 5MHz separation and a filter or pre selector would have 4Mhz of bandwidth. Sounds like he was trying to talk technical without knowing what he was trying to say. For his intended use a Quantar is way over kill....
-
Looking into the RKR1225, its a nice Part95 repeater
Always glad to see a 100% compliant rig. But sadly its 50% duty cycle at 100% output 
And its 30MHz separation in UHF. The Quantar is roughly 4MHz separation, and thats before duplexer tuning (yes I know the duplexer doesn't affect frequency spread, but it helps to have a radio already built to crisply define frequency separation rather than making the duplexer filter everything out).In other news, I really like ICS controllers. ICS and Open Repeater are an awesome combo.
I build repeaters, tune duplexes, transmit combiners and I have no idea what you are trying to say here.... What?
-
I have a repeater, Motorola 50 watt, cellwave 6 cavity band pass notch duplexer - 38 watt output after duplexer.
My brother now has a repeater 50 watt Motorola with vertex standard 6 cavity notch duplexer.
Our frequencies will be about 14mhz apart. mine - 462's and his - 448's
I use dx 400 max coax with a slim jim
He will use lmr 400 not sure about antenna???
Looking for some opinions about antenna spacing???
I have a vertical 20' pole mount on the 20' roof
Should we flip a coin and see who will be low man on a vertical split totem pole???? and how far apart?
or can we go horizontal with another mount???
I've heard of two repeaters sharing an antenna... but commercial repeaters set ups by bridgecom...
Any recommendations???
thank you
301
You will not have any issues at all, i have commercial pairs way closer then that and combining TX.
-
Thanks for the reply. All I get is a completely blank page when I click on the link you provided.
https://mygmrs.com click on the map link
-
Link is 404 now.
Because its live on the site
that was a link to test.Try this https://mygmrs.com/map/#/
-
Hi Rich, I noticed that the AZ GMRS club repeater no longer appears on the map. Is this an error or does a setting need to modified on the repeater listing in order for it to appear on the map?
You need to edit the repeater, it as simple as hit edit, hit save, that will get you current for a year and put you back on the map.
Corey
-
Mine are all public, anybody is free to use them. If a user is more then just passing thru and plans to use the systems often I require them to create a profile on my website should I need to contact them off the air. Frequent users that do not sign up are asked to or permission is revoked.
-
-
That is the new logo, he applied it yesterday. Hes been working on some long needed site improvements.
Corey
-
As a side thought, if GMRS is something you enjoy and plan to keep using save you penneys and purchase a new part 90 radio with real features and the ability to program 1000 channels any way you like. Yes these radios can be priced from 300 to 800 but well worth it. I have several HAM rigs in the 800 to 3000 range, an Aeroflex service monitor that costs me many thousands, its my hobby and I invested it. I would love to see anybody find 1 case of the FCC tracking down somebody and issuing a fine for using part 90 gear because its not going to happen. Calls to the FCC will get you a response like, so long as we are not investigating you for other violations your part 90 radio is just fine. I have run into FCC field officers at commercial tower sites and have addressed the question in person showing them my GMRS setup (Motorola XPR5550 with handheld control) and the response was, that's a nice radio. YOU GET WHAT YOU PAY FOR plain and simple, cheap is cheap for a reason.....
- Elkhunter521, berkinet, revclstoner and 2 others
-
5
-
I've asked this before.
Why can't somebody make a GMRS mobile radio that is 25 to 40 watts, works like we want for $150? And is part 95 certified?
1. Clean, on frequency emissions.
2. Wide or narrow band. (Narrow band to work best with bubblepack radios.)
3. Split pl tones for tx and rx. Or just squelch.
4. Multiple channels for the same repeater channel to allow preprogramming of pl tones for a trip.
This doesn't sound like rocket science.
Just an observation, I do not have an amature license. At the present, I am not planning to get one. I don't know any one with an amature license in my area. Radios don't do much if you don't know any one to talk to
You are asking a lot for 150 bucks, quality components and engineering cost money. The small profit margin would require every GMRS license holder in the US to purchase several 150 dollar radios just to recover the engineering costs let alone the rest of the expense of bringing a product to market. Its simple economics and GMRS is to little of a market share to invest in.
- Elkhunter521, n4gix, gortex2 and 2 others
-
5
-
This just makes it more obvious that we should just buy and use radios made in the USA. Hmmmmm, gonna get quiet if we do that!!
I have tested Motorola, Kenwood, Icom, Midland, Macom, etc.. All of these radios are for the most part spectrally clean, the audio does not over deviate and the error rate on the transmitters is always within spec. This just goes to show you get what you pay for in electronics.
-
This is no different from any of the cheap Chinese radios that have come across my bench. I think its time the FCC starts doing its own testing, this goes to show the Chinese manufactures dont care and will fudge the paperwork to make this junk sellable in the US. As I have stated before none of these CCR's belong in use on GMRS as even the certified ones don't meet spec or standard. The spurs in the 900 band where strong enough to pick them up several 100 feet away on a scanner.
- gman1971, Elkhunter521 and marcspaz
-
3
-
I will let these images do the talking... All tests done on Wideband 462.550, High power, 1 min on 5 min off for a total of 10 min TX time over 60 min at 14.7V. I have worse results but these will do. After the 3rd cycle the power output started to drop and the current draw increase. Not sure if poor thermal management is part of it but I am sure most of it is the junk output transistors.
http://mwgmrs.com/mygmrs/50x1/1.jpg
http://mwgmrs.com/mygmrs/50x1/12.jpg
http://mwgmrs.com/mygmrs/50x1/9.jpg
http://mwgmrs.com/mygmrs/50x1/testresults.jpg
-
Corey, I see your using, the XPR series, how do change the PL on the fly? Or would you still have to put it on the computer.
I program all the repeaters I want in the radio and update the program as needed.
I don't have FPP on any of my radios.
-
Corey
I am still a bit new to the radio world. Those attic mounted antenna attract lightning? If it does how does the lightning grounding work?
No lightning to worry about but induced voltage from lightning is. Grounding is still an important part of any antenna system. Because I am in a condo I used a #4 wire attached to a cold water pipe and grounded the shield on all of my hardlines with bonding kits. Since the UHF and VHF antennas are folded dipoles any static buildup is shunted to ground. The scanner antenna has an add on suppressor for stray voltage.
The performance of the antennas for the most part is great. I regularly talk 40 miles simplex on VHF and work repeaters 50 miles away with little trouble. The results are a little less on UHF, simplex is good for 25 miles and repeaters about 45. UHF can be funny during the winter if we get snow build up on the roof, it cuts simplex distance in half but little change on repeaters. I spared no expense when picking and installing my antennas as the antenna is the single biggest factor in the performance of any radio system.
The antennas are as follows and in order of the photos.
UHF = https://www.theantennafarm.com/catalog/commscope-db404-b-4267 = Covers 450-470 MHz 5dB
SCANNER= https://www.theantennafarm.com/catalog/mp-antenna-08-ant-0863-7002 = Covers 25-1300 MHz
VHF = https://www.theantennafarm.com/catalog/telewave-ant150d3-4446 = Covers 138-174 MHz 6dB
-
DB-404 in the attic of my 2 story condo, simplex base to base 25 miles and repeaters 45 miles.
http://mwgmrs.com/mygmrs/uhfbase2.jpg
Fed with 1/2 hardline
http://mwgmrs.com/mygmrs/hole.jpg
Into a custom wall plate with N female bulkheads. I have a UHF, VHF and Scanner antenna up there.
http://mwgmrs.com/mygmrs/wallplate.jpg
http://mwgmrs.com/mygmrs/scanner.jpg
http://mwgmrs.com/mygmrs/vhf.jpg
-
Sounds like another decoder issue. I have got wind of this issue from several users of this unit. This is caused by overloading the front end, or simply being to close to a base or repeater. This is what cheap hardware gets you, in order to cut costs you have to cut quality and engineering. For the record it can be repaired but in the end its not worth it. I don't know about others but my min charge is an hr and that is more then the radio costs new.
-
Oh, I'm well aware it's a ham repeater at the moment. I'm just pleased that someone's working on something that could be adapted to legal, off-the-shelf GMRS use for under a grand, new.
Emphasis new.
Sooner or later, the surplus will either run out, or get priced out of affordability as it gets scarce.
Hopefully this sort of thing will be available before that happens.
I have to know, why are you so set on a repeater like this? Unless a Manufacture knows its going to sell 100's of units its not going to put the time and money into this. Even construction sites that only need a repeater for a few blocks install full size repeaters simply for the duty cycle and reliability. Now in the part 90 world you can have your self a Motorola SLR1000 these do analog or DMR and are made to be tower mounted. This is all deal breakers for your wish list, its not part 95 and it will set you back $1900 but hey it is "new". I have state of the art SLR5700's in use on a business system and many 15 year old MTR 2000's in use on GMRS. For the record the SLR5700's I own (2 @ $2200 each) have given me more issues in 2 years than 10 USED MTR2000 have in 4 years. In fact one needs to go back to the depot for repair again! NEW is not always better, the list price on a NEW MTR2000 was upward of $8000 so I am more then happy to run a USED $8000 repeater I got for $800 bucks or less vs a NEW machine I paid $800 to $1000 for.
In your price point and requirement of off the shelf and legal I envision this big lunch box size FRS/GMRS radio with a 4' telescopic center loaded antenna and a rechargeable battery inside. I'm sure adding a solar panel and maybe a dynamo crank to charge the battery, a local mic, weather channels, maybe even a flashlight and an AM/FM radio will help sell more to the masses. This all sounds good (ha ha) but an off the shelf turn key repeater marketed as part 95 for GMRS is just a bad idea. Last thing we need is 100's of unlicensed repeaters all over the place with kids on them causing interference to real repeaters that people invested time and money into. If you need an example just look at all the FRS/GMRS combo radios that never got a licence and the FCC just made them licence by rule, again not good for GMRS. This unicorn you have been hunting will work about as good as simplex without an antenna at significant height above ground.
- berkinet and Elkhunter521
-
2
-
Well, from what I see on ebay for GR1225 UHF repeaters, there are several at or below the $399 price tag for the Retevis RT97. On a good (I.e. lucky) day you could even get an MTR2000 under $400.
BTW, should you decide to go for the GR1225, make sure you get a guarantee that the final PA is good. These radios have a nasty habit of either blowing or desoldering the final if run at too high a duty cycle, or too high power output. You should also ask to have the duplexer tuned for you.
However, if you run a GR1225 at 50% duty cycle and 1/2 power, it will give you excellent service and is small enough to be portable.
You cant go wrong with an MRT2000, this lunchbox repeater idea has been beat to death and tried with mostly poor results by many. I have not seen a single lunchbox or ammo can repeater outperform simplex. I currently own many MTR2000's with 5 of them in GMRS service at this time. I have also built and sold several others as turn key repeaters for people without a single complaint. I looked into this retevis RT97 and it has no FCC certification, its intended market is HAM or out of the country use.
-
I would not worry about it, 1000's of them in use and nobody is doing anything about it so 6 sitting in survival kits is null.
I think your survival bag is a fantastic idea with the way things are in the world that bag may be all somebody has.
It don't matter if its a natural disaster or armageddon people that have communication will be the ones that survive.
-
Several of our GMRS repeaters provide 20+ miles of portable coverage, if you can find a good high spot for a repeater a used part 90 repeater with some good front end filtering and a preamp will give good portable performance. MURS VHF on the other hand can be used without a license and can legally have external base antennas with no restrictions on ERP but limited to a transmitter power of 2W.
10 MHz Split vs. Filter Technology
in FCC Rules Discussion
Posted
Saw this on YouTube....
https://www.youtube.com/watch?v=0EBJasGAymY