SvenMarbles
-
Posts
240 -
Joined
-
Last visited
-
Days Won
2
Content Type
Profiles
Forums
Events
Gallery
Classifieds
Posts posted by SvenMarbles
-
-
Here’s a simple way to explain antenna gain to children.
take a garden hose and turn it on upright in your fist. The water will gush out as you’d expect it to. That’s a zero gain scenario. Now put your thumb on it to spray it further. That’s antenna gain
. There’s no net increase in water volume, you’ve just concentrated it in a direction, and in doing so it’s pretty effective..
ERP is a metric to assume how, that now more concentrated and directed water, is behaving supposing that you hypothetically accomplished that same “splash out” by increasing your net power instead of concentrating it…
-
18 hours ago, WRQW589 said:
I was reading the CHIRP python code for the RA-87 and spotted a few interesting sections:
1: A listing of the actual (targeted) power level for each of the power settings (low, low2, low3, mid, high).
POWER_LEVELS = [chirp_common.PowerLevel("Low", watts=5.00), chirp_common.PowerLevel("Low2", watts=10.00), chirp_common.PowerLevel("Low3", watts=15.00), chirp_common.PowerLevel("Mid", watts=20.00), chirp_common.PowerLevel("High", watts=40.00)]2: The programming indicates that the "left" and "right" side of the radio have rather independent memories. This is also described a bit in the manual. But to be a little clearer, the radio is marketed as having 200 memory slots for programming, and while this is correct, 100 of them are the left side, and 100 of them are the right side. In the highly unlikely event that you would ever need more than 100 repeaters programmed into your device, for example, you would need to program some of them into the left, and some into the right. For GMRS this is not terribly significant; though there may be a few people who use a lot of memory banks, I suspect that most of us aren't using more than 100. If you need <100 total, then you could make left and right both contain the same things. But I suppose for those who want many configuration combinations for GMRS frequencies, you could burn through 100 and have to start using the left side and right side for separate configuration storage.
3: The CHIRP driver for the RA-87 sets "VALID_BANDS" to [(400000000, 480000000)]. It would be interesting to see what happens if one added more ranges to VALID_BANDS. (Bricking the radio is a possible "what happens", though.) This seems to align with what others have posted, that this radio will scan frequencies between 400MHz and 480MHz but not outside that range. It does look like tuning steps can be set to 5, 6.25, 10, 12.5, 15, 20, 25, 30, 50, and 100 (kHZ?).
4: The RA87StyleRadio class definition sets _gmrs = True. I imagine this results in allowing transmission on GMRS frequencies. In searching the code, I do see other radios setting _gmrs = True, or False, and see that other common settings for other radios are _ham, _murs, _pmr... with appropriate bands set in various ways.
There is another thread on mygmrs where the question is asked whether the RA87 can scan 2m frequencies (and another comment that the manual doesn't mention any such capability). It is possible that this is simply not a capability of the RA87 hardware, but it would be interesting to modify the CHIRP driver for the RA87 to replace
VALID_BANDS = [(4000000000, 4800000000)]
with
VALID_BANDS = [(1440000000, 1480000000), (4000000000, 4800000000)]
...and upload that to the radio, hopefully not bricking it in the process. I'm sure that adding _ham = True would cross over the no-longer-type-accepted line, though. And who knows if the radio would die a sudden death if one were to key up in 2m.
For anyone who wants to look at the CHIRP driver code for this radio: https://chirpmyradio.com/projects/chirp/repository/github/revisions/d644af4b89c8edfe1b59f2f4aa929fc725056edd/entry/chirp/drivers/retevis_ra87.py
Very interesting. It seems like most radios of Chinese origin seem to be pretty wide open radios by default, and only set “boundaries” with software. It wouldn’t surprise me if the 87 is perfectly capable of doing VHF as well and that Retevis would release a new variant of it, but it would just be the same radio with those code parameters changed up a bit..
There actually is an option on the Retevis software on the very first prompt that has a drop box to select UHF or VHF. I tried selecting VHF when I first started playing with it, but it just doesn’t work. It just won’t read the radio/programming cable anymore if you switch that. So that’s a bit of a give away right there that they intend on future expansion with this radio..
I didn’t do my little write up/review of the radio yet because I kind of struggle to really have a great deal to get into with it. It’s just kind of a very simple and straightforward GMRS radio. It’s a good radio that “radios good”
. I’m told that I sound nice from others on the receiving side. Mic gain audio seems perfect out of the box. It definitely pumps out very near the 40 advertised watts. Mine is 39.3. It’s got a good and loud speaker. It’s a heavy and chunky steel radio that feels quality. The programming cable that is included works. I like that it can stay plugged into the radio and computer all the time because it’s a separate jack on the back. I can be in the middle of using it, open chirp, change something, and upload and the radio doesn’t even mute or anything while it happens. It’ll just power off and on again when finished and just right back to being used… It’s a nice feature for if you use it as a home/base radio on your desk right by your computer.
So I mean, yeah.. It’s just kind of a simple and good radio. There isn’t really anything that I find to be a shortcoming. Maybe just that the radio face and menu logic/buttons aren’t that intuitive. I haven’t figured out how to make it scan
. But I also don’t really need it to, so I haven’t spent much energy on looking into it. I wish the alpha tagging allowed more characters.
-
12 minutes ago, nokones said:
"Full of Smelly Stinky Stuff
16 minutes ago, nokones said:"Full of Smelly Stinky Stuff
Pipe down you two…
-
35 minutes ago, WSAE814 said:
With 1:1 dummy load mine are putting out around 32 - 34 watts
1.01 on a perfectly impedance matched antenna.
-
I use this one. https://kv5r.com/ham-radio/coax-loss-calculator/
This one will take into account, all varieties of coax at different lengths, actual frequencies (467, not 450), input wattage, your SWR, and antenna gain.
Don’t confuse DBI and DBD. Deduct 2.15 from your antenna’s dbi rating for the dbd.
-
For a while now, a repeater listed as "TORNADO 550: GREENWOOD, IN" is showing in the repeater listings for a far south/west suburb of Chicago. I know that this is an actual repeater down in Indy..
I don't know if this was a listing fudge or what, but it's bugging me a lot lol. I use the listings here frequently.
-
14 hours ago, WSAE814 said:
I have 4 of them. They are very good radios, very clean send and recieve,. Unfortunately they don't put out a full 40 watts. I took 2 of them and used them as a repeater thru a duplexer and they worked well. I had to use an id box with them. They had a slight delay over my vertex vxr-7000.
Mine makes 39.8 on the meter.
-
12 hours ago, WRUU653 said:
Check again. It’s supported by Chirp.
Oh really?! Maybe I gotta update my version. It wasn’t there when I scrolled the list!
That’s a major win if it’s on there.. I’ll check it out.
::edit:: I see it listed there on the webpage list of radios.
-
2 hours ago, WRQW589 said:
(d) 467 MHz interstitial channels. Only hand-held portable units may transmit on these 7 channels. The channel center frequencies are: 467.5625, 467.5875, 467.6125, 467.6375, 467.6625, 467.6875, and 467.7125 MHz.
(c) 467 MHz interstitial channels. The effective radiated power (ERP) of hand-held portable units transmitting on the 467 MHz interstitial channels must not exceed 0.5 Watt. Each GMRS transmitter type capable of transmitting on these channels must be designed such that the ERP does not exceed 0.5 Watt.
Putting that aside (because if I had been following along I would have seen that others already posted the rule), you are 100% correct that it is lazy if the manufacturer has simply designated *memory slots* 8-14 to not transmit, but hasn't placed restrictions on transmitting on *frequencies*.
If the mobile radio can transmit on the 467 interstitials just by placing one of those frequencies in a different memory slot, the radio probably shouldn't have been approved. And it clearly is rather braindead for the manufacturer to simply block transmitting on any frequency that has been programmed into memory slots 8-14. It sounds like the embedded system firmware developers didn't understand the assignment.
I can see how that can happen, since I work in the software industry. Somewhere some product person heard from legal that they need to prevent transmitting on the 467 interstitial frequencies. And by the time that got from legal to product to a Jira story to a developer, the "why" was forgotten, and the developer just delivered what he was asked: Make it so this radio can't transmit on 8-14.
Well I’m not even complaining about that really. I actually appreciate it when the “work around” of tyranny is plainly provided. In the CB days it was “as long as you don’t snip this arbitrarily provided jumper wire to convert this into a 10 meter radio
”.
Look. We’re all pretty well filled-in radio people. If we’ve come this far we know where the PS frequencies are. As long as nobody is being silly there, we’re fine to just carry on with our hobby.. The FCC knows that… The surface level measures to stop the ACTUAL dum dums who just plug things in and yell are adequate.
-
20 minutes ago, WRQC527 said:
I guess he's not "following along".
I stand corrected. I was sure it was input power.
-
12 minutes ago, WRQC527 said:
Another issue is that it would be pretty tough to get a mobile radio to emit half a watt ERP, especially when it's powered by a car battery or alternator and has a high gain antenna. They're more interested in compliance than with your ability to modify channels.
The rule isn’t ERP..
-
23 minutes ago, amaff said:
You can transmit on those channels with a handheld, but there are restrictions on power level and bandwidth. The radio doesn't care what memory slot I put those frequencies into, it'll obey the rules. And if I put a frequency that allows 5 watts in memory slot, say, 8, it uses high power.
Like Sven said, it's arbitrarily blocking off *memory slots* 8-14, no matter what's actually in those memory slots.
You definitely can't transmit on 467.5625 / Ch8 on a GMRS Mobile. But you can't transmit on that frequency whether or not you put it in memory channel 1 or 499. There's not something magical about *memory slots* 8-14. It's the actual frequencies that matter. If wants to put a repeater frequency in one of those memory slots, it not allowing transmit because "it's 8-14" is lazy programming.God damn I’m glad there’s someone following along…
-
10 minutes ago, amaff said:
Like I said, lazy programming.
But yeah if you can just skip memory slots 8-14 and do whatever you want (within The Rules) on the rest of them, seems like it's fairly easily ignorableIt is.. I just wish I knew this before I spent 45 minutes punching in all my stuff that I like to have
. And with this Retevis software it doesn’t let you “insert blank row below” like chirp. So basically everything south of channel 8 needs to be tediously re-typed in…
-
3 minutes ago, WRQC527 said:
It looks like in the manufacturer's efforts to maintain compliance with the FCC, the firmware is looking at only the channel numbers when you press the PTT, and doesn't care about what the frequencies are. From a firmware simplicity standpoint, it's probably easier for them to just lock out those seven channels instead of programming the firmware to look for specific frequencies, bandwidth and power levels.
Yeah it makes sense. “It satisfied the part 95 requirement”.. So it is so..
Now obviously I can stick “GMRS Channel 8” on memory channel 15 and blast 40 watts on it… But,.. like you said, it was a measure that satisfied the FCC requirements to get the cert.
-
6 minutes ago, WRQC527 said:
That's because for FRS, those frequencies are FCC-limited to a half a watt narrowband, and for GMRS, FCC-limited to handheld radios only and the same half watt narrowband. So on mobile radios, the manufacturer simply blocks them from transmitting, but still allows receiving.
§ 95.567 FRS transmit power.
Each FRS transmitter type must be designed such that the effective radiated power (ERP) on channels 8 through 14 does not exceed 0.5 Watts and the ERP on channels 1 through 7 and 15 through 22 does not exceed 2.0 Watts.
§ 95.1763 GMRS channels.
(d) 467 MHz interstitial channels. Only hand-held portable units may transmit on these 7 channels. The channel center frequencies are: 467.5625, 467.5875, 467.6125, 467.6375, 467.6625, 467.6875, and 467.7125 MHz.
I understand ALL of that. My point was that it’s MEMORY channel 8-14 that are locked. So regardless of how I choose to program the radio, perhaps with repeater channels on the first 5 and then GMRS simplexes 1-22 from memory channels 6 and down. It locks out TX on the memory channels 8-14 even though there are different “channels” on them now.
-
I actually really like this radio. Aside from this quirk, I don’t have any other complaints so far. I just got annoyed by this after completing my whole little custom programming session, and learned it after the fact and have this whole chunk of frequencies in the middle of my memories that I can’t transmit on.. The solution is pretty simple, I just will skip over programming 8-14 entirely
. Turning the knob will just go from 7 to 15, and I alpha tag what the channel is anyway since I don’t put FRS/GMRS 1 at channel 1. I just have to re-do my programming is all..
I was going to do a review of this radio in the Reviews forum in another day or so, and it’s shaping up to be a positive one. Dumb issues like this, and only having 6 characters for alpha aside. It’s a radio that radios good. It’s a 40 watter that puts 40 watts on the meter, on the dot. Super loud speaker, and “loud full quieting” reports from my end on my radio checks.. Built super well. It’s a hunk of steel. Good mic, tactile ptt click. Doesn’t feel cheap.
-
I watch his videos. The smarmy shtick gets a little tiresome but he’s usually pretty well on top of the new radio releases and is among the first to get hands on videos of them uploaded. He’s not everyone’s favorite flavor but he’s pretty much the only GMRS specific “unboxer/reviewer guy” we’ve got.
He’s also useful for people brand new to radio trying to get into GMRS. Laying things out in a straightforward way and not over complicating things, or as he would say “to avoid confukulation”. Because it is true that ham guys will often respond to questions about radio with completely convoluted jargon, more for self serving purposes than to actually help someone have an answer to a question.He lurks this forum BTW and is probably reading this topic and chuckling
.
-
I recently purchased a Retevis RA87. Typically when I get a radio that already has all of those pre-programmed channels, I’ll connect it with the programming software and more or less wipe those and organize my channels and frequencies the way I like and alpha tag things etc.. I’ll make the first 5 or 6 channel memories as my local repeaters, and then have the 1-22 standard channel plan following that.
The problem is that on the RA87, it appears that the channels 8-14 will not allow you to key up REGARDLESS of what frequencies you’ve programmed into them. I understand about the thing of mobiles supposing to have these channels locked per part 95. But the programming software is such that it seems to provide the ability to be able to have your memory channels be what you’d like, yet it maintains the TX lock out on 8-14. So why even provide the apparent option to be able to reprogram the frequencies in the channels? If it’s going to hard-lock out those channel spots for TX no matter what…
The RA87 doesn’t currently have Chirp support and the Retevis software does work FINE, but there doesn’t appear to be any sort of work around for this issue in any of the menus..
Anyone else experience this or know a work around? I suppose I’ll just put it back the way it comes and use it that way, but it seems odd that it would provide for a customization that is completely in conflict to some type of baked-in lock out on the radio..
-
7 minutes ago, WRXP381 said:
I want so badly to like retivis but EVERY person I know that has ever tried one ends up dumping them pretty fast. The fit and feel seam ok but they seam to have many problems after a few weeks or months of use. The price seams good but they don’t seam to last very long. I hope this one works out for you. Many people tell me my tyt radios don’t last but I abuse them every day in wet hot dusty snowy bumpy old trucks and they do fine and have done fine for a long while of hard use. So…
We’ll see. I got it at a sale price. Mine would be indoors at a desk.
-
I’m just curious if anyone here has an RA87 and have used it for a while, and what you might think of it.
-
So you have to defeat a little bit of glue.. I see what they did there
The whole nod to the customers' desire to do more than what the FCC allows is nothing new.
Mars Mods are often, "hey just snip this jumper wire that for some arbitrary reason is just readily accessible to snip".... Since the CB radio times..
-
Just have other radios that do other things. It’s fun to get new radios anyway
.
-
Another thing to consider though, and this isn't meant to be a rebuke to what you're talking about, because I agree with all of that. but when people discuss "dirty RF output" or spurs on harmonics, it's not always in the context that they're being good natured for cleanliness of the RF spectrum. If your radio has an output rating of 10 watts lets say,.. You'll put it on a meter, and sure enough you get 9.8-10 watts. Checks out,.. That meter detected a NET output wattage squirting out of the antenna hole.. But if you've got a dirty radio, it may be the case that some substantial portion of that RF output isn't even on the desired frequency. It takes wattage to power those harmonics as well,... So for selfish reasons, you may not want a dirty RF emitting radio because your effective radiating wattage might be inefficient. You might be getting 70% power where you want it, and 30% on spurs many harmonics up and down the spectrum..
-
People really need to wake up and start checking our governments. Let me ask this,.. Was there some sort of insane uptick in ham radio related driving accidents? I'm going to speculate that there wasn't... So why is it that the state of Pennsylvania feels compelled to just decide to impose a seemingly punitive law upon the people? I feel like we're just too many generations of people removed from the times when people conceptualized and understood the proper dynamic of government and the citizenry who ALLOW it. We're not just supposed to be a ruled people. We're not supposed to just live and accept the rules that mom and dad politicians make for us. These sorts of laws for "the good of public safety" should generally be a consensus (more people than not) agreement by the citizenry and the governing bodies that we both fund and give/entrust the authority to govern with. Any time some thing of this type comes about, ask yourself this question. "If this issue went to referendum, would The People sign off and agree to this?'. If you really feel like that's a no, then the government are acting as criminals and intervention is necessary.
You just got your GMRS license, now you want your own repeater?
in General Discussion
Posted
Some people don't agree with how repeaters should be used. I actually don't really care for these linked repeaters that give a lot of traffic from 2 people 8 miles apart in Indianapolis. For some reason I have to listen to that in the Chicago area. I might be compelled to put a louder one over top of it if I were independently wealthy...
There are only 8 repeater channels and they fill in metro areas.