Icom: Icom IC-2820H - What Is Diversity and Do I NEED 2 Antennas for Plain Ol' 2M/70cm?

[kudzu_kid]

Hi All,

Pardon the amateur amateur questions!


I'm pondering getting back into the hobby after maybe a 20-year or so break. I had an IC-2410H in my car. Someone tossed a brick through my car window and relieved me of it. No insurance covered it. I was heartbroken and radioless until now.


I am about to purchase an Icom IC-2820H. (~$150 used). I'll also need an antenna. But I know things have changed a bit since I was last in the game. As I read a bit about the rig, I see talk about a "diversity" feature. Can someone explain that like I'm 5?! Do I HAVE TO HAVE 2 antennas, or can I just get a single dual-band antenna now and maybe add another later if I want to take advantage of the feature (is it worth the extra $80 or whatever for another Diamond?)?


If I can only use one antenna - but the Icom has 2 separate antenna cables (1 UHF, 1 VHF?) do I need a duplexer of some sort or what do I do with the 2nd cable?

Another Question: Is D-Star "all that"? Or something that was hot for a while but has since faded away? All I have as I type right now is a SDS-200 scanner. I like it, but miss some of the repeaters when traveling, etc. Now that I'm retired, I have time and interest o enjoy the hobby again.


And for the $125-150 range, is this a decent dual-bander to be looking at for the $?



Thanks for any help, non-RTFM hints, etc.

 

[hill]

Next time ask a moderator to move the post if put in the wrong forum.

You can use the report like at the bottom of the post to request to move it.

Don't just post the same stuff in two different forums.

 

[mmckenna]

I am about to purchase an Icom IC-2820H. (~$150 used). I'll also need an antenna. But I know things have changed a bit since I was last in the game. As I read a bit about the rig, I see talk about a "diversity" feature. Can someone explain that like I'm 5?! Do I HAVE TO HAVE 2 antennas, or can I just get a single dual-band antenna now and maybe add another later if I want to take advantage of the feature (is it worth the extra $80 or whatever for another Diamond?)?


If I can only use one antenna - but the Icom has 2 separate antenna cables (1 UHF, 1 VHF?) do I need a duplexer of some sort or what do I do with the 2nd cable?

There are two antenna jacks on the radio:
One is Receive and Transmit for both VHF and UHF.
The other is a diversity RECEIVER port.

Diversity receive is just a way of using a second received signal to give the radio an option if it's suffering from multipath. It is NOT required. It's a cool toy, but you just need one GOOD antenna.

You do not need a duplexer or diplexer. Just one GOOD dual band antenna properly mounted on your vehicle.

I wouldn't spend $80 on a Diamond antenna. I'd get a good dual band antenna, like one of the Larsen NMO-2/70 antennas, and put some effort into mounting it correctly.

Another Question: Is D-Star "all that"? Or something that was hot for a while but has since faded away? All I have as I type right now is a SDS-200 scanner. I like it, but miss some of the repeaters when traveling, etc. Now that I'm retired, I have time and interest o enjoy the hobby again.

If you ask a D-Star fan, yes, D-Star *IS* all that, and we're all idiots for not using it.
If you ask a DMR fan, DMR is better and we're all idiots for not using that.
If you ask a System Fusion fan, System Fusion is better and we're all idiots for not using that.
If you ask a P25 guy, you'll get a correct answer.

D-Star is an option. It is only compatible with D-Star capable radios or repeaters. If you have a D-Star repeater in your area, you might find a use for it. If you do not, you can enjoy talking to yourself on D-Star. Most of the repeaters are pretty quiet, so further subdividing the bands into "digital cliques" isn't beneficial, in my mind, but it's a hobby and fun to play with new stuff. Unless you know locals are actually using it, you may not find much usage.

Most of the 2 meter/70 centimeter stuff is still analog. It's fun to play with digital, so you decide if that's what you want. You'll likely spend more time on analog.

And for the $125-150 range, is this a decent dual-bander to be looking at for the $?

Icom makes pretty good stuff. As a mobile dual band radio, you'll probably be happy with it once you learn the interface. Price is reasonable IF it's in good shape.

 

[KevinC]

As I read a bit about the rig, I see talk about a "diversity" feature.

I don't know what kind of magic uses in their diversity algorithm, but you typically need the two antennas spaced a certain distance apart to take advantage of a diversity feature. So that's something check on/keep in mind.

 

[N4KVL]

The radio does not need the diversity antenna to operate. It is a "nice to have" feature in mobile installations that reduces picket-fencing on receive only.

You need only one dual-band (or two single band antennas and a diplexer) on the primary antenna connector. Each port supports both bands, but the diversity is receive only.

IC-2820H is listed as CHIRP compatible. ICOM has their own dedicated programming software for the radio - CS-2820.

 

[kudzu_kid]

Next time ask a moderator to move the post if put in the wrong forum.

You can use the report like at the bottom of the post to request to move it.

Don't just post the same stuff in two different forums.

OK, thanks for that. I thought that Report was mainly for disciplinary review type issues, not administrivia. I thought I was just overlooking a delete message function somewhere. Perhaps not. I'll report the duplicate post. Thanks again!

 

[kudzu_kid]

There are two antenna jacks on the radio:
One is Receive and Transmit for both VHF and UHF.
The other is a diversity RECEIVER port.

Diversity receive is just a way of using a second received signal to give the radio an option if it's suffering from multipath. It is NOT required. It's a cool toy, but you just need one GOOD antenna.

You do not need a duplexer or diplexer. Just one GOOD dual band antenna properly mounted on your vehicle.

I wouldn't spend $80 on a Diamond antenna. I'd get a good dual band antenna, like one of the Larsen NMO-2/70 antennas, and put some effort into mounting it correctly.



If you ask a D-Star fan, yes, D-Star *IS* all that, and we're all idiots for not using it.
If you ask a DMR fan, DMR is better and we're all idiots for not using that.
If you ask a System Fusion fan, System Fusion is better and we're all idiots for not using that.
If you ask a P25 guy, you'll get a correct answer.

D-Star is an option. It is only compatible with D-Star capable radios or repeaters. If you have a D-Star repeater in your area, you might find a use for it. If you do not, you can enjoy talking to yourself on D-Star. Most of the repeaters are pretty quiet, so further subdividing the bands into "digital cliques" isn't beneficial, in my mind, but it's a hobby and fun to play with new stuff. Unless you know locals are actually using it, you may not find much usage.

Most of the 2 meter/70 centimeter stuff is still analog. It's fun to play with digital, so you decide if that's what you want. You'll likely spend more time on analog.



Icom makes pretty good stuff. As a mobile dual band radio, you'll probably be happy with it once you learn the interface. Price is reasonable IF it's in good shape.

Thanks! @mmckenna I appreciate your explanations and information. Perfect. I especially appreciate the info about diversity and referral to the Larson. Eons ago I had a Diamond (SG-7900 I think it was!). Nice antenna but is kinda pricey if I recall. Haven't started looking at prices, but if you say the Larsen NMO-2/70's are competitive, then I'll certainly look at them.

Again, thanks for all the info!

 

[mmckenna]

if you say the Larsen NMO-2/70's are competitive, then I'll certainly look at them.

Again, thanks for all the info!

There are at least two versions, and they are well respected:

The full length NMO-2/70. It's a taller antenna, but people that want the extra gain like it.

There's an NMO-2/70SH that's a shorted version, about 19" tall. I ran one of those for a while. Spring base, so worked well off road/parking garages, etc.

 

[AK9R]

And for the $125-150 range, is this a decent dual-bander to be looking at for the $?

So, you are looking at used radios? That can be risky. You have to either trust the seller or be able to check the radio before buying it.

If you are looking at used dual-band mobiles, the Kenwood TM-V71A is very well regarded.

Are you familiar with eham.net? Their "reviews" are useful when radio shopping as you'll get opinions from users. https://www.eham.net/reviews

 

[kudzu_kid]

So, you are looking at used radios? That can be risky. You have to either trust the seller or be able to check the radio before buying it.

If you are looking at used dual-band mobiles, the Kenwood TM-V71A is very well regarded.

Are you familiar with eham.net? Their "reviews" are useful when radio shopping as you'll get opinions from users. https://www.eham.net/reviews

Welp, I was looking on eBay, but the Icom I was looking at sold while I was posting here - someone did a "Buy It Now" and bypassed the auction aspect. C'est la vie. I'll keep looking.


I've had good experience with Kenwood and moreso (longer term) with Icom. In fact, my very first rig was a Kenwood TM-4000 that I bought used off of a friend. That was a fun rig. But I REALLY loved that Icom IC-2410H before someone relieved me of it. The thief probably got a nickel on the dollar and smoked/swallowed/injected the proceeds. Sigh.


As far as the risky aspect goes, I'm only looking at sellers (individuals or sites) that offer satisfaction / 30+ day returns, etc. eBay generally does offer returns and purchasing against a credit card helps. I am going to an area hamfest in OK this weekend. I will be holding my breath that IF I buy something it'll be a worthy purchase and not a boat anchor. I need a dual-band something with ~30-50W output (OK can get pretty rural outside of Tulsa or OKC).

I'll happily look at the Kenwood TM-V71A. Not yet familiar with it. I'm vaguely familiar with eham.net. They've come up a few times in my searches. I've also seen RigPix (RigPix Database - Main) referenced several times. Icom & Kenwood would be my "go to"'s here, I think. Just haven't had any experience with Yeasu at all but they're well-regarded (so I understand).



Thanks to you and @mmckenna for the words of wisdom as I ease back into this...

 

[PreferredCustomer]

Welp, I was looking on eBay, but the Icom I was looking at sold while I was posting here - someone did a "Buy It Now" and bypassed the auction aspect. C'est la vie. I'll keep looking.


I've had good experience with Kenwood and moreso (longer term) with Icom. In fact, my very first rig was a Kenwood TM-4000 that I bought used off of a friend. That was a fun rig. But I REALLY loved that Icom IC-2410H before someone relieved me of it. The thief probably got a nickel on the dollar and smoked/swallowed/injected the proceeds. Sigh.


As far as the risky aspect goes, I'm only looking at sellers (individuals or sites) that offer satisfaction / 30+ day returns, etc. eBay generally does offer returns and purchasing against a credit card helps. I am going to an area hamfest in OK this weekend. I will be holding my breath that IF I buy something it'll be a worthy purchase and not a boat anchor. I need a dual-band something with ~30-50W output (OK can get pretty rural outside of Tulsa or OKC).

I'll happily look at the Kenwood TM-V71A. Not yet familiar with it. I'm vaguely familiar with eham.net. They've come up a few times in my searches. I've also seen RigPix (RigPix Database - Main) referenced several times. Icom & Kenwood would be my "go to"'s here, I think. Just haven't had any experience with Yeasu at all but they're well-regarded (so I understand).



Thanks to you and @mmckenna for the words of wisdom as I ease back into this...

I think you would have better luck buying off QRZ. They are well policed by admins, and a seller bets their reputation on what they are selling.

 

[kudzu_kid]

There are at least two versions, and they are well respected:

The full length NMO-2/70. It's a taller antenna, but people that want the extra gain like it.

There's an NMO-2/70SH that's a shorted version, about 19" tall. I ran one of those for a while. Spring base, so worked well off road/parking garages, etc.

I looked at those and a few other Larson's on DX Engineering site last night. I distinctly remember seeing the 19" Larsen - and likely the others as well. I was wondering really how good it could be (vis-a-vis a cut coat hanger /sarcasm). But did give it serious thought - and put in the spreadsheet* for things to consider.



Whatever I do, I think I'll probably have to go with a trunk lid mount, as I'm currently "borrowing" my son's car for the next month or so while I have my usual car worked on with the local mechanic (who is very skilled but very slow and very busy!). While perusing DX Engineering, I saw a trunk lid mount for NMO -( Larsen NMO Trunk Mount & Coax LSN-NMOTLP ) so the setup can easily be moved from vehicle to vehicle. I'm leaning in that direction unless there's a compelling reason not to.



As always, thanks for taking the time to answer my ramblings and dumb@$$ questions with accurate & useful info.



* = Sorry, after 40+ years in IT, old habits die hard. "Death by spreadsheet!" ruled my life for decades! (Yeah, I'm a real hit at parties!)

 

[kudzu_kid]

I think you would have better luck buying off QRZ. They are well policed by admins, and a seller bets their reputation on what they are selling.

Thanks for that suggestion. I'm not familiar with them - but will look into them! Thanks again!

 

[mmckenna]

I looked at those and a few other Larson's on DX Engineering site last night. I distinctly remember seeing the 19" Larsen - and likely the others as well. I was wondering really how good it could be (vis-a-vis a cut coat hanger /sarcasm). But did give it serious thought - and put in the spreadsheet* for things to consider.

Larsen makes antennas used in professional/public safety applications. I've been using them at work for years.
They have a reputation to uphold amongst radio shops and public safety agencies that purchase a lot of antennas. If their antennas didn't last and perform, they'd lose business and likely disappear.
Amateur/hobby oriented companies rely on sales to individual users that often have never bought, or rarely buy antennas. To most hobbyists, the only antenna they currently own is the "best" and they have nothing to compare it to.

Totally your choice if you want to go with the professional grade or the hobby grade (or the coat hanger). But one thing I've found is that the professional grade stuff lasts (I have 30 year old antennas), it's durable, there's no BS marketing claims, and if something does break, you can easily get replacement parts.

Whatever I do, I think I'll probably have to go with a trunk lid mount, as I'm currently "borrowing" my son's car for the next month or so while I have my usual car worked on with the local mechanic (who is very skilled but very slow and very busy!). While perusing DX Engineering, I saw a trunk lid mount for NMO -( Larsen NMO Trunk Mount & Coax LSN-NMOTLP ) so the setup can easily be moved from vehicle to vehicle. I'm leaning in that direction unless there's a compelling reason not to.

That should be fine. Trunk lip mounts can work if you locate them properly. They will damage the underside of the trunk slightly, but probably won't show.

 

[paulears]

Diversity reception is one of those things that does make a difference. I have quite a few Sennheiser Radio mic systems in my hire stock and diversity reception is a key feature to prevent the usual dropouts. Normal practice is to separate the two antennas by more than the recommended distance, but even small distances are better than nothing. In practice, radio mics, in small areas do suffer badly from multi-path cancellation and the feature is virtually essential - when even a small drop in signal strength can create noise and worse, no signal at all. Mobile radio wise, I'm not sure of the benefit really - signal strength changes very differently and it's less common to move a vehicle a few feet and lose the signal totally.

 

[bill4long]

If you ask a D-Star fan, yes, D-Star *IS* all that, and we're all idiots for not using it.
If you ask a DMR fan, DMR is better and we're all idiots for not using that.
If you ask a System Fusion fan, System Fusion is better and we're all idiots for not using that.
If you ask a P25 guy, you'll get a correct answer.

Thanks for any help, non-RTFM hints, etc.

Since I use, or have used, all four I'll toss in my 4 cents:

D-Star is all but dead these days dead. When my D-Star radio died I didn't bother to replace it or repair it.

DMR audio quality is better than D-Star and is widely used. Lots of inexpensive "Cheap Chinese Radios" (CCRs) to choose from, which no doubt has driven its popularity.

Yaesu/Fusion/C4FM has better audio quality than DMR, IMO, and gets some use, but not nearly as much as DMR. If there is not a local repeater that is connected to the Fusion network, it's going to be another couple hundred $ to get on the network.

P25 has best audio qualify and is not used much. Florida has a nice large network, but it was built for emcoms, and is not used for rag chewing. There are some very small networks, but mostly used by small cliques. Radios are more expensive because you have to use commercial radios. At least I have never come across any CCR P25 radios. Maybe someone makes one now, but I don't know.

These radios are generally used with Internet networking, but also can be used locally. Good luck trying to find anyone to talk to without using networking and being in a large metro area such as NY, Chicago, L.A, etc. Getting on a network is relatively simple, and DMR is dirt cheap to get a "hot spot" online.

Bottom line, if you want low cost radios and a lot of people to yack with, DMR is where the action is by far. (Brandmeister and TGIF are the two main worldwide networks.) This has nothing to do with whether anyone is an idiot or not, it's just the facts. Personally, I use DMR and Fusion regularly, and P25 very occasionally.

 

[kg7jqh]

Check out Repeaterbook.com, select your state and then look at System Fusion, DMR and DSTAR listings. Around the Tulsa and Oklahoma areas it looks like System Fusion wins out by number of repeaters, then DMR, then DSTAR. BUT, that doesn't mean one is used more than another.

Have you considered an HT? It would be a lower cost option to see if there is traffic in your area. It can be hooked up to the trunk mount antenna for better receive. A Yaesu FT-70 ($175) is probably the cheapest way to see how much System Fusion is active in your area.

If there's a local Ham Radio store, they may have recommendations and radios set up that you can play with...

 

[JustinWHT]

lk about a "diversity" feature. Can someone explain that like I'm 5?!

Diversity means you have a diverse or alternative path. In a some applications us two antennas called MIMO - multiple in, multiple out.

Telephone companies use two bands, 6 and 12 GHz, if one path was fading the other path wasn't.
Dual polarity antennas work also.
And two antennas separated vertically or horizontally also used.

Pics from a 2014 job in Florida for several seasonal trailer parks. 2.4 GHz wifi access points using two vertical omni antennas.

 

[bill4long]

DEI? Bwahahaha.

 

[GlobalNorth]

I can speak to the quality of the Larsen NMO-2m/70 cm short and long antennae. The short one is on my truck and the longer whip resides on my Jeep. Both work and I've never had an issue with them.