eHam

eHam Forums => VHF / UHF => Topic started by: K1QQQ on February 21, 2023, 11:45:25 AM

Title: VANISHING BAND ?
Post by: K1QQQ on February 21, 2023, 11:45:25 AM
900 MHZ ? I guess nobody uses it. (?) I'd guess not enough  amateurs to cover all bands. (?)

If I wanted to transmit on 900 mhz any suggestion of a radio ? used ? cheap ? A rumor said some Motorola is programmable for 900 mhz. Don't know. (I do possess an Alinco HT that covers 220/900 mhz. (forgot about that but 2 way needs 2 ..?)

Motorola ?https://www.ebay.com/contact/sendmsg?item_id=403617946799&recipient=kylind16&message_type_id=14 (https://www.ebay.com/contact/sendmsg?item_id=403617946799&recipient=kylind16&message_type_id=14)

????
Title: Re: VANISHING BAND ?
Post by: W1VT on February 21, 2023, 11:52:43 AM
Personal Radio Service in Japan
https://www.rigpix.com/900mhz/icom_gt3.htm

https://ve3ips.wordpress.com/2020/02/12/japanese-cb-radio/
158 channels from 903 to 904 MHz.
I've heard that two radios will link up on a calling channel and jump to a clear frequency as normal operation.
Title: Re: VANISHING BAND ?
Post by: W3PX on February 21, 2023, 12:45:35 PM
Vanishing band? Maybe someday, but plenty of VHF/UHF weak signal operators still use 902/903 MHz.

There is a good bit of activity outside the FM band segment.
Title: Re: VANISHING BAND ?
Post by: K0XM on February 21, 2023, 01:46:56 PM
Yes there is activity on FM, DMR and P-25 in various parts of the country.
Besides the Alinco you have, a good beginner radio is the Motorola GTX.
The Motorolas can be put in the ham band, but it is not for the squemish. Kenwood Mobiles  and HT's also. TK481 and 981's
To move a commercial radio to the ham band they have to essentially be "hacked" with modified software. Commercial users have a 45MHz split and we have a 25MHz split.

https://w6aer.com/getting-started-with-900mhz-ham-band/ (https://w6aer.com/getting-started-with-900mhz-ham-band/)

https://www.qsl.net/kb9mwr/projects/900mhz/plan.html (https://www.qsl.net/kb9mwr/projects/900mhz/plan.html)


Chuck K0XM
Title: Re: VANISHING BAND ?
Post by: K4JJL on February 22, 2023, 06:47:07 AM
There are a couple dozen guys in S FL who use 900 P25 pretty regular.  We're all running Motorola XTLs and XTSs.  Repeater is a Quantar.  The "hacking" was minimal.  Just change a couple of numbers using a hex editor (procedure is widely documented on several websites).

BTW, that's an 800 MHz radio in the ebay listing you posted. 

This is more along the lines of something that will work...
https://www.ebay.com/itm/134227045831 (https://www.ebay.com/itm/134227045831)
Title: Re: VANISHING BAND ?
Post by: K5LXP on February 22, 2023, 07:23:20 AM
Better buy two of whatever you get, that way you can give one to another ham and have someone to talk to.  Otherwise, 900MHz (and 220, 1.2GHz) is a lonely place most everywhere you go.

Mark K5LXP
Albuquerque, NM

Title: Re: VANISHING BAND ?
Post by: G4AON on February 23, 2023, 03:17:55 AM
The band of more serious concern is 23cms, the European Galileo (GPS) satellite people are making representations to the 2023 world radio conference (WRC-23) to bump radio amateurs off the band, or at least severely us.

Some details: https://rsgb.org/main/news/special-focus/wrc-23/ (https://rsgb.org/main/news/special-focus/wrc-23/)

73 Dave
Title: Re: VANISHING BAND ?
Post by: K1QQQ on February 23, 2023, 06:42:08 AM
YES. Spectrum is valuable. Use or lose. Can sell it !!!! Without snooping I hear nothing of 900 mhz operation for amateur radio. I picked up that Alinco HT a few years ago and just went into my box of possessions. Recent I told myself I have nothing for 1.2 ghz so got an Alinco G7 that covers 1.2 at 1 watt.Some new ICOM stuff has 1.2.



220 ? Much Chinese stuff to cover 220 now. An Alinco DR-MD520  at 5 watts.    http://www.alinco.com/Products/ham/mbl/DR-MD520/DR-MD520TE.pdf       I  do not know if Alinco went all Chinese but their new stuff just says Alinco JAPAN on them. Their USA outlet says their major problem is parts as the old manufacturers just do not want to make things as unimportant as amateur radio.

Some Yaesu HT's cover 220 but low power.


900  hmmm where o where  I am not sure of the investment or time trying to figure out. A cheap used radio. A new economical one.  Programming !!  I do have 1 radio but #2 for any communication.

I will study the links and info posted in this thread.


Somebody talking on 900 but no ability ? Digital Modes are what is happening but old fashioned analog is nice.



Motorola XTL2500 P25 900 MHz Mobile Radio   ok..research !!!



https://www.rigpix.com/900mhz/900mhz.htm   



-----------------------------------------------------
Title: Re: VANISHING BAND ?
Post by: SOFAR on February 23, 2023, 09:19:19 AM
I've read about medical equipment being on 900 mHz. Not sure if that's still accurate.

"Basically the 902MHz to 928 MHz range has been allocated to hams on the secondary basis meaning, we have to accept interference from other sources as we are not the primary users of the band."

https://w6aer.com/getting-started-with-900mhz-ham-band/ (https://w6aer.com/getting-started-with-900mhz-ham-band/)
Title: Re: VANISHING BAND ?
Post by: WA3SKN on February 23, 2023, 09:35:48 AM
OK there are several repeaters in the Baltimore area. Check TMARC for locations in their area.  But there is not enough money for most of the popular radio companies.  The new IC905 should be of help here, but if you really want this band I would suggest contacting Q5signal.com.  They will build a radio or transverter for you.  Or you could build your own!

-Mike.
Title: Re: VANISHING BAND ?
Post by: W3PX on February 23, 2023, 09:46:07 AM
OK there are several repeaters in the Baltimore area. Check TMARC for locations in their area.  But there is not enough money for most of the popular radio companies.  The new IC905 should be of help here, but if you really want this band I would suggest contacting Q5signal.com.  They will build a radio or transverter for you.  Or you could build your own!

-Mike.

The IC-905 Doesn't Support 902/903 MHz.
Title: Re: VANISHING BAND ?
Post by: K4JJL on February 24, 2023, 01:33:28 PM
Somebody talking on 900 but no ability ? Digital Modes are what is happening but old fashioned analog is nice.

Analog on 900 sounds terrible.  Believe me, I tried.  I ran old analog Spectras on 900 years ago.  There's so much garbage interference out there.  Crashes, pops, garbling, muffled audio, etc.  Motorola's solution was called HearClear.  It didn't live up to its name.

I think there's some DMR out there on 900, as well.  That's even cheaper.  You can get a used XPR6580 for under $100.

Digital filters all that out.
Title: Re: VANISHING BAND ?
Post by: WA3SKN on February 24, 2023, 04:10:57 PM
I don't have much 900 MHz noise here... must be "location".
And we "share" all bands above 400 MHz as secondary users here in the USA, so it would be easy to lose them... we are not "primary" users.  There is now a "commercial demand" now that it is economical to use the bandwidth.

-Mike.
Title: Re: VANISHING BAND ?
Post by: K1QQQ on February 25, 2023, 06:12:35 AM
Probably more 'noise' in urban areas. I just hate to loose a band. NO notice of band loss yet but no-use-loose
     
That transverter link       http://q5signal.com/index.php?route=product/category&path=68



Always wondered why that site cost so much.  OK..not many options but feel somebody is making money. (sensible)
I know I have seen HT's covering 900 mhz but flea-power assumed/

Enough....



There is/was a transverter place in Ukraine that sold them for common bands but do not know how good such are. Acouple years ago I bought a couple but yet to try out.  50-28 mhz  220-28 mhz

Transverters do not seem as popular as they were once. If you have a HF rig not covering 6/2/220/440 (vhf-uhf)  play with a transverter. Again,,thanks for info and links...
Title: Re: VANISHING BAND ?
Post by: W1VT on February 25, 2023, 06:21:33 AM
High quality transverters are expensive because of the difficulty involved in preserving "tone quality 9" CW signals for weak signal DXing.
Oscillator standards can be relaxed for FM voice.  Key down an inexpensive FM radio and listen to the carrier on an SSB/CW rig to hear the quality of the oscillator.
Title: Re: VANISHING BAND ?
Post by: KB3QWC on February 25, 2023, 12:00:50 PM
I know that the last Frost Fest in Richmond, VA the group was promoting more activity on 900 MHz. 

They were selling already converted and programmed for the area EF Johnson 5100s for a good price.

I don't have any 900 MHz gear, but if activity would like to try, as like WA3SKN said many repeaters my local Baltimore Area.

I am in Richmond twice a week for and with staying over have a lot of time to play ham radio in the evenings. 

Going forward I will most likely program the have repeaters in both areas into one of my scanners to listen for activity. 
Title: Re: VANISHING BAND ?
Post by: N1YFA on March 04, 2023, 02:29:17 PM
900 MHZ ? I guess nobody uses it. (?) I'd guess not enough  amateurs to cover all bands. (?)

It pretty simple. Out of all the Hams I have talked to most don't want to bother with anything that doesn't involve chucking a wire in a tree and talking (wait for it............ here it comes) around the world. There are what? almost 3/4 of a million license holders? (I read somewhere). There are plenty of Hams to occupy those bands. Unfortunately, I know of Hams who are in the process of upgrading their license or have upgraded their license because they literally think that the only privileges they have are a tiny portion on 10m, 6m, 2m, and 70cm. They literally have no idea that they have almost 2 GHz worth of bands to play with. Technicians have all privileges and all modes on all Ham bands from 50 MHz on up.
 The issue is that most get their ticket, jump on 2 meters, try to have a conversation and find that no one is there except for one or two guys who tell them they have to upgrade to go where the action is - on HF. Once they do that, they almost never bother with anything above 10 meters. Now multiply that by how many Hams do that and well....... you want to know why there are no Hams using these very local shorter wavelength bands....... That HF contesting..... Its like a drug no one can kick.

Personally I would love to experiment with a lot of those bands 1.25m, 23cm, and higher.  However it takes two people to talk, and even if it is a one person activity such as the mesh networks you can work with, I am about as familiar with it as a 100 year old person is with building an operating system for a computer from scratch. I would need a lot of help. When everyone is on HF and they refuse to play with anything up there and you are in the bands that literally don't get used with the exception of a few groups spread out over the whole United States, well, your Ham Radio experience will be not so good. This is why the FCC takes Ham Bands away. Some rich billionaire or company comes along needing frequencies and are willing to pay. Hams aren't using the bands? Well, you know where those frequencies go. Money talks and you know what walks. Its the sad truth. I feel real bad for those who actually do use those bands or want to use them. One day we wont have any of them. Already, 900 MHz is a shared band with low power devices and intercoms last I knew.
Title: Re: VANISHING BAND ?
Post by: W1VT on March 04, 2023, 03:17:14 PM
When I played with 10GHz I built a dozen transverters and lent them out to my friends.
I'd try different circuits.  Some of them worked really well and some not so well. 
 I learned how to rebuild/fix a lot of circuits and cobbled scraps into perfectly usable
transverters with about 200mW out and 3 dB NF. 
Which could cover a lot of ground on CW with a 20 dBi horn from a good mountaintop location.

Zak W1VT
Title: Re: VANISHING BAND ?
Post by: W7XTV on March 04, 2023, 07:59:53 PM
I don't have much 900 MHz noise here... must be "location".
And we "share" all bands above 400 MHz as secondary users here in the USA, so it would be easy to lose them... we are not "primary" users.  There is now a "commercial demand" now that it is economical to use the bandwidth.

-Mike.

Yes, but the military has more than a little say about that.  Somehow I doubt that the rest of our UHF/SHF spectrum will be sold, other than what has already happened.  AFAIK, there has been no effort by Big Telecom to snag more military frequencies for their commercial use.

We're on the verge of losing 3300-3500 MHz, but will it be missed?  It just isn't being used much by hams.  420-450 and 1240-1300 MHz are probably safe.  902-928 MHz is predominately ISM; not going anywhere.  Most, if not all of the 2.4 and 5.6 GHz bands definitely are safe, if only because of the millions upon millions of WiFi users that post no threat to military use.  I don't see ham use being discontinued, either.