1. You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
    Dismiss Notice

How To: Use crossband repeat legally on your base station

Discussion in 'Ham Equipment' started by Moleculo, Sep 24, 2009.

  1. Moleculo

    Moleculo Administrator
    Staff Member

    Joined:
    Apr 14, 2002
    Messages:
    8,831
    Likes Received:
    855
    Many VHF/UHF mobile and base rigs provide the ability to crossband repeat - that is, to fully duplex, automatically repeat what is heard on 2 meters onto a 440mhz frequency and vice-versa. If you've never used this type of functionality or are just new to the whole concept, you might be thinking, "what does this do for me?" If you own an HT and also have a VHF/UHF rig with crossband repeat (or are considering purchasing a VHF/UHF rig for the house) wouldn't you like to have the freedom to move around the house & yard while talking to your buddies on the radio, but use the power and antenna capabilities of a base station? That's what crossband repeat can do for you.

    You'll notice that I used the word "legally" in the thread title. The usage of this functionality has caused quite a bit of controversy for several reasons. The FCC requirements that are relevant to this discussion are that the Control Operator must ID every 10 minutes on all frequencies being transmitted on, remote stations must have ID timers, and remote stations must have a way to remotely control or shut them off. The latter two of the three requirements mentioned are the easiest to satisfy. Simply put, if you are capable of walking over to the rig doing the crossband repeating, it is under your direct control. You don't need a ID timer and you can just simply turn it off whenever you need to. The requirement to ID on every frequency is the tricky one to satisfy.

    For the uninitiated, let's first go over the fundamental setup and concepts in play. The typical use-case scenario for this setup is like this:

    Base Antenna <--> 2m <--> VHF/UHF Rig <--> 440mhz <--> HT

    Anything that is heard on the Base Antenna on 2m, is picked up by the VHF/UHF Rig and broadcast simultaneously on 440mhz where the HT is listening. Conversly, anthing that is transmitted by the HT on 440mhz is picked up by the VHF/UHF Rig where it is simultaneously transmitted using the Base Antenna on 2m. You can probably now see the advantage of going through this excercise. You have the flexibility of moving aroud with the HT, but the power output and reception of the vhf/uhf rig and base antenna.

    When you give your callsign using your voice on the HT, it will be transmitted out on both the 440mhz and 2m frequencies. When another station talking back to you IDs, it will also be sent on the 2m and 440 frequencies. Here's where it is easy to violate the intent of the FCC regulations: Let's say you have the UHF side of the rig set on full power. If your base antenna is a 2m/440 antenna, when the other station that you're talkign to ID's, it is being rebroadcast on 440Mhz at 35watts (probably) over a base antenna. No problem. However, when you ID on your HT, it is only being broadcast at 5 watts over a little rubber ducky on UHF. The VHF side gets the full 50 watts of the VHF/UHF rig and the power of the base antenna, but the 440mhz side only used your HT. Distant stations monitoring the 440mhz side will probably never hear your callsign. This is the problem that must be corrected to keep you legal.

    Some of the newer crossband repeat rigs can auto-id on the 440 side while crossband repeating using CW. This makes the whole problem moot. However, for the vast majority of rigs that don't do this, there is a very simple way to solve this problem to keep you from getting written up by an "Official Observer". Simply put, the solution involves doing two things: 1. Reducing the power output of the VHF/UHF rig on the 440Mhz side and, 2. changing the antenna system used on the UHF side of the crossband repeater.

    Step 1 is easy: Just turn the UHF power output on the crossband repeater to it's lowest setting. Most, if not all crossband repeat rigs have seperate power output settings for each band. The lowest power output setting for UHF is usually around 5 watts. However, if you're transmitting 5 watts into a base 440mhz antenna, your range will still be far greater than the 5 watts coming out of your HT duckie antenna. That's why you need step 2.

    Step 2: Between the base antenna and the crossband repeater, install a VHF/UHF duplexer right at the rig. On the 2m side, attach the feedline for your 2m base antenna. On the 440 side install a very small antenna that will limit the range of your crossband repeater. I use a small 1/4 wave 440mhz rare earth gumdrop magmount antenna stuck on a piece of metal that is sitting on my window sill. The 1/4 wave 440 mhz antenna is only about 6 inches long. That, coupled with the feedline loss in the cheap coax on the magmount and the signal loss from passing through my house and adjacent houses gives my crossband repeat station an effective range of about 6 blocks. Your distance may vary based on your surroundings. Now I know that when I ID on my HT, the signal output from the HT on the 440mhz frequency is being carried farther than when the crossband repeater transmitts on 440. When I really want to reduce the effective range of the 440mhz side, I use a dummy load set on the floor for the 440mhz antenna on the crossband repeater. The dummy load still radiates a little and also receives my 440mhz HT transmissions, but the effective range is now reduced to about 1 house on either side of my own, if that.



    Measuring the effective range of the crossband repeater is pretty simple also. Just set it up and find someone to talk to on 2m. Now start walking away from your station with your HT while having your conversation. When the other station starts to crackle and get hard to understand, you're reaching the end of your range. Now just ask yourself (or get a friend to help you) if your HT can be heard by itself on 440mhz back to your base from where you're at. If it can be, then you've met the requirement that you have ID'd on every frequency and any station that can hear the transmission from your crossband repeater can also hear your HT.

    When setting up your crossband repeat base station there are a few other considerations worth mentioning. First, make sure you're using a 440mhz frequency that isn't allocated to something else nearby. If you've greatly reduced the effective range of the 440mhz side as suggested, this is not nearly that big of an issue but you should still do a little homework. Secondly, make sure you use a CTCSS tone or DCS code between your HT and crossband repeater. This will make it so someone won't accidentally get into your crossband repeater and unkowningly transmit on 440mhz. Also remember to turn the system off when not in use so that crossband repeater doesn't pick up traffic on 2m and start repeating it on 440mhz while you're not around to ID every 10 minutes.

    I've been using this setup for years in the busy Los Angeles metro area with no problems. If you haven't thought about setting this up, give it a try and free yourself from your desk :D.
     
    Shadetree Mechanic likes this.

  2. C2

    C2 Sr. Member

    Joined:
    Aug 3, 2005
    Messages:
    2,409
    Likes Received:
    65
    I think the antenna that spawns your signal must also be the source for your ID, as the antenna is an integral part of your station.

    Aside from what you are doing here, what you are saying is that I can tx on my HT, then run over to my mobile and ID and that is OK since my mobile has more power.

    What if I had two HTs and I tx on one and then every 10 minutes pick up the other just to ID; is that OK?

    Another thought, if I tx to a repeater with tone and then ID without tone (repeater does not key), is that OK?
     
  3. KD8LWX

    KD8LWX Active Member

    Joined:
    Aug 17, 2009
    Messages:
    162
    Likes Received:
    0
    Thank you &

    Is there any reason why this couldn't be setup be setup as
    2M and 2M
    or
    2M and 6M
    or
    2M and HF
    or
    440 and HF
    or
    440 and 6M?

    I assume that the 440 band allows less distance?

    If I understand you correctly there is no legal way to setup a temporary repeater for a group of friends, correct?

    Please name a few rigs which can be setup as repeaters.
     
  4. C2

    C2 Sr. Member

    Joined:
    Aug 3, 2005
    Messages:
    2,409
    Likes Received:
    65
    you can legally set up a temporary repeater, as long as it follows the ID requirements and you have a way to control the repeater either remotely or directly.

    This is called an uncoordinated repeater and as long as it does not interfere, it is fine.
     
  5. Moleculo

    Moleculo Administrator
    Staff Member

    Joined:
    Apr 14, 2002
    Messages:
    8,831
    Likes Received:
    855

    Specifically,
    It doesn't say anywhere that the call sign sent on the transmitted channel must be using a common antenna. This example illuminates one of the biggest problems (in my opinion) of amateur radio: everyone reads into the rules what they want to believe is correct instead of just reading the regulations as they are written.

    It says that the purpose of the call sign transmission is to "clearly make the source of the transmissions...known to those receiving the transmissions". It doesn't matter how you do this as long as any station receiving the transmission knows its source. This is why you need to make sure that your HT is able to TX the same distance as the crossband repeat rig; that insures that the source of the transmission is always able to be identified.

    The issue of TX'ing into a repeater using a tone and then ID'ing without a tone is pretty much irrelevant because any station can choose to receive all transmissions regardless of the accompanying tone. The ID'ing station is still sending its call sign, but the receiving station chooses to hear it based on whether or not they are using the CTCSS tone. The FCC rules are clear: you just need to ID on the frequency in use...it says nothing about accompanying tones.
     
  6. Moleculo

    Moleculo Administrator
    Staff Member

    Joined:
    Apr 14, 2002
    Messages:
    8,831
    Likes Received:
    855
    There isn't a "legal" reason why you couldn't do the things listed, but there are technical and cost reasons. The most common method desired is to use 2m/440, so that is why you see rigs that can do it on those bands. The Kenwood TS-2000 can do it between several bands, which is pretty neat.

    Some current rigs that can do this:

    Yaesu FT-8800r
    Yaeus FT-8900r
    Icom 2820h
    Kenwood TS-2000
    Alinco DR-635
     
  7. C2

    C2 Sr. Member

    Joined:
    Aug 3, 2005
    Messages:
    2,409
    Likes Received:
    65
    I consider a "station" as inclusive of the antenna AND exclusive of other stations; i.e., two HTs constitute two different stations and each must ID their transmissions.

    In your case, I belive that the base station must ID on 440, even if you have crippled the base station's antenna and presume that your HT (many feet away) will cover the same TX range. The first part of this statement is also important, "No station may transmit unidentified communications or signals, or transmit as the station call sign, any call sign not authorized to the station."

    I do not believe that I could set up my base station to auto ID every 10 minutes and then walk around my property all day TXing on my HT and never ID, and still be legal, even if it was all done on the same frequency.



    The reason I asked about IDing without a tone when using a repeater (presumably one that requires a tone) is because then the repeater would not TX your ID, even though you were using the repeater. This would kink the other users as well as defeat the "intent" clause in your argument.

    I don't believe either is an accepted practice as one defies the literal definition and the other defies the purpose of the definition.
     
  8. Moleculo

    Moleculo Administrator
    Staff Member

    Joined:
    Apr 14, 2002
    Messages:
    8,831
    Likes Received:
    855
    I disagree completely. Look at it this way: I have two HF antennas installed that cover some of the same bands. I have a coax switch that allows me to switch back and forth between them depending on which one I feel like using. If I apply your reasoning, then I must make sure I ID on each antenna I talk on. However, If I'm talking on one antenna and then start talking to a different station and switch antennas because it allows me to hear that station better, there is no requirement that I switch back the first antenna I started on and ID there within ten minutes.

    If that interpretation applies to one scenario, it has to apply to all scenarios which just is not the case.

    Your "station" is not defined as a piece of a equipment as you defined it. It is a location and it encompasses all of your equipment at that location.

     
  9. KD8LWX

    KD8LWX Active Member

    Joined:
    Aug 17, 2009
    Messages:
    162
    Likes Received:
    0
    Please verify that the Yaesu 817, 857, 897 do not have this capability.
     
  10. Moleculo

    Moleculo Administrator
    Staff Member

    Joined:
    Apr 14, 2002
    Messages:
    8,831
    Likes Received:
    855
    They do not.
     
  11. C2

    C2 Sr. Member

    Joined:
    Aug 3, 2005
    Messages:
    2,409
    Likes Received:
    65
    So you believe it is within the rules to TX on your HT all day long and never ID on that HT, as long as you have a completely separate base station that auto IDs every 10 minutes?

    The HF station you describe is a single station with multiple antennas, not two completely separate stations. There are many common elements, such as the radio. But since you mention it, wouldn't that also violate your premiss that the ID is "for the purpose of clearly making the source of the transmissions from the station known to those receiving the transmissions." Thus, changing to a different antenna with a different forward direction would violate the purpose for the ID.
     
  12. Moleculo

    Moleculo Administrator
    Staff Member

    Joined:
    Apr 14, 2002
    Messages:
    8,831
    Likes Received:
    855
    If you with your HT and your base operating at the same location, then yes as long as it's being done on all the frequencies in use. This is exactly the reason why some of the newer crossband repeat rigs started coming with the ability to auto-id on both bands. The rules don't say that you have to ID using every radio/antenna/piece of equipment that you operate on at the station. It says that the Control Op must ID on every frequency in use and you can do it using CW or whatever other mode you're using. The distinction that you're making is that you believe that your HT is a self contained station separate from the base. I'm saying that when you set it up like I have described, it is now a single, integrated system and as long as long as you're within a distance that you can easily control both rigs in use, you are at the station control.
     
  13. AE7RS

    AE7RS Member

    Joined:
    Sep 27, 2009
    Messages:
    3
    Likes Received:
    0
    Every transmitter transmission under your control must be identified with your call sign per 97.119 (a) unless it qualifies as a Part 15 device. :bdh:
     
  14. C2

    C2 Sr. Member

    Joined:
    Aug 3, 2005
    Messages:
    2,409
    Likes Received:
    65
    Wait a minute...the horse is alive!

    Moleculo's angle seems to be that his HT and Base station constitute ONE "station."

    But I read that his repeater is a station and his HT is another, different station.

    Another one of Moleculo's angle seems to be that, regardless if he is using one station or 10 stations, he only needs to ID his communications on any one of the stations that provide equal or greater coverage than all of the others.

    The rules leave quite a bit of room for interpretation and I'm sure nothing would ever come of it given the way the system is being operated. Who would ever know one way or another unless they really rolled up their sleeves and did some real investigation. Even at that, the most likely outcome would be a clarification of the rules.
     
    ke7vvt likes this.
  15. Moleculo

    Moleculo Administrator
    Staff Member

    Joined:
    Apr 14, 2002
    Messages:
    8,831
    Likes Received:
    855

    That's not what 97.119(a) says. It says, "each station", not "each transmitter". And I already quoted the part where it defines an "amateur station" - it's defined as all of the "apparatus necessary for carrying on radiocommunications". By that definition, "station" includes the coax, mic, key, power supply, antenna, computer, transceiver, etc.

    I agree with C2...the rules are (in)sufficiently worded such that it leaves quite a bit of room for interpretation.
     

Share This Page

  • About Us

    The WorldwideDX Radio Forum was originally established in 2001. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. We are working every day to make sure our community is the best Radio Hobbyist's site.
  • Like us on Facebook

  • Premium VIP Member

    The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. Care to buy us a beer? We'd really appreciate it!

    Donate to us!