CSQ or DPL for SAR group

[spareparts]

I have a license in coordination for a SAR group. The frequency is 155.1600 Mhz. Mode is 20K0F3E Proposed license is 1 station as base (FBT) at 40 W and for 45 mobiles (MO) @ 110 W max.

I was intending to program the radio's as CSQ as there are several other SAR groups on the same frequency. How do you set up SAR radio's ?

[The Pager Geek]

Well, depends on the region.

In NY:
RX: CSQ or 131.8
TX: 131.8

tpg

[nmfire10]

This is not really something anyone here can tell you one way or another. We can offer advice on how to make a decision but ultimately you need to make it.

If there are other people who will need to talk to you, they will need your PL to do so. If they don't have your PL now and it would be impractical for them to get it, you should probably remain CSQ. Also, the primary reason for having a PL/DPL is blocking annoying noise and other users. There isn't much to generate unwanted electrical noises in the middle of the woods. So you would probably not be too annoyed with CSQ either.

[Jim1348]

I think that either PL or DPL is a good idea even if you are in rural area. That frequency is pretty well used in much of the US and I think the plain old carrier squelch only could be frustrating. You could consider using more than one channel if you have a need for both PL and carrier squelch. I know of one local volunteer group that does that in this area. They use both 155.160 and 155.295. One of them can be PL 162.2 hZ and another channel is the same frequency with 186.2 hZ. You may not want to make things too complicated for the end users, but it is an option for you.

Actually, now that I think of it, a nearby ski patrol has 155.160 and 155.220 or something similar. They have a plan where channel 1 and 2 are the same frequency. One with PL one without. Channel 3 and 4 are the other frequency, again one with PL tone and one without. If you have ample memory capacity it might be worth thinking about.

[RKG]

In addition to the question of CSQ vs. tone controlled access is the question of PL vs. DPL (assuming you have elected for tone access). I discourage the use of DPLs over PLs unless your system requires it (either for compatibility or because PLs are taken), for a couple of reasons.

First, if you go DPL, get yourself a copy of the Midian chart and limit yourself to the "standard" DPL codes. This is about 83 out of about 500 mathematically possible codes; the non-standard DPLs are subject to falsing (either positively or negatively).

Second, if your system employs more than one type of subscriber equipment, you can get into the question of "inverted" vs. "normal" DPL. The fact of the matter is that, even within a single equipment manufacturer, there is no agreement about how the waveform starts. As a result, you may find that your subscriber equipment doesn't open up the base unless it sends "inverted" DPL for some units and "normal" for others.

Third, if have a mix of "inverted" and "normal" DPLs, you cannot use a "direct" button, at least for that equipment that drags Rx freq but not Rx tone via a "direct" button. You end up having to program a separate channel slot for simplex tactical operations.

[k2hz]

I would recommend you have the capability to select CSQ when needed for interoperability with other teams but you will probably want PL for normal operations.

I don't know your situation but in my area both those channels are infested with constant chatter from school bus operations. It can be very annoying if you don't have PL.

You should see if other groups you may work with have adopted a common PL for the area. I would also suggest PL instead of DPL for the reasons RKG discussed.

It is questionable if you can get a new license for 20K0F3E unless this is an addition to an existing system. You will probably have to go narrow band (11K).

[bellersley]

Just a suggestion based on personal experience. I would either go with CSQ or PL, NOT DPL. DPL works great, but I've found that when you're in a fringe area, DPL often fails to unmute the audio whereas PL works great every time.

[spareparts]

Most of the area SAR groups run PL or CSQ. The "smallest" radio is 4 channel. I will program the same frequency as PL & CSQ side by side. position 1 in CSQ, repeating the same frequency with a PL in position 2.

Thanks for the help & insight (especially on the fringe DPL issue)

[KB2ZTX]

Well I'll flip on my "communications advisor" hat for NYSFEDSAR and say you want PL on TX, and for 99% of the time you will be fine. Now if I put on my "team coordinator" hat for WSAR, I would say PL/CTCSS on both TX and RX. Our area uses 155.160 for just about every darn school bus around. For all our mobile units and base stations we have PL on both TX/RX, however all my portable equipment has PL on TX Only. You will not interfere with anyone if you program it this way.

Just my 2 cents...

JAS

[AEC]

If this SAR is based around amateur comms only, then I would suggest CSQ only as a means to prevent congestion and missed conversations.

In spite of the fact that almost every 'modern' UHF or VHF ham rig does both PL and DPL, there are those that still use NON toned equipment.

Use of any tone in an emergency is unwise as someone who might be making a distress call, just might BE the one not able to encode a PL or DPL tone/code.

This is why I say CSQ ONLY for SAR members.

I want to be able to hear and talk to the person we are in search of, and without a tone, the radios will receive 'better' and the chances of missing a call are minimized as well.

Of course, this is moot if the people being searched for are not hams, nor have access to amateur gear, but the issue is still valid nonetheless.

[spareparts]

If this SAR is based around amateur comms only, then I would suggest CSQ only as a means to prevent congestion and missed conversations.

The equipment is to be used by team members who have completed SARTECH I/II and the communications module. My main concern was that during a large search there may be other SAR groups nearby on the same frequency that would be interfered with/by "my" grouips communications.

[RKG]

The use of PL or DPL unmuting does not preclude your transmissions from interfering with a co-channel user.

Indeed, if there is a co-channel issue, PL by itself tends to exacerbate problems, because it makes it easy to ignore your "monitor before transmitting" obligation.