150hz PL...

batwing4ever · Post by **batwing4ever** » Sun Aug 29, 2004 6:58 am

I sometimes do exercises with the National Guard and it's a pain because I have to issue and collect radios from them every time there is an exercise. It's really only so their evaluators can listen to the traffic on a ham repeater. It would be much easier to just let them use the radios they already have. A 6 meter remote base would work fine for this.

The problem is that the PL tone for the military hardware is 150hz and the portable military radios use only PL for squelch and can't do carrier squelch. So I would need a 150hz PL reed for a low band Motorola radio.

Does anyone know if an after-market reed is available for this or am I stuck with having to reverse-engineer a Motorola PL reed?

If I have to go the reverse-engineering route, any advice would be appreciated. The Motorola radio would need only to encode the PL and carrier squelch would be fine for the receive.

Thanks!

MSS-Dave · Post by **MSS-Dave** » Sun Aug 29, 2004 8:49 am

Believe it or not, I use 150 Hz for a custom application. I use Com Spec TS 64 or old TS 32 when I can find them. Just have to change the crystal freq on the board. I'll look at work on Monday and get the freq of the crystal for you. I just set the DIP or solder pads for the tone below 150 hz and the crystal does the rest.

*** Having said all of this......reviewing your post says you are using Moto radios. Most of these have capability to do any sub audible tone (custom) by entering the exact freq you need. What radios are you using??

Dave

batwing4ever · Post by **batwing4ever** » Sun Aug 29, 2004 10:35 am

THANKS!

Unfortunately, programming a free-form PL won't work because the radio is a Mitrek. I only found this out a few minutes ago.

I don't know if I'm going to have to go through the whole 6 meter modification process of changing out a whole load of caps because I plan to use it on 50.50MHz which is in the "FM Simplex" portion of the 6m bandplan. It's only 500KHz out of band, but I don't have any experience with Mitrek radios so I don't know for sure.

Most military radios tune in 50KHz steps, so the "National Simplex" freq. is out because it's 50.525MHz.

Jay · Post by **Jay** » Sun Aug 29, 2004 11:15 am

Actually, it's 52.525. Still a little hard to reach on some radios without hardware mods....

As the others report, if you have a radio that will perform there (maxtrac, mt1000, etc) that has all ready been hardware modified, you can type in the PL.

Jay

PETNRDX · Post by **PETNRDX** » Sun Aug 29, 2004 1:28 pm

Another idea is to just get one of the old "tunable" pl encoders. That is what I used for the same reason. If that is the only PL you need, it works just fine. These were the rage before the ComSpec x32 dip switch programmable type came out.

Andy Brinkley · Post by **Andy Brinkley** » Sun Aug 29, 2004 4:56 pm

Which PL board do you have?

If it is the "reedless" that used a TRN-4224 Permacode then you can make one from 100K resistors.

If it uses a Reed, you might try Bramco.

If you decide to use a Com-Spec TS-32, we can reprogram the IC-110 versions to whatever tone you need. We bought the programmer about 10 years ago for setting some special tones for a customer.

Will · Post by **Will** » Sun Aug 29, 2004 6:58 pm

151.4 hz is the standard tone. I have some for the Mitrek that use the Reeds.

The 42-50 range Mitrek sould tune 50 to 52 without much problem.

jcobb · Post by **jcobb** » Sun Aug 29, 2004 7:41 pm

We set one up for the NG, along with a simplex repeater. Used a Mitrek (on 46 MHz, though), with a tunable PL unit.

Been working great for years.

Jack

bernie · Post by **bernie** » Sun Sep 05, 2004 10:14 pm

My two bits worth:
Ah yes, "Army New Squelch"
The last time I had anything to do with this I think they were using A/N PRC44 (not sure of the model) but the problem was that they were wide band. I mean wide band in the 1960 context, 15KC deviation.
This created problems at the time since Micor did not have any available wide band IF filters, we used a Motrac receiver, since we could get a wide band Permakay filter, I installed a mobile exciter in the base, since it would do 15KC, the direct FM base model would not.
This was used on a bombing range.

The PL reeds came from Motorola parts Dept marked SP.
I think that code 5Z, 151.5 probably would work.

Astro Spectra · Post by **Astro Spectra** » Tue Sep 21, 2004 10:12 pm

Bernie makes a key point; low band military radios come from a strong wideband heritage.

The standard used by the likes of the vehicle mounted ‘524 and the portable ’77 set used a 30 kHz wide IF filter with at least +/- 10 kHz deviation and 150 Hz tone deviation of +/- 3 kHz.

Newer ’25 kHz’ equipment employs a roughly 16kHz wide IF with typically +/- 6 KHz deviation and the 150 Hz tone is set to +/- 2 kHz deviation. The 150 Hz tone only needs to be within +/- 2Hz. However not all new equipment is ‘narrow band’ even if it has 25 kHz steps.

Ask your guys if the radios they use now are '77 set compatible, if so you’ll need to be talking WIDE band.