OT: SVR200 Vehicle Repeater & TK-790H Kenwood

[KG4LHQ]

Hello,

Our bright local Motorola dealer installed a Pyramid SVR200 Vehicle Repeater to our Kenwood TK-790H in our Rescue Truck last week.

It doesn't work with a $hit. We have a SVR-200 that connects to the Kenwood TK-790H, then from the antenna out on the SVR goes to a in band filter that is tuned for 159.210 mhz that then runs to a bunch of T connectors and a bunch of jumpers that connect to another in band filter tuned for 153.815 ( Our Fire Input Transmit Frequency ), the 790H antenna is on the roof of the rescue truck ( ambulance box type but a rescue truck ) the repeater antenna 1/4 wave 19" whip is installed on top of the box about 6 inches back on the passenger side.

Handheld keys the repeater about 200 feet and then cuts out and doesn't work.

If the signal is not strong coming from the county repeater all we get is static on the handheld and thats it.

It works like a piece of junk - Suggestions?

[Will]

Look like the there is NOT a separate antenna for the SVR. From your post sounds like it was 'goturized'.

[KG4LHQ]

There is a seperate antenna. The 1/4 wave on top of the box is used for the repeater antenna, the radio antenna is on the roof of the cab. I really thought it was way to close and is desensing.

[n7maq]

The NOTCH filter (of the SVR's freq) should be on the TK790, the PASS filter (also on the SVR's freq) should be on the TK790. So both the notch, and pass should be tuned for the same freq. I have SO deputies using their SVR's up to four miles away when they get on their ATV's. The mobile is a HP TK790 with a 3dB roof mount, and the SVR on a 1/4 wave fender mount. Freq separation is only 4 megs but we use the better filter set.

Jim

[KG4LHQ]

Heading to the firehouse to get some pics so with your guys help can figure out what the heck is wrong.

[KG4LHQ]

OK:

Radio Antenna on the Roof of the Cab of the Rescue Truck.


SVR-200 Repeater Antenna:


We told them we wanted it installed farther towards the back of the truck and the nimrods didn't listen

The repeater:


Filter #1: BPF-1604 - Tuned to 159.210mhz


Close up:


Filter #2: Tuned to 153.815 - County Fire Repeater input frequency.


Looks like a cluster of adapters that really doesn't appear to be necessary:


Another picture of the #2 Filter:


So it runs repeater to filter number one out to first adapter then connects with a T to Filter Number 2: Another jumper goes from T adapter number 1 to T adapter #2 that then connects another jumper going to the In of Filter #2 then one coming out that connects to the 1/4 wave antenna.

Whats the problem with this setup guys?

[Jim202]

I could be wrong, but why is there a coax cable trying to short out the band pass filter? Looks like the tech got carried away with the T connectors and added 2 too many and an extra coax cable.

I would try removing the T connectors on both the input and output of the band pass filter. Then connect the coax cables directly. See if that doesn't help some.

Jim

[Will]

I hope the "bright local Motorola dealer" did NOT use any LMR cable in the overkill installation. The LMR type cables will cause noise and contribute to desense. (Due to dis similar metals in the shield.)

[KG4LHQ]

Hell it doesnt matter as it doesnt work with a crap anyway.

Also, Jim, are you saying run repeater coax jumper to filter 1 then jumper from filter 1 to filter 2 then antenna to the other connector?

[KG4LHQ]

If thats what your saying Jim we did that. It sounds a whole lot better but there is no range about 75-100 feet and the repeater fades out with a handheld.

[Bigred]

From what I gather, the two filters are connected together by a jumper? This is wrong. Each should have it's own separate filter and antenna.

From the SVR-200, the coax should run into the BPF and then out to the antenna on the box. The 790 should jumper to the BRF and the out from that to the cab antenna. No connection between the two filters. Leave all the tee's and copper colored jumpers in place on the BRF.

[KG4LHQ]

From the information Ive gathered from a friend this install is all jacked up:

Its suppose to be like this

TK-790H out to 1602 In
1602 In to Roof Antenna

SVR-200 out to 1604 In
1604 Out to 1/4 antenna

Both filters are to be tuned to same frequency that the handheld will be talking to the repeater.

[Jim202]

I am not sure from the photos what all the cable connections and filters are, but the SVR-200 repeater is really a simplex radio. It should TX and RX on the same frequency (159.210 if I understand your description). The antenna for it should be mounted as far away as possible from the Kenwood main radio antenna. The antenna for the repeater should come in and go to the repeater filters. Then the other side of the filters would go to the repeater. The filters are so that it will allow just the repeater frequency through and try to attenuate every thing else.

On the Pyramid site there is some very limited information on the filters they have. The BRF-1602 is a notch filter for 2 MHz spacing. The BRF-1601 is a notch filter for 5 MHz spacing. The BRF-1604 is a band pass filter. The 1602 would be tuned to notch out the mobile transmitter at the 153.815 frequency. The band pass filter would be tuned for the SVR-200 operating frequency of 159.210. Both the band pass and the notch filters would be run in series between the Pyramid antenna and the SVR-200 box itself. The band pass connected to the antenna and the notch filter to the SVR-200 with a short cable between them.

On the mobile, it is the same thing. Come in from the mobile antenna, go through the band pass filter for it and on the other side, you go to the radio. Again the band pass filter is trying to only allow the mobile frequency through. Not sure what power rating these small filters have. The band pass filter might not stand up to the 100 watt Kenwood transmitter. You might try contacting Pyramid and talking to one of their engineers.

I don't understand what all the T connectors and extra cable is all about. Maybe if you had some spec info from pyramid about all the filters, it would be better to understand. With only a 5.3 meg split between the mobile output and the Pyramid vehicle repeater, those filters are probably not going to cut it. It takes some hi Q cavities to provide the isolation you need to make this work. Normally in a repeater package those cavities at the VHF band need to be about a minimum of 3 inches in diameter (6 inches is even better)and about 3 feet long. Takes 6 of them (3 on the RX side and 3 on the TX side) to provide the required 70 to 100 db of isolation to make a repeater work with a 100 watt transmitter.

I could be all wet about what is going on, but being in this field for over 45 years, I learned long ago that you can't fool the law of physics. There is a limit as to what will work correctly.

Jim

From the information Ive gathered from a friend this install is all jacked up:

Its suppose to be like this

TK-790H out to 1602 In
1602 In to Roof Antenna

SVR-200 out to 1604 In
1604 Out to 1/4 antenna

Both filters are to be tuned to same frequency that the handheld will be talking to the repeater.

[n7maq]

From the information Ive gathered from a friend this install is all jacked up:

Its suppose to be like this

TK-790H out to 1602 In
1602 In to Roof Antenna

SVR-200 out to 1604 In
1604 Out to 1/4 antenna

Both filters are to be tuned to same frequency that the handheld will be talking to the repeater.

The above is correct, I have never seen a NOTCH (1602) inline on the SVR, but as long as you don't use it on other channels (with a different TX freq) I don't see an issue. Call SVR tech support, they are great to deal with.

Jim

[KG4LHQ]

For information:

http://texasdir.pyramidcomm.com/pdf/fil ... F-1602.pdf
http://texasdir.pyramidcomm.com/pdf/fil ... F-1604.PDF

Confirms what my friend told me. Now just need to get one retuned and clean the "dealers" mess up!

[KG4LHQ]

Called Pyramid and they were upset and intend to follow up with this moto dealer about why they are installing all these repeaters incorrectly.

Sent filter back to Pyramid and they will be tuning correctly.

[KG4LHQ]

Just a follow up:

Sent filter off to be tuned, they retuned for 159.210mhz and got it back, installed it and from handheld to truck is good for about 2 miles now. Works fine w/ no issues. I'm sure if the antenna was farther back towards the end of the cab it would work even better however we feel the only time we will be using this is on medical assists and car wrecks where the truck isn't anymore than rock throwing distance or maybe alittle farther.

Thanks everyone for the help.

One down 19 to go to refix.

[Bigred]

As you can see by the above posts there is a little confusion still about how those filters work in an in-band set up. Installed the way Pyramid designed them it works great. Glad you got it all straightened out and a finger wag to the Moto shop. Two miles is great.

I'll throw out one more gotcha on these things. You said coverage would be in the close proximity of the truck and that is basically designed for. With that in mind, the squelch in the SVR200 should be set rather tight to reflect this. The reason is that anytime the repeater detects a carrier without a PL tone, it assumes another SVR200 has come on scene and shuts off its repeat function to allow the new kid on the block to take over the repeat duties. Trouble is, ANY RFI that can bust the squelch will cause this to happen. Cranking the squelch level up will make your repeater much more reliable.

[KG4LHQ]

Ours have the CTCSS PL tone on it and the rarity of multiple vehicle repeaters on the scene at one incident is rare.

[n7maq]

I'll throw out one more gotcha on these things. You said coverage would be in the close proximity of the truck and that is basically designed for. With that in mind, the squelch in the SVR200 should be set rather tight to reflect this. The reason is that anytime the repeater detects a carrier without a PL tone, it assumes another SVR200 has come on scene and shuts off its repeat function to allow the new kid on the block to take over the repeat duties. Trouble is, ANY RFI that can bust the squelch will cause this to happen. Cranking the squelch level up will make your repeater much more reliable.

The above is not correct, the SVR puts out a lock tone when it is first activated and when the other last in SVR hears that tone it will shut down and let the last arrived unit take over. There is a bit more to it than that, the service manual describes it in detail.

As far as setting the SQL, I agree it should be set high, the last Pyramid class I was in the factory techs were recommending at least .75uv. We have been using 1.25 to 1.5uv as the opening point and they work great. With a 1/4 wave antenna for the repeater fender mounted we have some deputies getting three to five miles when out in the forest depending on terrain. This is in band with 110 Watt TK79O's.

Jim

[KG4LHQ]

Ok so now another issue has came up.

The police cars are running 1604 and 1601 filters, the 1601 filter is good for 5mhz seperation. The stupid radio shop decided to tune them for 158.805mhz so essentially knocking out any spread right in the heart of that spread where most repeater inputs This has caused one local police department that works closely with 2 surrounding agencies that fall in that spread including just talking radio to dispatch therefore not allowing those cars to be able to talk to those surrounding counties. Pyramid has said the radio can not transmit anywhere in that 5mhz seperation due to damage that could occur. So from 153.805 to 163.805 useless.

Yes even with the 1602 filter the two repeater inputs just happen to be in that 2mhz seperation.

Do I have any option for them? I know alot of people use these on 173 which could be done however assuming would require a license and complete retune of the repeater and filters.

[Bigred]

The above is not correct, the SVR puts out a lock tone when it is first activated and when the other last in SVR hears that tone it will shut down and let the last arrived unit take over.

That is one condition. The other is a SVR200 that comes on scene already activated. When the first repeater sees carrier activity (SVR200s are not supposed transmit PL) and a receive condition on its mobile radio, it assumes another repeater has come on scene and relinquishes its repeat function. The flaw is any squelch break while the mobile is receiving will trigger this. Been there. A higher squelch level helps prevent the clams from falsing the repeater into standby.

Pyramid's in band repeaters work well IF you follow there engineering specs. This includes a radio survey of channels that will or will not work in a certain setup. In the case of the cop shop there are two options. One is to move the repeater frequency to a more friendlier separation. Usually SVR's are way high up in the band, or down in the 150's, and yes they'll have to change and license a new channel. The second would be tighter filters to make the current frequency fit into the scheme. Pyramid does not provide those and also they will get very big. Size and the fact they can get quirky with vibration make this a poor option to pursue, not considering the cost. Easier to apply for a channel somewhere out in the weeds.

[KG4LHQ]

Another screw up on the radio shop behalf. No studies!!! How hard is it to get a high freq license?

[MrPink007]

To KG4LHQ: There is another alternative to moving the SVR200 frequency: Pyramid makes a coaxial switch that can "remove" the BRF-1601 notch filter from the mobile's antenna line when the repeater is not active. Assuming the mobile's primary Tx frequency is far enough away from the SVR200 Tx/Rx frequency in the first place (>5 Mhz), the BRF-1601 will do its job only when the SVR200 is active and the mobile is on its primary frequency (make take some training with the officers to ensure this). Note: This only applys to the BRF-1601 not the BRF-1602. Not a perfect solution, but a workable one. I suggest contacting their tech support directly and they can explain the alternatives. They are one of the few companies out there that answer their phones (no automated system).

[MrPink007]

KG4LHQ: From the pix you posted, it looks like you are using a gain antenna on the SVR200 as well as the mobile. Pyramid recommends using a ¼ wave antenna, or better still, a low profile antenna like the Antennex Phantom series (TRA1500) which is lower gain and narrowband. It should give you another 3~6dB of isolation vs a ¼ wave. The others posters are correct: Even with the filters, you will want as much antenna separation as possible (vertical as well as horizontal distance if possible). The TRA1500 works well when installed behind the grill of a vehicle, not only because of its size, but there is no whip to short to ground.

[Mikey]

My experience with Pyramid is that they want customers to be happy with there products. If you contact them and talk with them about the problems, i would almost bet they will remedy the situation and make it right, then they will go after the radio dealer who has to be "Certified" to install Pyramid products. I know cause i went through Pyramids Certification Class.

Mike

[andrewshowers]

Sounds like they did not tune the front end of the SVR. I had a similar issue when first dealing with the pyramid repeaters. They come with tuned filters, but each and every repeater has to be tuned at the dealer as pyramid does not tune them before they send them out, due to so many variables. Contact your dealer, or who installed them and ask them if this was done, because I would bet a buck that it was not.

[KG4LHQ]

What are you talking about Andrew? Ours work great just our local Moto dealer decided to install them incorrectly.

[loband]

Hi All, does anyone know what the rf power output of your SVRs are set to? I know the range is 250mw to 2w. Motorola highly recomends setting no more power out than 275-300mw and a 1/4 wave antenna. Any higher power and the VRS & SVR will out talk a 4w portable according to Moto due to the tight squelch settings on the mobile repeaters. I am in the process of installing & testing a UHF SVR200 on a 110w VHF/UHF Moto APX7500. We set our SVR to 1w and .5mv squelch and it does out talk the portable.