VHF HT1000 speaker mic with antenna

Reslock · Post by **Reslock** » Thu Sep 13, 2001 7:26 pm

Just wondering if anyone has used the public safety mic (the one with the antenna mount on top) with VHF or UHF?

A little bird once told me that they can only be used for 800MHz and up, but I have just aquired a VHF HT1000 that has the RF switch in place and works.

Just wondering if it is better to have my brain pounded with RF, or my kidneys? (har har)

Input about the mic would be appreciated
thanks
JT

RadioSouth · Post by **RadioSouth** » Thu Sep 13, 2001 8:38 pm

I've used the Public Safety Speaker Mic. on both VHF and UHF and the increased elevation
and possibly your body making somewhat
of a groundplane does give you an advantage
in fringe areas. The antenna for VHF is a bit large on the Jedi types, stick to the
Visar type antenna's for VHF and I can tell you that that I've used this combo. and did out-perform the stock antenna at waist level.
As far as RF remove the speaker mic. from the epulet when possible before transmitting.
Tilting the antenna away from you at close to a 90 degree angle supposedly reduces RF absorption quite a bit but also reduces fringe performance.

Tom in D.C. · Post by **Tom in D.C.** » Fri Sep 14, 2001 5:44 am

I use a Saber speaker/mic with the antenna on top of the unit on both UHF (which it was designed for) and VHF. The VHF antenna is a Larsen which is the same length as the UHF antenna but just fatter; both of course are TNC connector units. Also, note that the reason the cable on the spkr/mic which has the antenna is straight rather than coiled is because of the effect a coiled cable would have on the RF running through the cable.

Tom in D.C.

amckie · Post by **amckie** » Sat Sep 15, 2001 10:15 am

I have a question about the PS mics on Jedi radios: does the connector switch completely divert the RF energy to the mic antenna connector, or can it still go to the radio's antenna? I've seen some police in my city using PS mics with no antenna, just leaving a regular whip on the radio - I had thought that would leave the RF energy with nowhere to go?

Will · Post by **Will** » Sat Sep 15, 2001 7:17 pm

You need the correct antenna on the PS s/m.
The PS spkr/mic has a pin that depresses the Antenna switch on the radio's side and that directs all the antenna tx and rx up the cable to the PS speaker/mic antenna jack and the antenna.. Some departments that use the PS spkr/mic's have a "dust cap" cover on the radio's antenna jack.
Some times the plastic pin tip is worn off or
filed down, and this can be tested using a wattmeter and a TNC adaptor on the spkr/mic antenna jack. You should get about 75 to 90 %
of the tx power up to the spkr/mic's antenna jack.
There are some aftermarket Spkr/mics that look like the Motorola Public Safety (remote antenna) Speaker mics. They have coil cords and do not have antenna jacks.

amckie · Post by **amckie** » Sun Sep 16, 2001 12:24 am

That's kind of interesting, since the (admittedly few) officers I have seen without an antenna on their PS mics (which definitely do have antenna connectors) have left the antennas on the radios. How that can not cause problems with a) getting a decent signal in or out from a usability point of view and b) having no normal path for the RF energy, makes me wonder. All of this is why I ask in the first place.

Reslock · Post by **Reslock** » Sun Sep 16, 2001 2:00 pm

Even without the antenna on the ps mic, you can still hit a well covered system. It does not do good things for the radio, but when you don't own it you don't care as much.