Amateur (Ham) Radio BS and Callsign Thread!

As part of my work I have access to the emergency operations center at one of the local hospitals. I was happy to see some ham radios setup ready to go.

After the 1964 earthquake ham radio is what got a lot of needed supplies up to Alaska.

 

This. Is the way to do it. Well done

 

Do you mean the salt shakers? They're pretty awful for 2m. For one thing, they're really narrow bandwidth. They might say "130-150" but you need to tune it. They're generally ~1 MHz wide for < 2:1 SWR. So you can't even tune across the entire repeater portion of the band.

I like using cheap 1/4 wave whips. Broadbanded, effective, and very flexible. Mine smacks the garage everyday. No problems.

 

Is that a gai-tronics tone remote in the lower right? They have a variety of tone remotes, some quite sophisticated. I was trying to figure out if I can hack a different model (I forget the model #) to operate a TM-D710G. I want to look at their line, I think they also have one that will control multiple RF Chassis. So you could build a "dual band" tone remote for 2m / 70cm.

Our local EOC requires a 500+ ft run of coax to the antennas. The guy that designed the station didn't do any math on coax loss, lol. Squirting 50w at the EOC results < 1w out at the antenna. Transmit is not terrible, but receive RSSI is awful.

I proposed using tone remotes on commercial radios. I was told that is a terrible option for hams because commercial radios lack VFO mode. While I agree it's less then ideal, well thought out programming will resolve most issues.

Instead we're dealing with -110dbm signal strength of the primary repeater in the county and lack the ability to make the repeaters of any neighboring county. I'd gladly give up VFO mode to have a strong signal into pre-programmed radios.

 

Yeah, Just intrigued by the low profile nature of them. A lot of what I have heard about them jives with your comments about poor performance though.

If that's the case though, how is it that so many police cruisers, etc seem to go with that kind of antenna? I know they generally stick to a very narrow frweq band, so maybe they can get away with it?

I'm a relative newbie, but the minute he threw out "500 ft" I would have started looking for a new guy...

 

So after reading a few recovery stories this AM that were greatly aided by APRS, I'm on the hunt.

Does 19+ inches of separation seem correct if I was considering a second 2m rig/antenna for full time APRS use in addition to my primary FT-7900? Trying to manage the real estate on my roof, and I basically have the middle 6 inches laterally of a Prinsu to work with since I have a recovery case and sand ladders or ski racks on both sides.

Usually run 146.46-147.5 if that matters against 144.39 APRS

 

A combination of factors. They have more sophisticated systems, with multiple input sites and voted receive. They're only on one frequency, so it's tuned at that frequency. Many of them are 800 MHz.

 

It will de-sense 2m recieve, each time an APRS packet is transmitted. Avoiding that is probably not possible. It's only for a brief interval. If you're using 70cm for FM phone, then it doesn't really matter.

 

19 is great, I have 18 between my 2. 18" is the very min of separation needed.

 

edit: 18" min distance for 1/4 wave

 

That's my thoughts as well.

The downside of having offroader friends that got HAM capabilities is most of them basically know how to turn the damn thing on, and key the mic. Trying to get them to understand how much "money on the table" they are leaving is sorta frustrating, so I am doing my best to be the RTO / "Echo" of the group.

Good to know. Thanks!

 

This guy?

Here's one of the 2 radios as well.

 

Yes. I have some experience with CPI tone remotes. One of our customers just installed a gai-tronics remote. But I didn't do the install. I'm interested to learn more about them. The one that I saw had an LCD and needed programming.

 

I redid my mounting setup for my 710G. I originally put it down in front of the shifter but the angle made it hard to see. The screen is best when it's angled towards you but in that spot it was facing straight towards the center console and level with the truck. When it was bright out I'd have to lean over to get a good look at the screen.

When I get more time I want to move the compass to the useless sunglass holder position and recess the radio in the front position.

 

Just get an Outback center console. Much easier. Now getting one to the US can be fun.

 

Do you have details on that console? I so want to put one in my truck. I assume that's from a Hilux or Prado and has been customized for the Tacoma ceiling shape?

 

You need way more than 1/4 wavelength on the same band. The 1/4 wavelength recommendation might be true for antennas on different bands, but not on the same band. You get about 10 dB of free space attenuation at 1/4 wavelength, 1 wavelength is 22 dB and decreases by 20 dB for each factor of 10 after that. So 10 wavelengths is 22 + 20 = 42 dB of attenuation.

A 50 watt transmitter is +47 dBm, which is going to produce 50 V into 50 ohms. Reducing power can help, using 5 W (+37 dBm) Your receiver is designed around uV sensitivities, for VHF S9 (the 0 dB relative calibration and each S-unit is -6 dB lower) which is 5 uV into 50 ohms produced by a relative signal strength of -93 dBm. At 1/4 wavelength you're at +37 dBm, which is the same as connecting a 5 W transmitter directly into the antenna input. At 10 wavelengths you're going to only be down to +5 dBm so even at those levels you're lucky to just desense the receiver.

Being +100 dB at 10 wavelengths compared to an S9 is 100,000 times voltage of a very strong signal. That can easily damage the receiver. At 1/4 wavelength you're going to be another 32 dB or 40 times higher, e.g. a voltage of 4 million over an S9.

Since radio front ends are so sensitive with lots of gain they have ways to shunt excessive voltage since things can happen, nearby lightning, human ESD, etc. These are designed for high voltages, 70 V for example, so will at least partially conduct being in the near field of another transmitter. But they may not fully turn on (thus still allowing some portion of the overload in, like being in a brown out) and they aren't designed necessarily to get hit repeatedly and regularly. So they can blow out, too.

Consider this, when you build a repeater on VHF there's typically around 60 dB of attenuation in the cavity filters and even with a combined 120 dB bandpass/notch attenuation then they still offset the antennas vertically to keep the strong area of the TX field away from the RX highest sensitivity region.

 

Dave start here.

https://www.4wdinteriors.com

Look for the 2005 + model number for a Hilux. It will fit closer then what I did here. I used a model meant for an FJ Cruiser. I had to contour the top to match my headliner better and completely redo the brackets for attachment. I have been told the Hilux model number needs much less work to get it to fit. Once you find that model number, call David up at Toytec x103 and see if he can order it through ARB.

 

The antenna farm on the roof looking really nerdy, 2 perm. mounted antennas and 1 mag mounted. Something needed to be done. Made a perminant home for the scanner antenna on the ultra mega expensive Wilco Spare Tire Gate. Since the antenna is receive only, achieving proper ground plane isnt neccessay..

Beeps on the voltmeter thingy, continuity good, good to go..


Semi prebuilt coax by Laird, need to solder the proper connector at the radio side. 17' of teflon coated, tis the reason why its white. Teflon coating makes it easy for pulling through tight spaces.

 

Help me choose my next dual band UHF/VHF radio!
My old Kenwood is finally giving up the ghost.

I have narrowed it down to the following radios.

ICOM ID-4100A

$530 ICOM ID-5100A DELUXE 144/440 Amateur Radio Mobile Transciver with Touch Screen, D-Star and Internal GPS

ICOM ID-5100A
YEASU FTM-400DR
KENWOOD TM-D710GA

Any help, advice, experience or opinions would be greatly appreciated.

Thank you, Daryl
KD7SIE